1. 20 May, 2011 1 commit
    • Linus Torvalds's avatar
      sanitize <linux/prefetch.h> usage · 268bb0ce
      Linus Torvalds authored
      Commit e66eed65
       ("list: remove prefetching from regular list
      iterators") removed the include of prefetch.h from list.h, which
      uncovered several cases that had apparently relied on that rather
      obscure header file dependency.
      So this fixes things up a bit, using
         grep -L linux/prefetch.h $(git grep -l '[^a-z_]prefetchw*(' -- '*.[ch]')
         grep -L 'prefetchw*(' $(git grep -l 'linux/prefetch.h' -- '*.[ch]')
      to guide us in finding files that either need <linux/prefetch.h>
      inclusion, or have it despite not needing it.
      There are more of them around (mostly network drivers), but this gets
      many core ones.
      Reported-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
  2. 05 Jan, 2010 1 commit
  3. 30 Dec, 2009 1 commit
    • Jan Beulich's avatar
      x86-64: Modify copy_user_generic() alternatives mechanism · 1b1d9258
      Jan Beulich authored
      In order to avoid unnecessary chains of branches, rather than
      implementing copy_user_generic() as a function consisting of
      just a single (possibly patched) branch, instead properly deal
      with patching call instructions in the alternative instructions
      framework, and move the patching into the callers.
      As a follow-on, one could also introduce something like
      __EXPORT_SYMBOL_ALT() to avoid patching call sites in modules.
      Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      LKML-Reference: <4B2BB8180200007800026AE7@vpn.id2.novell.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  4. 16 Nov, 2009 1 commit
    • Frederic Weisbecker's avatar
      x86: Add missing might_fault() checks to copy_{to,from}_user() · 3c93ca00
      Frederic Weisbecker authored
      On x86-64, copy_[to|from]_user() rely on assembly routines that
      never call might_fault(), making us missing various lockdep
      This doesn't apply to __copy_from,to_user() that explicitly
      handle these calls, neither is it a problem in x86-32 where
      copy_to,from_user() rely on the "__" prefixed versions that
      also call might_fault().
      Signed-off-by: default avatarFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Arjan van de Ven <arjan@infradead.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      LKML-Reference: <1258382538-30979-1-git-send-email-fweisbec@gmail.com>
      [ v2: fix module export ]
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  5. 15 Nov, 2009 1 commit
    • Jan Beulich's avatar
      x86-64: __copy_from_user_inatomic() adjustments · 14722485
      Jan Beulich authored
      This v2.6.26 commit:
          ad2fc2cd: x86: fix copy_user on x86
      rendered __copy_from_user_inatomic() identical to
      copy_user_generic(), yet didn't make the former just call the
      latter from an inline function.
      Furthermore, this v2.6.19 commit:
      : [PATCH] Add proper sparse __user casts to __copy_to_user_inatomic
      converted the return type of __copy_to_user_inatomic() from
      unsigned long to int, but didn't do the same to
      Signed-off-by: default avatarJan Beulich <jbeulich@novell.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Alexander Viro <viro@zeniv.linux.org.uk>
      Cc: Arjan van de Ven <arjan@infradead.org>
      Cc: Andi Kleen <andi@firstfloor.org>
      Cc: <v.mayatskih@gmail.com>
      LKML-Reference: <4AFD5778020000780001F8F4@vpn.id2.novell.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  6. 26 Sep, 2009 1 commit
    • Arjan van de Ven's avatar
      x86: Use __builtin_object_size() to validate the buffer size for copy_from_user() · 9f0cf4ad
      Arjan van de Ven authored
      gcc (4.x) supports the __builtin_object_size() builtin, which
      reports the size of an object that a pointer point to, when known
      at compile time. If the buffer size is not known at compile time, a
      constant -1 is returned.
      This patch uses this feature to add a sanity check to
      copy_from_user(); if the target buffer is known to be smaller than
      the copy size, the copy is aborted and a WARNing is emitted in
      memory debug mode.
      These extra checks compile away when the object size is not known,
      or if both the buffer size and the copy length are constants.
      Signed-off-by: default avatarArjan van de Ven <arjan@linux.intel.com>
      LKML-Reference: <20090926143301.2c396b94@infradead.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  7. 21 Jul, 2009 1 commit
  8. 02 Mar, 2009 1 commit
    • Ingo Molnar's avatar
      x86, mm: dont use non-temporal stores in pagecache accesses · f1800536
      Ingo Molnar authored
      Impact: standardize IO on cached ops
      On modern CPUs it is almost always a bad idea to use non-temporal stores,
      as the regression in this commit has shown it:
      : x86: fix performance regression in write() syscall
      The kernel simply has no good information about whether using non-temporal
      stores is a good idea or not - and trying to add heuristics only increases
      complexity and inserts fragility.
      The regression on cached write()s took very long to be found - over two
      years. So dont take any chances and let the hardware decide how it makes
      use of its caches.
      The only exception is drivers/gpu/drm/i915/i915_gem.c: there were we are
      absolutely sure that another entity (the GPU) will pick up the dirty
      data immediately and that the CPU will not touch that data before the
      GPU will.
      Also, keep the _nocache() primitives to make it easier for people to
      experiment with these details. There may be more clear-cut cases where
      non-cached copies can be used, outside of filemap.c.
      Cc: Salman Qazi <sqazi@google.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  9. 25 Feb, 2009 2 commits
    • Ingo Molnar's avatar
      x86: usercopy: check for total size when deciding non-temporal cutoff · 95108fa3
      Ingo Molnar authored
      Impact: make more types of copies non-temporal
      This change makes the following simple fix:
      : x86: fix performance regression in write() syscall
      A bit more sophisticated: we check the 'total' number of bytes
      written to decide whether to copy in a cached or a non-temporal
      This will for example cause the tail (modulo 4096 bytes) chunk
      of a large write() to be non-temporal too - not just the page-sized
      Cc: Salman Qazi <sqazi@google.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
    • Ingo Molnar's avatar
      x86, mm: pass in 'total' to __copy_from_user_*nocache() · 3255aa2e
      Ingo Molnar authored
      Impact: cleanup, enable future change
      Add a 'total bytes copied' parameter to __copy_from_user_*nocache(),
      and update all the callsites.
      The parameter is not used yet - architecture code can use it to
      more intelligently decide whether the copy should be cached or
      Cc: Salman Qazi <sqazi@google.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  10. 24 Feb, 2009 1 commit
    • Salman Qazi's avatar
      x86: fix performance regression in write() syscall · 30d697fa
      Salman Qazi authored
      While the introduction of __copy_from_user_nocache (see commit:
      ) may have been an improvement
      for sufficiently large writes, there is evidence to show that it is
      deterimental for small writes.  Unixbench's fstime test gives the
      following results for 256 byte writes with MAX_BLOCK of 2000:
          2.6.29-rc6 ( 5 samples, each in KB/sec ):
          283750, 295200, 294500, 293000, 293300
          2.6.29-rc6 + this patch (5 samples, each in KB/sec):
          313050, 3106750, 293350, 306300, 307900
          395700, 342000, 399100, 366050, 359850
          See w_test() in src/fstime.c in unixbench version 4.1.0.  Basically, the above test
          consists of counting how much we can write in this manner:
          while (!sigalarm) {
                  for (f_blocks = 0; f_blocks < 2000; ++f_blocks) {
                         write(f, buf, 256);
                  lseek(f, 0L, 0);
      Note, there are other components to the write syscall regression
      that are not addressed here.
      Signed-off-by: default avatarSalman Qazi <sqazi@google.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  11. 18 Nov, 2008 1 commit
  12. 23 Oct, 2008 2 commits
  13. 02 Oct, 2008 1 commit
  14. 11 Sep, 2008 1 commit
  15. 10 Sep, 2008 1 commit
    • Nick Piggin's avatar
      x86: some lock annotations for user copy paths · c10d38dd
      Nick Piggin authored
      copy_to/from_user and all its variants (except the atomic ones) can take a
      page fault and perform non-trivial work like taking mmap_sem and entering
      the filesyste/pagecache.
      Unfortunately, this often escapes lockdep because a common pattern is to
      use it to read in some arguments just set up from userspace, or write data
      back to a hot buffer. In those cases, it will be unlikely for page reclaim
      to get a window in to cause copy_*_user to fault.
      With the new might_lock primitives, add some annotations to x86. I don't
      know if I caught all possible faulting points (it's a bit of a maze, and I
      didn't really look at 32-bit). But this is a starting point.
      Boots and runs OK so far.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
  16. 22 Jul, 2008 1 commit
    • Vegard Nossum's avatar
      x86: consolidate header guards · 77ef50a5
      Vegard Nossum authored
      This patch is the result of an automatic script that consolidates the
      format of all the headers in include/asm-x86/.
      The format:
      1. No leading underscore. Names with leading underscores are reserved.
      2. Pathname components are separated by two underscores. So we can
         distinguish between mm_types.h and mm/types.h.
      3. Everything except letters and numbers are turned into single
      Signed-off-by: default avatarVegard Nossum <vegard.nossum@gmail.com>
  17. 09 Jul, 2008 19 commits
  18. 17 Apr, 2008 1 commit
  19. 04 Feb, 2008 1 commit
  20. 30 Jan, 2008 1 commit