1. 07 3月, 2010 3 次提交
    • F
      frv: remove pci_dma_sync_single() and pci_dma_sync_sg() · 68221908
      FUJITA Tomonori 提交于
      No architecture except for frv has pci_dma_sync_single() and
      pci_dma_sync_sg().  The APIs are deprecated.
      Signed-off-by: NFUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
      Acked-by: NDavid S. Miller <davem@davemloft.net>
      Acked-by: NDavid Howells <dhowells@redhat.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      68221908
    • R
      mm: change anon_vma linking to fix multi-process server scalability issue · 5beb4930
      Rik van Riel 提交于
      The old anon_vma code can lead to scalability issues with heavily forking
      workloads.  Specifically, each anon_vma will be shared between the parent
      process and all its child processes.
      
      In a workload with 1000 child processes and a VMA with 1000 anonymous
      pages per process that get COWed, this leads to a system with a million
      anonymous pages in the same anon_vma, each of which is mapped in just one
      of the 1000 processes.  However, the current rmap code needs to walk them
      all, leading to O(N) scanning complexity for each page.
      
      This can result in systems where one CPU is walking the page tables of
      1000 processes in page_referenced_one, while all other CPUs are stuck on
      the anon_vma lock.  This leads to catastrophic failure for a benchmark
      like AIM7, where the total number of processes can reach in the tens of
      thousands.  Real workloads are still a factor 10 less process intensive
      than AIM7, but they are catching up.
      
      This patch changes the way anon_vmas and VMAs are linked, which allows us
      to associate multiple anon_vmas with a VMA.  At fork time, each child
      process gets its own anon_vmas, in which its COWed pages will be
      instantiated.  The parents' anon_vma is also linked to the VMA, because
      non-COWed pages could be present in any of the children.
      
      This reduces rmap scanning complexity to O(1) for the pages of the 1000
      child processes, with O(N) complexity for at most 1/N pages in the system.
       This reduces the average scanning cost in heavily forking workloads from
      O(N) to 2.
      
      The only real complexity in this patch stems from the fact that linking a
      VMA to anon_vmas now involves memory allocations.  This means vma_adjust
      can fail, if it needs to attach a VMA to anon_vma structures.  This in
      turn means error handling needs to be added to the calling functions.
      
      A second source of complexity is that, because there can be multiple
      anon_vmas, the anon_vma linking in vma_adjust can no longer be done under
      "the" anon_vma lock.  To prevent the rmap code from walking up an
      incomplete VMA, this patch introduces the VM_LOCK_RMAP VMA flag.  This bit
      flag uses the same slot as the NOMMU VM_MAPPED_COPY, with an ifdef in mm.h
      to make sure it is impossible to compile a kernel that needs both symbolic
      values for the same bitflag.
      
      Some test results:
      
      Without the anon_vma changes, when AIM7 hits around 9.7k users (on a test
      box with 16GB RAM and not quite enough IO), the system ends up running
      >99% in system time, with every CPU on the same anon_vma lock in the
      pageout code.
      
      With these changes, AIM7 hits the cross-over point around 29.7k users.
      This happens with ~99% IO wait time, there never seems to be any spike in
      system time.  The anon_vma lock contention appears to be resolved.
      
      [akpm@linux-foundation.org: cleanups]
      Signed-off-by: NRik van Riel <riel@redhat.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Larry Woodman <lwoodman@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5beb4930
    • A
      bitops: rename for_each_bit() to for_each_set_bit() · 984b3f57
      Akinobu Mita 提交于
      Rename for_each_bit to for_each_set_bit in the kernel source tree.  To
      permit for_each_clear_bit(), should that ever be added.
      
      The patch includes a macro to map the old for_each_bit() onto the new
      for_each_set_bit().  This is a (very) temporary thing to ease the migration.
      
      [akpm@linux-foundation.org: add temporary for_each_bit()]
      Suggested-by: NAlexey Dobriyan <adobriyan@gmail.com>
      Suggested-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
      Cc: "David S. Miller" <davem@davemloft.net>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Artem Bityutskiy <dedekind@infradead.org>
      Cc: Stephen Rothwell <sfr@canb.auug.org.au>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      984b3f57
  2. 06 3月, 2010 1 次提交
  3. 04 3月, 2010 5 次提交
  4. 03 3月, 2010 8 次提交
  5. 02 3月, 2010 5 次提交
  6. 01 3月, 2010 18 次提交