The file opened in acct_on and freshly stored in the ns->bacct struct can
be closed in acct_file_reopen by a concurrent call after we release
acct_lock and before we call mntput(file->f_path.mnt).
Record file->f_path.mnt in a local variable and use this variable only.
Signed-off-by: Renaud Lottiaux <renaud.lottiaux@kerlabs.com>
Signed-off-by: Louis Rilling <louis.rilling@kerlabs.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When the 32-bit signed quantities get assigned to the u64 resource_size_t,
they are incorrectly sign-extended.
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=13253
Addresses http://bugzilla.kernel.org/show_bug.cgi?id=9905
Signed-off-by: Zhang Rui <rui.zhang@intel.com>
Reported-by: Leann Ogasawara <leann@ubuntu.com>
Cc: Pierre Ossman <drzeus@drzeus.cx>
Reported-by: <pablomme@googlemail.com>
Tested-by: <pablomme@googlemail.com>
Cc: <stable@kernel.org>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Bugfix to spi_bitbang infrastructure: make sure to always set transfer
parameters on the first pass through the message's per-transfer loop.
This can matter with drivers that replace the per-word or per-buffer
transfer primitives, on busses with multiple SPI devices.
Previously, this could have started messages using the settings left after
previous messages. The problem was observed when a high speed chip
(m25p80 type flash) was running very slowly because a low speed device
(avr8 microcontroller) had previously used the bus. Similar faults could
have driven the low speed device too fast, or used an unexpected word
size.
Acked-by: Steven A. Falco <sfalco@harris.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a mutex to avoid a circular locking problem between the mm layer
semaphore and fbdev ioctl mutex through the fb_mmap() call.
Also, add mutex to all places where smem_start and smem_len fields change
so the mutex inside the fb_mmap() is actually used. Changing of these
fields before calling the framebuffer_register() are not mutexed.
This is 2.6.31 material. It removes one lockdep (fb_mmap() and
register_framebuffer()) but there is still another one (fb_release() and
register_framebuffer()). It also cleans up handling of the smem_start and
smem_len fields used by mutexed section of the fb_mmap().
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add a new spi_master.flags word listing constraints relevant to that
controller. Define the first constraint bit: a half duplex restriction.
Include that constraint in the OMAP1 MicroWire controller driver.
Have the mmc_spi host be the first customer of this flag. Its coding
relies heavily on full duplex transfers, so it must fail when the
underlying controller driver won't perform them.
(The spi_write_then_read routine could use it too: use the
temporarily-withdrawn full-duplex speedup unless this flag is set, in
which case the existing code applies. Similarly, any spi_master
implementing only SPI_3WIRE should set the flag.)
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add two new spi_device.mode bits to accomodate more protocol options, and
pass them through to usermode drivers:
* SPI_NO_CS ... a second 3-wire variant, where the chipselect
line is removed instead of a data line; transfers are still
full duplex.
This obviously has STRONG protocol implications since the
chipselect transitions can't be used to synchronize state
transitions with the SPI master.
* SPI_READY ... defines open drain signal that's pulled low
to pause the clock. This defines a 5-wire variant (normal
4-wire SPI plus READY) and two 4-wire variants (READY plus
each of the 3-wire flavors).
Such hardware flow control can be a big win. There are ADC
converters and flash chips that expose READY signals, but not
many host controllers support it today.
The spi_bitbang code should be changed to use SPI_NO_CS instead of its
current nonportable hack. That's a mode most hardware can easily support
(unlike SPI_READY).
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Cc: "Paulraj, Sandeep" <s-paulraj@ti.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
show_pools() walks the page_list of a pool w/o protection against the list
modifications in alloc/free. Take pool->lock to avoid stomping into
nirvana.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
ext2_iget() returns -ESTALE if invoked on a deleted inode, in order to
report errors to NFS properly. However, in ext[234]_lookup(), this
-ESTALE can be propagated to userspace if the filesystem is corrupted such
that a directory entry references a deleted inode. This leads to a
misleading error message - "Stale NFS file handle" - and confusion on the
part of the admin.
The bug can be easily reproduced by creating a new filesystem, making a
link to an unused inode using debugfs, then mounting and attempting to ls
-l said link.
This patch thus changes ext2_lookup to return -EIO if it receives -ESTALE
from ext2_iget(), as ext2 does for other filesystem metadata corruption;
and also invokes the appropriate ext*_error functions when this case is
detected.
Signed-off-by: Bryan Donlan <bdonlan@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
With ELF, at generating coredump, some more headers other than used
vmas are added.
When max_map_count == 65536, a core generated by following kinds of
code can be unreadable because the number of ELF's program header is
written in 16bit in Ehdr (please see elf.h) and the number overflows.
==
... = mmap(); (munmap, mprotect, etc...)
if (failed)
abort();
==
This can happen in mmap/munmap/mprotect/etc...which calls split_vma().
I think 65536 is not safe as _default_ and reduce it to 65530 is good
for avoiding unexpected corrupted core.
Anyway, max_map_count can be enlarged by sysctl if a user is brave..
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Jakub Jelinek <jakub@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Since some new MPC85xx SOCs support DDR3 memory now, so add DDR3 memory
type for MPC85xx EDAC.
Signed-off-by: Yang Shi <yang.shi@windriver.com>
Cc: Doug Thompson <norsk5@yahoo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Commonly available versions of cp and tar don't work well with special
files created using seq_file. Mention this problem in the gcov
documentation and update the helper script example to work around these
problems.
Signed-off-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
alpha percpu access requires custom SHIFT_PERCPU_PTR() definition for
modules to work around addressing range limitation. This is done via
generating inline assembly using C preprocessing which forces the
assembler to generate external reference. This happens behind the
compiler's back and makes the compiler think that static percpu variables
in modules are unused.
This used to be worked around by using __unused attribute for percpu
variables which prevent the compiler from omitting the variable; however,
recent declare/definition attribute unification change broke this as
__used can't be used for declaration. Also, in the process,
PER_CPU_ATTRIBUTES definition in alpha percpu.h got broken.
This patch adds PER_CPU_DEF_ATTRIBUTES which is only used for definitions
and make alpha use it to add __used for percpu variables in modules. This
also fixes the PER_CPU_ATTRIBUTES double definition bug.
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: maximilian attems <max@stro.at>
Acked-by: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Richard Henderson <rth@twiddle.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
When building with a 4.1.x compiler on powerpc64 (at least) we get this
error:
drivers/video/logo/logo_linux_mono.c:81: error: logo_linux_mono causes a section type conflict
This was introduced by commit ae52bb2384
("fbdev: move logo externs to header file"). This is a partial revert of
that commit sufficient to not hit the compiler bug.
Also convert _clut arrays from __initconst to __initdata.
Sam said:
Al analysed this some time ago. When we say something is const then
_sometimes_ gcc annotate the section as const(?) - sometimes not. So if
we have two variables/functions annotated __*const and gcc decides to
annotate the section const only in one case we get a section type
conflict.
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Sam Ravnborg <sam@ravnborg.org>
Cc: Krzysztof Helt <krzysztof.h1@poczta.fm>
Cc: Geert Uytterhoeven <Geert.Uytterhoeven@sonycom.com>
Cc: Kyle McMartin <kyle@mcmartin.ca>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
The ctors section for each object file is eight byte aligned (on 64 bit).
However the __ctors_start symbol starts at an arbitrary address dependent
on the size of the previous sections.
Therefore the linker may add some zeroes after __ctors_start to make sure
the ctors contents are properly aligned. However the extra zeroes at the
beginning aren't expected by the code. When walking the functions
pointers contained in there and extra zeroes are added this may result in
random jumps. So make sure that the __ctors_start symbol is always
aligned as well.
Fixes this crash on an allyesconfig on s390:
[ 0.582482] Kernel BUG at 0000000000000012 [verbose debug info unavailable]
[ 0.582489] illegal operation: 0001 [#1] SMP DEBUG_PAGEALLOC
[ 0.582496] Modules linked in:
[ 0.582501] CPU: 0 Tainted: G W 2.6.31-rc1-dirty #273
[ 0.582506] Process swapper (pid: 1, task: 000000003f218000, ksp: 000000003f2238e8)
[ 0.582510] Krnl PSW : 0704200180000000 0000000000000012 (0x12)
[ 0.582518] R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:0 CC:2 PM:0 EA:3
[ 0.582524] Krnl GPRS: 0000000000036727 0000000000000010 0000000000000001 0000000000000001
[ 0.582529] 00000000001dfefa 0000000000000000 0000000000000000 0000000000000040
[ 0.582534] 0000000001fff0f0 0000000001790628 0000000002296048 0000000002296048
[ 0.582540] 00000000020c438e 0000000001786000 0000000002014a66 000000003f223e60
[ 0.582553] Krnl Code:>0000000000000012: 0000 unknown
[ 0.582559] 0000000000000014: 0000 unknown
[ 0.582564] 0000000000000016: 0000 unknown
[ 0.582570] 0000000000000018: 0000 unknown
[ 0.582575] 000000000000001a: 0000 unknown
[ 0.582580] 000000000000001c: 0000 unknown
[ 0.582585] 000000000000001e: 0000 unknown
[ 0.582591] 0000000000000020: 0000 unknown
[ 0.582596] Call Trace:
[ 0.582599] ([<0000000002014a46>] kernel_init+0x622/0x7a0)
[ 0.582607] [<0000000000113e22>] kernel_thread_starter+0x6/0xc
[ 0.582615] [<0000000000113e1c>] kernel_thread_starter+0x0/0xc
[ 0.582621] INFO: lockdep is turned off.
[ 0.582624] Last Breaking-Event-Address:
[ 0.582627] [<0000000002014a64>] kernel_init+0x640/0x7a0
Cc: Peter Oberparleiter <oberpar@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Change the eventfd interface to de-couple the eventfd memory context, from
the file pointer instance.
Without such change, there is no clean way to racely free handle the
POLLHUP event sent when the last instance of the file* goes away. Also,
now the internal eventfd APIs are using the eventfd context instead of the
file*.
This patch is required by KVM's IRQfd code, which is still under
development.
Signed-off-by: Davide Libenzi <davidel@xmailserver.org>
Cc: Gregory Haskins <ghaskins@novell.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Benjamin LaHaise <bcrl@kvack.org>
Cc: Avi Kivity <avi@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If we try to modify one of the md/ sysfs files
suspend_lo or suspend_hi
when the array is not active, we dereference a NULL.
Protect against that.
Cc: stable@kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>
Switch MD over to the new disk_stack_limits() function which checks for
aligment and adjusts preferred I/O sizes when stacking.
Also indicate preferred I/O sizes where applicable.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>
So that we can filter by comm. Symbols in other comms won't be
accounted for.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1246399282-20934-3-git-send-email-acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
So that we can filter by dso. Symbols in other dsos won't be
accounted for.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1246399282-20934-2-git-send-email-acme@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
I'm taking my sabbatical from Intel for July/August 2009.
Fenghua Yu will handle ia64 architecture while I'm gone.
Signed-off-by: Tony Luck <tony.luck@intel.com>
perfmon.c has a dubious cast directly from "int" to "void *". Add
an intermediate cast to "long" to keep gcc happy.
salinfo.c uses "down_trylock()" in a highly creative way (explained
in the comments in the file) ... but it does kick out this warning:
arch/ia64/kernel/salinfo.c:195: warning: ignoring return value of 'down_trylock'
which people occasionally try to "fix" in ways that do not work. Use some
casts to keep gcc quiet.
Signed-off-by: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
This happens to work at the moment but isn't a good idea so fix it the
simple way.
Resolves-bug: http://bugzilla.kernel.org/show_bug.cgi?id=13576
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Don't unlock on vfs_rejected_lock path in afs_do_setlk, since the lock
is unlocked after abort_attempt label.
Signed-off-by: Jiri Slaby <jirislaby@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Alas current delaying of freeing old tnodes by RCU in trie_rebalance
is still not enough because we can free a top tnode before updating a
t->trie pointer.
Reported-by: Pawel Staszewski <pstaszewski@itcare.pl>
Tested-by: Pawel Staszewski <pstaszewski@itcare.pl>
Signed-off-by: Jarek Poplawski <jarkao2@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This is the same fix as commit
7959ea254e ("bnx2: Fix the behavior of
ethtool when ONBOOT=no"), but for bnx2x:
--------------------
When configure in ifcfg-eth* is ONBOOT=no,
the behavior of ethtool command is wrong.
# grep ONBOOT /etc/sysconfig/network-scripts/ifcfg-eth2
ONBOOT=no
# ethtool eth2 | tail -n1
Link detected: yes
I think "Link detected" should be "no".
--------------------
Signed-off-by: Naohiro Ooiwa <nooiwa@miraclelinux.com>
Acked-by: Eilon Greenstein <eilong@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
I.e. we can't handle these two kinds of files in the same way:
1) prelinked system library:
[acme@doppio pahole]$ readelf -s /usr/lib64/libdw-0.141.so | egrep 'FUNC.+GLOBAL.+dwfl_report_elf'
278: 00000030450105a0 261 FUNC GLOBAL DEFAULT 12 dwfl_report_elf@@ELFUTILS_0.122
2) not prelinked library with debug information from a -debuginfo package:
[acme@doppio pahole]$ readelf -s /usr/lib/debug/usr/lib64/libdw-0.141.so.debug | egrep 'FUNC.+GLOBAL.+dwfl_report_elf'
629: 00000000000105a0 261 FUNC GLOBAL DEFAULT 12 dwfl_report_elf
[acme@doppio pahole]$
Now the numbers I got for a pahole perf run are in line with
the numbers I get from oprofile.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20090630144317.GB12663@ghostprotocols.net>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
The offset passed to blk_stack_limits() must be in bytes not sectors.
Fixes false warnings like the following:
device-mapper: table: 254:1: target device sda6 is misaligned
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Reported-by: Frans Pop <elendil@planet.nl>
Tested-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
Fix exception store name handling.
We need to reference exception store by zero terminated string.
Fixes regression introduced in commit f6bd4eb73c
Cc: Yi Yang <yi.y.yang@intel.com>
Cc: Jonathan Brassow <jbrassow@redhat.com>
Cc: stable@kernel.org
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Milan Broz <mbroz@redhat.com>
Signed-off-by: Alasdair G Kergon <agk@redhat.com>
This provides a way to mark a counter to be enabled on the next
exec. This is useful for measuring the total activity of a
program without including overhead from the process that
launches it.
This also changes the perf stat command to use this new
facility.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <19017.43927.838745.689203@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/ide-2.6:
ide: memory overrun in ide_get_identity_ioctl() on big endian machines using ioctl HDIO_OBSOLETE_IDENTITY
ide: fix resume for CONFIG_BLK_DEV_IDEACPI=y
ide-cd: handle fragmented packet commands gracefully
ide: always kill the whole request on error
ide: fix ide_kill_rq() for special ide-{floppy,tape} driver requests
Commit 'net: skb->dst accessors'(adf30907d6)
broken the sctp protocol stack, the sctp packet can never be sent out after
Eric Dumazet's patch, which have typo in the sctp code.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Vlad Yasevich <vladisalv.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Clean up to use xfrm_addr_cmp() instead of compare addresses directly.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
If a socket starts out on a non-TSO route, and then switches to
a TSO route, then we will tack on data to the tail of the tx queue
even if it started out life as non-TSO. This is suboptimal because
all of it will then be copied and checksummed unnecessarily.
This patch fixes this by ensuring that skb->ip_summed is set to
CHECKSUM_PARTIAL before appending extra data beyond the MSS.
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
If a socket starts out on a non-TSO route, and then switches to
a TSO route, then the tail on the tx queue can morph into a TSO
packet, causing mischief because the rest of the stack does not
expect a partially linear TSO packet.
This patch fixes this by ensuring that skb->ip_summed is set to
CHECKSUM_PARTIAL before declaring a packet as TSO.
Reported-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>
This patch fixes a memory overrun in function ide_get_identity_ioctl() which
chooses the size of a memory buffer depending on the ioctl command that led
to the function call, however, passes that buffer to a function which needs the
buffer size to be always chosen unconditionally.
Due to conditional compilation the memory overrun can only happen on big endian
machines. The error can be triggered using ioctl HDIO_OBSOLETE_IDENTITY. Usage
of ioctl HDIO_GET_IDENTITY is safe.
Signed-off-by: Christian Engelmayer <christian.engelmayer@frequentis.com>
Acked-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
commit 2f0d0fd2a6 ("ide-acpi: cleanup
do_drive_get_GTF()") didn't account for the lack of hwif->acpidata
check in generic_ide_suspend() [ indirect user of do_drive_get_GTF()
through ide_acpi_exec_tfs() ] resulting in broken resume when ACPI
support is enabled but ACPI data is unavailable.
Fix it by adding ide_port_acpi() helper for checking if port needs
ACPI handling and cleaning generic_ide_{suspend,resume}() to use it
instead of hiding hwif->acpidata and ide_noacpi checks in IDE ACPI
helpers (this should help in preventing similar bugs in the future).
While at it:
- kill superfluous debugging printks in ide_acpi_{get,push}_timing()
Reported-and-tested-by: Etienne Basset <etienne.basset@numericable.fr>
Also-reported-and-tested-by: Jeff Chua <jeff.chua.linux@gmail.com>
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Vince Weaver reported a 'perf stat' measurement overhead in the
count of retired instructions, which can amount to a +6000
instructions inflated count in the reported count.
At present, perf stat creates its counters on the perf process. Thus
the counters count the fork and various other activity in both the
parent and child, such as the resolver overhead for resolving PLT
entries for any libc functions that haven't been called before, such
as execvp.
This reduces the overhead by creating the counters on the child process
after the fork, using a couple of pipes to synchronize so that the
child process waits until the parent has created the counters before
doing the exec. To eliminate the PLT resolution overhead on calling
execvp, this does a dummy execvp first which will always fail.
With this, the overhead of executing a program goes down from over
4800 instructions to about 90 instructions on powerpc (32-bit).
This was measured with a statically-linked program written in
assembler which only does the 3 instructions needed to call _exit(0).
Before:
$ perf stat -e 0:1:u ./three
Performance counter stats for './three':
4858 instructions
0.001274523 seconds time elapsed
After:
$ perf stat -e 0:1:u ./three
Performance counter stats for './three':
92 instructions
0.000468153 seconds time elapsed
Reported-by: Vince Weaver <vince@deater.net>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <19016.41425.814043.870352@cargo.ozlabs.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Peter expressed a strong preference for percentage based
display of scaled values - so revert to that from the
recently introduced multiplication-factor unit.
Reported-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jaswinder Singh Rajput <jaswinder@kernel.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
LKML-Reference: <new-submission>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tiwai/sound-2.6:
sound: OSS: mpu401, fix deadlock
ALSA: hda - Add missing initializations for ALC268 and ALC269
ALSA: cmi8330: fix MPU-401 PnP init copy&paste bug
ALSA: hda - Line In for Acer Inspire 6530G model
sound: oxygen: make mic volume control mono
MAINTAINERS: Add entry for twl4030 series soc codec driver
ALSA: lx6464es - configure ethersound io channels
sound: Use PCI_VDEVICE for CREATIVE and ECTIVA
sound: Use PCI_VDEVICE
ALSA: hda - Use model=acer-aspire-6530g for Acer Aspire 6930G
ALSA: hda - Fix acer-aspire-6530g model quirk
ALSA: hda - Add pin-sense trigger when needed for Realtek codecs
ALSA: hda - Fix support for Samsung P50 with AD1986A codec
ALSA: hda - Generalize the pin-detect quirk for Lenovo N100
ALSA: hda - Simplify AD1986A mixer definitions
