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This is mostly for cleanup value:
- We don't need several gotos to handle the case where the first
waiter is a writer. Two simple tests will do (and generate very
similar code).
- In the remainder of the function, we know the first waiter is a reader,
so we don't have to double check that. We can use do..while loops
to iterate over the readers to wake (generates slightly better code).
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We can skip the initial trylock in rwsem_down_write_failed() if there
are known active lockers already, thus saving one likely-to-fail
cmpxchg.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In rwsem_down_write_failed(), if there are active locks after we wake up
(i.e. the lock got stolen from us), skip taking the wait_lock and go
back to sleep immediately.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Using rwsem_atomic_update to try stealing the write lock forced us to
undo the adjustment in the failure path. We can have simpler and faster
code by using cmpxchg instead.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Some small code simplifications can be achieved by doing more agressive
lock stealing:
- When rwsem_down_write_failed() notices that there are no active locks
(and thus no thread to wake us if we decided to sleep), it used to wake
the first queued process. However, stealing the lock is also sufficient
to deal with this case, so we don't need this check anymore.
- In try_get_writer_sem(), we can steal the lock even when the first waiter
is a reader. This is correct because the code path that wakes readers is
protected by the wait_lock. As to the performance effects of this change,
they are expected to be minimal: readers are still granted the lock
(rather than having to acquire it themselves) when they reach the front
of the wait queue, so we have essentially the same behavior as in
rwsem-spinlock.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When waking writers, we never grant them the lock - instead, they have
to acquire it themselves when they run, and remove themselves from the
wait_list when they succeed.
As a result, we can do a few simplifications in rwsem_down_write_failed():
- We don't need to check for !waiter.task since __rwsem_do_wake() doesn't
remove writers from the wait_list
- There is no point releaseing the wait_lock before entering the wait loop,
as we will need to reacquire it immediately. We can change the loop so
that the lock is always held at the start of each loop iteration.
- We don't need to get a reference on the task structure, since the task
is responsible for removing itself from the wait_list. There is no risk,
like in the rwsem_down_read_failed() case, that a task would wake up and
exit (thus destroying its task structure) while __rwsem_do_wake() is
still running - wait_lock protects against that.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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When trying to acquire a read lock, the RWSEM_ACTIVE_READ_BIAS
adjustment doesn't cause other readers to block, so we never have to
worry about waking them back after canceling this adjustment in
rwsem_down_read_failed().
We also never want to steal the lock in rwsem_down_read_failed(), so we
don't have to grab the wait_lock either.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Remove the rwsem_down_failed_common function and replace it with two
identical copies of its code in rwsem_down_{read,write}_failed.
This is because we want to make different optimizations in
rwsem_down_{read,write}_failed; we are adding this pure-duplication
step as a separate commit in order to make it easier to check the
following steps.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This change reduces the size of the spinlocked and TASK_UNINTERRUPTIBLE
sections in rwsem_down_failed_common():
- We only need the sem->wait_lock to insert ourselves on the wait_list;
the waiter node can be prepared outside of the wait_lock.
- The task state only needs to be set to TASK_UNINTERRUPTIBLE immediately
before checking if we actually need to sleep; it doesn't need to protect
the entire function.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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We are not planning to add some new waiter flags, so we can convert the
waiter type into an enumeration.
Background: David Howells suggested I do this back when I tried adding
a new waiter type for unfair readers. However, I believe the cleanup
applies regardless of that use case.
Signed-off-by: Michel Lespinasse <walken@google.com>
Reviewed-by: Rik van Riel <riel@redhat.com>
Reviewed-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Give the OID registry file module information so that it doesn't taint the
kernel when compiled as a module and loaded.
Reported-by: Dros Adamson <Weston.Adamson@netapp.com>
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Trond Myklebust <Trond.Myklebust@netapp.com>
cc: stable@vger.kernel.org
cc: linux-nfs@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Pull drm updates from Dave Airlie:
"This is the main drm pull request for 3.10.
Wierd bits:
- OMAP drm changes required OMAP dss changes, in drivers/video, so I
took them in here.
- one more fbcon fix for font handover
- VT switch avoidance in pm code
- scatterlist helpers for gpu drivers - have acks from akpm
Highlights:
- qxl kms driver - driver for the spice qxl virtual GPU
Nouveau:
- fermi/kepler VRAM compression
- GK110/nvf0 modesetting support.
Tegra:
- host1x core merged with 2D engine support
i915:
- vt switchless resume
- more valleyview support
- vblank fixes
- modesetting pipe config rework
radeon:
- UVD engine support
- SI chip tiling support
- GPU registers initialisation from golden values.
exynos:
- device tree changes
- fimc block support
Otherwise:
- bunches of fixes all over the place."
* 'drm-next' of git://people.freedesktop.org/~airlied/linux: (513 commits)
qxl: update to new idr interfaces.
drm/nouveau: fix build with nv50->nvc0
drm/radeon: fix handling of v6 power tables
drm/radeon: clarify family checks in pm table parsing
drm/radeon: consolidate UVD clock programming
drm/radeon: fix UPLL_REF_DIV_MASK definition
radeon: add bo tracking debugfs
drm/radeon: add new richland pci ids
drm/radeon: add some new SI PCI ids
drm/radeon: fix scratch reg handling for UVD fence
drm/radeon: allocate SA bo in the requested domain
drm/radeon: fix possible segfault when parsing pm tables
drm/radeon: fix endian bugs in atom_allocate_fb_scratch()
OMAPDSS: TFP410: return EPROBE_DEFER if the i2c adapter not found
OMAPDSS: VENC: Add error handling for venc_probe_pdata
OMAPDSS: HDMI: Add error handling for hdmi_probe_pdata
OMAPDSS: RFBI: Add error handling for rfbi_probe_pdata
OMAPDSS: DSI: Add error handling for dsi_probe_pdata
OMAPDSS: SDI: Add error handling for sdi_probe_pdata
OMAPDSS: DPI: Add error handling for dpi_probe_pdata
...
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
"This fixes the cputime scaling overflow problems for good without
having bad 32-bit overhead, and gets rid of the div64_u64_rem() helper
as well."
* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
Revert "math64: New div64_u64_rem helper"
sched: Avoid prev->stime underflow
sched: Do not account bogus utime
sched: Avoid cputime scaling overflow
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git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull VFS updates from Al Viro,
Misc cleanups all over the place, mainly wrt /proc interfaces (switch
create_proc_entry to proc_create(), get rid of the deprecated
create_proc_read_entry() in favor of using proc_create_data() and
seq_file etc).
7kloc removed.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (204 commits)
don't bother with deferred freeing of fdtables
proc: Move non-public stuff from linux/proc_fs.h to fs/proc/internal.h
proc: Make the PROC_I() and PDE() macros internal to procfs
proc: Supply a function to remove a proc entry by PDE
take cgroup_open() and cpuset_open() to fs/proc/base.c
ppc: Clean up scanlog
ppc: Clean up rtas_flash driver somewhat
hostap: proc: Use remove_proc_subtree()
drm: proc: Use remove_proc_subtree()
drm: proc: Use minor->index to label things, not PDE->name
drm: Constify drm_proc_list[]
zoran: Don't print proc_dir_entry data in debug
reiserfs: Don't access the proc_dir_entry in r_open(), r_start() r_show()
proc: Supply an accessor for getting the data from a PDE's parent
airo: Use remove_proc_subtree()
rtl8192u: Don't need to save device proc dir PDE
rtl8187se: Use a dir under /proc/net/r8180/
proc: Add proc_mkdir_data()
proc: Move some bits from linux/proc_fs.h to linux/{of.h,signal.h,tty.h}
proc: Move PDE_NET() to fs/proc/proc_net.c
...
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Merge third batch of fixes from Andrew Morton:
"Most of the rest. I still have two large patchsets against AIO and
IPC, but they're a bit stuck behind other trees and I'm about to
vanish for six days.
- random fixlets
- inotify
- more of the MM queue
- show_stack() cleanups
- DMI update
- kthread/workqueue things
- compat cleanups
- epoll udpates
- binfmt updates
- nilfs2
- hfs
- hfsplus
- ptrace
- kmod
- coredump
- kexec
- rbtree
- pids
- pidns
- pps
- semaphore tweaks
- some w1 patches
- relay updates
- core Kconfig changes
- sysrq tweaks"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (109 commits)
Documentation/sysrq: fix inconstistent help message of sysrq key
ethernet/emac/sysrq: fix inconstistent help message of sysrq key
sparc/sysrq: fix inconstistent help message of sysrq key
powerpc/xmon/sysrq: fix inconstistent help message of sysrq key
ARM/etm/sysrq: fix inconstistent help message of sysrq key
power/sysrq: fix inconstistent help message of sysrq key
kgdb/sysrq: fix inconstistent help message of sysrq key
lib/decompress.c: fix initconst
notifier-error-inject: fix module names in Kconfig
kernel/sys.c: make prctl(PR_SET_MM) generally available
UAPI: remove empty Kbuild files
menuconfig: print more info for symbol without prompts
init/Kconfig: re-order CONFIG_EXPERT options to fix menuconfig display
kconfig menu: move Virtualization drivers near other virtualization options
Kconfig: consolidate CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
relay: use macro PAGE_ALIGN instead of FIX_SIZE
kernel/relay.c: move FIX_SIZE macro into relay.c
kernel/relay.c: remove unused function argument actor
drivers/w1/slaves/w1_ds2760.c: fix the error handling in w1_ds2760_add_slave()
drivers/w1/slaves/w1_ds2781.c: fix the error handling in w1_ds2781_add_slave()
...
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Signed-off-by: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The Kconfig help text for MEMORY_NOTIFIER_ERROR_INJECT and
OF_RECONFIG_NOTIFIER_ERROR_INJECT has mismatched module names.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The help text for this config is duplicated across the x86, parisc, and
s390 Kconfig.debug files. Arnd Bergman noted that the help text was
slightly misleading and should be fixed to state that enabling this
option isn't a problem when using pre 4.4 gcc.
To simplify the rewording, consolidate the text into lib/Kconfig.debug
and modify it there to be more explicit about when you should say N to
this config.
Also, make the text a bit more generic by stating that this option
enables compile time checks so we can cover architectures which emit
warnings vs. ones which emit errors. The details of how an
architecture decided to implement the checks isn't as important as the
concept of compile time checking of copy_from_user() calls.
While we're doing this, remove all the copy_from_user_overflow() code
that's duplicated many times and place it into lib/ so that any
architecture supporting this option can get the function for free.
Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Ingo Molnar <mingo@kernel.org>
Acked-by: H. Peter Anvin <hpa@zytor.com>
Cc: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Helge Deller <deller@gmx.de>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Account for the rbtree having 2**bh(v)-1 internal nodes.
While this can be seen as a consequence of other checks, Michel states
that it nicely sums up what the other properties are for.
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Reviewed-by: Michel Lespinasse <walken@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There is kernel function to do the job in generic way. Let's use it.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Jason Baron <jbaron@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There are several places in kernel where modules unescapes input to convert
C-Style Escape Sequences into byte codes.
The patch provides generic implementation of such approach. Test cases are
also included into the patch.
[akpm@linux-foundation.org: clarify comment]
[akpm@linux-foundation.org: export get_random_int() to modules]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Samuel Thibault <samuel.thibault@ens-lyon.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Baron <jbaron@redhat.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: William Hubbs <w.d.hubbs@gmail.com>
Cc: Chris Brannon <chris@the-brannons.com>
Cc: Kirk Reiser <kirk@braille.uwo.ca>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Both dump_stack() and show_stack() are currently implemented by each
architecture. show_stack(NULL, NULL) dumps the backtrace for the
current task as does dump_stack(). On some archs, dump_stack() prints
extra information - pid, utsname and so on - in addition to the
backtrace while the two are identical on other archs.
The usages in arch-independent code of the two functions indicate
show_stack(NULL, NULL) should print out bare backtrace while
dump_stack() is used for debugging purposes when something went wrong,
so it does make sense to print additional information on the task which
triggered dump_stack().
There's no reason to require archs to implement two separate but mostly
identical functions. It leads to unnecessary subtle information.
This patch expands the dummy fallback dump_stack() implementation in
lib/dump_stack.c such that it prints out debug information (taken from
x86) and invokes show_stack(NULL, NULL) and drops arch-specific
dump_stack() implementations in all archs except blackfin. Blackfin's
dump_stack() does something wonky that I don't understand.
Debug information can be printed separately by calling
dump_stack_print_info() so that arch-specific dump_stack()
implementation can still emit the same debug information. This is used
in blackfin.
This patch brings the following behavior changes.
* On some archs, an extra level in backtrace for show_stack() could be
printed. This is because the top frame was determined in
dump_stack() on those archs while generic dump_stack() can't do that
reliably. It can be compensated by inlining dump_stack() but not
sure whether that'd be necessary.
* Most archs didn't use to print debug info on dump_stack(). They do
now.
An example WARN dump follows.
WARNING: at kernel/workqueue.c:4841 init_workqueues+0x35/0x505()
Hardware name: empty
Modules linked in:
CPU: 0 PID: 1 Comm: swapper/0 Not tainted 3.9.0-rc1-work+ #9
0000000000000009 ffff88007c861e08 ffffffff81c614dc ffff88007c861e48
ffffffff8108f50f ffffffff82228240 0000000000000040 ffffffff8234a03c
0000000000000000 0000000000000000 0000000000000000 ffff88007c861e58
Call Trace:
[<ffffffff81c614dc>] dump_stack+0x19/0x1b
[<ffffffff8108f50f>] warn_slowpath_common+0x7f/0xc0
[<ffffffff8108f56a>] warn_slowpath_null+0x1a/0x20
[<ffffffff8234a071>] init_workqueues+0x35/0x505
...
v2: CPU number added to the generic debug info as requested by s390
folks and dropped the s390 specific dump_stack(). This loses %ksp
from the debug message which the maintainers think isn't important
enough to keep the s390-specific dump_stack() implementation.
dump_stack_print_info() is moved to kernel/printk.c from
lib/dump_stack.c. Because linkage is per objecct file,
dump_stack_print_info() living in the same lib file as generic
dump_stack() means that archs which implement custom dump_stack()
- at this point, only blackfin - can't use dump_stack_print_info()
as that will bring in the generic version of dump_stack() too. v1
The v1 patch broke build on blackfin due to this issue. The build
breakage was reported by Fengguang Wu.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Jesper Nilsson <jesper.nilsson@axis.com>
Acked-by: Vineet Gupta <vgupta@synopsys.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com> [s390 bits]
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Mike Frysinger <vapier@gentoo.org>
Cc: Fengguang Wu <fengguang.wu@intel.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Richard Kuo <rkuo@codeaurora.org> [hexagon bits]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial
Pull fixup for trivial branch from Jiri Kosina:
"Unfortunately I made a mistake when merging into for-linus branch, and
omitted one pre-requisity patch for a few other patches (which have
been Acked by the appropriate maintainers) in the series. Mea culpa
maxima, sorry for that."
The trivial branch added %pSR usage before actually teaching vsnprintf()
about the 'R' part of %pSR. The 'R' causes the symbol translation to do
a "__builtin_extract_return_addr()" before symbol lookup.
That said, on most architectures __builtin_extract_return_addr() isn't
likely to do anything special, so it probably is not normally
noticeable.
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial:
vsprintf: Add extension %pSR - print_symbol replacement
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print_symbol takes a long and converts it to a function
name and offset. %pS does something similar, but doesn't
translate the address via __builtin_extract_return_addr.
%pSR does the translation.
This will enable replacing multiple calls like
printk(...);
printk_symbol(addr);
printk("\n");
with a single non-interleavable in dmesg
printk("... %pSR\n", (void *)addr);
Update documentation too.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
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This reverts commit f792685006274a850e6cc0ea9ade275ccdfc90bc.
The cputime scaling code was changed/fixed and does not need the
div64_u64_rem() primitive anymore. It has no other users, so let's
remove them.
Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: rostedt@goodmis.org
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Dave Hansen <dave@sr71.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1367314507-9728-4-git-send-email-sgruszka@redhat.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler changes from Ingo Molnar:
"The main changes in this development cycle were:
- full dynticks preparatory work by Frederic Weisbecker
- factor out the cpu time accounting code better, by Li Zefan
- multi-CPU load balancer cleanups and improvements by Joonsoo Kim
- various smaller fixes and cleanups"
* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (45 commits)
sched: Fix init NOHZ_IDLE flag
sched: Prevent to re-select dst-cpu in load_balance()
sched: Rename load_balance_tmpmask to load_balance_mask
sched: Move up affinity check to mitigate useless redoing overhead
sched: Don't consider other cpus in our group in case of NEWLY_IDLE
sched: Explicitly cpu_idle_type checking in rebalance_domains()
sched: Change position of resched_cpu() in load_balance()
sched: Fix wrong rq's runnable_avg update with rt tasks
sched: Document task_struct::personality field
sched/cpuacct/UML: Fix header file dependency bug on the UML build
cgroup: Kill subsys.active flag
sched/cpuacct: No need to check subsys active state
sched/cpuacct: Initialize cpuacct subsystem earlier
sched/cpuacct: Initialize root cpuacct earlier
sched/cpuacct: Allocate per_cpu cpuusage for root cpuacct statically
sched/cpuacct: Clean up cpuacct.h
sched/cpuacct: Remove redundant NULL checks in cpuacct_acount_field()
sched/cpuacct: Remove redundant NULL checks in cpuacct_charge()
sched/cpuacct: Add cpuacct_acount_field()
sched/cpuacct: Add cpuacct_init()
...
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Use preferable function name which implies using a pseudo-random
number generator.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Use prandom_bytes() to generate 16 bytes of pseudo-random bytes.
Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: Huang Ying <ying.huang@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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As Tejun points out, there are several users of the IDR facility that
attempt to use it in a cyclic fashion. These users are likely to see
-ENOSPC errors after the counter wraps one or more times however.
This patchset adds a new idr_alloc_cyclic routine and converts several
of these users to it. Many of these users are in obscure parts of the
kernel, and I don't have a good way to test some of them. The change is
pretty straightforward though, so hopefully it won't be an issue.
There is one other cyclic user of idr_alloc that I didn't touch in
ipc/util.c. That one is doing some strange stuff that I didn't quite
understand, but it looks like it should probably be converted later
somehow.
This patch:
Thus spake Tejun Heo:
Ooh, BTW, the cyclic allocation is broken. It's prone to -ENOSPC
after the first wraparound. There are several cyclic users in the
kernel and I think it probably would be best to implement cyclic
support in idr.
This patch does that by adding new idr_alloc_cyclic function that such
users in the kernel can use. With this, there's no need for a caller to
keep track of the last value used as that's now tracked internally. This
should prevent the ENOSPC problems that can hit when the "last allocated"
counter exceeds INT_MAX.
Later patches will convert existing cyclic users to the new interface.
Signed-off-by: Jeff Layton <jlayton@redhat.com>
Reviewed-by: Tejun Heo <tj@kernel.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: "J. Bruce Fields" <bfields@fieldses.org>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Jack Morgenstein <jackm@dev.mellanox.co.il>
Cc: John McCutchan <john@johnmccutchan.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Or Gerlitz <ogerlitz@mellanox.com>
Cc: Robert Love <rlove@rlove.org>
Cc: Roland Dreier <roland@purestorage.com>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Cc: Steve Wise <swise@opengridcomputing.com>
Cc: Tom Tucker <tom@opengridcomputing.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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There are at least two users of isodigit(). Let's make it a public
function of ctype.h.
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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argv_split() allocates argv[count_argc(str)] array and assumes that it
will find the same number of arguments later. This is obviously wrong if
this string can be changed, say, by sysctl.
With this patch argv_split() kstrndup's the whole string and does not
split it, we simply replace the spaces with zeroes and keep the allocated
memory in argv[-1] for argv_free(arg).
We do not use argv[0] because:
- str can be all-spaces or empty. In fact this case is fine,
we could kfree() it before return, but:
- str can have a space at the start, and we can not rely on
kstrndup(skip_spaces(str)) because it can equally race if
this string is mutable.
Also, simplify count_argc() and kill the no longer used skip_arg().
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Optimize the current version of the shift-and-subtract (hardware)
algorithm, described by John von Newmann[1] and Guy L Steele.
Iterating 1,000,000 times, perf shows for the current version:
Performance counter stats for './sqrt-curr' (10 runs):
27.170996 task-clock # 0.979 CPUs utilized ( +- 3.19% )
3 context-switches # 0.103 K/sec ( +- 4.76% )
0 cpu-migrations # 0.004 K/sec ( +-100.00% )
104 page-faults # 0.004 M/sec ( +- 0.16% )
64,921,199 cycles # 2.389 GHz ( +- 0.03% )
28,967,789 stalled-cycles-frontend # 44.62% frontend cycles idle ( +- 0.18% )
<not supported> stalled-cycles-backend
104,502,623 instructions # 1.61 insns per cycle
# 0.28 stalled cycles per insn ( +- 0.00% )
34,088,368 branches # 1254.587 M/sec ( +- 0.00% )
4,901 branch-misses # 0.01% of all branches ( +- 1.32% )
0.027763015 seconds time elapsed ( +- 3.22% )
And for the new version:
Performance counter stats for './sqrt-new' (10 runs):
0.496869 task-clock # 0.519 CPUs utilized ( +- 2.38% )
0 context-switches # 0.000 K/sec
0 cpu-migrations # 0.403 K/sec ( +-100.00% )
104 page-faults # 0.209 M/sec ( +- 0.15% )
590,760 cycles # 1.189 GHz ( +- 2.35% )
395,053 stalled-cycles-frontend # 66.87% frontend cycles idle ( +- 3.67% )
<not supported> stalled-cycles-backend
398,963 instructions # 0.68 insns per cycle
# 0.99 stalled cycles per insn ( +- 0.39% )
70,228 branches # 141.341 M/sec ( +- 0.36% )
3,364 branch-misses # 4.79% of all branches ( +- 5.45% )
0.000957440 seconds time elapsed ( +- 2.42% )
Furthermore, this saves space in instruction text:
text data bss dec hex filename
111 0 0 111 6f lib/int_sqrt-baseline.o
89 0 0 89 59 lib/int_sqrt.o
[1] http://en.wikipedia.org/wiki/First_Draft_of_a_Report_on_the_EDVAC
Signed-off-by: Davidlohr Bueso <davidlohr.bueso@hp.com>
Reviewed-by: Jonathan Gonzalez <jgonzlez@linets.cl>
Tested-by: Jonathan Gonzalez <jgonzlez@linets.cl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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This patch adds three exported functions to lib/genalloc.c:
devm_gen_pool_create, dev_get_gen_pool, and of_get_named_gen_pool.
devm_gen_pool_create is a managed version of gen_pool_create that keeps
track of the pool via devres and allows the management code to
automatically destroy it after device removal.
dev_get_gen_pool retrieves the gen_pool for a given device, if it was
created with devm_gen_pool_create, using devres_find.
of_get_named_gen_pool retrieves the gen_pool for a given device node and
property name, where the property must contain a phandle pointing to a
platform device node. The corresponding platform device is then fed into
dev_get_gen_pool and the resulting gen_pool is returned.
[akpm@linux-foundation.org: make the of_get_named_gen_pool() stub static, fixing a zillion link errors]
[akpm@linux-foundation.org: squish "struct device declared inside parameter list" warning]
Signed-off-by: Philipp Zabel <p.zabel@pengutronix.de>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Michal Simek <monstr@monstr.eu>
Cc: Fabio Estevam <fabio.estevam@freescale.com>
Cc: Matt Porter <mporter@ti.com>
Cc: Dong Aisheng <dong.aisheng@linaro.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Rob Herring <rob.herring@calxeda.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Javier Martin <javier.martin@vista-silicon.com>
Cc: Huang Shijie <shijie8@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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On large systems with a lot of memory, walking all RAM to determine page
types may take a half second or even more.
In non-blockable contexts, the page allocator will emit a page allocation
failure warning unless __GFP_NOWARN is specified. In such contexts, irqs
are typically disabled and such a lengthy delay may even result in NMI
watchdog timeouts.
To fix this, suppress the page walk in such contexts when printing the
page allocation failure warning.
Signed-off-by: David Rientjes <rientjes@google.com>
Cc: Mel Gorman <mgorman@suse.de>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Dave Hansen <dave@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull kdump fixes from Peter Anvin:
"The kexec/kdump people have found several problems with the support
for loading over 4 GiB that was introduced in this merge cycle. This
is partly due to a number of design problems inherent in the way the
various pieces of kdump fit together (it is pretty horrifically manual
in many places.)
After a *lot* of iterations this is the patchset that was agreed upon,
but of course it is now very late in the cycle. However, because it
changes both the syntax and semantics of the crashkernel option, it
would be desirable to avoid a stable release with the broken
interfaces."
I'm not happy with the timing, since originally the plan was to release
the final 3.9 tomorrow. But apparently I'm doing an -rc8 instead...
* 'x86-kdump-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
kexec: use Crash kernel for Crash kernel low
x86, kdump: Change crashkernel_high/low= to crashkernel=,high/low
x86, kdump: Retore crashkernel= to allocate under 896M
x86, kdump: Set crashkernel_low automatically
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fixes from Peter Anvin:
"Three groups of fixes:
1. Make sure we don't execute the early microcode patching if family
< 6, since it would touch MSRs which don't exist on those
families, causing crashes.
2. The Xen partial emulation of HyperV can be dealt with more
gracefully than just disabling the driver.
3. More EFI variable space magic. In particular, variables hidden
from runtime code need to be taken into account too."
* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86, microcode: Verify the family before dispatching microcode patching
x86, hyperv: Handle Xen emulation of Hyper-V more gracefully
x86,efi: Implement efi_no_storage_paranoia parameter
efi: Export efi_query_variable_store() for efivars.ko
x86/Kconfig: Make EFI select UCS2_STRING
efi: Distinguish between "remaining space" and actually used space
efi: Pass boot services variable info to runtime code
Move utf16 functions to kernel core and rename
x86,efi: Check max_size only if it is non-zero.
x86, efivars: firmware bug workarounds should be in platform code
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Matt Fleming (1):
x86, efivars: firmware bug workarounds should be in platform
code
Matthew Garrett (3):
Move utf16 functions to kernel core and rename
efi: Pass boot services variable info to runtime code
efi: Distinguish between "remaining space" and actually used
space
Richard Weinberger (2):
x86,efi: Check max_size only if it is non-zero.
x86,efi: Implement efi_no_storage_paranoia parameter
Sergey Vlasov (2):
x86/Kconfig: Make EFI select UCS2_STRING
efi: Export efi_query_variable_store() for efivars.ko
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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Chao said that kdump does does work well on his system on 3.8
without extra parameter, even iommu does not work with kdump.
And now have to append crashkernel_low=Y in first kernel to make
kdump work.
We have now modified crashkernel=X to allocate memory beyong 4G (if
available) and do not allocate low range for crashkernel if the user
does not specify that with crashkernel_low=Y. This causes regression
if iommu is not enabled. Without iommu, swiotlb needs to be setup in
first 4G and there is no low memory available to second kernel.
Set crashkernel_low automatically if the user does not specify that.
For system that does support IOMMU with kdump properly, user could
specify crashkernel_low=0 to save that 72M low ram.
-v3: add swiotlb_size() according to Konrad.
-v4: add comments what 8M is for according to hpa.
also update more crashkernel_low= in kernel-parameters.txt
-v5: update changelog according to Vivek.
-v6: Change description about swiotlb referring according to HATAYAMA.
Reported-by: WANG Chao <chaowang@redhat.com>
Tested-by: WANG Chao <chaowang@redhat.com>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1366089828-19692-2-git-send-email-yinghai@kernel.org
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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We want to be able to use the utf16 functions that are currently present
in the EFI variables code in platform-specific code as well. Move them to
the kernel core, and in the process rename them to accurately describe what
they do - they don't handle UTF16, only UCS2.
Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Signed-off-by: Matt Fleming <matt.fleming@intel.com>
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Anatol Pomozov identified a race condition that hits module unloading
and re-loading. To quote Anatol:
"This is a race codition that exists between kset_find_obj() and
kobject_put(). kset_find_obj() might return kobject that has refcount
equal to 0 if this kobject is freeing by kobject_put() in other
thread.
Here is timeline for the crash in case if kset_find_obj() searches for
an object tht nobody holds and other thread is doing kobject_put() on
the same kobject:
THREAD A (calls kset_find_obj()) THREAD B (calls kobject_put())
splin_lock()
atomic_dec_return(kobj->kref), counter gets zero here
... starts kobject cleanup ....
spin_lock() // WAIT thread A in kobj_kset_leave()
iterate over kset->list
atomic_inc(kobj->kref) (counter becomes 1)
spin_unlock()
spin_lock() // taken
// it does not know that thread A increased counter so it
remove obj from list
spin_unlock()
vfree(module) // frees module object with containing kobj
// kobj points to freed memory area!!
kobject_put(kobj) // OOPS!!!!
The race above happens because module.c tries to use kset_find_obj()
when somebody unloads module. The module.c code was introduced in
commit 6494a93d55fa"
Anatol supplied a patch specific for module.c that worked around the
problem by simply not using kset_find_obj() at all, but rather than make
a local band-aid, this just fixes kset_find_obj() to be thread-safe
using the proper model of refusing the get a new reference if the
refcount has already dropped to zero.
See examples of this proper refcount handling not only in the kref
documentation, but in various other equivalent uses of this pattern by
grepping for atomic_inc_not_zero().
[ Side note: the module race does indicate that module loading and
unloading is not properly serialized wrt sysfs information using the
module mutex. That may require further thought, but this is the
correct fix at the kobject layer regardless. ]
Reported-analyzed-and-tested-by: Anatol Pomozov <anatol.pomozov@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
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Backmerge Linux 3.9-rc5 since I want to merge a few dp clock cleanups
for -next, but they will conflict all over the place with
commit 9d1a455b0ca1c2c956b4d9ab212864a8695270f1
Author: Takashi Iwai <tiwai@suse.de>
Date: Mon Mar 18 11:25:36 2013 +0100
drm/i915: Use the fixed pixel clock for eDP in intel_dp_set_m_n()
from -fixes.
Conflicts:
drivers/gpu/drm/i915/intel_dp.c: Simply adjacent lines changed.
drivers/gpu/drm/i915/intel_panel.c: A field rename in -next
conflicts with a bugfix in -fixes. Take the version from
-fixes and apply the rename.
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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The i915 driver uses sg lists for memory without backing 'struct page'
pages, similarly to other IO memory regions, setting only the DMA
address for these. It does this, so that it can program the HW MMU
tables in a uniform way both for sg lists with and without backing pages.
Without a valid page pointer we can't call nth_page to get the current
page in __sg_page_iter_next, so add a helper that relevant users can
call separately. Also add a helper to get the DMA address of the current
page (idea from Daniel).
Convert all places in i915, to use the new API.
Signed-off-by: Imre Deak <imre.deak@intel.com>
Reviewed-by: Damien Lespiau <damien.lespiau@intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
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New helper to be able to consolidate more updates
into a single transaction.
Without this, we can only grab a single refcount
on an updated element while preparing a transaction.
lc_get_cumulative - like lc_get; also finds to-be-changed elements
@lc: the lru cache to operate on
@enr: the label to look up
Unlike lc_get this also returns the element for @enr, if it is belonging to
a pending transaction, so the return values are like for lc_get(),
plus:
pointer to an element already on the "to_be_changed" list.
In this case, the cache was already marked %LC_DIRTY.
Caller needs to make sure that the pending transaction is completed,
before proceeding to actually use this element.
Signed-off-by: Philipp Reisner <philipp.reisner@linbit.com>
Signed-off-by: Lars Ellenberg <lars.ellenberg@linbit.com>
Fixed up by Jens to export lc_get_cumulative().
Signed-off-by: Jens Axboe <axboe@kernel.dk>
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There were reports of the igb driver unmapping buffers without calling
dma_mapping_error. On closer inspection issues were found in the DMA
debug API and how it handled multiple mappings of the same buffer.
The issue I found is the fact that the debug_dma_mapping_error would
only set the map_err_type to MAP_ERR_CHECKED in the case that the was
only one match for device and device address. However in the case of
non-IOMMU, multiple addresses existed and as a result it was not setting
this field once a second mapping was instantiated. I have resolved this
by changing the search so that it instead will now set MAP_ERR_CHECKED
on the first buffer that matches the device and DMA address that is
currently in the state MAP_ERR_NOT_CHECKED.
A secondary side effect of this patch is that in the case of multiple
buffers using the same address only the last mapping will have a valid
map_err_type. The previous mappings will all end up with map_err_type
set to MAP_ERR_CHECKED because of the dma_mapping_error call in
debug_dma_map_page. However this behavior may be preferable as it means
you will likely only see one real error per multi-mapped buffer, versus
the current behavior of multiple false errors mer multi-mapped buffer.
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Shuah Khan <shuah.khan@hp.com>
Tested-by: Shuah Khan <shuah.khan@hp.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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In check_unmap() it is possible to get into a dead-locked state if
dma_mapping_error is called. The problem is that the bucket is locked in
check_unmap, and locked again by debug_dma_mapping_error which is called
by dma_mapping_error. To resolve that we must release the lock on the
bucket before making the call to dma_mapping_error.
[akpm@linux-foundation.org: restore 80-col trickery to be consistent with the rest of the file]
Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Cc: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Shuah Khan <shuah.khan@hp.com>
Tested-by: Shuah Khan <shuah.khan@hp.com>
Cc: Jakub Kicinski <kubakici@wp.pl>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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wake_up_klogd() is useless when CONFIG_PRINTK=n because neither printk()
nor printk_sched() are in use and there are actually no waiter on
log_wait waitqueue. It should be a stub in this case for users like
bust_spinlocks().
Otherwise this results in this warning when CONFIG_PRINTK=n and
CONFIG_IRQ_WORK=n:
kernel/built-in.o In function `wake_up_klogd':
(.text.wake_up_klogd+0xb4): undefined reference to `irq_work_queue'
To fix this, provide an off-case for wake_up_klogd() when
CONFIG_PRINTK=n.
There is much more from console_unlock() and other console related code
in printk.c that should be moved under CONFIG_PRINTK. But for now,
focus on a minimal fix as we passed the merged window already.
[akpm@linux-foundation.org: include printk.h in bust_spinlocks.c]
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Reported-by: James Hogan <james.hogan@imgtec.com>
Cc: James Hogan <james.hogan@imgtec.com>
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>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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GFP_NOIO is often used for idr_alloc() inside preloaded section as the
allocation mask doesn't really matter. If the idr tree needs to be
expanded, idr_alloc() first tries to allocate using the specified
allocation mask and if it fails falls back to the preloaded buffer. This
order prevent non-preloading idr_alloc() users from taking advantage of
preloading ones by using preload buffer without filling it shifting the
burden of allocation to the preload users.
Unfortunately, this allowed/expected-to-fail kmem_cache allocation ends up
generating spurious slab lowmem warning before succeeding the request from
the preload buffer.
This patch makes idr_layer_alloc() add __GFP_NOWARN to the first
kmem_cache attempt and try kmem_cache again w/o __GFP_NOWARN after
allocation from preload_buffer fails so that lowmem warning is generated
if not suppressed by the original @gfp_mask.
Signed-off-by: Tejun Heo <tj@kernel.org>
Reported-by: David Teigland <teigland@redhat.com>
Tested-by: David Teigland <teigland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Commit 5dc49c75a26b ("decompressors: make the default XZ_DEC_* config
match the selected architecture") added
default y if POWERPC
to lib/xz/Kconfig. But there is no Kconfig symbol POWERPC. The most
general Kconfig symbol for the powerpc architecture is PPC. So let's
use that.
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Cc: Florian Fainelli <florian@openwrt.org>
Cc: Lasse Collin <lasse.collin@tukaani.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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