There are few functions here and there along with type definitions that
provide UUID API. This series consolidates everything under one hood
and converts current users.
This has been tested for a while internally, however it doesn't mean we
covered all possible cases (especially accuracy of UUID constants after
conversion). So, please test this as much as you can and provide your
tag. We appreciate the effort.
The ACPI conversion is postponed for now to sort more generic things out
first.
This patch (of 9):
Since we have hex_byte_pack_upper() we may use it directly and avoid
second loop.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Matt Fleming <matt@codeblueprint.co.uk>
Cc: Dmitry Kasatkin <dmitry.kasatkin@gmail.com>
Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It looks like the email address for this mailing list doesn't exist anymore:
<spear-devel@list.st.com>: host mxb-00178001.gslb.pphosted.com[91.207.212.93] said:
550 5.1.1 User Unknown (in reply to RCPT TO command)
Signed-off-by: Eric Engestrom <eric.engestrom@imgtec.com>
Acked-by: Viresh Kumar <viresh.kumar@linaro.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kalle Valo <kvalo@codeaurora.org>
Cc: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: Jiri Slaby <jslaby@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In NMI context, printk() messages are stored into per-CPU buffers to
avoid a possible deadlock. They are normally flushed to the main ring
buffer via an IRQ work. But the work is never called when the system
calls panic() in the very same NMI handler.
This patch tries to flush NMI buffers before the crash dump is
generated. In this case it does not risk a double release and bails out
when the logbuf_lock is already taken. The aim is to get the messages
into the main ring buffer when possible. It makes them better
accessible in the vmcore.
Then the patch tries to flush the buffers second time when other CPUs
are down. It might be more aggressive and reset logbuf_lock. The aim
is to get the messages available for the consequent kmsg_dump() and
console_flush_on_panic() calls.
The patch causes vprintk_emit() to be called even in NMI context again.
But it is done via printk_deferred() so that the console handling is
skipped. Consoles use internal locks and we could not prevent a
deadlock easily. They are explicitly called later when the crash dump
is not generated, see console_flush_on_panic().
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: David Miller <davem@davemloft.net>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Testing has shown that the backtrace sometimes does not fit into the 4kB
temporary buffer that is used in NMI context. The warnings are gone
when I double the temporary buffer size.
This patch doubles the buffer size and makes it configurable.
Note that this problem existed even in the x86-specific implementation
that was added by the commit a9edc88093 ("x86/nmi: Perform a safe NMI
stack trace on all CPUs"). Nobody noticed it because it did not print
any warnings.
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We could not resize the temporary buffer in NMI context. Let's warn if
a message is lost.
This is rather theoretical. printk() should not be used in NMI. The
only sensible use is when we want to print backtrace from all CPUs. The
current buffer should be enough for this purpose.
[akpm@linux-foundation.org: whitespace fixlet]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
printk() takes some locks and could not be used a safe way in NMI
context.
The chance of a deadlock is real especially when printing stacks from
all CPUs. This particular problem has been addressed on x86 by the
commit a9edc88093 ("x86/nmi: Perform a safe NMI stack trace on all
CPUs").
The patchset brings two big advantages. First, it makes the NMI
backtraces safe on all architectures for free. Second, it makes all NMI
messages almost safe on all architectures (the temporary buffer is
limited. We still should keep the number of messages in NMI context at
minimum).
Note that there already are several messages printed in NMI context:
WARN_ON(in_nmi()), BUG_ON(in_nmi()), anything being printed out from MCE
handlers. These are not easy to avoid.
This patch reuses most of the code and makes it generic. It is useful
for all messages and architectures that support NMI.
The alternative printk_func is set when entering and is reseted when
leaving NMI context. It queues IRQ work to copy the messages into the
main ring buffer in a safe context.
__printk_nmi_flush() copies all available messages and reset the buffer.
Then we could use a simple cmpxchg operations to get synchronized with
writers. There is also used a spinlock to get synchronized with other
flushers.
We do not longer use seq_buf because it depends on external lock. It
would be hard to make all supported operations safe for a lockless use.
It would be confusing and error prone to make only some operations safe.
The code is put into separate printk/nmi.c as suggested by Steven
Rostedt. It needs a per-CPU buffer and is compiled only on
architectures that call nmi_enter(). This is achieved by the new
HAVE_NMI Kconfig flag.
The are MN10300 and Xtensa architectures. We need to clean up NMI
handling there first. Let's do it separately.
The patch is heavily based on the draft from Peter Zijlstra, see
https://lkml.org/lkml/2015/6/10/327
[arnd@arndb.de: printk-nmi: use %zu format string for size_t]
[akpm@linux-foundation.org: min_t->min - all types are size_t here]
Signed-off-by: Petr Mladek <pmladek@suse.com>
Suggested-by: Peter Zijlstra <peterz@infradead.org>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Jan Kara <jack@suse.cz>
Acked-by: Russell King <rmk+kernel@arm.linux.org.uk> [arm part]
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Cc: Jiri Kosina <jkosina@suse.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: David Miller <davem@davemloft.net>
Cc: Daniel Thompson <daniel.thompson@linaro.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
In include/linux/syscalls.h, the four functions sys_kill, sys_tgkill,
sys_tkill and sys_rt_sigqueueinfo are declared with "int pid" and "int
tgid".
However, in kernel/signal.c, the corresponding definitions use the more
appropriate "pid_t" (which is a typedef'd int).
This patch changes "int" to "pid_t" in the declarations of sys_kill,
sys_tgkill, sys_tkill and sys_rt_sigqueueinfo in <linux/syscalls.h> in
order to harmonize the function declarations with their respective
definitions.
Link: http://lkml.kernel.org/r/57302FDA.7020205@renenyffenegger.ch
Signed-off-by: René Nyffenegger <mail@renenyffenegger.ch>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Josh Triplett <josh@joshtriplett.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: "Steven Rostedt (Red Hat)" <rostedt@goodmis.org>
Cc: Zach Brown <zab@redhat.com>
Cc: Milosz Tanski <milosz@adfin.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
We need to call exit_thread from copy_process in a fail path. So make it
accept task_struct as a parameter.
[v2]
* s390: exit_thread_runtime_instr doesn't make sense to be called for
non-current tasks.
* arm: fix the comment in vfp_thread_copy
* change 'me' to 'tsk' for task_struct
* now we can change only archs that actually have exit_thread
[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Define HAVE_EXIT_THREAD for archs which want to do something in
exit_thread. For others, let's define exit_thread as an empty inline.
This is a cleanup before we change the prototype of exit_thread to
accept a task parameter.
[akpm@linux-foundation.org: fix mips]
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Chen Liqin <liqin.linux@gmail.com>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Chris Zankel <chris@zankel.net>
Cc: David Howells <dhowells@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Guan Xuetao <gxt@mprc.pku.edu.cn>
Cc: Haavard Skinnemoen <hskinnemoen@gmail.com>
Cc: Hans-Christian Egtvedt <egtvedt@samfundet.no>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: James Hogan <james.hogan@imgtec.com>
Cc: Jeff Dike <jdike@addtoit.com>
Cc: Jesper Nilsson <jesper.nilsson@axis.com>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: Jonas Bonn <jonas@southpole.se>
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
Cc: Lennox Wu <lennox.wu@gmail.com>
Cc: Ley Foon Tan <lftan@altera.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Mikael Starvik <starvik@axis.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Rich Felker <dalias@libc.org>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Richard Kuo <rkuo@codeaurora.org>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russell King <linux@arm.linux.org.uk>
Cc: Steven Miao <realmz6@gmail.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Will Deacon <will.deacon@arm.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The PR_DUMPABLE flag causes the pid related paths of the proc file
system to be owned by ROOT.
The implementation of pthread_set/getname_np however needs access to
/proc/<pid>/task/<tid>/comm. If PR_DUMPABLE is false this
implementation is locked out.
This patch installs a special permission function for the file "comm"
that grants read and write access to all threads of the same group
regardless of the ownership of the inode. For all other threads the
function falls back to the generic inode permission check.
[akpm@linux-foundation.org: fix spello in comment]
Signed-off-by: Janis Danisevskis <jdanis@google.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Cyrill Gorcunov <gorcunov@openvz.org>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Minfei Huang <mnfhuang@gmail.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Calvin Owens <calvinowens@fb.com>
Cc: Jann Horn <jann@thejh.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
It's not possible to read the process umask without also modifying it,
which is what umask(2) does. A library cannot read umask safely,
especially if the main program might be multithreaded.
Add a new status line ("Umask") in /proc/<PID>/status. It contains the
file mode creation mask (umask) in octal. It is only shown for tasks
which have task->fs.
This patch is adapted from one originally written by Pierre Carrier.
The use case is that we have endless trouble with people setting weird
umask() values (usually on the grounds of "security"), and then
everything breaking. I'm on the hook to fix these. We'd like to add
debugging to our program so we can dump out the umask in debug reports.
Previous versions of the patch used a syscall so you could only read
your own umask. That's all I need. However there was quite a lot of
push-back from those, so this new version exports it in /proc.
See:
https://lkml.org/lkml/2016/4/13/704 [umask2]
https://lkml.org/lkml/2016/4/13/487 [getumask]
Signed-off-by: Richard W.M. Jones <rjones@redhat.com>
Acked-by: Konstantin Khlebnikov <koct9i@gmail.com>
Acked-by: Jerome Marchand <jmarchan@redhat.com>
Acked-by: Kees Cook <keescook@chromium.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Pierre Carrier <pierre@spotify.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
debug_stat sysfs is read-only and represents various debugging data that
zram developers may need. This file is not meant to be used by anyone
else: its content is not documented and will change any time w/o any
notice. Therefore, the output of debug_stat file contains a version
string. To avoid any confusion, we will increase the version number
every time we modify the output.
At the moment this file exports only one value -- the number of
re-compressions, IOW, the number of times compression fast path has
failed. This stat is temporary any will be useful in case if any
per-cpu compression streams regressions will be reported.
Link: http://lkml.kernel.org/r/20160513230834.GB26763@bbox
Link: http://lkml.kernel.org/r/20160511134553.12655-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Remove the internal part of max_comp_streams interface, since we
switched to per-cpu streams. We will keep RW max_comp_streams attr
around, because:
a) we may (silently) switch back to idle compression streams list and
don't want to disturb user space
b) max_comp_streams attr must wait for the next 'lay off cycle'; we
give user space 2 years to adjust before we remove/downgrade the attr,
and there are already several attrs scheduled for removal in 4.11, so
it's too late for max_comp_streams.
This slightly change a user visible behaviour:
- First, reading from max_comp_stream file now will always return the
number of online CPUs.
- Second, writing to max_comp_stream will not take any effect.
Link: http://lkml.kernel.org/r/20160503165546.25201-1-sergey.senozhatsky@gmail.com
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change the return type of zs_pool_stat_create() to void, and remove the
logic to abort pool creation if the stat debugfs dir/file could not be
created.
The debugfs stat file is for debugging/information only, and doesn't
affect operation of zsmalloc; there is no reason to abort creating the
pool if the stat file can't be created. This was seen with zswap, which
used the same name for all pool creations, which caused zsmalloc to fail
to create a second pool for zswap if CONFIG_ZSMALLOC_STAT was enabled.
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Dan Streetman <dan.streetman@canonical.com>
Cc: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a work_struct to struct zswap_pool, and change __zswap_pool_empty to
use the workqueue instead of using call_rcu().
When zswap destroys a pool no longer in use, it uses call_rcu() to
perform the destruction/freeing. Since that executes in softirq
context, it must not sleep. However, actually destroying the pool
involves freeing the per-cpu compressors (which requires locking the
cpu_add_remove_lock mutex) and freeing the zpool, for which the
implementation may sleep (e.g. zsmalloc calls kmem_cache_destroy, which
locks the slab_mutex). So if either mutex is currently taken, or any
other part of the compressor or zpool implementation sleeps, it will
result in a BUG().
It's not easy to reproduce this when changing zswap's params normally.
In testing with a loaded system, this does not fail:
$ cd /sys/module/zswap/parameters
$ echo lz4 > compressor ; echo zsmalloc > zpool
nor does this:
$ while true ; do
> echo lzo > compressor ; echo zbud > zpool
> sleep 1
> echo lz4 > compressor ; echo zsmalloc > zpool
> sleep 1
> done
although it's still possible either of those might fail, depending on
whether anything else besides zswap has locked the mutexes.
However, changing a parameter with no delay immediately causes the
schedule while atomic BUG:
$ while true ; do
> echo lzo > compressor ; echo lz4 > compressor
> done
This is essentially the same as Yu Zhao's proposed patch to zsmalloc,
but moved to zswap, to cover compressor and zpool freeing.
Fixes: f1c54846ee ("zswap: dynamic pool creation")
Signed-off-by: Dan Streetman <ddstreet@ieee.org>
Reported-by: Yu Zhao <yuzhao@google.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dan Streetman <dan.streetman@canonical.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Pass GFP flags to zs_malloc() instead of using a fixed mask supplied to
zs_create_pool(), so we can be more flexible, but, more importantly, we
need this to switch zram to per-cpu compression streams -- zram will try
to allocate handle with preemption disabled in a fast path and switch to
a slow path (using different gfp mask) if the fast one has failed.
Apart from that, this also align zs_malloc() interface with zspool/zbud.
[sergey.senozhatsky@gmail.com: pass GFP flags to zs_malloc() instead of using a fixed mask]
Link: http://lkml.kernel.org/r/20160429150942.GA637@swordfish
Link: http://lkml.kernel.org/r/20160429150942.GA637@swordfish
Signed-off-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Clean up function parameter ordering to order higher data structure
first.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are many BUG_ON in zsmalloc.c which is not recommened so change
them as alternatives.
Normal rule is as follows:
1. avoid BUG_ON if possible. Instead, use VM_BUG_ON or VM_BUG_ON_PAGE
2. use VM_BUG_ON_PAGE if we need to see struct page's fields
3. use those assertion in primitive functions so higher functions can
rely on the assertion in the primitive function.
4. Don't use assertion if following instruction can trigger Oops
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Clean up function parameter "struct page". Many functions of zsmalloc
expect that page paramter is "first_page" so use "first_page" rather
than "page" for code readability.
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Exchange between user and kernel memory is coded in assembly language.
Which means that such accesses won't be spotted by KASAN as a compiler
instruments only C code.
Add explicit KASAN checks to user memory access API to ensure that
userspace writes to (or reads from) a valid kernel memory.
Note: Unlike others strncpy_from_user() is written mostly in C and KASAN
sees memory accesses in it. However, it makes sense to add explicit
check for all @count bytes that *potentially* could be written to the
kernel.
[aryabinin@virtuozzo.com: move kasan check under the condition]
Link: http://lkml.kernel.org/r/1462869209-21096-1-git-send-email-aryabinin@virtuozzo.com
Link: http://lkml.kernel.org/r/1462538722-1574-4-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Memory access coded in an assembly won't be seen by KASAN as a compiler
can instrument only C code. Add kasan_check_[read,write]() API which is
going to be used to check a certain memory range.
Link: http://lkml.kernel.org/r/1462538722-1574-3-git-send-email-aryabinin@virtuozzo.com
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Acked-by: Alexander Potapenko <glider@google.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a test that makes sure ksize() unpoisons the whole chunk.
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Instead of calling kasan_krealloc(), which replaces the memory
allocation stack ID (if stack depot is used), just unpoison the whole
memory chunk.
Signed-off-by: Alexander Potapenko <glider@google.com>
Acked-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Konstantin Serebryany <kcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Quarantine isolates freed objects in a separate queue. The objects are
returned to the allocator later, which helps to detect use-after-free
errors.
When the object is freed, its state changes from KASAN_STATE_ALLOC to
KASAN_STATE_QUARANTINE. The object is poisoned and put into quarantine
instead of being returned to the allocator, therefore every subsequent
access to that object triggers a KASAN error, and the error handler is
able to say where the object has been allocated and deallocated.
When it's time for the object to leave quarantine, its state becomes
KASAN_STATE_FREE and it's returned to the allocator. From now on the
allocator may reuse it for another allocation. Before that happens,
it's still possible to detect a use-after free on that object (it
retains the allocation/deallocation stacks).
When the allocator reuses this object, the shadow is unpoisoned and old
allocation/deallocation stacks are wiped. Therefore a use of this
object, even an incorrect one, won't trigger ASan warning.
Without the quarantine, it's not guaranteed that the objects aren't
reused immediately, that's why the probability of catching a
use-after-free is lower than with quarantine in place.
Quarantine isolates freed objects in a separate queue. The objects are
returned to the allocator later, which helps to detect use-after-free
errors.
Freed objects are first added to per-cpu quarantine queues. When a
cache is destroyed or memory shrinking is requested, the objects are
moved into the global quarantine queue. Whenever a kmalloc call allows
memory reclaiming, the oldest objects are popped out of the global queue
until the total size of objects in quarantine is less than 3/4 of the
maximum quarantine size (which is a fraction of installed physical
memory).
As long as an object remains in the quarantine, KASAN is able to report
accesses to it, so the chance of reporting a use-after-free is
increased. Once the object leaves quarantine, the allocator may reuse
it, in which case the object is unpoisoned and KASAN can't detect
incorrect accesses to it.
Right now quarantine support is only enabled in SLAB allocator.
Unification of KASAN features in SLAB and SLUB will be done later.
This patch is based on the "mm: kasan: quarantine" patch originally
prepared by Dmitry Chernenkov. A number of improvements have been
suggested by Andrey Ryabinin.
[glider@google.com: v9]
Link: http://lkml.kernel.org/r/1462987130-144092-1-git-send-email-glider@google.com
Signed-off-by: Alexander Potapenko <glider@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrey Konovalov <adech.fo@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Konstantin Serebryany <kcc@google.com>
Cc: Dmitry Chernenkov <dmitryc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If page migration fails due to -ENOMEM, nr_failed should still be
incremented for proper statistics.
This was encountered recently when all page migration vmstats showed 0,
and inferred that migrate_pages() was never called, although in reality
the first page migration failed because compaction_alloc() failed to
find a migration target.
This patch increments nr_failed so the vmstat is properly accounted on
ENOMEM.
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1605191510230.32658@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
While testing the kcompactd in my platform 3G MEM only DMA ZONE. I
found the kcompactd never wakeup. It seems the zoneindex has already
minus 1 before. So the traverse here should be <=.
It fixes a regression where kswapd could previously compact, but
kcompactd not. Not a crash fix though.
[akpm@linux-foundation.org: fix kcompactd_do_work() as well, per Hugh]
Link: http://lkml.kernel.org/r/1463659121-84124-1-git-send-email-puck.chen@hisilicon.com
Fixes: accf62422b ("mm, kswapd: replace kswapd compaction with waking up kcompactd")
Signed-off-by: Chen Feng <puck.chen@hisilicon.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Cc: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Zhuangluan Su <suzhuangluan@hisilicon.com>
Cc: Yiping Xu <xuyiping@hisilicon.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If a large value is written to scan_sleep_millisecs, for example, that
period must lapse before khugepaged will wake up for periodic
collapsing.
If this value is tuned to 1 day, for example, and then re-tuned to its
default 10s, khugepaged will still wait for a day before scanning again.
This patch causes khugepaged to wakeup immediately when the value is
changed and then sleep until that value is rewritten or the new value
lapses.
Link: http://lkml.kernel.org/r/alpine.DEB.2.10.1605181453200.4786@chino.kir.corp.google.com
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When nfsd is exporting a filesystem over NFS which is then NFS-mounted
on the local machine there is a risk of deadlock. This happens when
there are lots of dirty pages in the NFS filesystem and they cause NFSD
to be throttled, either in throttle_vm_writeout() or in
balance_dirty_pages().
To avoid this problem the PF_LESS_THROTTLE flag is set for NFSD threads
and it provides a 25% increase to the limits that affect NFSD. Any
process writing to an NFS filesystem will be throttled well before the
number of dirty NFS pages reaches the limit imposed on NFSD, so NFSD
will not deadlock on pages that it needs to write out. At least it
shouldn't.
All processes are allowed a small excess margin to avoid performing too
many calculations: ratelimit_pages.
ratelimit_pages is set so that if a thread on every CPU uses the entire
margin, the total will only go 3% over the limit, and this is much less
than the 25% bonus that PF_LESS_THROTTLE provides, so this margin
shouldn't be a problem. But it is.
The "total memory" that these 3% and 25% are calculated against are not
really total memory but are "global_dirtyable_memory()" which doesn't
include anonymous memory, just free memory and page-cache memory.
The "ratelimit_pages" number is based on whatever the
global_dirtyable_memory was on the last CPU hot-plug, which might not be
what you expect, but is probably close to the total freeable memory.
The throttle threshold uses the global_dirtable_memory at the moment
when the throttling happens, which could be much less than at the last
CPU hotplug. So if lots of anonymous memory has been allocated, thus
pushing out lots of page-cache pages, then NFSD might end up being
throttled due to dirty NFS pages because the "25%" bonus it gets is
calculated against a rather small amount of dirtyable memory, while the
"3%" margin that other processes are allowed to dirty without penalty is
calculated against a much larger number.
To remove this possibility of deadlock we need to make sure that the
margin granted to PF_LESS_THROTTLE exceeds that rate-limit margin.
Simply adding ratelimit_pages isn't enough as that should be multiplied
by the number of cpus.
So add "global_wb_domain.dirty_limit / 32" as that more accurately
reflects the current total over-shoot margin. This ensures that the
number of dirty NFS pages never gets so high that nfsd will be throttled
waiting for them to be written.
Link: http://lkml.kernel.org/r/87futgowwv.fsf@notabene.neil.brown.name
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently we check page->flags twice for "HWPoisoned" case of
check_new_page_bad(), which can cause a race with unpoisoning.
This race unnecessarily taints kernel with "BUG: Bad page state".
check_new_page_bad() is the only caller of bad_page() which is
interested in __PG_HWPOISON, so let's move the hwpoison related code in
bad_page() to it.
Link: http://lkml.kernel.org/r/20160518100949.GA17299@hori1.linux.bs1.fc.nec.co.jp
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Acked-by: Mel Gorman <mgorman@techsingularity.net>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When CONFIG_PAGE_POISONING and CONFIG_KASAN is enabled,
free_pages_prepare()'s codeflow is below.
1)kmemcheck_free_shadow()
2)kasan_free_pages()
- set shadow byte of page is freed
3)kernel_poison_pages()
3.1) check access to page is valid or not using kasan
---> error occur, kasan think it is invalid access
3.2) poison page
4)kernel_map_pages()
So kasan_free_pages() should be called after poisoning the page.
Link: http://lkml.kernel.org/r/1463220405-7455-1-git-send-email-iamyooon@gmail.com
Signed-off-by: seokhoon.yoon <iamyooon@gmail.com>
Cc: Andrey Ryabinin <a.ryabinin@samsung.com>
Cc: Laura Abbott <labbott@fedoraproject.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
fault_around aims to reduce minor faults of file-backed pages via
speculative ahead pte mapping and relying on readahead logic. However,
on non-HW access bit architecture the benefit is highly limited because
they should emulate the young bit with minor faults for reclaim's page
aging algorithm. IOW, we cannot reduce minor faults on those
architectures.
I did quick a test on my ARM machine.
512M file mmap sequential every word read on eSATA drive 4 times.
stddev is stable.
= fault_around 4096 =
elapsed time(usec): 6747645
= fault_around 65536 =
elapsed time(usec): 6709263
0.5% gain.
Even when I tested it with eMMC there is no gain because I guess with
slow storage the major fault is the dominant factor.
Also, fault_around has the side effect of shrinking slab more
aggressively and causes higher vmpressure, so if such speculation fails,
it can evict slab more which can result in page I/O (e.g., inode cache).
In the end, it would make void any benefit of fault_around.
So let's make the default "disabled" on those architectures.
Link: http://lkml.kernel.org/r/20160518014229.GB21538@bbox
Signed-off-by: Minchan Kim <minchan@kernel.org>
Cc: Kirill A. Shutemov <kirill@shutemov.name>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Currently, faultaround code produces young pte. This can screw up
vmscan behaviour[1], as it makes vmscan think that these pages are hot
and not push them out on first round.
During sparse file access faultaround gets more pages mapped and all of
them are young. Under memory pressure, this makes vmscan swap out anon
pages instead, or to drop other page cache pages which otherwise stay
resident.
Modify faultaround to produce old ptes, so they can easily be reclaimed
under memory pressure.
This can to some extend defeat the purpose of faultaround on machines
without hardware accessed bit as it will not help us with reducing the
number of minor page faults.
We may want to disable faultaround on such machines altogether, but
that's subject for separate patchset.
Minchan:
"I tested 512M mmap sequential word read test on non-HW access bit
system (i.e., ARM) and confirmed it doesn't increase minor fault any
more.
old: 4096 fault_around
minor fault: 131291
elapsed time: 6747645 usec
new: 65536 fault_around
minor fault: 131291
elapsed time: 6709263 usec
0.56% benefit"
[1] https://lkml.kernel.org/r/1460992636-711-1-git-send-email-vinmenon@codeaurora.org
Link: http://lkml.kernel.org/r/1463488366-47723-1-git-send-email-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Minchan Kim <minchan@kernel.org>
Tested-by: Minchan Kim <minchan@kernel.org>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vinayak Menon <vinmenon@codeaurora.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since commit 92923ca3aa ("mm: meminit: only set page reserved in the
memblock region") the reserved bit is set on reserved memblock regions.
However start and end address are passed as unsigned long. This is only
32bit on i386, so it can end up marking the wrong pages reserved for
ranges at 4GB and above.
This was observed on a 32bit Xen dom0 which was booted with initial
memory set to a value below 4G but allowing to balloon in memory
(dom0_mem=1024M for example). This would define a reserved bootmem
region for the additional memory (for example on a 8GB system there was
a reverved region covering the 4GB-8GB range). But since the addresses
were passed on as unsigned long, this was actually marking all pages
from 0 to 4GB as reserved.
Fixes: 92923ca3aa ("mm: meminit: only set page reserved in the memblock region")
Link: http://lkml.kernel.org/r/1463491221-10573-1-git-send-email-stefan.bader@canonical.com
Signed-off-by: Stefan Bader <stefan.bader@canonical.com>
Cc: <stable@vger.kernel.org> [4.2+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
userfaultfd_file_create() increments mm->mm_users; this means that the
memory won't be unmapped/freed if mm owner exits/execs, and UFFDIO_COPY
after that can populate the orphaned mm more.
Change userfaultfd_file_create() and userfaultfd_ctx_put() to use
mm->mm_count to pin mm_struct. This means that
atomic_inc_not_zero(mm->mm_users) is needed when we are going to
actually play with this memory. Except handle_userfault() path doesn't
need this, the caller must already have a reference.
The patch adds the new trivial helper, mmget_not_zero(), it can have
more users.
Link: http://lkml.kernel.org/r/20160516172254.GA8595@redhat.com
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Comparing an u64 variable to >= 0 returns always true and can therefore
be removed. This issue was detected using the -Wtype-limits gcc flag.
This patch fixes following type-limits warning:
mm/memblock.c: In function `__next_reserved_mem_region':
mm/memblock.c:843:11: warning: comparison of unsigned expression >= 0 is always true [-Wtype-limits]
if (*idx >= 0 && *idx < type->cnt) {
Link: http://lkml.kernel.org/r/20160510103625.3a7f8f32@g0hl1n.net
Signed-off-by: Richard Leitner <dev@g0hl1n.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch introduces z3fold, a special purpose allocator for storing
compressed pages. It is designed to store up to three compressed pages
per physical page. It is a ZBUD derivative which allows for higher
compression ratio keeping the simplicity and determinism of its
predecessor.
This patch comes as a follow-up to the discussions at the Embedded Linux
Conference in San-Diego related to the talk [1]. The outcome of these
discussions was that it would be good to have a compressed page
allocator as stable and deterministic as zbud with with higher
compression ratio.
To keep the determinism and simplicity, z3fold, just like zbud, always
stores an integral number of compressed pages per page, but it can store
up to 3 pages unlike zbud which can store at most 2. Therefore the
compression ratio goes to around 2.6x while zbud's one is around 1.7x.
The patch is based on the latest linux.git tree.
This version has been updated after testing on various simulators (e.g.
ARM Versatile Express, MIPS Malta, x86_64/Haswell) and basing on
comments from Dan Streetman [3].
[1] https://openiotelc2016.sched.org/event/6DAC/swapping-and-embedded-compression-relieves-the-pressure-vitaly-wool-softprise-consulting-ou
[2] https://lkml.org/lkml/2016/4/21/799
[3] https://lkml.org/lkml/2016/5/4/852
Link: http://lkml.kernel.org/r/20160509151753.ec3f9fda3c9898d31ff52a32@gmail.com
Signed-off-by: Vitaly Wool <vitalywool@gmail.com>
Cc: Seth Jennings <sjenning@redhat.com>
Cc: Dan Streetman <ddstreet@ieee.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Comment is partly wrong, this improves it by including the case of
split_huge_pmd_address() called by try_to_unmap_one if TTU_SPLIT_HUGE_PMD
is set.
Link: http://lkml.kernel.org/r/1462547040-1737-4-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
compound_mapcount() is only called after PageCompound() has already been
checked by the caller, so there's no point to check it again. Gcc may
optimize it away too because it's inline but this will remove the
runtime check for sure and add it'll add an assert instead.
Link: http://lkml.kernel.org/r/1462547040-1737-3-git-send-email-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
