If we're going to implement smp_call_function_single() on three architecture
with the same prototype then it should have a declaration in a
non-arch-specific header file.
Move it into <linux/smp.h>.
Cc: Stephane Eranian <eranian@hpl.hp.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
In many places we will need to use the same combination of flags. Specify
a single GFP_THISNODE definition for ease of use in gfp.h.
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 uncached allocator manages per node pools. Specify __GFP_THISNODE in
order to force allocation on the indicated node or fail. The uncached
allocator has already logic to deal with failing allocations.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: Andy Whitcroft <apw@shadowen.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Make ZONE_DMA32 optional
- Add #ifdefs around ZONE_DMA32 specific code and definitions.
- Add CONFIG_ZONE_DMA32 config option and use that for x86_64
that alone needs this zone.
- Remove the use of CONFIG_DMA_IS_DMA32 and CONFIG_DMA_IS_NORMAL
for ia64 and fix up the way per node ZVCs are calculated.
- Fall back to prior GFP_ZONEMASK of 0x03 if there is no
DMA32 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>
Assume that a cpu is *physically* offlined at boot time...
Because smpboot.c::smp_boot_cpu_map() canoot find cpu's sapicid,
numa.c::build_cpu_to_node_map() cannot build cpu<->node map for
offlined cpu.
For such cpus, cpu_to_node map should be fixed at cpu-hot-add.
This mapping should be done before cpu onlining.
This patch also handles cpu hotremove case.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Problem description:
We have additional_cpus= option for allocating possible_cpus. But nid
for possible cpus are not fixed at boot time. cpus which is offlined at
boot or cpus which is not on SRAT is not tied to its node. This will
cause panic at cpu onlining.
Usually, pxm_to_nid() mapping is fixed at boot time by SRAT.
But, unfortunately, some system (my system!) do not include
full SRAT table for possible cpus. (Then, I use
additiona_cpus= option.)
For such possible cpus, pxm<->nid should be fixed at
hot-add. We now have acpi_map_pxm_to_node() which is also
used at boot. It's suitable here.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Take default arch/*/kernel/audit.c to lib/, have those with special
needs (== biarch) define AUDIT_ARCH in their Kconfig.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
The sn_cpu_init() is required for cpu initialization on SN platforms.
Change __init to __cpuinit so that the function is not freed with init code/data.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
The SN PROM uses the register stack in the slave loop. The contents
must be preserved for the OS to return to the slave loop via offlining
a cpu or for kexec. A 'flushrs" is needed to force the stack to be written
to memory prior to changing bspstore.
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
The syscalls set/get_robust_list must not be wired up until
futex_atomic_cmpxchg_inatomic is implemented. Otherwise the kernel will
hang in handle_futex_death.
Signed-off-by: Andreas Schwab <schwab@suse.de>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix a bug in sys_perfmonctl() whereby it was not correctly
decrementing the file descriptor reference count.
Signed-off-by: stephane eranian <eranian@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This prevents cross-region mappings on IA64 and SPARC which could lead
to system crash. They were correctly trapped for normal mmap() calls,
but not for the kernel internal calls generated by executable loading.
This code just moves the architecture-specific cross-region checks into
an arch-specific "arch_mmap_check()" macro, and defines that for the
architectures that needed it (ia64, sparc and sparc64).
Architectures that don't have any special requirements can just ignore
the new cross-region check, since the mmap() code will just notice on
its own when the macro isn't defined.
Signed-off-by: Pavel Emelianov <xemul@openvz.org>
Signed-off-by: Kirill Korotaev <dev@openvz.org>
Acked-by: David Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
[ Cleaned up to not affect architectures that don't need it ]
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6:
[IA64] Increase default nodes shift to 10, nr_cpus to 1024
[IA64] remove redundant local_irq_save() calls from sn_sal.h
[IA64] panic if topology_init kzalloc fails
[IA64-SGI] Silent data corruption caused by XPC V2.
Change both the NODES_SHIFT and the NR_CPUS so that even big machines
can boot all nodes and processors with a generic kernel.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
There really is no sense trying to continue if the kzalloc of sysfs_cpus[]
fails in ia64 topology_init. The code calling into here doesn't check
errors very well, and one ends up with a nonobvious boot failure that
wastes peoples time debugging.
See for example the lkml thread at:
http://lkml.org/lkml/2006/3/2/215
Since the system is totally dead when this kzalloc fails, not having yet
even booted, might as well announce one's death boldly and plainly.
Signed-off-by: Paul Jackson <pj@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Tony Luck <tony.luck@intel.com>
ACPI 3.0 appended a variable length UID string to the LAPIC structure
as part of support for > 256 processors. So the BAD_MADT_ENTRY() sanity
check can no longer compare for equality with a fixed structure length.
Signed-off-by: Alexey Y Starikovskiy <alexey.y.starikovskiy@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>
Previously the message was "Fatal exception: panic_on_oops", as introduced
in a recent patch whith removed a somewhat dangerous call to ssleep() in
the panic_on_oops path. However, Paul Mackerras suggested that this was
somewhat confusing, leadind people to believe that it was panic_on_oops
that was the root cause of the fatal exception. On his suggestion, this
patch changes the message to simply "Fatal exception". A suitable oops
message should already have been displayed.
Signed-off-by: Simon Horman <horms@verge.net.au>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Jack Steiner identified a problem where XPC can cause a silent
data corruption. On module load, the placement may cause the
xpc_remote_copy_buffer to span two physical pages. DMA transfers are
done to the start virtual address translated to physical.
This patch changes the buffer from a statically allocated buffer to a
kmalloc'd buffer. Dean Nelson reviewed this before posting. I have
tested it in the configuration that was showing the memory corruption
and verified it works. I also added a BUG_ON statement to help catch
this if a similar situation is encountered.
Signed-off-by: Robin Holt <holt@sgi.com>
Signed-off-by: Dean Nelson <dcn@sgi.com>
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Conflicts:
arch/ia64/hp/sim/simscsi.c
Stylistic differences in two separate fixes for buffer->request_buffer
problem.
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
The uncached allocator has a function, uncached_get_new_chunk(), that needs
to be serialized on a per node basis. It also has a global variable,
allocated_granules, which should be defined on a per node basis and protected
by that serialization. Additionally, all error returns from functions called
(like ia64_pal_mc_drain()) should be handled appropriately.
Signed-off-by: Dean Nelson <dcn@sgi.com>
Acked-by: Jes Sorenson <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
contig.c (FLATMEM) requires the same optimization as in discontig.c for show_mem
when VIRTUAL_MEM_MAP is in use. Otherwise FLATMEM has softlockup timeouts.
This was boot tested for memory configuration: SPARSEMEM,
DISCONTIG+VIRTUAL_MEM_MAP, FLATMEM, FLATMEM+VIRTUAL_MEM_MAP and
FLATMEM+VIRTUAL_MEM_MAP with largest memory gap less than LARGE_GAP by
using boot parameter "mem=".
This was boot tested and "echo m >/proc/sysrq-trigger" output evaluated for
: FLATMEM, FLATMEM+VIRTUAL_MEM_MAP, DISCONTIGMEM+VIRTUAL_MEM_MAP and
SPARSEMEM.
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Assure that vmem_map's high endpoint is MAX_ORDER aligned. Not doing so violates
the buddy allocator algorithm. Also anyone using mem=XXX on boot line and
not aligned to MAX_ORDER requires this patch in order to satisfy buddy
allocator. vmem_map always starts at pfn 0. The potentially large MAX_ORDER
on ia64 (due to hugetlbfs) requires that the end of vmem_map be aligned
to MAX_ORDER_NR_PAGES.
This was boot tested for: FLATMEM, FLATMEM+VIRTUAL_MEM_MAP,
DISCONTIGMEM+VIRTUAL_MEM_MAP and SPARSEMEM.
Signed-off-by: Bob Picco <bob.picco@hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
CONFIG_MD_RAID5 became CONFIG_MD_RAID456 in drivers/md/Kconfig. Make
the same change in arch/ia64
Signed-off-by: Prarit Bhargava <prarit@redhat.com>
Signed-off-by: Aron Griffis <aron@hp.com>
Acked-by: Jes Sorenson <jes@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
I think ia64_switch_mode_phys and ia64_switch_mode_virt
does not need to alloc an empty frame.
An empty frame is required by loadrs but flushrs
does not need that.
Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
We found an issue in pal.S.
According to the software runtime SPEC,
The caller's output registers do not need to be preserved for
caller. The callee may reuse input registers for any other
purpose within the procedure.
in ia64_pal_call_phys_stacked,
input registers are copied to output registers before call
into ia64_switch_mode_phys, then used to call into PAL. This
assumes output registers are preserved in ia64_switch_mode_phys,
which may not be true.
In this particular case, ia64_switch_mode_phys alloc a null frame
, and mask off psr.i.
If an interrupt comes at this small window,
or an MCA comes inside the procedure, output registers
maybe changed,
then the pal call may got some staled input registers.
This patch moves the copies from input to output
after ia64_switch_mode_phys to follow the software
runtime convention.
It also removed some unused labels in
ia64_pal_call_phys_stacked.
Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Fix some sparse warnings on ia64. Large constants that should be long
instead of int. Use NULL instead of 0. Add some missing __iomem
casts. Replace a non-C99 structure assignment.
Signed-off-by: Keith Owens <kaos@sgi.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
The latest toolchains can produce a new ELF section in DSOs and
dynamically-linked executables. The new section ".gnu.hash" replaces
".hash", and allows for more efficient runtime symbol lookups by the
dynamic linker. The new ld option --hash-style={sysv|gnu|both} controls
whether to produce the old ".hash", the new ".gnu.hash", or both. In some
new systems such as Fedora Core 6, gcc by default passes --hash-style=gnu
to the linker, so that a standard invocation of "gcc -shared" results in
producing a DSO with only ".gnu.hash". The new ".gnu.hash" sections need
to be dealt with the same way as ".hash" sections in all respects; only the
dynamic linker cares about their contents. To work with older dynamic
linkers (i.e. preexisting releases of glibc), a binary must have the old
".hash" section. The --hash-style=both option produces binaries that a new
dynamic linker can use more efficiently, but an old dynamic linker can
still handle.
The new section runs afoul of the custom linker scripts used to build vDSO
images for the kernel. On ia64, the failure mode for this is a boot-time
panic because the vDSO's PT_IA_64_UNWIND segment winds up ill-formed.
This patch addresses the problem in two ways.
First, it mentions ".gnu.hash" in all the linker scripts alongside ".hash".
This produces correct vDSO images with --hash-style=sysv (or old tools),
with --hash-style=gnu, or with --hash-style=both.
Second, it passes the --hash-style=sysv option when building the vDSO
images, so that ".gnu.hash" is not actually produced. This is the most
conservative choice for compatibility with any old userland. There is some
concern that some ancient glibc builds (though not any known old production
system) might choke on --hash-style=both binaries. The optimizations
provided by the new style of hash section do not really matter for a DSO
with a tiny number of symbols, as the vDSO has. If someone wants to use
=gnu or =both for their vDSO builds and worry less about that
compatibility, just change the option and the linker script changes will
make any choice work fine.
Signed-off-by: Roland McGrath <roland@redhat.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
The SGI IOC4 IDE device always shares an interrupt with other devices which
are part of IOC4. As such, IDEPCI_SHARE_IRQ should always be enabled when
BLK_DEV_SGIIOC4 is enabled.
Signed-off-by: Brent Casavant <bcasavan@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use hotplug version of register_cpu_notifier in late init functions.
Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Andi Kleen <ak@muc.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This patch is part of an effort to unify the panic_on_oops behaviour across
all architectures that implement it.
It was pointed out to me by Andi Kleen that if an oops has occured in
interrupt context, then calling sleep() in the oops path will only cause a
panic, and that it would be really better for it not to be in the path at
all.
This patch removes the ssleep() call and reworks the console message
accordinly. I have a slght concern that the resulting console message is
too long, feedback welcome.
For powerpc it also unifies the 32bit and 64bit behaviour.
Fror x86_64, this patch only updates the console message, as ssleep() is
already not present.
Signed-off-by: Horms <horms@verge.net.au>
Acked-by: Paul Mackerras <paulus@samba.org>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Andi Kleen <ak@muc.de>
Cc: Chris Zankel <chris@zankel.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Kprobe inserts breakpoint instruction in probepoint and then jumps to
instruction slot when breakpoint is hit, the instruction slot icache must
be consistent with dcache. Here is the patch which invalidates instruction
slot icache area.
Without this patch, in some machines there will be fault when executing
instruction slot where icache content is inconsistent with dcache.
Signed-off-by: bibo,mao <bibo.mao@intel.com>
Acked-by: "Luck, Tony" <tony.luck@intel.com>
Acked-by: Keshavamurthy Anil S <anil.s.keshavamurthy@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
arch/ia64/hp/sim/simscsi.c: In function `simscsi_sg_readwrite':
arch/ia64/hp/sim/simscsi.c:154: error: structure has no member named `buffer'
arch/ia64/hp/sim/simscsi.c: In function `simscsi_fillresult':
arch/ia64/hp/sim/simscsi.c:247: error: structure has no member named `buffer'
hch said:
>Just change it to access the request_buffer member instead. buffer
>and request_buffer have been synonymous 99% of the time, and a driver
>never even wants to access buffer.
Signed-off-by: Tony Luck <tony.luck@intel.com>
/proc/pal/*/version_info is a bit confusing. HP firmware, at least,
reports 07.31 instead of 0.7.31. Also, the comment is out of place;
it's an internal detail about the implementation of ia64_pal_version.
Since the 2.2 revision of the SDM still states that PAL_VERSION can
be called in virtual mode, correct the comment to be more accurate.
Signed-off-by: Matthew Wilcox <matthew@wil.cx>
Signed-off-by: Tony Luck <tony.luck@intel.com>
On Thu, Jul 27, 2006 at 01:03:24AM -0700, Andrew Morton wrote:
> arch/ia64/hp/sim/simscsi.c: In function `simscsi_sg_readwrite':
> arch/ia64/hp/sim/simscsi.c:154: error: structure has no member named `buffer'
> arch/ia64/hp/sim/simscsi.c: In function `simscsi_fillresult':
> arch/ia64/hp/sim/simscsi.c:247: error: structure has no member named `buffer'
> arch/ia64/hp/sim/simscsi.c: At top level:
> arch/ia64/hp/sim/simscsi.c:87: warning: 'simscsi_setup' defined but not used
Signed-off-by: James Bottomley <James.Bottomley@SteelEye.com>
Newer ARMs have a 40 bit physical address space, but mapping physical
memory above 4G needs a special page table format which we (currently?) do
not use for userspace mappings, so what happens instead is that mapping an
address >= 4G will happily discard the upper bits and wrap.
There is a valid_mmap_phys_addr_range() arch hook where we could check for
>= 4G addresses and deny the mapping, but this hook takes an unsigned long
address:
static inline int valid_mmap_phys_addr_range(unsigned long addr, size_t size);
And drivers/char/mem.c:mmap_mem() calls it like this:
static int mmap_mem(struct file * file, struct vm_area_struct * vma)
{
size_t size = vma->vm_end - vma->vm_start;
if (!valid_mmap_phys_addr_range(vma->vm_pgoff << PAGE_SHIFT, size))
So that's not much help either.
This patch makes the hook take a pfn instead of a phys address.
Signed-off-by: Lennert Buytenhek <buytenh@wantstofly.org>
Cc: Bjorn Helgaas <bjorn.helgaas@hp.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
screen_info.h doesn't have anything to do with the tty layer and shouldn't be
included by tty.h. This patches removes the include and modifies all users to
directly include screen_info.h. struct screen_info is mainly used to
communicate with the console drivers in drivers/video/console. Note that this
patch touches every arch and I have no way of testing it. If there is a
mistake the worst thing that will happen is a compile error.
[akpm@osdl.org: fix arm build]
[akpm@osdl.org: fix alpha build]
Signed-off-by: Jon Smirl <jonsmir@gmail.com>
Signed-off-by: Antonino Daplas <adaplas@pol.net>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
I found a bug in memory hot-add code for ia64.
IA64's code has copies of pgdat's array on each node to reduce memory
access over crossing node. This array is used by NODE_DATA() macro. When
new node is hot-added, this pgdat's array should be updated and copied on
new node too.
However, I used for_each_online_node() in scatter_node_data() to copy
it. This meant its array is not copied on new node.
Because initialization of structures for new node was halfway,
so online_node_map couldn't be set at this time.
To copy arrays on new node, I changed it to check value of pgdat_list[]
which is source array of copies. I tested this patch with my Memory Hotadd
emulation on Tiger4. This patch is for 2.6.17-git20.
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
cleanup: remove task_t and convert all the uses to struct task_struct. I
introduced it for the scheduler anno and it was a mistake.
Conversion was mostly scripted, the result was reviewed and all
secondary whitespace and style impact (if any) was fixed up by hand.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Use the new IRQF_ constants and remove the SA_INTERRUPT define
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Allow to tie upper bits of syscall bitmap in audit rules to kernel-defined
sets of syscalls. Infrastructure, a couple of classes (with 32bit counterparts
for biarch targets) and actual tie-in on i386, amd64 and ia64.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Per zone counter infrastructure
The counters that we currently have for the VM are split per processor. The
processor however has not much to do with the zone these pages belong to. We
cannot tell f.e. how many ZONE_DMA pages are dirty.
So we are blind to potentially inbalances in the usage of memory in various
zones. F.e. in a NUMA system we cannot tell how many pages are dirty on a
particular node. If we knew then we could put measures into the VM to balance
the use of memory between different zones and different nodes in a NUMA
system. For example it would be possible to limit the dirty pages per node so
that fast local memory is kept available even if a process is dirtying huge
amounts of pages.
Another example is zone reclaim. We do not know how many unmapped pages exist
per zone. So we just have to try to reclaim. If it is not working then we
pause and try again later. It would be better if we knew when it makes sense
to reclaim unmapped pages from a zone. This patchset allows the determination
of the number of unmapped pages per zone. We can remove the zone reclaim
interval with the counters introduced here.
Futhermore the ability to have various usage statistics available will allow
the development of new NUMA balancing algorithms that may be able to improve
the decision making in the scheduler of when to move a process to another node
and hopefully will also enable automatic page migration through a user space
program that can analyse the memory load distribution and then rebalance
memory use in order to increase performance.
The counter framework here implements differential counters for each processor
in struct zone. The differential counters are consolidated when a threshold
is exceeded (like done in the current implementation for nr_pageache), when
slab reaping occurs or when a consolidation function is called.
Consolidation uses atomic operations and accumulates counters per zone in the
zone structure and also globally in the vm_stat array. VM functions can
access the counts by simply indexing a global or zone specific array.
The arrangement of counters in an array also simplifies processing when output
has to be generated for /proc/*.
Counters can be updated by calling inc/dec_zone_page_state or
_inc/dec_zone_page_state analogous to *_page_state. The second group of
functions can be called if it is known that interrupts are disabled.
Special optimized increment and decrement functions are provided. These can
avoid certain checks and use increment or decrement instructions that an
architecture may provide.
We also add a new CONFIG_DMA_IS_NORMAL that signifies that an architecture can
do DMA to all memory and therefore ZONE_NORMAL will not be populated. This is
only currently set for IA64 SGI SN2 and currently only affects
node_page_state(). In the best case node_page_state can be reduced to
retrieving a single counter for the one zone on the node.
[akpm@osdl.org: cleanups]
[akpm@osdl.org: export vm_stat[] for filesystems]
Signed-off-by: Christoph Lameter <clameter@sgi.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>
