Commit graph

195550 commits

Author SHA1 Message Date
Eric Dumazet
ab6e3feba1 net: No dst refcounting in ip_queue_xmit()
TCP outgoing packets can avoid two atomic ops, and dirtying
of previously higly contended cache line using new refdst
infrastructure.

Note 1: loopback device excluded because of !IFF_XMIT_DST_RELEASE
Note 2: UDP packets dsts are built before ip_queue_xmit().

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 17:18:52 -07:00
Eric Dumazet
4a94445c9a net: Use ip_route_input_noref() in input path
Use ip_route_input_noref() in ip fast path, to avoid two atomic ops per
incoming packet.

Note: loopback is excluded from this optimization in ip_rcv_finish()

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 17:18:51 -07:00
Eric Dumazet
407eadd996 net: implements ip_route_input_noref()
ip_route_input() is the version returning a refcounted dst, while
ip_route_input_noref() returns a non refcounted one.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 17:18:51 -07:00
Eric Dumazet
7fee226ad2 net: add a noref bit on skb dst
Use low order bit of skb->_skb_dst to tell dst is not refcounted.

Change _skb_dst to _skb_refdst to make sure all uses are catched.

skb_dst() returns the dst, regardless of noref bit set or not, but
with a lockdep check to make sure a noref dst is not given if current
user is not rcu protected.

New skb_dst_set_noref() helper to set an notrefcounted dst on a skb.
(with lockdep check)

skb_dst_drop() drops a reference only if skb dst was refcounted.

skb_dst_force() helper is used to force a refcount on dst, when skb
is queued and not anymore RCU protected.

Use skb_dst_force() in __sk_add_backlog(), __dev_xmit_skb() if
!IFF_XMIT_DST_RELEASE or skb enqueued on qdisc queue, in
sock_queue_rcv_skb(), in __nf_queue().

Use skb_dst_force() in dev_requeue_skb().

Note: dst_use_noref() still dirties dst, we might transform it
later to do one dirtying per jiffies.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 17:18:50 -07:00
Eric Dumazet
ebda37c27d rps: avoid one atomic in enqueue_to_backlog
If CONFIG_SMP=y, then we own a queue spinlock, we can avoid the atomic
test_and_set_bit() from napi_schedule_prep().

We now have same number of atomic ops per netif_rx() calls than with
pre-RPS kernel.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 17:18:50 -07:00
Neil Jones
3f78d1f210 drivers/net/usb/asix.c: Fix unaligned accesses
Using this driver can cause unaligned accesses in the IP layer
This has been fixed by aligning the skb data correctly using the
spare room left over by the 4 byte header inserted between packets
by the device.

Signed-off-by: Neil Jones <NeilJay@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 17:18:28 -07:00
Brian King
e7a3af5d8c ibmveth: Add suspend/resume support
Adds support for resuming from suspend for IBM virtual ethernet devices.
We may have lost an interrupt over the suspend, so we just kick the
interrupt handler to process anything that is outstanding.

Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 17:09:10 -07:00
Florian Westphal
0771275b25 ipv6 addrlabel: permit deletion of labels assigned to removed dev
as addrlabels with an interface index are left alone when the
interface gets removed this results in addrlabels that can no
longer be removed.

Restrict validation of index to adding new addrlabels.

Signed-off-by: Florian Westphal <fw@strlen.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2010-05-17 17:08:08 -07:00
James Morris
539c99fd7f Merge branch 'next' into for-linus 2010-05-18 08:57:00 +10:00
Dan Carpenter
4d09ec0f70 KEYS: Return more accurate error codes
We were using the wrong variable here so the error codes weren't being returned
properly.  The original code returns -ENOKEY.

Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>
2010-05-18 08:50:55 +10:00
Ingo Molnar
9c6f7e43b4 stop_machine: Move local variable closer to the usage site in cpu_stop_cpu_callback()
This addresses the following compiler warning:

 kernel/stop_machine.c: In function 'cpu_stop_cpu_callback':
 kernel/stop_machine.c:297: warning: unused variable 'work'

Cc: Tejun Heo <tj@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <tip-3fc1f1e27a5b807791d72e5d992aa33b668a6626@git.kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2010-05-18 00:17:44 +02:00
H. Peter Anvin
c59bd56882 x86, hweight: Use a 32-bit popcnt for __arch_hweight32()
Use a 32-bit popcnt instruction for __arch_hweight32(), even on
x86-64.  Even though the input register will *usually* be
zero-extended due to the standard operation of the hardware, it isn't
necessarily so if the input value was the result of truncating a
64-bit operation.

Note: the POPCNT32 variant used on x86-64 has a technically
unnecessary REX prefix to make it five bytes long, the same as a CALL
instruction, therefore avoiding an unnecessary NOP.

Reported-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <alpine.LFD.2.00.1005171443060.4195@i5.linux-foundation.org>
2010-05-17 15:17:16 -07:00
Arnaldo Carvalho de Melo
94f3ca9578 perf tools: Add mode to build without newt support
make NO_NEWT=1

Will avoid building the newt (tui) support.

Suggested-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 18:18:11 -03:00
Jeff Layton
4065c802da cifs: fix noserverino handling when unix extensions are enabled
The uniqueid field sent by the server when unix extensions are enabled
is currently used sometimes when it shouldn't be. The readdir codepath
is correct, but most others are not. Fix it.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-05-17 20:59:21 +00:00
Arnaldo Carvalho de Melo
2f51903bc3 perf symbols: symbol inconsistency message should be done only at verbose=1
That happened for an old perf.data file that had no fake MMAP events for
the kernel modules, but even then it should warn once for each module,
not one time for every symbol in every module not found.

Reported-by: Ingo Molnar <mingo@elte.hu>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 17:57:59 -03:00
Jeff Layton
84f30c66c3 cifs: don't update uniqueid in cifs_fattr_to_inode
We use this value to find an inode within the hash bucket, so we can't
change this without re-hashing the inode. For now, treat this value
as immutable.

Eventually, we should probably use an inode number change on a path
based operation to indicate that the lookup cache is invalid, but that's
a bit more code to deal with.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-05-17 20:57:27 +00:00
Jeff Layton
db19272edc cifs: always revalidate hardlinked inodes when using noserverino
The old cifs_revalidate logic always revalidated hardlinked inodes.
This hack allowed CIFS to pass some connectathon tests when server inode
numbers aren't used (basic test7, in particular).

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
2010-05-17 20:55:58 +00:00
Linus Torvalds
ba2e1c5f25 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/geert/linux-m68k:
  m68k: amiga - Floppy platform device conversion
  m68k: amiga - Sound platform device conversion
  m68k: amiga - Frame buffer platform device conversion
  m68k: amiga - Zorro host bridge platform device conversion
  m68k: amiga - Zorro bus modalias support
  platform: Make platform resource input parameters const
  m68k: invoke oom-killer from page fault
  serial167: Kill unused variables
  m68k: Implement generic_find_next_{zero_,}le_bit()
  m68k: hp300 - Checkpatch cleanup
  m68k: Remove trailing spaces in messages
  m68k: Simplify param.h by using <asm-generic/param.h>
  m68k: Remove BKL from rtc implementations
2010-05-17 13:54:29 -07:00
Linus Torvalds
7d32c0aca4 Merge git://git.kernel.org/pub/scm/linux/kernel/git/joern/logfs
* git://git.kernel.org/pub/scm/linux/kernel/git/joern/logfs:
  logfs: handle powerfail on NAND flash
  logfs: handle errors from get_mtd_device()
  logfs: remove unused variable
  logfs: fix sync
  logfs: fix compile failure
  logfs: initialize li->li_refcount
  logfs: commit reservations under space pressure
  logfs: survive logfs_buf_recover read errors
  logfs: Close i_ino reuse race
  logfs: fix logfs_seek_hole()
  logfs: Return -EINVAL if filesystem image doesn't match
  LogFS: Fix typo in b6349ac8
  logfs: testing the wrong variable
2010-05-17 13:53:35 -07:00
Linus Torvalds
3d2c978e0c Merge branch 'bkl/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing
* 'bkl/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/random-tracing:
  ptrace: Cleanup useless header
  ptrace: kill BKL in ptrace syscall
2010-05-17 13:48:10 -07:00
Arnaldo Carvalho de Melo
63aa9e7e3a perf tui: Add explicit -lslang option
At least on rawhide using -lnewt is not enough if we use SLang routines
directly, so add an explicit -lslang since we use SLang routines.

Reported-by: Ingo Molnar <mingo@elte.hu>
Tested-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 16:42:37 -03:00
Geert Uytterhoeven
92183b346f m68k: amiga - Floppy platform device conversion
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:37:45 +02:00
Geert Uytterhoeven
ff2db7c5ab m68k: amiga - Sound platform device conversion
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:37:44 +02:00
Geert Uytterhoeven
fa6688e1c7 m68k: amiga - Frame buffer platform device conversion
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:37:43 +02:00
Geert Uytterhoeven
0d305464ae m68k: amiga - Zorro host bridge platform device conversion
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:37:42 +02:00
Geert Uytterhoeven
bf54a2b3c0 m68k: amiga - Zorro bus modalias support
Add Amiga Zorro bus modalias and uevent support

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:37:41 +02:00
Geert Uytterhoeven
0b7f1a7efb platform: Make platform resource input parameters const
Make the platform resource input parameters of platform_device_add_resources()
and platform_device_register_simple() const, as the resources are copied and
never modified.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
2010-05-17 21:37:40 +02:00
Nick Piggin
adbf6e6952 m68k: invoke oom-killer from page fault
As explained in commit 1c0fe6e3bd, we want to call the architecture independent
oom killer when getting an unexplained OOM from handle_mm_fault, rather than
simply killing current.

Cc: linux-m68k@lists.linux-m68k.org
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: linux-arch@vger.kernel.org
Signed-off-by: Nick Piggin <npiggin@suse.de>
Acked-by: David Rientjes <rientjes@google.com>
[Geert] Kill 2 introduced compiler warnings
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:37:39 +02:00
Geert Uytterhoeven
f3c7f317c9 serial167: Kill unused variables
commits 638157bc14 ("serial167: prepare to push
BKL down into drivers") and 4165fe4ef7 ("tty:
Fix up char drivers request_room usage") removed code without removing the
corresponding variables:

| drivers/char/serial167.c: In function 'cd2401_rx_interrupt':
| drivers/char/serial167.c:630: warning: unused variable 'len'
| drivers/char/serial167.c: In function 'cy_ioctl':
| drivers/char/serial167.c:1531: warning: unused variable 'val'

Remove the variables to kill the warnings.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:37:38 +02:00
Peter Ujfalusi
2d4cdd6fc9 ASoC: tlv320dac33: Avoid powering off while in BIAS_OFF
Avoid calling the dac33_hard_power when the codec was
already in BIAS_OFF state.
This could happen in device suspend and module removal
time.

Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-05-17 20:34:15 +01:00
Felipe Balbi
7fd1d74bfc ASoC: tlv320dac33: Use dev_dbg in dac33_hard_power function
Since the cases when the same power state would be set again
handled gracefully, we do not need to use dev_warn.

Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Peter Ujfalusi <peter.ujfalusi@nokia.com>
Acked-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
Signed-off-by: Liam Girdwood <lrg@slimlogic.co.uk>
2010-05-17 20:34:10 +01:00
Arnaldo Carvalho de Melo
edb7c60e27 perf options: Type check all the remaining OPT_ variants
OPT_SET_INT was renamed to OPT_SET_UINT since the only use in these
tools is to set something that has an enum type, that is builtin
compatible with unsigned int.

Several string constifications were done to make OPT_STRING require a
const char * type.

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 16:22:41 -03:00
Arnaldo Carvalho de Melo
8035458fbb perf options: Type check OPT_BOOLEAN and fix the offenders
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 16:22:37 -03:00
Geert Uytterhoeven
b52dd0077c m68k: Implement generic_find_next_{zero_,}le_bit()
linux-next:
fs/udf/balloc.c: In function 'udf_bitmap_new_block':
fs/udf/balloc.c:274: error: implicit declaration of function 'generic_find_next_le_bit'

Convert ext2_find_next_{zero_,}bit() into generic_find_next_{zero_,}le_bit(),
and wrap the ext2_find_next_{zero_,}bit() around the latter.

Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:15:40 +02:00
Andrea Gelmini
9881bbb269 m68k: hp300 - Checkpatch cleanup
arch/m68k/hp300/time.h:2: WARNING: space prohibited between function name and open parenthesis '('

Signed-off-by: Andrea Gelmini <andrea.gelmini@gelma.net>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:15:40 +02:00
Frans Pop
b9b0d8b430 m68k: Remove trailing spaces in messages
Signed-off-by: Frans Pop <elendil@planet.nl>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:15:40 +02:00
Robert P. J. Day
291d7e9553 m68k: Simplify param.h by using <asm-generic/param.h>
Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:15:39 +02:00
Thomas Gleixner
b1f3bb494e m68k: Remove BKL from rtc implementations
m68k does not support SMP. The access to the rtc is already serialized
with local_irq_save/restore which is sufficient on UP.

The open() protection in arch/m68k/mvme16x/rtc.c is not pretty but
sufficient on UP and safe w/o the BKL.

open() in arch/m68k/bvme6000/rtc.c can do with the same atomic logic
as arch/m68k/mvme16x/rtc.c

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
2010-05-17 21:15:39 +02:00
Arnaldo Carvalho de Melo
1967936d68 perf options: Check v type in OPT_U?INTEGER
To avoid problems like the one fixed by Stephane Eranian in 3de29ca, now
we'll got this instead:

	bench/sched-messaging.c:259: error: negative width in bit-field ‘<anonymous>’
	bench/sched-messaging.c:261: error: negative width in bit-field ‘<anonymous>’

Which is rather cryptic, but is how BUILD_BUG_ON_ZERO works, so kernel
hackers should be already used to this.

With it in place found some problems, fixed by changing the affected
variables to sensible types or changed some OPT_INTEGER to OPT_UINTEGER.

Next csets will go thru converting each of the remaining OPT_ so that
review can be made easier by grouping changes per type per patch.

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 15:43:38 -03:00
Arnaldo Carvalho de Melo
c100edbee8 perf options: Introduce OPT_UINTEGER
For unsigned int options to be parsed, next patches will make use of it.

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 15:30:00 -03:00
John W. Linville
6fe70aae0d Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-next-2.6 into for-davem 2010-05-17 13:57:43 -04:00
John W. Linville
0c348d7c14 Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/linville/wireless-2.6 2010-05-17 13:31:05 -04:00
Andreas Herrmann
fec84e3307 x86, hpet: Add reference to chipset erratum documentation for disable-hpet-msi-quirk
(At the moment the "SB700 Family Product Errata" document is available
at http://support.amd.com/us/Embedded_TechDocs/46837.pdf)

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20100517164324.GB10254@alberich.amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2010-05-17 10:04:43 -07:00
Russell King
ac1d426e82 Merge branch 'devel-stable' into devel
Conflicts:
	arch/arm/Kconfig
	arch/arm/include/asm/system.h
	arch/arm/mm/Kconfig
2010-05-17 17:24:04 +01:00
Russell King
fda0e18c8a Merge branch 'devel-pmu' into devel 2010-05-17 17:21:23 +01:00
Hartley Sweeten
98830bc996 ARM: 6136/1: ARCH_REQUIRE_GPIOLIB selects GENERIC_GPIO
The ARCH_REQUIRE_GPIOLIB config option will select GPIOLIB which
in turn will select GENERIC_GPIO.  Because of this, there is no
reason to do the select GENERIC_GPIO in arch/arm/Kconfig for the
architectures that have ARCH_REQUIRE_GPIOLIB.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2010-05-17 17:21:16 +01:00
Arnaldo Carvalho de Melo
dc4ff19341 perf tui: Add workaround for slang < 2.1.4
Older versions of the slang library didn't used the 'const' specifier,
causing problems with modern compilers of this kind:

util/newt.c:252: error: passing argument 1 of ‘SLsmg_printf’ discards
qualifiers from pointer target type

Fix it by using some wrappers that when needed const the affected
parameters back to plain (char *).

Reported-by: Lin Ming <ming.m.lin@intel.com>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Lin Ming <ming.m.lin@intel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <20100517145421.GD29052@ghostprotocols.net>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 12:28:34 -03:00
Stephane Eranian
3de29cab1f perf record: Fix bug mismatch with -c option definition
The -c option defines the user requested sampling period. It was implemented
using an unsigned int variable but the type of the option was OPT_LONG. Thus,
the option parser was overwriting memory belonging to other variables, namely
the mmap_pages leading to a zero page sampling buffer. The bug was exposed only
when compiling at -O0, probably because the compiler was padding variables at
higher optimization levels.

This patch fixes this problem by declaring user_interval as u64. This also
avoids wrap-around issues for large period on 32-bit systems.

Commiter note:

Made it use OPT_U64(user_interval) after implementing OPT_U64 in the
previous patch.

Cc: David S. Miller <davem@davemloft.net>
Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
LKML-Reference: <4bf11ae9.e88cd80a.06b0.ffffa8e3@mx.google.com>
Signed-off-by: Stephane Eranian <eranian@google.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 12:23:18 -03:00
Arnaldo Carvalho de Melo
6ba85cea87 perf options: Introduce OPT_U64
We have things like user_interval (-c/--count) in 'perf record' that
needs this.

Cc: Frédéric Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2010-05-17 12:16:48 -03:00
Anton Blanchard
81880d603d atomic_t: Remove volatile from atomic_t definition
When looking at a performance problem on PowerPC, I noticed some awful code
generation:

c00000000051fc98:       3b 60 00 01     li      r27,1
...
c00000000051fca0:       3b 80 00 00     li      r28,0
...
c00000000051fcdc:       93 61 00 70     stw     r27,112(r1)
c00000000051fce0:       93 81 00 74     stw     r28,116(r1)
c00000000051fce4:       81 21 00 70     lwz     r9,112(r1)
c00000000051fce8:       80 01 00 74     lwz     r0,116(r1)
c00000000051fcec:       7d 29 07 b4     extsw   r9,r9
c00000000051fcf0:       7c 00 07 b4     extsw   r0,r0

c00000000051fcf4:       7c 20 04 ac     lwsync
c00000000051fcf8:       7d 60 f8 28     lwarx   r11,0,r31
c00000000051fcfc:       7c 0b 48 00     cmpw    r11,r9
c00000000051fd00:       40 c2 00 10     bne-    c00000000051fd10
c00000000051fd04:       7c 00 f9 2d     stwcx.  r0,0,r31
c00000000051fd08:       40 c2 ff f0     bne+    c00000000051fcf8
c00000000051fd0c:       4c 00 01 2c     isync

We create two constants, write them out to the stack, read them straight back
in and sign extend them. What a mess.

It turns out this bad code is a result of us defining atomic_t as a
volatile int.

We removed the volatile attribute from the powerpc atomic_t definition years
ago, but commit ea43546750 (atomic_t: unify all
arch definitions) added it back in.

To dig up an old quote from Linus:

> The fact is, volatile on data structures is a bug. It's a wart in the C
> language. It shouldn't be used.
>
> Volatile accesses in *code* can be ok, and if we have "atomic_read()"
> expand to a "*(volatile int *)&(x)->value", then I'd be ok with that.
>
> But marking data structures volatile just makes the compiler screw up
> totally, and makes code for initialization sequences etc much worse.

And screw up it does :)

With the volatile removed, we see much more reasonable code generation:

c00000000051f5b8:       3b 60 00 01     li      r27,1
...
c00000000051f5c0:       3b 80 00 00     li      r28,0
...

c00000000051fc7c:       7c 20 04 ac     lwsync
c00000000051fc80:       7c 00 f8 28     lwarx   r0,0,r31
c00000000051fc84:       7c 00 d8 00     cmpw    r0,r27
c00000000051fc88:       40 c2 00 10     bne-    c00000000051fc98
c00000000051fc8c:       7f 80 f9 2d     stwcx.  r28,0,r31
c00000000051fc90:       40 c2 ff f0     bne+    c00000000051fc80
c00000000051fc94:       4c 00 01 2c     isync

Six instructions less.

Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-17 07:57:27 -07:00