linux-toradex.git/arch/x86/include, branch v3.11.4

sched/x86: Optimize switch_mm() for multi-threaded workloads

2013-09-27T00:21:43+00:00

commit 8f898fbbe5ee5e20a77c4074472a1fd088dc47d1 upstream.

Dick Fowles, Don Zickus and Joe Mario have been working on
improvements to perf, and noticed heavy cache line contention
on the mm_cpumask, running linpack on a 60 core / 120 thread
system.

The cause turned out to be unnecessary atomic accesses to the
mm_cpumask. When in lazy TLB mode, the CPU is only removed from
the mm_cpumask if there is a TLB flush event.

Most of the time, no such TLB flush happens, and the kernel
skips the TLB reload. It can also skip the atomic memory
set & test.

Here is a summary of Joe's test results:

 * The __schedule function dropped from 24% of all program cycles down
   to 5.5%.

 * The cacheline contention/hotness for accesses to that bitmask went
   from being the 1st/2nd hottest - down to the 84th hottest (0.3% of
   all shared misses which is now quite cold)

 * The average load latency for the bit-test-n-set instruction in
   __schedule dropped from 10k-15k cycles down to an average of 600 cycles.

 * The linpack program results improved from 133 GFlops to 144 GFlops.
   Peak GFlops rose from 133 to 153.

Reported-by: Don Zickus 
Reported-by: Joe Mario 
Tested-by: Joe Mario 
Signed-off-by: Rik van Riel 
Reviewed-by: Paul Turner 
Acked-by: Linus Torvalds 
Link: http://lkml.kernel.org/r/20130731221421.616d3d20@annuminas.surriel.com
[ Made the comments consistent around the modified code. ]
Signed-off-by: Ingo Molnar 
Signed-off-by: Greg Kroah-Hartman

x86/mce: Pay no attention to 'F' bit in MCACOD when parsing 'UC' errors

2013-09-27T00:21:43+00:00

commit 0ca06c0857aee11911f91621db14498496f2c2cd upstream.

The 0x1000 bit of the MCACOD field of machine check MCi_STATUS
registers is only defined for corrected errors (where it means
that hardware may be filtering errors see SDM section 15.9.2.1).

For uncorrected errors it may, or may not be set - so we should mask
it out when checking for the architecturaly defined recoverable
error signatures (see SDM 15.9.3.1 and 15.9.3.2)

Acked-by: Naveen N. Rao 
Signed-off-by: Tony Luck 
Signed-off-by: Greg Kroah-Hartman

x86, smap: Handle csum_partial_copy_*_user()

2013-09-27T00:21:43+00:00

commit 7263dda41b5a28ae6566fd126d9b06ada73dd721 upstream.

Add SMAP annotations to csum_partial_copy_to/from_user().  These
functions legitimately access user space and thus need to set the AC
flag.

TODO: add explicit checks that the side with the kernel space pointer
really points into kernel space.

Signed-off-by: H. Peter Anvin 
Link: http://lkml.kernel.org/n/tip-2aps0u00eer658fd5xyanan7@git.kernel.org
Signed-off-by: Greg Kroah-Hartman

crypto: xor - Check for osxsave as well as avx in crypto/xor

2013-09-14T14:06:46+00:00

commit edb6f29464afc65fc73767540b854abf63ae7144 upstream.

This affects xen pv guests with sufficiently old versions of xen and
sufficiently new hardware.  On such a system, a guest with a btrfs
root won't even boot.

Signed-off-by: John Haxby 
Signed-off-by: Herbert Xu 
Reported-by: Michael Marineau 
Signed-off-by: Greg Kroah-Hartman

Merge branch 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2013-08-19T16:18:29+00:00

Pull x86 fixes from Ingo Molnar:
 "Two AMD microcode loader fixes and an OLPC firmware support fix"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86, microcode, AMD: Fix early microcode loading
  x86, microcode, AMD: Make cpu_has_amd_erratum() use the correct struct cpuinfo_x86
  x86: Don't clear olpc_ofw_header when sentinel is detected

Merge branch 'akpm' (patches from Andrew Morton)

2013-08-14T17:04:43+00:00

Merge a bunch of fixes from Andrew Morton.

* emailed patches from Andrew Morton :
  fs/proc/task_mmu.c: fix buffer overflow in add_page_map()
  arch: *: Kconfig: add "kernel/Kconfig.freezer" to "arch/*/Kconfig"
  ocfs2: fix null pointer dereference in ocfs2_dir_foreach_blk_id()
  x86 get_unmapped_area(): use proper mmap base for bottom-up direction
  ocfs2: fix NULL pointer dereference in ocfs2_duplicate_clusters_by_page
  ocfs2: Revert 40bd62e to avoid regression in extended allocation
  drivers/rtc/rtc-stmp3xxx.c: provide timeout for potentially endless loop polling a HW bit
  hugetlb: fix lockdep splat caused by pmd sharing
  aoe: adjust ref of head for compound page tails
  microblaze: fix clone syscall
  mm: save soft-dirty bits on file pages
  mm: save soft-dirty bits on swapped pages
  memcg: don't initialize kmem-cache destroying work for root caches

Merge tag 'amd_ucode_fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bp/bp into x86/urgent

2013-08-14T10:16:28+00:00

Pull AMD microcode fixes from Borislav Petkov:

 " Those are basically two fixes which correct the AMD early ucode loader
   from accessing cpu_data too early, i.e. before smp_store_cpu_info()
   has copied the boot_cpu_data ontop and overwritten an already empty
   structure (which we shouldn't access that early in the first place
   anyway).

   The second patch is kinda largish for that late in the game but it
   shouldn't be problematic because we're simply switching from using
   cpu_data to use the CPU family number directly and thus again, not use
   uninitialized cpu_data structure. "

Signed-off-by: Ingo Molnar

mm: save soft-dirty bits on file pages

2013-08-14T00:57:48+00:00

Andy reported that if file page get reclaimed we lose the soft-dirty bit
if it was there, so save _PAGE_BIT_SOFT_DIRTY bit when page address get
encoded into pte entry.  Thus when #pf happens on such non-present pte
we can restore it back.

Reported-by: Andy Lutomirski 
Signed-off-by: Cyrill Gorcunov 
Acked-by: Pavel Emelyanov 
Cc: Matt Mackall 
Cc: Xiao Guangrong 
Cc: Marcelo Tosatti 
Cc: KOSAKI Motohiro 
Cc: Stephen Rothwell 
Cc: Peter Zijlstra 
Cc: "Aneesh Kumar K.V" 
Cc: Minchan Kim 
Cc: Wanpeng Li 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: save soft-dirty bits on swapped pages

2013-08-14T00:57:47+00:00

Andy Lutomirski reported that if a page with _PAGE_SOFT_DIRTY bit set
get swapped out, the bit is getting lost and no longer available when
pte read back.

To resolve this we introduce _PTE_SWP_SOFT_DIRTY bit which is saved in
pte entry for the page being swapped out.  When such page is to be read
back from a swap cache we check for bit presence and if it's there we
clear it and restore the former _PAGE_SOFT_DIRTY bit back.

One of the problem was to find a place in pte entry where we can save
the _PTE_SWP_SOFT_DIRTY bit while page is in swap.  The _PAGE_PSE was
chosen for that, it doesn't intersect with swap entry format stored in
pte.

Reported-by: Andy Lutomirski 
Signed-off-by: Cyrill Gorcunov 
Acked-by: Pavel Emelyanov 
Cc: Matt Mackall 
Cc: Xiao Guangrong 
Cc: Marcelo Tosatti 
Cc: KOSAKI Motohiro 
Cc: Stephen Rothwell 
Cc: Peter Zijlstra 
Cc: "Aneesh Kumar K.V" 
Reviewed-by: Minchan Kim 
Reviewed-by: Wanpeng Li 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

sched: fix the theoretical signal_wake_up() vs schedule() race

2013-08-13T15:19:26+00:00

This is only theoretical, but after try_to_wake_up(p) was changed
to check p->state under p->pi_lock the code like

	__set_current_state(TASK_INTERRUPTIBLE);
	schedule();

can miss a signal. This is the special case of wait-for-condition,
it relies on try_to_wake_up/schedule interaction and thus it does
not need mb() between __set_current_state() and if(signal_pending).

However, this __set_current_state() can move into the critical
section protected by rq->lock, now that try_to_wake_up() takes
another lock we need to ensure that it can't be reordered with
"if (signal_pending(current))" check inside that section.

The patch is actually one-liner, it simply adds smp_wmb() before
spin_lock_irq(rq->lock). This is what try_to_wake_up() already
does by the same reason.

We turn this wmb() into the new helper, smp_mb__before_spinlock(),
for better documentation and to allow the architectures to change
the default implementation.

While at it, kill smp_mb__after_lock(), it has no callers.

Perhaps we can also add smp_mb__before/after_spinunlock() for
prepare_to_wait().

Signed-off-by: Oleg Nesterov 
Acked-by: Peter Zijlstra 
Signed-off-by: Linus Torvalds