Make shrink_all_memory() repeat the attempts to free more memory if there
seems to be no pages to free.
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
follow_hugetlb_page() walks a range of user virtual address and then fills
in list of struct page * into an array that is passed from the argument
list. It also gets a reference count via get_page(). For compound page,
get_page() actually traverse back to head page via page_private() macro and
then adds a reference count to the head page. Since we are doing a virt to
pte look up, kernel already has a struct page pointer into the head page.
So instead of traverse into the small unit page struct and then follow a
link back to the head page, optimize that with incrementing the reference
count directly on the head page.
The benefit is that we don't take a cache miss on accessing page struct for
the corresponding user address and more importantly, not to pollute the
cache with a "not very useful" round trip of pointer chasing. This adds a
moderate performance gain on an I/O intensive database transaction
workload.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Turns out the hugepage logic in free_pgtables() was doubly broken. The
loop coalescing multiple normal page VMAs into one call to free_pgd_range()
had an off by one error, which could mean it would coalesce one hugepage
VMA into the same bundle (checking 'vma' not 'next' in the loop). I
transferred this bug into the new is_vm_hugetlb_page() based version.
Here's the fix.
This one didn't bite on powerpc previously for the same reason the
is_hugepage_only_range() problem didn't: powerpc's hugetlb_free_pgd_range()
is identical to free_pgd_range(). It didn't bite on ia64 because the
hugepage region is distant enough from any other region that the separated
PMD_SIZE distance test would always prevent coalescing the two together.
No libhugetlbfs testsuite regressions (ppc64, POWER5).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
free_pgtables() has special logic to call hugetlb_free_pgd_range() instead
of the normal free_pgd_range() on hugepage VMAs. However, the test it uses
to do so is incorrect: it calls is_hugepage_only_range on a hugepage sized
range at the start of the vma. is_hugepage_only_range() will return true
if the given range has any intersection with a hugepage address region, and
in this case the given region need not be hugepage aligned. So, for
example, this test can return true if called on, say, a 4k VMA immediately
preceding a (nicely aligned) hugepage VMA.
At present we get away with this because the powerpc version of
hugetlb_free_pgd_range() is just a call to free_pgd_range(). On ia64 (the
only other arch with a non-trivial is_hugepage_only_range()) we get away
with it for a different reason; the hugepage area is not contiguous with
the rest of the user address space, and VMAs are not permitted in between,
so the test can't return a false positive there.
Nonetheless this should be fixed. We do that in the patch below by
replacing the is_hugepage_only_range() test with an explicit test of the
VMA using is_vm_hugetlb_page().
This in turn changes behaviour for platforms where is_hugepage_only_range()
returns false always (everything except powerpc and ia64). We address this
by ensuring that hugetlb_free_pgd_range() is defined to be identical to
free_pgd_range() (instead of a no-op) on everything except ia64. Even so,
it will prevent some otherwise possible coalescing of calls down to
free_pgd_range(). Since this only happens for hugepage VMAs, removing this
small optimization seems unlikely to cause any trouble.
This patch causes no regressions on the libhugetlbfs testsuite - ppc64
POWER5 (8-way), ppc64 G5 (2-way) and i386 Pentium M (UP).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Originally, mm/hugetlb.c just handled the hugepage physical allocation path
and its {alloc,free}_huge_page() functions were used from the arch specific
hugepage code. These days those functions are only used with mm/hugetlb.c
itself. Therefore, this patch makes them static and removes their
prototypes from hugetlb.h. This requires a small rearrangement of code in
mm/hugetlb.c to avoid a forward declaration.
This patch causes no regressions on the libhugetlbfs testsuite (ppc64,
POWER5).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
These days, hugepages are demand-allocated at first fault time. There's a
somewhat dubious (and racy) heuristic when making a new mmap() to check if
there are enough available hugepages to fully satisfy that mapping.
A particularly obvious case where the heuristic breaks down is where a
process maps its hugepages not as a single chunk, but as a bunch of
individually mmap()ed (or shmat()ed) blocks without touching and
instantiating the pages in between allocations. In this case the size of
each block is compared against the total number of available hugepages.
It's thus easy for the process to become overcommitted, because each block
mapping will succeed, although the total number of hugepages required by
all blocks exceeds the number available. In particular, this defeats such
a program which will detect a mapping failure and adjust its hugepage usage
downward accordingly.
The patch below addresses this problem, by strictly reserving a number of
physical hugepages for hugepage inodes which have been mapped, but not
instatiated. MAP_SHARED mappings are thus "safe" - they will fail on
mmap(), not later with an OOM SIGKILL. MAP_PRIVATE mappings can still
trigger an OOM. (Actually SHARED mappings can technically still OOM, but
only if the sysadmin explicitly reduces the hugepage pool between mapping
and instantiation)
This patch appears to address the problem at hand - it allows DB2 to start
correctly, for instance, which previously suffered the failure described
above.
This patch causes no regressions on the libhugetblfs testsuite, and makes a
test (designed to catch this problem) pass which previously failed (ppc64,
POWER5).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, no lock or mutex is held between allocating a hugepage and
inserting it into the pagetables / page cache. When we do go to insert the
page into pagetables or page cache, we recheck and may free the newly
allocated hugepage. However, since the number of hugepages in the system
is strictly limited, and it's usualy to want to use all of them, this can
still lead to spurious allocation failures.
For example, suppose two processes are both mapping (MAP_SHARED) the same
hugepage file, large enough to consume the entire available hugepage pool.
If they race instantiating the last page in the mapping, they will both
attempt to allocate the last available hugepage. One will fail, of course,
returning OOM from the fault and thus causing the process to be killed,
despite the fact that the entire mapping can, in fact, be instantiated.
The patch fixes this race by the simple method of adding a (sleeping) mutex
to serialize the hugepage fault path between allocation and insertion into
pagetables and/or page cache. It would be possible to avoid the
serialization by catching the allocation failures, waiting on some
condition, then rechecking to see if someone else has instantiated the page
for us. Given the likely frequency of hugepage instantiations, it seems
very doubtful it's worth the extra complexity.
This patch causes no regression on the libhugetlbfs testsuite, and one
test, which can trigger this race now passes where it previously failed.
Actually, the test still sometimes fails, though less often and only as a
shmat() failure, rather processes getting OOM killed by the VM. The dodgy
heuristic tests in fs/hugetlbfs/inode.c for whether there's enough hugepage
space aren't protected by the new mutex, and would be ugly to do so, so
there's still a race there. Another patch to replace those tests with
something saner for this reason as well as others coming...
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move the loops used in mm/hugetlb.c to clear and copy hugepages to their
own functions for clarity. As we do so, we add some checks of need_resched
- we are, after all copying megabytes of memory here. We also add
might_sleep() accordingly. We generally dropped locks around the clear and
copy, already but not everyone has PREEMPT enabled, so we should still be
checking explicitly.
For this to work, we need to remove the clear_huge_page() from
alloc_huge_page(), which is called with the page_table_lock held in the COW
path. We move the clear_huge_page() to just after the alloc_huge_page() in
the hugepage no-page path. In the COW path, the new page is about to be
copied over, so clearing it was just a waste of time anyway. So as a side
effect we also fix the fact that we held the page_table_lock for far too
long in this path by calling alloc_huge_page() under it.
It causes no regressions on the libhugetlbfs testsuite (ppc64, POWER5).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2.6.16-rc3 uses hugetlb on-demand paging, but it doesn_t support hugetlb
mprotect.
From: David Gibson <david@gibson.dropbear.id.au>
Remove a test from the mprotect() path which checks that the mprotect()ed
range on a hugepage VMA is hugepage aligned (yes, really, the sense of
is_aligned_hugepage_range() is the opposite of what you'd guess :-/).
In fact, we don't need this test. If the given addresses match the
beginning/end of a hugepage VMA they must already be suitably aligned. If
they don't, then mprotect_fixup() will attempt to split the VMA. The very
first test in split_vma() will check for a badly aligned address on a
hugepage VMA and return -EINVAL if necessary.
From: "Chen, Kenneth W" <kenneth.w.chen@intel.com>
On i386 and x86-64, pte flag _PAGE_PSE collides with _PAGE_PROTNONE. The
identify of hugetlb pte is lost when changing page protection via mprotect.
A page fault occurs later will trigger a bug check in huge_pte_alloc().
The fix is to always make new pte a hugetlb pte and also to clean up
legacy code where _PAGE_PRESENT is forced on in the pre-faulting day.
Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com>
Cc: David Gibson <david@gibson.dropbear.id.au>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The current current get_init_ra_size is not optimal across different IO
sizes and max_readahead values. Here is a quick summary of sizes computed
under current design and under the attached patch. All of these assume 1st
IO at offset 0, or 1st detected sequential IO.
32k max, 4k request
old new
-----------------
8k 8k
16k 16k
32k 32k
128k max, 4k request
old new
-----------------
32k 16k
64k 32k
128k 64k
128k 128k
128k max, 32k request
old new
-----------------
32k 64k <-----
64k 128k
128k 128k
512k max, 4k request
old new
-----------------
4k 32k <----
16k 64k
64k 128k
128k 256k
512k 512k
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Steven Pratt <slpratt@austin.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If get_next_ra_size() does not grow fast enough, ->prev_page can overrun
the ahead window. This means the caller will read the pages from
->ahead_start + ->ahead_size to ->prev_page synchronously.
Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Steven Pratt <slpratt@austin.ibm.com>
Cc: Ram Pai <linuxram@us.ibm.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
shmem.c was named and shamed in Jesper's "Building 100 kernels" warnings:
shmem_parse_mpol is only used when CONFIG_TMPFS parses mount options; and
only called from that one site, so mark it inline like its non-NUMA stub.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
As suggested by Marcelo:
1. The optimization introduced recently for not calling
page_referenced() during zone reclaim makes two additional checks in
shrink_list unnecessary.
2. The if (unlikely(sc->may_swap)) in refill_inactive_zone is optimized
for the zone_reclaim case. However, most peoples system only does swap.
Undo that.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Put a few more checks under CONFIG_DEBUG_VM
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
prep_zero_page() uses KM_USER0 and hence may not be used from IRQ context, at
least for highmem pages.
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move the prep_ stuff into prep_new_page.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
set_page_count usage outside mm/ is limited to setting the refcount to 1.
Remove set_page_count from outside mm/, and replace those users with
init_page_count() and set_page_refcounted().
This allows more debug checking, and tighter control on how code is allowed
to play around with page->_count.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Now that compound page handling is properly fixed in the VM, move nommu
over to using compound pages rather than rolling their own refcounting.
nommu vm page refcounting is broken anyway, but there is no need to have
divergent code in the core VM now, nor when it gets fixed.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: David Howells <dhowells@redhat.com>
(Needs testing, please).
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove __put_page from outside the core mm/. It is dangerous because it does
not handle compound pages nicely, and misses 1->0 transitions. If a user
later appears that really needs the extra speed we can reevaluate.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Now that it's madvisable, remove two pieces of VM_DONTCOPY bogosity:
1. There was and is no logical reason why VM_DONTCOPY should be in the
list of flags which forbid vma merging (and those drivers which set
it are also setting VM_IO, which itself forbids the merge).
2. It's hard to understand the purpose of the VM_HUGETLB, VM_DONTCOPY
block in vm_stat_account: but never mind, it's under CONFIG_HUGETLB,
which (unlike CONFIG_HUGETLB_PAGE or CONFIG_HUGETLBFS) has never been
defined.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Cc: William Lee Irwin III <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In shrink_inactive_list(), nr_scan is not accounted when nr_taken is 0.
But 0 pages taken does not mean 0 pages scanned.
Move the goto statement below the accounting code to fix it.
Signed-off-by: Wu Fengguang <wfg@mail.ustc.edu.cn>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In isolate_lru_pages(), *scanned reports one more scan because the scan
counter is increased one more time on exit of the while-loop.
Change the while-loop to for-loop to fix it.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <wfg@mail.ustc.edu.cn>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add some comments to explain how zone reclaim works. And it fixes the
following issues:
- PF_SWAPWRITE needs to be set for RECLAIM_SWAP to be able to write
out pages to swap. Currently RECLAIM_SWAP may not do that.
- remove setting nr_reclaimed pages after slab reclaim since the slab shrinking
code does not use that and the nr_reclaimed pages is just right for the
intended follow up action.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We have:
try_to_free_pages
->shrink_caches(struct zone **zones, ..)
->shrink_zone(struct zone *, ...)
->shrink_cache(struct zone *, ...)
->shrink_list(struct list_head *, ...)
->refill_inactive_list((struct zone *, ...)
which is fairly irrational.
Rename things so that we have
try_to_free_pages
->shrink_zones(struct zone **zones, ..)
->shrink_zone(struct zone *, ...)
->shrink_inactive_list(struct zone *, ...)
->shrink_page_list(struct list_head *, ...)
->shrink_active_list(struct zone *, ...)
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change all the vmscan functions to retunr the number-of-reclaimed pages and
remove scan_conrtol.nr_reclaimed.
Saves ten-odd bytes of text and makes things clearer and more consistent.
The patch also changes the behaviour of zone_reclaim() when it falls back to slab shrinking. Christoph says
"Setting this to one means that we will rescan and shrink the slab for
each allocation if we are out of zone memory and RECLAIM_SLAB is set. Plus
if we do an order 0 allocation we do not go off node as intended.
"We better set this to zero. This means the allocation will go offnode
despite us having potentially freed lots of memory on the zone. Future
allocations can then again be done from this zone."
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Turn basically everything in vmscan.c into `unsigned long'. This is to avoid
the possibility that some piece of code in there might decide to operate upon
more than 4G (or even 2G) of pages in one hit.
This might be silly, but we'll need it one day.
Cc: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Initialise as much of scan_control as possible at the declaration site. This
tidies things up a bit and assures us that all unmentioned fields are zeroed
out.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make nr_to_scan and priority a parameter instead of putting it into scan
control. This allows various small optimizations and IMHO makes the code
easier to read.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
SLAB_NO_REAP is documented as an option that will cause this slab not to be
reaped under memory pressure. However, that is not what happens. The only
thing that SLAB_NO_REAP controls at the moment is the reclaim of the unused
slab elements that were allocated in batch in cache_reap(). Cache_reap()
is run every few seconds independently of memory pressure.
Could we remove the whole thing? Its only used by three slabs anyways and
I cannot find a reason for having this option.
There is an additional problem with SLAB_NO_REAP. If set then the recovery
of objects from alien caches is switched off. Objects not freed on the
same node where they were initially allocated will only be reused if a
certain amount of objects accumulates from one alien node (not very likely)
or if the cache is explicitly shrunk. (Strangely __cache_shrink does not
check for SLAB_NO_REAP)
Getting rid of SLAB_NO_REAP fixes the problems with alien cache freeing.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We have struct kmem_cache now so use it instead of the old typedef.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove cachep->spinlock. Locking has moved to the kmem_list3 and most of
the structures protected earlier by cachep->spinlock is now protected by
the l3->list_lock. slab cache tunables like batchcount are accessed always
with the cache_chain_mutex held.
Patch tested on SMP and NUMA kernels with dbench processes running,
constant onlining/offlining, and constant cache tuning, all at the same
time.
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Christoph Lameter <christoph@lameter.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
slab.c has become a bit revolting again. Try to repair it.
- Coding style fixes
- Don't do assignments-in-if-statements.
- Don't typecast assignments to/from void*
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Extract setup_cpu_cache() function from kmem_cache_create() to make the
latter a little less complex.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Clean up the object to index mapping that has been spread around mm/slab.c.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Insert "fresh" huge pages into the hugepage allocator by the same means as
they are freed back into it. This reduces code size and allows
enqueue_huge_page to be inlined into the hugepage free fastpath.
Eliminate occurances of hugepages on the free list with non-zero refcount.
This can allow stricter refcount checks in future. Also required for
lockless pagecache.
Signed-off-by: Nick Piggin <npiggin@suse.de>
"This patch also eliminates a leak "cleaned up" by re-clobbering the
refcount on every allocation from the hugepage freelists. With respect to
the lockless pagecache, the crucial aspect is to eliminate unconditional
set_page_count() to 0 on pages with potentially nonzero refcounts, though
closer inspection suggests the assignments removed are entirely spurious."
Acked-by: William Irwin <wli@holomorphy.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The bootmem code added to page_alloc.c duplicated some page freeing code
that it really doesn't need to because it is not so performance critical.
While we're here, make prefetching work properly by actually prefetching
the page we're about to use before prefetching ahead to the next one (ie.
get the most important transaction started first). Also prefetch just a
single page ahead rather than leaving a gap of 16.
Jack Steiner reported no problems with SGI's ia64 simulator.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Have an explicit mm call to split higher order pages into individual pages.
Should help to avoid bugs and be more explicit about the code's intention.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: David Howells <dhowells@redhat.com>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Yoichi Yuasa <yoichi_yuasa@tripeaks.co.jp>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The VM has an interesting race where a page refcount can drop to zero, but it
is still on the LRU lists for a short time. This was solved by testing a 0->1
refcount transition when picking up pages from the LRU, and dropping the
refcount in that case.
Instead, use atomic_add_unless to ensure we never pick up a 0 refcount page
from the LRU, thus a 0 refcount page will never have its refcount elevated
until it is allocated again.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
More atomic operation removal from page allocator
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In the page release paths, we can be sure that nobody will mess with our
page->flags because the refcount has dropped to 0. So no need for atomic
operations here.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
PG_active is protected by zone->lru_lock, it does not need TestSet/TestClear
operations.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
PG_lru is protected by zone->lru_lock. It does not need TestSet/TestClear
operations.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If vmscan finds a zero refcount page on the lru list, never ClearPageLRU
it. This means the release code need not hold ->lru_lock to stabilise
PageLRU, so that lock may be skipped entirely when releasing !PageLRU pages
(because we know PageLRU won't have been temporarily cleared by vmscan,
which was previously guaranteed by holding the lock to synchronise against
vmscan).
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
__get_page_state() has an open-coded for_each_cpu_mask() loop in it.
Tidy that up, then notice that the code was buggy:
while (cpu < NR_CPUS) {
unsigned long *in, *out, off;
if (!cpu_isset(cpu, *cpumask))
continue;
an obvious infinite loop. I guess we just never call it with a holey cpu
mask.
Even after my cpumask size-reduction work, this patch increases code size :(
Cc: Paul Jackson <pj@sgi.com>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Lee Revell reported 28ms latency when process with lots of swapped memory
exits.
2.6.15 introduced a latency regression when unmapping: in accounting the
zap_work latency breaker, pte_none counted 1, pte_present PAGE_SIZE, but a
swap entry counted nothing at all. We think of pages present as the slow
case, but Lee's trace shows that free_swap_and_cache's radix tree lookup
can make a lot of work - and we could have been doing it many thousands of
times without a latency break.
Move the zap_work update up to account swap entries like pages present.
This does account non-linear pte_file entries, and unmap_mapping_range
skipping over swap entries, by the same amount even though they're quick:
but neither of those cases deserves complicating the code (and they're
treated no worse than they were in 2.6.14).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Nick Piggin <npiggin@suse.de>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We can call try_to_release_page() with PagePrivate off and a valid
page->mapping This may cause all sorts of trouble for the filesystem
*_releasepage() handlers. XFS bombs out in that case.
Lock the page before checking for page private.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently the migration of anonymous pages will silently fail if no swap is
setup. This patch makes page migration functions check for available swap
and fail with -ENODEV if no swap space is available.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
It seems that setting scheduling policy and priorities is also the kind of
thing that might be performed in apps that also use the NUMA API, so it
would seem consistent to use CAP_SYS_NICE for NUMA also.
So use CAP_SYS_NICE for controlling migration permissions.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
page migration currently simply retries a couple of times if try_to_unmap()
fails without inspecting the return code.
However, SWAP_FAIL indicates that the page is in a vma that has the
VM_LOCKED flag set (if ignore_refs ==1). We can check for that return code
and avoid retrying the migration.
migrate_page_remove_references() now needs to return a reason why the
failure occured. So switch migrate_page_remove_references to use -Exx
style error messages.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The cache reaper currently tries to free all alien caches and all remote
per cpu pages in each pass of cache_reap. For a machines with large number
of nodes (such as Altix) this may lead to sporadic delays of around ~10ms.
Interrupts are disabled while reclaiming creating unacceptable delays.
This patch changes that behavior by adding a per cpu reap_node variable.
Instead of attempting to free all caches, we free only one alien cache and
the per cpu pages from one remote node. That reduces the time spend in
cache_reap. However, doing so will lengthen the time it takes to
completely drain all remote per cpu pagesets and all alien caches. The
time needed will grow with the number of nodes in the system. All caches
are drained when they overflow their respective capacity. So the drawback
here is only that a bit of memory may be wasted for awhile longer.
Details:
1. Rename drain_remote_pages to drain_node_pages to allow the specification
of the node to drain of pcp pages.
2. Add additional functions init_reap_node, next_reap_node for NUMA
that manage a per cpu reap_node counter.
3. Add a reap_alien function that reaps only from the current reap_node.
For us this seems to be a critical issue. Holdoffs of an average of ~7ms
cause some HPC benchmarks to slow down significantly. F.e. NAS parallel
slows down dramatically. NAS parallel has a 12-16 seconds runtime w/o rotor
compared to 5.8 secs with the rotor patches. It gets down to 5.05 secs with
the additional interrupt holdoff reductions.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When pages are onlined, not only zone->present_pages but also
pgdat->node_present_pages should be refreshed.
This parameter is used to show information at
/sys/device/system/node/nodeX/meminfo via si_meminfo_node().
So, it shows strange value for MemUsed which is calculated
(node_present_pages - all zones free pages).
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If the process has already set PF_MALLOC and is already using
current->reclaim_state then do not try to reclaim memory from the zone.
This is set by kswapd and/or synchrononous global reclaim which will not
take it lightly if we zap the reclaim_state.
Signed-off-by: Christoph Lameter <clameter@sig.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove two early-development BUG_ONs from page_add_file_rmap.
The pfn_valid test (originally useful for checking that nobody passed an
artificial struct page) comes too late, since we already have the struct
page.
The PageAnon test (useful when anon was first distinguished from file rmap)
prevents ->nopage implementations from reusing ->mapping, which would
otherwise be available.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
kmem_cache_init() incorrectly assumes that the cache_cache object will fit
in an order 0 allocation. On very large systems, this is not true. Change
the code to try larger order allocations if order 0 fails.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Implement percpu_counter_sum(). This is a more accurate but slower version of
percpu_counter_read_positive().
We need this for Alex's speedup-ext3_statfs patch and for the nr_file
accounting fix. Otherwise these things would be too inaccurate on large CPU
counts.
Cc: Ravikiran G Thirumalai <kiran@scalex86.org>
Cc: Alex Tomas <alex@clusterfs.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix the mm/mempolicy.c build for !CONFIG_HUGETLB_PAGE.
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Martin Bligh <mbligh@google.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Instead of having a hard-to-read and confusing conditional in the
caller, just make the slab order calculation handle this special case,
since it's simple and obvious there.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change the format of numa_maps to be more compact and contain additional
information that is useful for managing and troubleshooting memory on a
NUMA system. Numa_maps can now also support huge pages.
Fixes:
1. More compact format. Only display fields if they contain additional
information.
2. Always display information for all vmas. The old numa_maps did not display
vma with no mapped entries. This was a bit confusing because page
migration removes ptes for file backed vmas. After page migration
a part of the vmas vanished.
3. Rename maxref to maxmap. This is the maximum mapcount of all the pages
in a vma and may be used as an indicator as to how many processes
may be using a certain vma.
4. Include the ability to scan over huge page vmas.
New items shown:
dirty
Number of pages in a vma that have either the dirty bit set in the
page_struct or in the pte.
file=<filename>
The file backing the pages if any
stack
Stack area
heap
Heap area
huge
Huge page area. The number of pages shows is the number of huge
pages not the regular sized pages.
swapcache
Number of pages with swap references. Must be >0 in order to
be shown.
active
Number of active pages. Only displayed if different from the number
of pages mapped.
writeback
Number of pages under writeback. Only displayed if >0.
Sample ouput of a process using huge pages:
00000000 default
2000000000000000 default file=/lib/ld-2.3.90.so mapped=13 mapmax=30 N0=13
2000000000044000 default file=/lib/ld-2.3.90.so anon=2 dirty=2 swapcache=2 N2=2
2000000000064000 default file=/lib/librt-2.3.90.so mapped=2 active=1 N1=1 N3=1
2000000000074000 default file=/lib/librt-2.3.90.so
2000000000080000 default file=/lib/librt-2.3.90.so anon=1 swapcache=1 N2=1
2000000000084000 default
2000000000088000 default file=/lib/libc-2.3.90.so mapped=52 mapmax=32 active=48 N0=52
20000000002bc000 default file=/lib/libc-2.3.90.so
20000000002c8000 default file=/lib/libc-2.3.90.so anon=3 dirty=2 swapcache=3 active=2 N1=1 N2=2
20000000002d4000 default anon=1 swapcache=1 N1=1
20000000002d8000 default file=/lib/libpthread-2.3.90.so mapped=8 mapmax=3 active=7 N2=2 N3=6
20000000002fc000 default file=/lib/libpthread-2.3.90.so
2000000000308000 default file=/lib/libpthread-2.3.90.so anon=1 dirty=1 swapcache=1 N1=1
200000000030c000 default anon=1 dirty=1 swapcache=1 N1=1
2000000000320000 default anon=1 dirty=1 N1=1
200000000071c000 default
2000000000720000 default anon=2 dirty=2 swapcache=1 N1=1 N2=1
2000000000f1c000 default
2000000000f20000 default anon=2 dirty=2 swapcache=1 active=1 N2=1 N3=1
200000000171c000 default
2000000001720000 default anon=1 dirty=1 swapcache=1 N1=1
2000000001b20000 default
2000000001b38000 default file=/lib/libgcc_s.so.1 mapped=2 N1=2
2000000001b48000 default file=/lib/libgcc_s.so.1
2000000001b54000 default file=/lib/libgcc_s.so.1 anon=1 dirty=1 active=0 N1=1
2000000001b58000 default file=/lib/libunwind.so.7.0.0 mapped=2 active=1 N1=2
2000000001b74000 default file=/lib/libunwind.so.7.0.0
2000000001b80000 default file=/lib/libunwind.so.7.0.0
2000000001b84000 default
4000000000000000 default file=/media/huge/test9 mapped=1 N1=1
6000000000000000 default file=/media/huge/test9 anon=1 dirty=1 active=0 N1=1
6000000000004000 default heap
607fffff7fffc000 default anon=1 dirty=1 swapcache=1 N2=1
607fffffff06c000 default stack anon=1 dirty=1 active=0 N1=1
8000000060000000 default file=/mnt/huge/test0 huge dirty=3 N1=3
8000000090000000 default file=/mnt/huge/test1 huge dirty=3 N0=1 N2=2
80000000c0000000 default file=/mnt/huge/test2 huge dirty=3 N1=1 N3=2
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If we triggered the 'offslab_limit' test, we would return with
cachep->gfporder incremented once too many times.
This clarifies the logic somewhat, and fixes that bug.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
We want to use the "struct slab" size, not the size of the pointer to
same. As it is, we'd not print out the last <n> entry pointers in the
slab (where <n> is ~10, depending on whether it's a 32-bit or 64-bit
kernel).
Gaah, that slab code was written by somebody who likes unreadable crud.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
numa_maps should not scan over huge vmas in order not to cause problems for
non IA64 platforms that may have pte entries pointing to huge pages in a
variety of ways in their page tables. Add a simple check to ignore vmas
containing huge pages.
Signed-off-by: Christoph Lameter <clameter@engr.sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I seem to have lost this read_unlock().
While we're there, let's turn that interruptible sleep unto uninterruptible,
so we don't get a busywait if signal_pending(). (Again. We seem to have a
habit of doing this).
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Under some circumstances `points' can get printed before it's initialised.
Spotted by Carlos Martin <carlos@cmartin.tk>.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
remove_from_swap() currently attempts to use page_lock_anon_vma to obtain
an anon_vma lock. That is not working since the page may have been
remapped via swap ptes in order to move the page.
However, do_migrate_pages() obtain the mmap_sem lock and therefore there is
a guarantee that the anonymous vma will not vanish from under us. There is
therefore no need to use page_lock_anon_vma.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently sys_migrate_pages only moves pages belonging to a process. This
is okay when invoked from a regular user. But if invoked from root it
should move all pages as documented in the migrate_pages manpage.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- PF_SWAPWRITE needs to be set for RECLAIM_SWAP to be able to write
out pages to swap. Currently RECLAIM_SWAP may not do that.
- remove setting nr_reclaimed pages after slab reclaim since the slab shrinking
code does not use that and the nr_reclaimed pages is just right for the
intended follow up action.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
migrate_pages_to() allocates a list of new pages on the intended target
node or with the intended policy and then uses the list of new pages as
targets for the migration of a list of pages out of place.
When the pages are allocated it is not clear which of the out of place
pages will be moved to the new pages. So we cannot specify an address as
needed by alloc_page_vma(). This causes problem for MPOL_INTERLEAVE which
will currently allocate the pages on the first node of the set. If mbind
is used with vma that has the policy of MPOL_INTERLEAVE then the
interleaving of pages may be destroyed.
This patch fixes that by generating a fake address for each alloc_page_vma
which will result is a distribution of pages as prescribed by
MPOL_INTERLEAVE.
Lee also noted that the sequence of nodes for the new pages seems to be
inverted. So we also invert the way the lists of pages for migration are
build.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Looks-ok-to: Andi Kleen <ak@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I've been dissatisfied with the mpol_nodelist mount option which was
added to tmpfs earlier in -rc. Replace it by mpol=policy:nodelist.
And it was broken: a nodelist is a comma-separated list of numbers and
ranges; the mount options are a comma-separated list of token=values.
Whoops, blindly strsep'ing on commas doesn't work so well: since we've
no numeric tokens, and unlikely to add them, use that to distinguish.
Move the mpol= parsing to shmem_parse_mpol under CONFIG_NUMA, reject
all its options as invalid if not NUMA. /proc shows MPOL_PREFERRED
as "prefer", so use that name for the policy instead of "preferred".
Enforce that mpol=default has no nodelist; that mpol=prefer has one
node only; that mpol=bind has a nodelist; but let mpol=interleave use
node_online_map if no nodelist given. Describe this in tmpfs.txt.
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Acked-by: Robin Holt <holt@sgi.com>
Acked-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
[akpm; it happens that the code was still correct, only inefficient ]
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Signed-off-by: Luke Yang <luke.adi@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
maxnode is a bit index and can't be directly compared against a byte length
like PAGE_SIZE
Signed-off-by: Andi Kleen <ak@suse.de>
Cc: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some allocations are restricted to a limited set of nodes (due to memory
policies or cpuset constraints). If the page allocator is not able to find
enough memory then that does not mean that overall system memory is low.
In particular going postal and more or less randomly shooting at processes
is not likely going to help the situation but may just lead to suicide (the
whole system coming down).
It is better to signal to the process that no memory exists given the
constraints that the process (or the configuration of the process) has
placed on the allocation behavior. The process may be killed but then the
sysadmin or developer can investigate the situation. The solution is
similar to what we do when running out of hugepages.
This patch adds a check before we kill processes. At that point
performance considerations do not matter much so we just scan the zonelist
and reconstruct a list of nodes. If the list of nodes does not contain all
online nodes then this is a constrained allocation and we should kill the
current process.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In the badness() calculation, there's currently this piece of code:
/*
* Processes which fork a lot of child processes are likely
* a good choice. We add the vmsize of the children if they
* have an own mm. This prevents forking servers to flood the
* machine with an endless amount of children
*/
list_for_each(tsk, &p->children) {
struct task_struct *chld;
chld = list_entry(tsk, struct task_struct, sibling);
if (chld->mm = p->mm && chld->mm)
points += chld->mm->total_vm;
}
The intention is clear: If some server (apache) keeps spawning new children
and we run OOM, we want to kill the father rather than picking a child.
This -- to some degree -- also helps a bit with getting fork bombs under
control, though I'd consider this a desirable side-effect rather than a
feature.
There's one problem with this: No matter how many or few children there are,
if just one of them misbehaves, and all others (including the father) do
everything right, we still always kill the whole family. This hits in real
life; whether it's javascript in konqueror resulting in kdeinit (and thus the
whole KDE session) being hit or just a classical server that spawns children.
Sidenote: The killer does kill all direct children as well, not only the
selected father, see oom_kill_process().
The idea in attached patch is that we do want to account the memory
consumption of the (direct) children to the father -- however not fully.
This maintains the property that fathers with too many children will still
very likely be picked, whereas a single misbehaving child has the chance to
be picked by the OOM killer.
In the patch I account only half (rounded up) of the children's vm_size to
the parent. This means that if one child eats more mem than the rest of
the family, it will be picked, otherwise it's still the father and thus the
whole family that gets selected.
This is heuristics -- we could debate whether accounting for a fourth would
be better than for half of it. Or -- if people would consider it worth the
trouble -- make it a sysctl. For now I sticked to accounting for half,
which should IMHO be a significant improvement.
The patch does one more thing: As users tend to be irritated by the choice
of killed processes (mainly because the children are killed first, despite
some of them having a very low OOM score), I added some more output: The
selected (father) process will be reported first and it's oom_score printed
to syslog.
Description:
Only account for half of children's vm size in oom score calculation
This should still give the parent enough point in case of fork bombs. If
any child however has more than 50% of the vm size of all children
together, it'll get a higher score and be elected.
This patch also makes the kernel display the oom_score.
Signed-off-by: Kurt Garloff <garloff@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make sure maxnodes is safe size before calculating nlongs in
get_nodes().
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Change the find_next_best_node algorithm to correctly skip
over holes in the node online mask. Previously it would not handle
missing nodes correctly and cause crashes at boot.
[Written by Linus, tested by AK]
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The memory allocator doesn't like empty zones (which have an
uninitialized freelist), so a x86-64 system with a node fully
in GFP_DMA32 only would crash on mbind.
Fix that up by putting all possible zones as fallback into the zonelist
and skipping the empty ones.
In fact the code always enough allocated space for all zones,
but only used it for the highest. This change just uses all the
memory that was allocated before.
This should work fine for now, but whoever implements node hot removal
needs to fix this somewhere else too (or make sure zone datastructures
by itself never go away, only their memory)
Signed-off-by: Andi Kleen <ak@suse.de>
Acked-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
AMD SimNow!'s JIT doesn't like them at all in the guest. For distribution
installation it's easiest if it's a boot time option.
Also I moved the variable to a more appropiate place and make
it independent from sysctl
And marked __read_mostly which it is.
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently, copy-on-write may change the physical address of a page even if the
user requested that the page is pinned in memory (either by mlock or by
get_user_pages). This happens if the process forks meanwhile, and the parent
writes to that page. As a result, the page is orphaned: in case of
get_user_pages, the application will never see any data hardware DMA's into
this page after the COW. In case of mlock'd memory, the parent is not getting
the realtime/security benefits of mlock.
In particular, this affects the Infiniband modules which do DMA from and into
user pages all the time.
This patch adds madvise options to control whether memory range is inherited
across fork. Useful e.g. for when hardware is doing DMA from/into these
pages. Could also be useful to an application wanting to speed up its forks
by cutting large areas out of consideration.
Signed-off-by: Michael S. Tsirkin <mst@mellanox.co.il>
Acked-by: Hugh Dickins <hugh@veritas.com>
Cc: Michael Kerrisk <mtk-manpages@gmx.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Somehow I imagined that calling a NULL destructor would free a compound page
rather than oopsing. No, we must supply a default destructor, __free_pages_ok
using the order noted by prep_compound_page. hugetlb can still replace this
as before with its own free_huge_page pointer.
The case that needs this is not common: rarely does put_compound_page's
put_page_testzero bring the count down to 0. But if get_user_pages is applied
to some part of a compound page, without immediate release (e.g. AIO or
Infiniband), then it's possible for its put_page to come after the containing
vma has been unmapped and the driver done its free_pages.
That's just the kind of case compound pages are supposed to be guarding
against (but Nick points out, nor did PageReserved handle this right).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If a compound page has its own put_page_testzero destructor (the only current
example is free_huge_page), that is noted in page[1].mapping of the compound
page. But that's rather a poor place to keep it: functions which call
set_page_dirty_lock after get_user_pages (e.g. Infiniband's
__ib_umem_release) ought to be checking first, otherwise set_page_dirty is
liable to crash on what's not the address of a struct address_space.
And now I'm about to make that worse: it turns out that every compound page
needs a destructor, so we can no longer rely on hugetlb pages going their own
special way, to avoid further problems of page->mapping reuse. For example,
not many people know that: on 50% of i386 -Os builds, the first tail page of a
compound page purports to be PageAnon (when its destructor has an odd
address), which surprises page_add_file_rmap.
Keep the compound page destructor in page[1].lru.next instead. And to free up
the common pairing of mapping and index, also move compound page order from
index to lru.prev. Slab reuses page->lru too: but if we ever need slab to use
compound pages, it can easily stack its use above this.
(akpm: decoded version of the above: the tail pages of a compound page now
have ->mapping==NULL, so there's no need for the set_page_dirty[_lock]()
caller to check that they're not compund pages before doing the dirty).
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This puts the variables and the way to get to reclaim_mapped in one block.
And allows zone_reclaim or other things to skip the determination (maybe
this whole block of code does not belong into refill_inactive_zone()?)
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
shrink_zone() already increments reclaim_in_progress. No need to do it in
balance_pgdat.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
shrink_list() and refill_inactive() check all ptes pointing to a page for
reference bits in order to decide if the page should be put on the active
list. This is not necessary for zone_reclaim since we are only interested
in removing unmapped pages. Skip the checks in both functions.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This adds some additional comments in order to help others figure out how
exactly the code works. And fix a variable name.
Also swap_page does need to ignore all reference bits when unmapping a
page. Otherwise we may have to repeatedly unmap a frequently touched page.
So change the try_to_unmap parameter to 1.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Prevents deadlock situation between
kmem_cache_create()/kmem_cache_destory(), and kmem_cache_create() /cpu
hotplug. The locking order probably got moved over time.
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
fix CONFIG_SLOB=y (when CONFIG_SMP=y): get rid of the 'align' parameter
from its __alloc_percpu() implementation. Boot-tested on x86.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Compound pages on SMP systems can now often be freed from pagetables via
the release_pages path. This uses put_page_testzero which does not handle
compound pages at all. Releasing constituent pages from process mappings
decrements their count to a large negative number and leaks the reference
at the head page - net result is a memory leak.
The problem was hidden because the debug check in put_page_testzero itself
actually did take compound pages into consideration.
Fix the bug and the debug check.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Remove wrong and misleading comments.
Return VM_FAULT_OOM if the hugetlbpage fault handler cannot allocate a
page. do_no_page will end up doing do_exit(SIGKILL).
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
When hugepages are newly allocated to a file in mm/hugetlb.c, we clear them
with a call to clear_highpage() on each of the subpages. We should be
using clear_user_highpage(): on powerpc, at least, clear_highpage() doesn't
correctly mark the page as icache dirty so if the page is executed shortly
after it's possible to get strange results.
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The non-NUMA case would do an unmatched "free_alien_cache()" on an alien
pointer that had never been allocated.
It might not matter from a code generation standpoint (since in the
non-NUMA case, the code doesn't actually _do_ anything), but it not only
results in a compiler warning, it's really really ugly too.
Fix the compiler warning by just having a matching dummy allocation.
That also avoids an unnecessary #ifdef in the code.
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This fixes locking and bugs in cpu_down and cpu_up paths of the NUMA slab
allocator. Sonny Rao <sonny@burdell.org> reported problems sometime back on
POWER5 boxes, when the last cpu on the nodes were being offlined. We could
not reproduce the same on x86_64 because the cpumask (node_to_cpumask) was not
being updated on cpu down. Since that issue is now fixed, we can reproduce
Sonny's problems on x86_64 NUMA, and here is the fix.
The problem earlier was on CPU_DOWN, if it was the last cpu on the node to go
down, the array_caches (shared, alien) and the kmem_list3 of the node were
being freed (kfree) with the kmem_list3 lock held. If the l3 or the
array_caches were to come from the same cache being cleared, we hit on
badness.
This patch cleans up the locking in cpu_up and cpu_down path. We cannot
really free l3 on cpu down because, there is no node offlining yet and even
though a cpu is not yet up, node local memory can be allocated for it. So l3s
are usually allocated at keme_cache_create and destroyed at
kmem_cache_destroy. Hence, we don't need cachep->spinlock protection to get
to the cachep->nodelist[nodeid] either.
Patch survived onlining and offlining on a 4 core 2 node Tyan box with a 4
dbench process running all the time.
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Earlier, we had to disable on chip interrupts while taking the
cachep->spinlock because, at cache_grow, on every addition of a slab to a slab
cache, we incremented colour_next which was protected by the cachep->spinlock,
and cache_grow could occur at interrupt context. Since, now we protect the
per-node colour_next with the node's list_lock, we do not need to disable on
chip interrupts while taking the per-cache spinlock, but we just need to
disable interrupts when taking the per-node kmem_list3 list_lock.
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
colour_next is used as an index to add a colouring offset to a new slab in the
cache (colour_off * colour_next). Now with the NUMA aware slab allocator, it
makes sense to colour slabs added on the same node sequentially with
colour_next.
This patch moves the colouring index "colour_next" per-node by placing it on
kmem_list3 rather than kmem_cache.
This also helps simplify locking for CPU up and down paths.
Signed-off-by: Alok N Kataria <alokk@calsoftinc.com>
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Shai Fultheim <shai@scalex86.org>
Cc: Christoph Lameter <christoph@lameter.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I just spent some time researching a Bus Error. Turns out that the huge
page fault handler can return VM_FAULT_SIGBUS for various conditions where
no huge page is available.
Add a note explaining the reasoning in the source.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: William Lee Irwin III <wli@holomorphy.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
percpu_data blindly allocates bootmem memory to store NR_CPUS instances of
cpudata, instead of allocating memory only for possible cpus.
As a preparation for changing that, we need to convert various 0 -> NR_CPUS
loops to use for_each_cpu().
(The above only applies to users of asm-generic/percpu.h. powerpc has gone it
alone and is presently only allocating memory for present CPUs, so it's
currently corrupting memory).
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: James Bottomley <James.Bottomley@steeleye.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Cc: Jens Axboe <axboe@suse.de>
Cc: Anton Blanchard <anton@samba.org>
Acked-by: William Irwin <wli@holomorphy.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
> mm/mempolicy.c: In function `huge_zonelist':
> mm/mempolicy.c:1045: error: `HPAGE_SHIFT' undeclared (first use in this function)
> mm/mempolicy.c:1045: error: (Each undeclared identifier is reported only once
> mm/mempolicy.c:1045: error: for each function it appears in.)
> make[1]: *** [mm/mempolicy.o] Error 1
Need to wrap huge_zonelist function with CONFIG_HUGETLBFS.
Signed-off-by: Ken Chen <kenneth.w.chen@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Fix kzalloc() and kstrdup() caller report for CONFIG_DEBUG_SLAB. We must
pass the caller to __cache_alloc() instead of directly doing
__builtin_return_address(0) there; otherwise kzalloc() and kstrdup() are
reported as the allocation site instead of the real one.
Thanks to Valdis Kletnieks for reporting the problem and Steven Rostedt for
the original idea.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Replace uses of kmem_cache_t with proper struct kmem_cache in mm/slab.c.
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Rename the ac_data() function to more descriptive cpu_cache_get().
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Introduce virt_to_cache() and virt_to_slab() functions to reduce duplicate
code and introduce a proper abstraction should we want to support other kind
of mapping for address to slab and cache (eg. for vmalloc() or I/O memory).
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
From: Manfred Spraul <manfred@colorfullife.com>
Reduce the amount of inline functions in slab to the functions that
are used in the hot path:
- no inline for debug functions
- no __always_inline, inline is already __always_inline
- remove inline from a few numa support functions.
Before:
text data bss dec hex filename
13588 752 48 14388 3834 mm/slab.o (defconfig)
16671 2492 48 19211 4b0b mm/slab.o (numa)
After:
text data bss dec hex filename
13366 752 48 14166 3756 mm/slab.o (defconfig)
16230 2492 48 18770 4952 mm/slab.o (numa)
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Create two helper functions slab_get_obj() and slab_put_obj() to replace
duplicated code in mm/slab.c
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Create a helper function, slab_destroy_objs() which called from
slab_destroy(). This makes slab_destroy() smaller and more readable, and
moves ifdefs outside the function body.
Signed-off-by: Matthew Dobson <colpatch@us.ibm.com>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Clean up cache_estimate() in mm/slab.c and improves the algorithm from O(n) to
O(1). We first calculate the maximum number of objects a slab can hold after
struct slab and kmem_bufctl_t for each object has been given enough space.
After that, to respect alignment rules, we decrease the number of objects if
necessary. As required padding is at most align-1 and memory of obj_size is
at least align, it is always enough to decrease number of objects by one.
The optimization was originally made by Balbir Singh with more improvements
from Steven Rostedt. Manfred Spraul provider further modifications: no loop
at all for the off-slab case and added comments to explain the background.
Acked-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I noticed the code for index_of is a creative way of finding the cache
index using the compiler to optimize to a single hard coded number. But
I couldn't help noticing that it uses two methods to let you know that
someone used it wrong. One is at compile time (the correct way), and
the other is at run time (not good).
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Clean up kmem_cache_alloc_node a bit.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
An object cache has two different object lengths:
- the amount of memory available for the user (object size)
- the amount of memory allocated internally (buffer size)
This patch does some renames to make the code reflect that better.
Signed-off-by: Manfred Spraul <manfred@colorfullife.com>
Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Migrate a page with buffers without requiring writeback
This introduces a new address space operation migratepage() that may be used
by a filesystem to implement its own version of page migration.
A version is provided that migrates buffers attached to pages. Some
filesystems (ext2, ext3, xfs) are modified to utilize this feature.
The swapper address space operation are modified so that a regular
migrate_page() will occur for anonymous pages without writeback (migrate_pages
forces every anonymous page to have a swap entry).
Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Modify policy layer to support direct page migration
- Add migrate_pages_to() allowing the migration of a list of pages to a a
specified node or to vma with a specific allocation policy in sets of
MIGRATE_CHUNK_SIZE pages
- Modify do_migrate_pages() to do a staged move of pages from the source
nodes to the target nodes.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add remove_from_swap
remove_from_swap() allows the restoration of the pte entries that existed
before page migration occurred for anonymous pages by walking the reverse
maps. This reduces swap use and establishes regular pte's without the need
for page faults.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add direct migration support with fall back to swap.
Direct migration support on top of the swap based page migration facility.
This allows the direct migration of anonymous pages and the migration of file
backed pages by dropping the associated buffers (requires writeout).
Fall back to swap out if necessary.
The patch is based on lots of patches from the hotplug project but the code
was restructured, documented and simplified as much as possible.
Note that an additional patch that defines the migrate_page() method for
filesystems is necessary in order to avoid writeback for anonymous and file
backed pages.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Mike Kravetz <kravetz@us.ibm.com>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Check for PageSwapCache after looking up and locking a swap page.
The page migration code may change a swap pte to point to a different page
under lock_page().
If that happens then the vm must retry the lookup operation in the swap space
to find the correct page number. There are a couple of locations in the VM
where a lock_page() is done on a swap page. In these locations we need to
check afterwards if the page was migrated. If the page was migrated then the
old page that was looked up before was freed and no longer has the
PageSwapCache bit set.
Signed-off-by: Hirokazu Takahashi <taka@valinux.co.jp>
Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Christoph Lameter <clameter@@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
If large amounts of zone memory are used by empty slabs then zone_reclaim
becomes uneffective. This patch shakes the slab a bit.
The problem with this patch is that the slab reclaim is not containable to a
zone. Thus slab reclaim may affect the whole system and be extremely slow.
This also means that we cannot determine how many pages were freed in this
zone. Thus we need to go off node for at least one allocation.
The functionality is disabled by default.
We could modify the shrinkers to take a zone parameter but that would be quite
invasive. Better ideas are welcome.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In some situations one may want zone_reclaim to behave differently. For
example a process writing large amounts of memory will spew unto other nodes
to cache the writes if many pages in a zone become dirty. This may impact the
performance of processes running on other nodes.
Allowing writes during reclaim puts a stop to that behavior and throttles the
process by restricting the pages to the local zone.
Similarly one may want to contain processes to local memory by enabling
regular swap behavior during zone_reclaim. Off node memory allocation can
then be controlled through memory policies and cpusets.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Currently the zone_reclaim code has a fixed window of 30 seconds of off node
allocations should a local zone have no unused pagecache pages left. Reclaim
will be attempted again after this timeout period to avoid repeated useless
scans for memory. This is also useful to established sufficiently large off
node allocation chunks to relieve the local node.
It may be beneficial to adjust that time period for some special situations.
For example if memory use was exceeding node capacity one may want to give up
for longer periods of time. If memory spikes intermittendly then one may want
to shorten the time period to reduce the number of off node allocations.
This patch allows just that....
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Instead of scanning all the pages in a zone, imitate real swap and scan
only a portion of the pages and gradually scan more if we do not free up
enough pages. This avoids a zone suddenly loosing all unused pagecache
pages (we may after all access some of these again so they deserve another
chance) but it still frees up large chunks of memory if a zone only
contains unused pagecache pages.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
zone_reclaim should leave that to the real swapper. We are only interested
in evicting unmapped pages.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Improve the performance of slab_put_obj(). Without the cast, gcc considers
ptrdiff_t a 64 bit signed integer and ends up emitting code to use a full
signed 128 bit divide on EM64T, which is substantially slower than a 32 bit
unsigned divide.
I noticed this when looking at the profile of a case where the slab balance
is just on edge and thrashes back and forth freeing a block.
Signed-off-by: Benjamin LaHaise <benjamin.c.lahaise@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- If we only reclaim nr_pages then its okay to stay on node.
Switch from > to >= for the comparison.
- vm_table[] entry for zone_reclaim_mode is a bit screwed up.
- Add empty lines around shrink_zone to show that this is the
central function to be called.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make sc->may_writepage control the writeout behavior of shrink_list.
Remove the laptop_mode trick from shrink_list and instead set may_writepage
in try_to_free_pages properly.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Zone reclaim is usually only run on the local node. Headless nodes do not
have any local processors. This patch checks for headless nodes and
performs zone reclaim on them.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ensure that the performance of off node pages stays the same as before.
Off node pagefault tests showed an 18% drop in performance without this
patch.
- Increase the timeout to 30 seconds to reduce the overhead.
- Move all code possible out of the off node hot path for zone reclaim
(Sorry Andrew, the struct initialization had to be sacrificed).
The read_page_state() bit us there.
- Check first for the timeout before any other checks.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
__meminit has overzelously been modified and crept its way into marking
cpuup callbacks as __meminit.
Signed-off-by: Ashok Raj <ashok.raj@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Move the interrupt check from slab_node into ___cache_alloc and adds an
"unlikely()" to avoid pipeline stalls on some architectures.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch fixes a regression in 2.6.14 against 2.6.13 that causes an
imbalance in memory allocation during bootup.
The slab allocator in 2.6.13 is not numa aware and simply calls
alloc_pages(). This means that memory policies may control the behavior of
alloc_pages(). During bootup the memory policy is set to MPOL_INTERLEAVE
resulting in the spreading out of allocations during bootup over all
available nodes. The slab allocator in 2.6.13 has only a single list of
slab pages. As a result the per cpu slab cache and the spinlock controlled
page lists may contain slab entries from off node memory. The slab
allocator in 2.6.13 makes no effort to discern the locality of an entry on
its lists.
The NUMA aware slab allocator in 2.6.14 controls locality of the slab pages
explicitly by calling alloc_pages_node(). The NUMA slab allocator manages
slab entries by having lists of available slab pages for each node. The
per cpu slab cache can only contain slab entries associated with the node
local to the processor. This guarantees that the default allocation mode
of the slab allocator always assigns local memory if available.
Setting MPOL_INTERLEAVE as a default policy during bootup has no effect
anymore. In 2.6.14 all node unspecific slab allocations are performed on
the boot processor. This means that most of key data structures are
allocated on one node. Most processors will have to refer to these
structures making the boot node a potential bottleneck. This may reduce
performance and cause unnecessary memory pressure on the boot node.
This patch implements NUMA policies in the slab layer. There is the need
of explicit application of NUMA memory policies by the slab allcator itself
since the NUMA slab allocator does no longer let the page_allocator control
locality.
The check for policies is made directly at the beginning of __cache_alloc
using current->mempolicy. The memory policy is already frequently checked
by the page allocator (alloc_page_vma() and alloc_page_current()). So it
is highly likely that the cacheline is present. For MPOL_INTERLEAVE
kmalloc() will spread out each request to one node after another so that an
equal distribution of allocations can be obtained during bootup.
It is not possible to push the policy check to lower layers of the NUMA
slab allocator since the per cpu caches are now only containing slab
entries from the current node. If the policy says that the local node is
not to be preferred or forbidden then there is no point in checking the
slab cache or local list of slab pages. The allocation better be directed
immediately to the lists containing slab entries for the allowed set of
nodes.
This way of applying policy also fixes another strange behavior in 2.6.13.
alloc_pages() is controlled by the memory allocation policy of the current
process. It could therefore be that one process is running with
MPOL_INTERLEAVE and would f.e. obtain a new page following that policy
since no slab entries are in the lists anymore. A page can typically be
used for multiple slab entries but lets say that the current process is
only using one. The other entries are then added to the slab lists. These
are now non local entries in the slab lists despite of the possible
availability of local pages that would provide faster access and increase
the performance of the application.
Another process without MPOL_INTERLEAVE may now run and expect a local slab
entry from kmalloc(). However, there are still these free slab entries
from the off node page obtained from the other process via MPOL_INTERLEAVE
in the cache. The process will then get an off node slab entry although
other slab entries may be available that are local to that process. This
means that the policy if one process may contaminate the locality of the
slab caches for other processes.
This patch in effect insures that a per process policy is followed for the
allocation of slab entries and that there cannot be a memory policy
influence from one process to another. A process with default policy will
always get a local slab entry if one is available. And the process using
memory policies will get its memory arranged as requested. Off-node slab
allocation will require the use of spinlocks and will make the use of per
cpu caches not possible. A process using memory policies to redirect
allocations offnode will have to cope with additional lock overhead in
addition to the latency added by the need to access a remote slab entry.
Changes V1->V2
- Remove #ifdef CONFIG_NUMA by moving forward declaration into
prior #ifdef CONFIG_NUMA section.
- Give the function determining the node number to use a saner
name.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Some bits for zone reclaim exists in 2.6.15 but they are not usable. This
patch fixes them up, removes unused code and makes zone reclaim usable.
Zone reclaim allows the reclaiming of pages from a zone if the number of
free pages falls below the watermarks even if other zones still have enough
pages available. Zone reclaim is of particular importance for NUMA
machines. It can be more beneficial to reclaim a page than taking the
performance penalties that come with allocating a page on a remote zone.
Zone reclaim is enabled if the maximum distance to another node is higher
than RECLAIM_DISTANCE, which may be defined by an arch. By default
RECLAIM_DISTANCE is 20. 20 is the distance to another node in the same
component (enclosure or motherboard) on IA64. The meaning of the NUMA
distance information seems to vary by arch.
If zone reclaim is not successful then no further reclaim attempts will
occur for a certain time period (ZONE_RECLAIM_INTERVAL).
This patch was discussed before. See
http://marc.theaimsgroup.com/?l=linux-kernel&m=113519961504207&w=2http://marc.theaimsgroup.com/?l=linux-kernel&m=113408418232531&w=2http://marc.theaimsgroup.com/?l=linux-kernel&m=113389027420032&w=2http://marc.theaimsgroup.com/?l=linux-kernel&m=113380938612205&w=2
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Zone reclaim has a huge impact on NUMA performance (f.e. our maximum
throughput with XFS is raised from 4GB to 6GB/sec / page cache contamination
of numa nodes destroys locality if one just does a large copy operation which
results in performance dropping for good until reboot).
This patch:
Resurrect may_swap in struct scan_control
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Simplify migrate_page_add after feedback from Hugh. This also allows us to
drop one parameter from migrate_page_add.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Migration code currently does not take a reference to target page
properly, so between unlocking the pte and trying to take a new
reference to the page with isolate_lru_page, anything could happen to
it.
Fix this by holding the pte lock until we get a chance to elevate the
refcount.
Other small cleanups while we're here.
Signed-off-by: Nick Piggin <npiggin@suse.de>
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Ravikiran reports that this variable is bouncing all around nodes on NUMA
machines, causing measurable performance problems. Fix that up by only
writing to it when it actually changed.
And put it in a new cacheline to prevent it sharing with other things (this
happened).
Signed-off-by: Ravikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Add __meminit to the __init lineup to ensure functions default
to __init when memory hotplug is not enabled. Replace __devinit
with __meminit on functions that were changed when the memory
hotplug code was introduced.
Signed-off-by: Matt Tolentino <matthew.e.tolentino@intel.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The problem, reported in:
http://bugzilla.kernel.org/show_bug.cgi?id=5859
and by various other email messages and lkml posts is that the cpuset hook
in the oom (out of memory) code can try to take a cpuset semaphore while
holding the tasklist_lock (a spinlock).
One must not sleep while holding a spinlock.
The fix seems easy enough - move the cpuset semaphore region outside the
tasklist_lock region.
This required a few lines of mechanism to implement. The oom code where
the locking needs to be changed does not have access to the cpuset locks,
which are internal to kernel/cpuset.c only. So I provided a couple more
cpuset interface routines, available to the rest of the kernel, which
simple take and drop the lock needed here (cpusets callback_sem).
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Anything that writes into a tmpfs filesystem is liable to disproportionately
decrease the available memory on a particular node. Since there's no telling
what sort of application (e.g. dd/cp/cat) might be dropping large files
there, this lets the admin choose the appropriate default behavior for their
site's situation.
Introduce a tmpfs mount option which allows specifying a memory policy and
a second option to specify the nodelist for that policy. With the default
policy, tmpfs will behave as it does today. This patch adds support for
preferred, bind, and interleave policies.
The default policy will cause pages to be added to tmpfs files on the node
which is doing the writing. Some jobs expect a single process to create
and manage the tmpfs files. This results in a node which has a
significantly reduced number of free pages.
With this patch, the administrator can specify the policy and nodes for
that policy where they would prefer allocations.
This patch was originally written by Brent Casavant and Hugh Dickins. I
added support for the bind and preferred policies and the mpol_nodelist
mount option.
Signed-off-by: Brent Casavant <bcasavan@sgi.com>
Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This ensures that reserved pages are not migrated. Reserved pages
currently cause the WARN_ON to trigger in migrate_page_add()
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
- Move capable() from sched.h to capability.h;
- Use <linux/capability.h> where capable() is used
(in include/, block/, ipc/, kernel/, a few drivers/,
mm/, security/, & sound/;
many more drivers/ to go)
Signed-off-by: Randy Dunlap <rdunlap@xenotime.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Clarify in comments that GFP_ATOMIC means both "don't sleep" and "use
emergency pools", hence both ALLOC_HARDER and ALLOC_HIGH.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Let's switch mutex_debug_check_no_locks_freed() to take (addr, len) as
arguments instead, since all its callers were just calculating the 'to'
address for themselves anyway... (and sometimes doing so badly).
Signed-off-by: David Woodhouse <dwmw2@infradead.org>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
