Dan Streetman [Thu, 22 May 2014 00:43:40 +0000 (10:43 +1000)]
lib/plist.c: make CONFIG_DEBUG_PI_LIST selectable
Change CONFIG_DEBUG_PI_LIST to be user-selectable, and add a title and
description. Remove the dependency on DEBUG_RT_MUTEXES since they were
changed to use rbtrees, and there are other users of plists now.
Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Lasse Collin [Thu, 22 May 2014 00:43:38 +0000 (10:43 +1000)]
lib/xz: enable all filters by default in Kconfig
This restores the old behavior that existed before 2013-02-22, when
changes were made by 64dbfb444c150 ("decompressors: drop dependency on
CONFIG_EXPERT") and 5dc49c75a2 ("decompressors: make the default XZ_DEC_*
config match the selected architecture").
Disabling the filters only makes sense on embedded systems.
Signed-off-by: Lasse Collin <lasse.collin@tukaani.org> Acked-by: Kyle McMartin <kyle@infradead.org> Cc: Florian Fainelli <f.fainelli@gmail.com> Cc: Phillip Lougher <phillip@lougher.demon.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dan Streetman [Thu, 22 May 2014 00:43:38 +0000 (10:43 +1000)]
lib/plist.c: replace pr_debug with printk in plist_test()
Replace pr_debug() in lib/plist.c test function plist_test() with
printk(KERN_DEBUG ...).
Without DEBUG defined, pr_debug() is complied out, but the entire
plist_test() function is already inside CONFIG_DEBUG_PI_LIST, so printk
should just be used directly.
Signed-off-by: Dan Streetman <ddstreet@ieee.org> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dan Carpenter [Thu, 22 May 2014 00:43:38 +0000 (10:43 +1000)]
lib/string.c: use the name "C-string" in comments
For strncpy() and friends the source string may or may not have an actual
NUL character at the end. The documentation is confusing in this because
it specifically mentions that you are passing a "NUL-terminated" string.
Wikipedia says that "C-string" is an alternative name we can use instead.
Most mobile phones have Ambient Light Sensors and it changes brightness
according to the lux. It means it changes backlight brightness frequently
by just writing sysfs node, so it generates uevent.
Usually there's no user to use this backlight changes. But it forks udev
worker threads and it takes about 5ms. The main problem is that it hurts
other process activities. so remove it.
Kay said
"Uevents are for the major, low-frequent, global device state-changes,
not for carrying-out any sort of measurement data. Subsystems which
need that should use other facilities like poll()-able sysfs file or
any other subscription-based, client-tracking interface which does not
cause overhead if it isn't used. Uevents are not the right thing to
use here, and upstream udev should not paper-over broken kernel
subsystems."
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com> Cc: Henrique de Moraes Holschuh <hmh@hmh.eng.br> Cc: Matthew Garrett <mjg59@srcf.ucam.org> Cc: Kay Sievers <kay.sievers@vrfy.org> Acked-by: Jingoo Han <jg1.han@samsung.com> Cc: Henrique de Moraes Holschuh <ibm-acpi@hmh.eng.br> Cc: Richard Purdie <rpurdie@rpsys.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Tetsuo Handa [Thu, 22 May 2014 00:43:37 +0000 (10:43 +1000)]
lib/vsprintf: add %pT format specifier
Since task_struct->comm can be modified by other threads while the current
thread is reading it, it is recommended to use get_task_comm() for reading
it.
However, since get_task_comm() holds task_struct->alloc_lock spinlock,
some users cannot use get_task_comm(). Also, a lot of users are directly
reading from task_struct->comm even if they can use get_task_comm(). Such
users might obtain inconsistent result.
This patch introduces %pT format specifier for printing task_struct->comm.
Currently %pT does not provide consistency. I'm planning to change to
use RCU in the future. By using RCU, the comm name read from
task_struct->comm will be guaranteed to be consistent. But before
modifying set_task_comm() to use RCU, we need to kill direct ->comm users
who do not use get_task_comm().
An example for converting direct ->comm users is shown below. Since many
debug printings use p == current, you can pass NULL instead of p if p ==
current.
Borislav Petkov [Thu, 22 May 2014 00:43:37 +0000 (10:43 +1000)]
kernel/printk: use symbolic defines for console loglevels
... instead of naked numbers.
Stuff in sysrq.c used to set it to 8 which is supposed to mean above
default level so set it to DEBUG instead as we're terminating/killing all
tasks and we want to be verbose there.
There should be no functionality change resulting from this patch.
Signed-off-by: Borislav Petkov <bp@suse.de> Acked-by: Kees Cook <keescook@chromium.org> Acked-by: Randy Dunlap <rdunlap@infradead.org> Cc: Joe Perches <joe@perches.com> Cc: Valdis Kletnieks <Valdis.Kletnieks@vt.edu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Will Deacon [Thu, 22 May 2014 00:43:37 +0000 (10:43 +1000)]
printk: report dropping of messages from logbuf
If the log ring buffer becomes full, we silently overwrite old messages
with new data. console_unlock will detect this case and fast-forward the
console_* pointers to skip over the corrupted data, but nothing will be
reported to the user.
This patch hijacks the first valid log message after detecting that we
dropped messages and prefixes it with a note detailing how many messages
were dropped. For long (~1000 char) messages, this will result in some
truncation of the real message, but given that we're dropping things
anyway, that doesn't seem to be the end of the world.
Signed-off-by: Will Deacon <will.deacon@arm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Kay Sievers <kay@vrfy.org> Cc: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dan Streetman [Thu, 22 May 2014 00:43:36 +0000 (10:43 +1000)]
Documentation: expand/clarify debug documentation
The pr_debug() and related debug print macros all differ from the normal
pr_XXX() macros, in that the normal ones print unconditionally, while the
debug macros are compiled out unless DEBUG is defined or
CONFIG_DYNAMIC_DEBUG is set. This isn't obvious, and the only way to find
this out is either to review the actual printk.h code or to read
CodingStyle, and the message there doesn't highlight the fact.
Change Documentation/CodingStyle to clearly indicate that pr_debug() and
related debug printing macros behave differently than all other pr_XXX()
macros, and attempt to clarify when and where the different debug printing
methods might be used.
Add short comment to printk.h above the pr_XXX() macros indicating that
while these macros print unconditionally, pr_debug() does not.
Signed-off-by: Dan Streetman <ddstreet@ieee.org> Cc: Joe Perches <joe@perches.com> Cc: Fabian Frederick <fabf@skynet.be> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
John Stultz [Thu, 22 May 2014 00:43:36 +0000 (10:43 +1000)]
timekeeping: use printk_deferred when holding timekeeping seqlock
Jiri Bohac pointed out that there are rare but potential deadlock
possibilities when calling printk while holding the timekeeping
seqlock.
This is due to printk() triggering console sem wakeup, which can
cause scheduling code to trigger hrtimers which may try to read
the time.
Specifically, as Jiri pointed out, that path is:
printk
vprintk_emit
console_unlock
up(&console_sem)
__up
wake_up_process
try_to_wake_up
ttwu_do_activate
ttwu_activate
activate_task
enqueue_task
enqueue_task_fair
hrtick_update
hrtick_start_fair
hrtick_start_fair
get_time
ktime_get
--> endless loop on
read_seqcount_retry(&timekeeper_seq, ...)
This patch tries to avoid this issue by using printk_deferred (previously
named printk_sched) which should defer printing via a irq_work_queue.
Signed-off-by: John Stultz <john.stultz@linaro.org> Reported-by: Jiri Bohac <jbohac@suse.cz> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
John Stultz [Thu, 22 May 2014 00:43:36 +0000 (10:43 +1000)]
printk: Add printk_deferred_once
Two of the three prink_deferred uses are really printk_once style
uses, so add a printk_deferred_once macro to simplify those call
sites.
Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Bohac <jbohac@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
John Stultz [Thu, 22 May 2014 00:43:36 +0000 (10:43 +1000)]
printk: rename printk_sched to printk_deferred
After learning we'll need some sort of deferred printk functionality in
the timekeeping core, Peter suggested we rename the printk_sched function
so it can be reused by needed subsystems.
This only changes the function name. No logic changes.
Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Steven Rostedt <rostedt@goodmis.org> Cc: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Bohac <jbohac@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
John Stultz [Thu, 22 May 2014 00:43:35 +0000 (10:43 +1000)]
printk: disable preemption for printk_sched
An earlier change in -mm (printk: remove separate printk_sched
buffers...), removed the printk_sched irqsave/restore lines since it was
safe for current users. Since we may be expanding usage of
printk_sched(), disable preepmtion for this function to make it more
generally safe to call.
Signed-off-by: John Stultz <john.stultz@linaro.org> Reviewed-by: Jan Kara <jack@suse.cz> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Jiri Bohac <jbohac@suse.cz> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Steven Rostedt [Thu, 22 May 2014 00:43:35 +0000 (10:43 +1000)]
printk: remove separate printk_sched buffers and use printk buf instead
To prevent deadlocks with doing a printk inside the scheduler,
printk_sched() was created. The issue is that printk has a console_sem
that it can grab and release. The release does a wake up if there's a
task pending on the sem, and this wake up grabs the rq locks that is held
in the scheduler. This leads to a possible deadlock if the wake up uses
the same rq as the one with the rq lock held already.
What printk_sched() does is to save the printk write in a per cpu buffer
and sets the PRINTK_PENDING_SCHED flag. On a timer tick, if this flag is
set, the printk() is done against the buffer.
There's a couple of issues with this approach.
1) If two printk_sched()s are called before the tick, the second one
will overwrite the first one.
2) The temporary buffer is 512 bytes and is per cpu. This is a quite a
bit of space wasted for something that is seldom used.
In order to remove this, the printk_sched() can use the printk buffer
instead, and delay the console_trylock()/console_unlock() to the queued
work.
Because printk_sched() would then be taking the logbuf_lock, the
logbuf_lock must not be held while doing anything that may call into the
scheduler functions, which includes wake ups. Unfortunately, printk()
also has a console_sem that it uses, and on release, the up(&console_sem)
may do a wake up of any pending waiters. This must be avoided while
holding the logbuf_lock.
Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jan Kara [Thu, 22 May 2014 00:43:35 +0000 (10:43 +1000)]
printk: enable interrupts before calling console_trylock_for_printk()
We need interrupts disabled when calling console_trylock_for_printk() only
so that cpu id we pass to can_use_console() remains valid (for other
things console_sem provides all the exclusion we need and deadlocks on
console_sem due to interrupts are impossible because we use
down_trylock()). However if we are rescheduled, we are guaranteed to run
on an online cpu so we can easily just get the cpu id in
can_use_console().
We can lose a bit of performance when we enable interrupts in
vprintk_emit() and then disable them again in console_unlock() but OTOH it
can somewhat reduce interrupt latency caused by console_unlock()
especially since later in the patch series we will want to spin on
console_sem in console_trylock_for_printk().
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jan Kara [Thu, 22 May 2014 00:43:35 +0000 (10:43 +1000)]
printk: fix lockdep instrumentation of console_sem
Printk calls mutex_acquire() / mutex_release() by hand to instrument
lockdep about console_sem. However in some corner cases the
instrumentation is missing. Fix the problem by creating helper functions
for locking / unlocking console_sem which take care of lockdep
instrumentation as well.
Signed-off-by: Jan Kara <jack@suse.cz> Reported-by: Fabio Estevam <festevam@gmail.com> Reported-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Tested-by: Fabio Estevam <fabio.estevam@freescale.com> Tested-By: Valdis Kletnieks <valdis.kletnieks@vt.edu> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jan Kara [Thu, 22 May 2014 00:43:34 +0000 (10:43 +1000)]
printk: release lockbuf_lock before calling console_trylock_for_printk()
There's no reason to hold lockbuf_lock when entering
console_trylock_for_printk().
The first thing this function does is to call down_trylock(console_sem)
and if that fails it immediately unlocks lockbuf_lock. So lockbuf_lock
isn't needed for that branch. When down_trylock() succeeds, the rest of
console_trylock() is OK without lockbuf_lock (it is called without it from
other places), and the only remaining thing in
console_trylock_for_printk() is can_use_console() call. For that call
console_sem is enough (it iterates all consoles and checks CON_ANYTIME
flag).
So we drop logbuf_lock before entering console_trylock_for_printk() which
simplifies the code.
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
At that time release_console_sem() (today's equivalent is
console_unlock()) was indeed using lockbuf_lock to avoid races between
trylock on console_sem in printk() and unlock of console_sem. However
these days the interlocking is gone and the races are avoided by
rechecking logbuf state after releasing console_sem.
Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Petr Mladek [Thu, 22 May 2014 00:43:34 +0000 (10:43 +1000)]
printk: return really stored message length
I wonder if anyone uses printk return value but it is there and should be
counted correctly.
This patch modifies log_store() to return the number of really stored
bytes from the 'text' part. Also it handles the return value in
vprintk_emit().
Note that log_store() is used also in cont_flush() but we could ignore the
return value there. The function works with characters that were already
counted earlier. In addition, the store could newer fail here because the
length of the printed text is limited by the "cont" buffer and "dict" is
NULL.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Petr Mladek [Thu, 22 May 2014 00:43:33 +0000 (10:43 +1000)]
printk: shrink too long messages
We might want to print at least part of too long messages and add some
warning for debugging purpose.
The question is how long the shrunken message should be. If we use the
whole buffer, it might get rotated too soon. Let's try to use only 1/4 of
the buffer for now.
Also shrink the whole dictionary. We do not want to parse it or break it
in the middle of some pair of values. It would not cause any real harm
but still.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Petr Mladek [Thu, 22 May 2014 00:43:33 +0000 (10:43 +1000)]
printk: split message size computation
We will want to recompute the message size when shrinking too long
messages. Let's put the code into separate function.
The side effect of setting "pad_len" is not nice but it is worth removing
the code duplication. Note that I will probably have one more usage for
this function when handling messages safe way in NMI context.
This patch does not change the existing behavior.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Petr Mladek [Thu, 22 May 2014 00:43:33 +0000 (10:43 +1000)]
printk: ignore too long messages
There was no check for too long messages. The check for free space always
passed when first_seq and next_seq were equal. Enough free space was not
guaranteed, though.
log_store() might be called to store messages up to 64kB + 64kB + 16B.
This is sum of maximal text_len, dict_len values, and the size of the
structure printk_log.
On the other hand, the minimal size for the main log buffer currently is
4kB and it is enforced only by Kconfig.
The good news is that the usage looks safe right now. log_store() is
called only from vprintk_emit() and cont_flush(). Here the "text" part is
always passed via a static buffer and the length is limited to
LOG_LINE_MAX which is 1024. The "dict" part is NULL in most cases. The
only exceptions is when vprintk_emit() is called from printk_emit() and
dev_vprintk_emit(). But printk_emit() is currently used only in
devkmsg_writev() and here "dict" is NULL as well. In dev_vprintk_emit(),
"dict" is limited by the static buffer "hdr" of the size 128 bytes. It
meas that the current maximal printed text is 1024B + 128B + 16B and it
always fit the log buffer.
But it is only matter of time when someone calls printk_emit() with unsafe
parameters, especially the "dict" one.
This patch adds a check for the free space when the buffer is empty. It
reuses the already existing log_has_space() function but it has to add an
extra parameter. It defines whether the buffer is empty. Note that the
same values of "first_idx" and "next_idx" might also mean that the buffer
is full.
If the buffer is empty, we must respect the current position of the
indexes. We cannot reset them to the beginning of the buffer. Otherwise,
the functions reading the buffer would get crazy.
The question is what to do when the message is too long. This patch uses
the easiest solution and just ignores the problematic message. Let's do
something better in a followup patch.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Petr Mladek [Thu, 22 May 2014 00:43:33 +0000 (10:43 +1000)]
printk: split code for making free space in the log buffer
The check for free space in the log buffer always passes when "first_seq"
and "next_seq" are equal. In theory, it might cause writing outside of
the log buffer.
Fortunately, the current usage looks safe because the used "text" and
"dict" buffers are quite limited. See the second patch for more details.
Anyway, it is better to be on the safe side and add a check. An easy
solution is done in the 2nd patch and it is improved in the 4th patch.
5th patch fixes the computation of the printed message length.
1st and 3rd patches just do some code refactoring to make the other
patches easier.
This patch (of 5):
There will be needed some fixes in the check for free space. They will be
easier if the code is moved outside of the quite long log_store()
function.
This patch does not change the existing behavior.
Signed-off-by: Petr Mladek <pmladek@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Jiri Kosina <jkosina@suse.cz> Cc: Kay Sievers <kay@vrfy.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Gustavo Padovan [Thu, 22 May 2014 00:43:32 +0000 (10:43 +1000)]
drivers/misc/ti-st/st_core.c: fix NULL dereference on protocol type check
If the type we receive is greater than ST_MAX_CHANNELS we can't rely on
type as vector index since we would be accessing unknown memory when we use the type
as index.
Fabian Frederick [Thu, 22 May 2014 00:43:29 +0000 (10:43 +1000)]
kernel/cpu.c: convert printk to pr_foo()
no level printk converted to pr_warn (if err)
no level printk converted to pr_info (disabling non-boot cpus)
Other printk converted to respective level.
Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: "Rafael J. Wysocki" <rafael.j.wysocki@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
James Hogan [Thu, 22 May 2014 00:43:29 +0000 (10:43 +1000)]
compiler.h: avoid sparse errors in __compiletime_error_fallback()
Usually, BUG_ON and friends aren't even evaluated in sparse, but recently
compiletime_assert_atomic_type() was added, and that now results in a
sparse warning every time it is used.
The reason turns out to be the temporary variable, after it sparse no
longer considers the value to be a constant, and results in a warning and
an error. The error is the more annoying part of this as it suppresses
any further warnings in the same file, hiding other problems.
Unfortunately the condition cannot be simply expanded out to avoid the
temporary variable since it breaks compiletime_assert on old versions of
GCC such as GCC 4.2.4 which the latest metag compiler is based on.
Therefore #ifndef __CHECKER__ out the __compiletime_error_fallback which
uses the potentially negative size array to trigger a conditional compiler
error, so that sparse doesn't see it.
Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Johannes Berg <johannes.berg@intel.com> Cc: Daniel Santos <daniel.santos@pobox.com> Cc: Luciano Coelho <luciano.coelho@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Fabian Frederick [Thu, 22 May 2014 00:43:29 +0000 (10:43 +1000)]
fs/exportfs/expfs.c: kernel-doc warning fixes
Fixing 2 typo in function comments.
Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: "J. Bruce Fields" <bfields@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Fabian Frederick [Thu, 22 May 2014 00:43:28 +0000 (10:43 +1000)]
fs/efivarfs/super.c: use static const for dentry_operations
...like other filesystems.
Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: Matthew Garrett <matthew.garrett@nebula.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
sys_sgetmask and sys_ssetmask are obsolete system calls no longer
supported in libc.
This patch replaces architecture related __ARCH_WANT_SYS_SGETMAX by expert
mode configuration.That option is enabled by default for those
architectures.
Signed-off-by: Fabian Frederick <fabf@skynet.be> Cc: Steven Miao <realmz6@gmail.com> Cc: Mikael Starvik <starvik@axis.com> Cc: Jesper Nilsson <jesper.nilsson@axis.com> Cc: David Howells <dhowells@redhat.com> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Michal Simek <monstr@monstr.eu> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> Cc: Helge Deller <deller@gmx.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Greg Ungerer <gerg@uclinux.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Minchan Kim [Thu, 22 May 2014 00:43:27 +0000 (10:43 +1000)]
mm/vmalloc.c: export unmap_kernel_range()
zsmalloc needs exported unmap_kernel_range for building as a module. See
https://lkml.org/lkml/2013/1/18/487
I didn't send a patch to make unmap_kernel_range exportable at that time
because zram was staging stuff and I thought VM function exporting for
staging stuff makes no sense.
Now zsmalloc was promoted. If we can't build zsmalloc as module, it means
we can't build zram as module, either. Additionally, buddy map_vm_area is
already exported so let's export unmap_kernel_range to help his buddy.
Signed-off-by: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Jerome Marchand <jmarchan@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Weijie Yang [Thu, 22 May 2014 00:43:26 +0000 (10:43 +1000)]
zram: correct offset usage in zram_bio_discard
We want to skip the physical block(PAGE_SIZE) which is partially covered
by the discard bio, so we check the remaining size and subtract it if
there is a need to goto the next physical block.
The current offset usage in zram_bio_discard is incorrect, it will cause
its upper filesystem breakdown. Consider the following scenario:
On some architecture or config, PAGE_SIZE is 64K for example, filesystem
is set up on zram disk without PAGE_SIZE aligned, a discard bio leads to a
offset = 4K and size=72K, normally, it should not really discard any
physical block as it partially cover two physical blocks. However, with
the current offset usage, it will discard the second physical block and
free its memory, which will cause filesystem breakdown.
This patch corrects the offset usage in zram_bio_discard.
Signed-off-by: Weijie Yang <weijie.yang@samsung.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Acked-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Cc: Bob Liu <bob.liu@oracle.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Matthew Wilcox [Thu, 22 May 2014 00:43:26 +0000 (10:43 +1000)]
mm/msync.c: sync only the requested range in msync()
msync() currently syncs more than POSIX requires or BSD or Solaris
implement. It is supposed to be equivalent to fdatasync(), not fsync(),
and it is only supposed to sync the portion of the file that overlaps the
range passed to msync.
If the VMA is non-linear, fall back to syncing the entire file, but we
still optimise to only fdatasync() the entire file, not the full fsync().
akpm: there are obvious concerns with bck-compatibility: is anyone relying
on the undocumented side-effect for their data integrity? And how would
they ever know if this change broke their data integrity?
We think the risk is reasonably low, and this patch brings the kernel into
line with other OS's and with what the manpage has always said...
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Jeff Moyer <jmoyer@redhat.com> Cc: Chris Mason <clm@fb.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vlastimil Babka [Thu, 22 May 2014 00:43:25 +0000 (10:43 +1000)]
mm, compaction: properly signal and act upon lock and need_sched() contention
Compaction uses compact_checklock_irqsave() function to periodically check
for lock contention and need_resched() to either abort async compaction,
or to free the lock, schedule and retake the lock. When aborting,
cc->contended is set to signal the contended state to the caller. Two
problems have been identified in this mechanism.
First, compaction also calls directly cond_resched() in both scanners when
no lock is yet taken. This call either does not abort async compaction,
or set cc->contended appropriately. This patch introduces a new
compact_should_abort() function to achieve both. In isolate_freepages(),
the check frequency is reduced to once by SWAP_CLUSTER_MAX pageblocks to
match what the migration scanner does in the preliminary page checks. In
case a pageblock is found suitable for calling isolate_freepages_block(),
the checks within there are done on higher frequency.
Second, isolate_freepages() does not check if isolate_freepages_block()
aborted due to contention, and advances to the next pageblock. This
violates the principle of aborting on contention, and might result in
pageblocks not being scanned completely, since the scanning cursor is
advanced. This problem has been noticed in the code by Joonsoo Kim when
reviewing related patches. This patch makes isolate_freepages_block()
check the cc->contended flag and abort.
In case isolate_freepages() has already isolated some pages before
aborting due to contention, page migration will proceed, which is OK since
we do not want to waste the work that has been done, and page migration
has own checks for contention. However, we do not want another isolation
attempt by either of the scanners, so cc->contended flag check is added
also to compaction_alloc() and compact_finished() to make sure compaction
is aborted right after the migration.
The outcome of the patch should be reduced lock contention by async
compaction and lower latencies for higher-order allocations where direct
compaction is involved.
Reported-by: Joonsoo Kim <iamjoonsoo.kim@lge.com> Signed-off-by: Vlastimil Babka <vbabka@suse.cz> Reviewed-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Mel Gorman <mgorman@suse.de> Cc: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com> Cc: Michal Nazarewicz <mina86@mina86.com> Cc: Christoph Lameter <cl@linux.com> Cc: Rik van Riel <riel@redhat.com> Acked-by: Michal Nazarewicz <mina86@mina86.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jianyu Zhan [Thu, 22 May 2014 00:43:24 +0000 (10:43 +1000)]
mm/vmscan.c: use DIV_ROUND_UP for calculation of zone's balance_gap and correct comments.
Currently, we use (zone->managed_pages + KSWAPD_ZONE_BALANCE_GAP_RATIO-1)
/ KSWAPD_ZONE_BALANCE_GAP_RATIO to avoid a zero gap value. It's better to
use DIV_ROUND_UP macro for neater code and clear meaning.
Besides, the gap value is calculated against the per-zone "managed pages",
not "present pages". This patch also corrects the comment and do some
rephrasing.
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Rafael Aquini <aquini@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jianyu Zhan [Thu, 22 May 2014 00:43:24 +0000 (10:43 +1000)]
mm, hugetlb: move the error handle logic out of normal code path
alloc_huge_page() now mixes normal code path with error handle logic.
This patches move out the error handle logic, to make normal code path
more clean and redue code duplicate.
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Acked-by: Davidlohr Bueso <davidlohr@hp.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:23 +0000 (10:43 +1000)]
mm: avoid unnecessary atomic operations during end_page_writeback()
If a page is marked for immediate reclaim then it is moved to the tail of
the LRU list. This occurs when the system is under enough memory pressure
for pages under writeback to reach the end of the LRU but we test for this
using atomic operations on every writeback. This patch uses an optimistic
non-atomic test first. It'll miss some pages in rare cases but the
consequences are not severe enough to warrant such a penalty.
While the function does not dominate profiles during a simple dd test the
cost of it is reduced.
Mel Gorman [Thu, 22 May 2014 00:43:23 +0000 (10:43 +1000)]
mm: page_alloc: calculate classzone_idx once from the zonelist ref
Dan Carpenter reported the following bug
The patch a486e00b8283: "mm: page_alloc: calculate classzone_idx
once from the zonelist ref" from May 17, 2014, leads to the
following static checker warning:
mm/page_alloc.c:2543 __alloc_pages_slowpath()
warn: we tested 'nodemask' before and it was 'false'
mm/page_alloc.c
2537 * Find the true preferred zone if the allocation is unconstrained by
2538 * cpusets.
2539 */
2540 if (!(alloc_flags & ALLOC_CPUSET) && !nodemask) {
^^^^^^^^^
Patch introduces this test.
2541 struct zoneref *preferred_zoneref;
2542 preferred_zoneref = first_zones_zonelist(zonelist, high_zoneidx,
2543 nodemask ? : &cpuset_current_mems_allowed,
^^^^^^^^
Patch introduces this test as well.
Mel Gorman [Thu, 22 May 2014 00:43:22 +0000 (10:43 +1000)]
mm: non-atomically mark page accessed during page cache allocation where possible -fix
Prabhakar Lad reported the following problem
I see following issue on DA850 evm,
git bisect points me to
commit id: 975c3a671f11279441006a29a19f55ccc15fb320
( mm: non-atomically mark page accessed during page cache allocation
where possible)
pagep is set but not pointing to anywhere valid as it's an uninitialised
stack variable. This patch is a fix to
mm-non-atomically-mark-page-accessed-during-page-cache-allocation-where-possible.patch
Andrew Morton [Thu, 22 May 2014 00:43:22 +0000 (10:43 +1000)]
mm/shmem.c: don't run init_page_accessed() against an uninitialised pointer
If shmem_getpage() returned an error then it didn't necessarily initialise
*pagep. So shmem_write_begin() shouldn't be playing with *pagep in this
situation.
Fixes an oops when "mm: non-atomically mark page accessed during page
cache allocation where possible" (quite reasonably) left *pagep
uninitialized.
Reported-by: Prabhakar Lad <prabhakar.csengg@gmail.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Dave Hansen <dave.hansen@intel.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:22 +0000 (10:43 +1000)]
mm: non-atomically mark page accessed during page cache allocation where possible
aops->write_begin may allocate a new page and make it visible only to have
mark_page_accessed called almost immediately after. Once the page is
visible the atomic operations are necessary which is noticable overhead
when writing to an in-memory filesystem like tmpfs but should also be
noticable with fast storage. The objective of the patch is to initialse
the accessed information with non-atomic operations before the page is
visible.
The bulk of filesystems directly or indirectly use
grab_cache_page_write_begin or find_or_create_page for the initial
allocation of a page cache page. This patch adds an init_page_accessed()
helper which behaves like the first call to mark_page_accessed() but may
called before the page is visible and can be done non-atomically.
The primary APIs of concern in this care are the following and are used
by most filesystems.
All of them are very similar in detail to the patch creates a core helper
pagecache_get_page() which takes a flags parameter that affects its
behavior such as whether the page should be marked accessed or not. Then
old API is preserved but is basically a thin wrapper around this core
function.
Each of the filesystems are then updated to avoid calling
mark_page_accessed when it is known that the VM interfaces have already
done the job. There is a slight snag in that the timing of the
mark_page_accessed() has now changed so in rare cases it's possible a page
gets to the end of the LRU as PageReferenced where as previously it might
have been repromoted. This is expected to be rare but it's worth the
filesystem people thinking about it in case they see a problem with the
timing change. It is also the case that some filesystems may be marking
pages accessed that previously did not but it makes sense that filesystems
have consistent behaviour in this regard.
The test case used to evaulate this is a simple dd of a large file done
multiple times with the file deleted on each iterations. The size of the
file is 1/10th physical memory to avoid dirty page balancing. In the
async case it will be possible that the workload completes without even
hitting the disk and will have variable results but highlight the impact
of mark_page_accessed for async IO. The sync results are expected to be
more stable. The exception is tmpfs where the normal case is for the "IO"
to not hit the disk.
The test machine was single socket and UMA to avoid any scheduling or NUMA
artifacts. Throughput and wall times are presented for sync IO, only wall
times are shown for async as the granularity reported by dd and the
variability is unsuitable for comparison. As async results were variable
do to writback timings, I'm only reporting the maximum figures. The sync
results were stable enough to make the mean and stddev uninteresting.
The performance results are reported based on a run with no profiling.
Profile data is based on a separate run with oprofile running.
Mel Gorman [Thu, 22 May 2014 00:43:21 +0000 (10:43 +1000)]
fs: buffer: do not use unnecessary atomic operations when discarding buffers
Discarding buffers uses a bunch of atomic operations when discarding
buffers because ...... I can't think of a reason. Use a cmpxchg loop to
clear all the necessary flags. In most (all?) cases this will be a single
atomic operations.
Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:21 +0000 (10:43 +1000)]
mm: do not use unnecessary atomic operations when adding pages to the LRU
When adding pages to the LRU we clear the active bit unconditionally. As
the page could be reachable from other paths we cannot use unlocked
operations without risk of corruption such as a parallel
mark_page_accessed. This patch tests if is necessary to clear the active
flag before using an atomic operation. This potentially opens a tiny race
when PageActive is checked as mark_page_accessed could be called after
PageActive was checked. The race already exists but this patch changes it
slightly. The consequence is that that the page may be promoted to the
active list that might have been left on the inactive list before the
patch. It's too tiny a race and too marginal a consequence to always use
atomic operations for.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:21 +0000 (10:43 +1000)]
mm: shmem: avoid atomic operation during shmem_getpage_gfp
shmem_getpage_gfp uses an atomic operation to set the SwapBacked field
before it's even added to the LRU or visible. This is unnecessary as what
could it possible race against? Use an unlocked variant.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:20 +0000 (10:43 +1000)]
mm: page_alloc: convert hot/cold parameter and immediate callers to bool
cold is a bool, make it one. Make the likely case the "if" part of the
block instead of the else as according to the optimisation manual this is
preferred.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:20 +0000 (10:43 +1000)]
mm: page_alloc: use unsigned int for order in more places
X86 prefers the use of unsigned types for iterators and there is a
tendency to mix whether a signed or unsigned type if used for page order.
This converts a number of sites in mm/page_alloc.c to use unsigned int for
order where possible.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:19 +0000 (10:43 +1000)]
mm: page_alloc: use word-based accesses for get/set pageblock bitmaps
The test_bit operations in get/set pageblock flags are expensive. This
patch reads the bitmap on a word basis and use shifts and masks to isolate
the bits of interest. Similarly masks are used to set a local copy of the
bitmap and then use cmpxchg to update the bitmap if there have been no
other changes made in parallel.
In a test running dd onto tmpfs the overhead of the pageblock-related
functions went from 1.27% in profiles to 0.5%.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:19 +0000 (10:43 +1000)]
mm: page_alloc: take the ALLOC_NO_WATERMARK check out of the fast path
ALLOC_NO_WATERMARK is set in a few cases. Always by kswapd, always for
__GFP_MEMALLOC, sometimes for swap-over-nfs, tasks etc. Each of these
cases are relatively rare events but the ALLOC_NO_WATERMARK check is an
unlikely branch in the fast path. This patch moves the check out of the
fast path and after it has been determined that the watermarks have not
been met. This helps the common fast path at the cost of making the slow
path slower and hitting kswapd with a performance cost. It's a reasonable
tradeoff.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:19 +0000 (10:43 +1000)]
mm: page_alloc: only check the zone id check if pages are buddies
A node/zone index is used to check if pages are compatible for merging
but this happens unconditionally even if the buddy page is not free. Defer
the calculation as long as possible. Ideally we would check the zone boundary
but nodes can overlap.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Rik van Riel <riel@redhat.com> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Stephen Rothwell reported the following build failure on -next.
In file included from arch/powerpc/mm/numa.c:23:0:
include/linux/cpuset.h: In function 'cpusets_enabled':
include/linux/cpuset.h:21:2: error: implicit declaration of function 'static_key_false' [-Werror=implicit-function-declaration]
return static_key_false(&cpusets_enabled_key);
^
include/linux/cpuset.h: In function 'nr_cpusets':
include/linux/cpuset.h:27:2: error: implicit declaration of function 'static_key_count' [-Werror=implicit-function-declaration]
return static_key_count(&cpusets_enabled_key) + 1;
^
include/linux/cpuset.h: In function 'cpuset_inc':
include/linux/cpuset.h:32:2: error: implicit declaration of function 'static_key_slow_inc' [-Werror=implicit-function-declaration]
static_key_slow_inc(&cpusets_enabled_key);
^
include/linux/cpuset.h: In function 'cpuset_dec':
include/linux/cpuset.h:37:2: error: implicit declaration of function 'static_key_slow_dec' [-Werror=implicit-function-declaration]
static_key_slow_dec(&cpusets_enabled_key);
^
This is a fix to the mmotm patch mm-page_alloc-use-jump-labels-to-avoid-checking-number_of_cpusets.patch.
Signed-off-by: Mel Gorman <mgorman@suse.de> Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:18 +0000 (10:43 +1000)]
include/linux/jump_label.h: expose the reference count
This patch exposes the jump_label reference count in preparation for the
next patch. cpusets cares about both the jump_label being enabled and how
many users of the cpusets there currently are.
Signed-off-by: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Vlastimil Babka <vbabka@suse.cz> Cc: Jan Kara <jack@suse.cz> Cc: Michal Hocko <mhocko@suse.cz> Cc: Hugh Dickins <hughd@google.com> Cc: Dave Hansen <dave.hansen@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:18 +0000 (10:43 +1000)]
mm: page_alloc: do not treat a zone that cannot be used for dirty pages as "full"
If a zone cannot be used for a dirty page then it gets marked "full" which
is cached in the zlc and later potentially skipped by allocation requests
that have nothing to do with dirty zones.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Mel Gorman [Thu, 22 May 2014 00:43:17 +0000 (10:43 +1000)]
mm: page_alloc: do not update zlc unless the zlc is active
The zlc is used on NUMA machines to quickly skip over zones that are full.
However it is always updated, even for the first zone scanned when the
zlc might not even be active. As it's a write to a bitmap that
potentially bounces cache line it's deceptively expensive and most
machines will not care. Only update the zlc if it was active.
Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Vladimir Davydov [Thu, 22 May 2014 00:43:17 +0000 (10:43 +1000)]
slab: delete cache from list after __kmem_cache_shutdown succeeds
Currently, on kmem_cache_destroy we delete the cache from the slab_list
before __kmem_cache_shutdown, inserting it back to the list on failure.
Initially, this was done, because we could release the slab_mutex in
__kmem_cache_shutdown to delete sysfs slub entry, but since commit 41a212859a4d ("slub: use sysfs'es release mechanism for kmem_cache") we
remove sysfs entry later in kmem_cache_destroy after dropping the
slab_mutex, so that no implementation of __kmem_cache_shutdown can ever
release the lock. Therefore we can simplify the code a bit by moving
list_del after __kmem_cache_shutdown.
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Vladimir Davydov <vdavydov@parallels.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Marc Carino [Thu, 22 May 2014 00:43:16 +0000 (10:43 +1000)]
cma: increase CMA_ALIGNMENT upper limit to 12
Some systems require a larger maximum PAGE_SIZE order for CMA allocations.
To accommodate such systems, increase the upper-bound of the
CMA_ALIGNMENT range to 12 (which ends up being 16MB on systems with 4K
pages).
Signed-off-by: Marc Carino <marc.ceeeee@gmail.com> Cc: Marek Szyprowski <m.szyprowski@samsung.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dan Streetman [Thu, 22 May 2014 00:43:16 +0000 (10:43 +1000)]
swap: change swap_list_head to plist, add swap_avail_head
Originally get_swap_page() started iterating through the singly-linked
list of swap_info_structs using swap_list.next or highest_priority_index,
which both were intended to point to the highest priority active swap
target that was not full. The first patch in this series changed the
singly-linked list to a doubly-linked list, and removed the logic to start
at the highest priority non-full entry; it starts scanning at the highest
priority entry each time, even if the entry is full.
Replace the manually ordered swap_list_head with a plist, swap_active_head.
Add a new plist, swap_avail_head. The original swap_active_head plist
contains all active swap_info_structs, as before, while the new
swap_avail_head plist contains only swap_info_structs that are active and
available, i.e. not full. Add a new spinlock, swap_avail_lock, to protect
the swap_avail_head list.
Mel Gorman suggested using plists since they internally handle ordering
the list entries based on priority, which is exactly what swap was doing
manually. All the ordering code is now removed, and swap_info_struct
entries and simply added to their corresponding plist and automatically
ordered correctly.
Using a new plist for available swap_info_structs simplifies and
optimizes get_swap_page(), which no longer has to iterate over full
swap_info_structs. Using a new spinlock for swap_avail_head plist
allows each swap_info_struct to add or remove themselves from the
plist when they become full or not-full; previously they could not
do so because the swap_info_struct->lock is held when they change
from full<->not-full, and the swap_lock protecting the main
swap_active_head must be ordered before any swap_info_struct->lock.
Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Shaohua Li <shli@fusionio.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Hugh Dickins <hughd@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Cc: Weijie Yang <weijieut@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Bob Liu <bob.liu@oracle.com> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dan Streetman [Thu, 22 May 2014 00:43:16 +0000 (10:43 +1000)]
lib/plist: add plist_requeue
Add plist_requeue(), which moves the specified plist_node after all other
same-priority plist_nodes in the list. This is essentially an optimized
plist_del() followed by plist_add().
This is needed by swap, which (with the next patch in this set) uses a
plist of available swap devices. When a swap device (either a swap
partition or swap file) are added to the system with swapon(), the device
is added to a plist, ordered by the swap device's priority. When swap
needs to allocate a page from one of the swap devices, it takes the page
from the first swap device on the plist, which is the highest priority
swap device. The swap device is left in the plist until all its pages are
used, and then removed from the plist when it becomes full.
However, as described in man 2 swapon, swap must allocate pages from swap
devices with the same priority in round-robin order; to do this, on each
swap page allocation, swap uses a page from the first swap device in the
plist, and then calls plist_requeue() to move that swap device entry to
after any other same-priority swap devices. The next swap page allocation
will again use a page from the first swap device in the plist and requeue
it, and so on, resulting in round-robin usage of equal-priority swap
devices.
Also add plist_test_requeue() test function, for use by plist_test() to
test plist_requeue() function.
Signed-off-by: Dan Streetman <ddstreet@ieee.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Shaohua Li <shli@fusionio.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Cc: Weijie Yang <weijieut@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Bob Liu <bob.liu@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dan Streetman [Thu, 22 May 2014 00:43:16 +0000 (10:43 +1000)]
lib/plist: add helper functions
Add PLIST_HEAD() to plist.h, equivalent to LIST_HEAD() from list.h, to
define and initialize a struct plist_head.
Add plist_for_each_continue() and plist_for_each_entry_continue(),
equivalent to list_for_each_continue() and list_for_each_entry_continue(),
to iterate over a plist continuing after the current position.
Add plist_prev() and plist_next(), equivalent to (struct list_head*)->prev
and ->next, implemented by list_prev_entry() and list_next_entry(), to
access the prev/next struct plist_node entry. These are needed because
unlike struct list_head, direct access of the prev/next struct plist_node
isn't possible; the list must be navigated via the contained struct
list_head. e.g. instead of accessing the prev by list_prev_entry(node,
node_list) it can be accessed by plist_prev(node).
Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Shaohua Li <shli@fusionio.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Cc: Weijie Yang <weijieut@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Bob Liu <bob.liu@oracle.com> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Dan Streetman [Thu, 22 May 2014 00:43:15 +0000 (10:43 +1000)]
swap: change swap_info singly-linked list to list_head
The logic controlling the singly-linked list of swap_info_struct entries
for all active, i.e. swapon'ed, swap targets is rather complex, because:
-it stores the entries in priority order
-there is a pointer to the highest priority entry
-there is a pointer to the highest priority not-full entry
-there is a highest_priority_index variable set outside the swap_lock
-swap entries of equal priority should be used equally
this complexity leads to bugs such as: https://lkml.org/lkml/2014/2/13/181
where different priority swap targets are incorrectly used equally.
That bug probably could be solved with the existing singly-linked lists,
but I think it would only add more complexity to the already difficult to
understand get_swap_page() swap_list iteration logic.
The first patch changes from a singly-linked list to a doubly-linked list
using list_heads; the highest_priority_index and related code are removed
and get_swap_page() starts each iteration at the highest priority
swap_info entry, even if it's full. While this does introduce unnecessary
list iteration (i.e. Schlemiel the painter's algorithm) in the case where
one or more of the highest priority entries are full, the iteration and
manipulation code is much simpler and behaves correctly re: the above bug;
and the fourth patch removes the unnecessary iteration.
The second patch adds some minor plist helper functions; nothing new
really, just functions to match existing regular list functions. These
are used by the next two patches.
The third patch adds plist_requeue(), which is used by get_swap_page() in
the next patch - it performs the requeueing of same-priority entries
(which moves the entry to the end of its priority in the plist), so that
all equal-priority swap_info_structs get used equally.
The fourth patch converts the main list into a plist, and adds a new plist
that contains only swap_info entries that are both active and not full.
As Mel suggested using plists allows removing all the ordering code from
swap - plists handle ordering automatically. The list naming is also
clarified now that there are two lists, with the original list changed
from swap_list_head to swap_active_head and the new list named
swap_avail_head. A new spinlock is also added for the new list, so
swap_info entries can be added or removed from the new list immediately as
they become full or not full.
This patch (of 4):
Replace the singly-linked list tracking active, i.e. swapon'ed,
swap_info_struct entries with a doubly-linked list using struct
list_heads. Simplify the logic iterating and manipulating the list of
entries, especially get_swap_page(), by using standard list_head
functions, and removing the highest priority iteration logic.
The change fixes the bug:
https://lkml.org/lkml/2014/2/13/181
in which different priority swap entries after the highest priority entry
are incorrectly used equally in pairs. The swap behavior is now as
advertised, i.e. different priority swap entries are used in order, and
equal priority swap targets are used concurrently.
Signed-off-by: Dan Streetman <ddstreet@ieee.org> Acked-by: Mel Gorman <mgorman@suse.de> Cc: Shaohua Li <shli@fusionio.com> Cc: Hugh Dickins <hughd@google.com> Cc: Dan Streetman <ddstreet@ieee.org> Cc: Michal Hocko <mhocko@suse.cz> Cc: Christian Ehrhardt <ehrhardt@linux.vnet.ibm.com> Cc: Weijie Yang <weijieut@gmail.com> Cc: Rik van Riel <riel@redhat.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Bob Liu <bob.liu@oracle.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Paul Gortmaker <paul.gortmaker@windriver.com> Cc: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Jianyu Zhan [Thu, 22 May 2014 00:43:15 +0000 (10:43 +1000)]
mm: fold mlocked_vma_newpage() into its only call site
In previous commit(mm: use the light version __mod_zone_page_state in
mlocked_vma_newpage()) a irq-unsafe __mod_zone_page_state is used. And as
suggested by Andrew, to reduce the risks that new call sites incorrectly
using mlocked_vma_newpage() without knowing they are adding racing, this
patch folds mlocked_vma_newpage() into its only call site,
page_add_new_anon_rmap, to make it open-cocded for people to know what is
going on.
Signed-off-by: Jianyu Zhan <nasa4836@gmail.com> Suggested-by: Andrew Morton <akpm@linux-foundation.org> Suggested-by: Hugh Dickins <hughd@google.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
projects / karo-tx-linux.git / log