1. 20 10月, 2008 1 次提交
  2. 21 8月, 2008 1 次提交
  3. 05 8月, 2008 1 次提交
  4. 27 7月, 2008 3 次提交
    • J
      mm: print swapcache page count in show_swap_cache_info() · 2c97b7fc
      Johannes Weiner 提交于
      Every arch implements its own show_mem() function.  Most of them share
      quite some code, some of them are completely identical.
      
      This series implements a generic version of this function and migrates
      almost all architectures to it.
      
      This patch:
      
      Most show_mem() implementations calculate the amount of pages within
      the swapcache every time.  Move the output to a more appropriate place
      and use the anyway available total_swapcache_pages variable.
      Signed-off-by: NJohannes Weiner <hannes@saeurebad.de>
      Cc: Richard Henderson <rth@twiddle.net>
      Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
      Cc: Haavard Skinnemoen <hskinnemoen@atmel.com>
      Cc: Bryan Wu <cooloney@kernel.org>
      Cc: Chris Zankel <chris@zankel.net>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: David S. Miller <davem@davemloft.net>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
      Cc: Ralf Baechle <ralf@linux-mips.org>
      Cc: Greg Ungerer <gerg@uclinux.org>
      Cc: Geert Uytterhoeven <geert@linux-m68k.org>
      Cc: Roman Zippel <zippel@linux-m68k.org>
      Cc: Hirokazu Takata <takata@linux-m32r.org>
      Cc: Mikael Starvik <starvik@axis.com>
      Cc: Hugh Dickins <hugh@veritas.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2c97b7fc
    • N
      mm: spinlock tree_lock · 19fd6231
      Nick Piggin 提交于
      mapping->tree_lock has no read lockers.  convert the lock from an rwlock
      to a spinlock.
      Signed-off-by: NNick Piggin <npiggin@suse.de>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
      Reviewed-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      19fd6231
    • N
      mm: speculative page references · e286781d
      Nick Piggin 提交于
      If we can be sure that elevating the page_count on a pagecache page will
      pin it, we can speculatively run this operation, and subsequently check to
      see if we hit the right page rather than relying on holding a lock or
      otherwise pinning a reference to the page.
      
      This can be done if get_page/put_page behaves consistently throughout the
      whole tree (ie.  if we "get" the page after it has been used for something
      else, we must be able to free it with a put_page).
      
      Actually, there is a period where the count behaves differently: when the
      page is free or if it is a constituent page of a compound page.  We need
      an atomic_inc_not_zero operation to ensure we don't try to grab the page
      in either case.
      
      This patch introduces the core locking protocol to the pagecache (ie.
      adds page_cache_get_speculative, and tweaks some update-side code to make
      it work).
      
      Thanks to Hugh for pointing out an improvement to the algorithm setting
      page_count to zero when we have control of all references, in order to
      hold off speculative getters.
      
      [kamezawa.hiroyu@jp.fujitsu.com: fix migration_entry_wait()]
      [hugh@veritas.com: fix add_to_page_cache]
      [akpm@linux-foundation.org: repair a comment]
      Signed-off-by: NNick Piggin <npiggin@suse.de>
      Cc: Jeff Garzik <jeff@garzik.org>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
      Reviewed-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NDaisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
      Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Acked-by: NNick Piggin <npiggin@suse.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e286781d
  5. 30 4月, 2008 1 次提交
  6. 20 3月, 2008 1 次提交
  7. 08 2月, 2008 5 次提交
    • H
      memcgroup: revert swap_state mods · fa1de900
      Hugh Dickins 提交于
      If we're charging rss and we're charging cache, it seems obvious that we
      should be charging swapcache - as has been done.  But in practice that
      doesn't work out so well: both swapin readahead and swapoff leave the
      majority of pages charged to the wrong cgroup (the cgroup that happened to
      read them in, rather than the cgroup to which they belong).
      
      (Which is why unuse_pte's GFP_KERNEL while holding pte lock never showed up
      as a problem: no allocation was ever done there, every page read being
      already charged to the cgroup which initiated the swapoff.)
      
      It all works rather better if we leave the charging to do_swap_page and
      unuse_pte, and do nothing for swapcache itself: revert mm/swap_state.c to
      what it was before the memory-controller patches.  This also speeds up
      significantly a contained process working at its limit: because it no
      longer needs to keep waiting for swap writeback to complete.
      
      Is it unfair that swap pages become uncharged once they're unmapped, even
      though they're still clearly private to particular cgroups?  For a short
      while, yes; but PageReclaim arranges for those pages to go to the end of
      the inactive list and be reclaimed soon if necessary.
      
      shmem/tmpfs pages are a distinct case: their charging also benefits from
      this change, but their second life on the lists as swapcache pages may
      prove more unfair - that I need to check next.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Cc: Pavel Emelianov <xemul@openvz.org>
      Acked-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
      Cc: Paul Menage <menage@google.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Kirill Korotaev <dev@sw.ru>
      Cc: Herbert Poetzl <herbert@13thfloor.at>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fa1de900
    • B
      memory controller BUG_ON() · 35c754d7
      Balbir Singh 提交于
      Move mem_controller_cache_charge() above radix_tree_preload().
      radix_tree_preload() disables preemption, even though the gfp_mask passed
      contains __GFP_WAIT, we cannot really do __GFP_WAIT allocations, thus we
      hit a BUG_ON() in kmem_cache_alloc().
      
      This patch moves mem_controller_cache_charge() to above radix_tree_preload()
      for cache charging.
      Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      35c754d7
    • B
      Memory controller: make charging gfp mask aware · e1a1cd59
      Balbir Singh 提交于
      Nick Piggin pointed out that swap cache and page cache addition routines
      could be called from non GFP_KERNEL contexts.  This patch makes the
      charging routine aware of the gfp context.  Charging might fail if the
      cgroup is over it's limit, in which case a suitable error is returned.
      
      This patch was tested on a Powerpc box.  I am still looking at being able
      to test the path, through which allocations happen in non GFP_KERNEL
      contexts.
      
      [kamezawa.hiroyu@jp.fujitsu.com: problem with ZONE_MOVABLE]
      Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
      Cc: Pavel Emelianov <xemul@openvz.org>
      Cc: Paul Menage <menage@google.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Kirill Korotaev <dev@sw.ru>
      Cc: Herbert Poetzl <herbert@13thfloor.at>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
      Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e1a1cd59
    • B
      Memory controller: add switch to control what type of pages to limit · 8697d331
      Balbir Singh 提交于
      Choose if we want cached pages to be accounted or not.  By default both are
      accounted for.  A new set of tunables are added.
      
      echo -n 1 > mem_control_type
      
      switches the accounting to account for only mapped pages
      
      echo -n 3 > mem_control_type
      
      switches the behaviour back
      
      [bunk@kernel.org: mm/memcontrol.c: clenups]
      [akpm@linux-foundation.org: fix sparc32 build]
      Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
      Cc: Pavel Emelianov <xemul@openvz.org>
      Cc: Paul Menage <menage@google.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Kirill Korotaev <dev@sw.ru>
      Cc: Herbert Poetzl <herbert@13thfloor.at>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
      Signed-off-by: NAdrian Bunk <bunk@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8697d331
    • B
      Memory controller: memory accounting · 8a9f3ccd
      Balbir Singh 提交于
      Add the accounting hooks.  The accounting is carried out for RSS and Page
      Cache (unmapped) pages.  There is now a common limit and accounting for both.
      The RSS accounting is accounted at page_add_*_rmap() and page_remove_rmap()
      time.  Page cache is accounted at add_to_page_cache(),
      __delete_from_page_cache().  Swap cache is also accounted for.
      
      Each page's page_cgroup is protected with the last bit of the
      page_cgroup pointer, this makes handling of race conditions involving
      simultaneous mappings of a page easier.  A reference count is kept in the
      page_cgroup to deal with cases where a page might be unmapped from the RSS
      of all tasks, but still lives in the page cache.
      
      Credits go to Vaidyanathan Srinivasan for helping with reference counting work
      of the page cgroup.  Almost all of the page cache accounting code has help
      from Vaidyanathan Srinivasan.
      
      [hugh@veritas.com: fix swapoff breakage]
      [akpm@linux-foundation.org: fix locking]
      Signed-off-by: NVaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com>
      Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
      Cc: Pavel Emelianov <xemul@openvz.org>
      Cc: Paul Menage <menage@google.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Kirill Korotaev <dev@sw.ru>
      Cc: Herbert Poetzl <herbert@13thfloor.at>
      Cc: David Rientjes <rientjes@google.com>
      Cc: <Valdis.Kletnieks@vt.edu>
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8a9f3ccd
  8. 06 2月, 2008 6 次提交
    • N
      mm: fix PageUptodate data race · 0ed361de
      Nick Piggin 提交于
      After running SetPageUptodate, preceeding stores to the page contents to
      actually bring it uptodate may not be ordered with the store to set the
      page uptodate.
      
      Therefore, another CPU which checks PageUptodate is true, then reads the
      page contents can get stale data.
      
      Fix this by having an smp_wmb before SetPageUptodate, and smp_rmb after
      PageUptodate.
      
      Many places that test PageUptodate, do so with the page locked, and this
      would be enough to ensure memory ordering in those places if
      SetPageUptodate were only called while the page is locked.  Unfortunately
      that is not always the case for some filesystems, but it could be an idea
      for the future.
      
      Also bring the handling of anonymous page uptodateness in line with that of
      file backed page management, by marking anon pages as uptodate when they
      _are_ uptodate, rather than when our implementation requires that they be
      marked as such.  Doing allows us to get rid of the smp_wmb's in the page
      copying functions, which were especially added for anonymous pages for an
      analogous memory ordering problem.  Both file and anonymous pages are
      handled with the same barriers.
      
      FAQ:
      Q. Why not do this in flush_dcache_page?
      A. Firstly, flush_dcache_page handles only one side (the smb side) of the
      ordering protocol; we'd still need smp_rmb somewhere. Secondly, hiding away
      memory barriers in a completely unrelated function is nasty; at least in the
      PageUptodate macros, they are located together with (half) the operations
      involved in the ordering. Thirdly, the smp_wmb is only required when first
      bringing the page uptodate, wheras flush_dcache_page should be called each time
      it is written to through the kernel mapping. It is logically the wrong place to
      put it.
      
      Q. Why does this increase my text size / reduce my performance / etc.
      A. Because it is adding the necessary instructions to eliminate the data-race.
      
      Q. Can it be improved?
      A. Yes, eg. if you were to create a rule that all SetPageUptodate operations
      run under the page lock, we could avoid the smp_rmb places where PageUptodate
      is queried under the page lock. Requires audit of all filesystems and at least
      some would need reworking. That's great you're interested, I'm eagerly awaiting
      your patches.
      Signed-off-by: NNick Piggin <npiggin@suse.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0ed361de
    • H
      tmpfs: move swap swizzling into shmem · 73b1262f
      Hugh Dickins 提交于
      move_to_swap_cache and move_from_swap_cache functions (which swizzle a page
      between tmpfs page cache and swap cache, to avoid page copying) are only used
      by shmem.c; and our subsequent fix for unionfs needs different treatments in
      the two instances of move_from_swap_cache.  Move them from swap_state.c into
      their callsites shmem_writepage, shmem_unuse_inode and shmem_getpage, making
      add_to_swap_cache externally visible.
      
      shmem.c likes to say set_page_dirty where swap_state.c liked to say
      SetPageDirty: respect that diversity, which __set_page_dirty_no_writeback
      makes moot (and implies we should lose that "shift page from clean_pages to
      dirty_pages list" comment: it's on neither).
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      73b1262f
    • H
      tmpfs: shuffle add_to_swap_caches · f000944d
      Hugh Dickins 提交于
      add_to_swap_cache doesn't amount to much: merge it into its sole caller
      read_swap_cache_async.  But we'll be needing to call __add_to_swap_cache from
      shmem.c, so promote it to the new add_to_swap_cache.  Both were static, so
      there's no interface confusion to worry about.
      
      And lose that inappropriate "Anon pages are already on the LRU" comment in the
      merging: they're not already on the LRU, as Nick Piggin noticed.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      No-problems-with: Nick Piggin <npiggin@suse.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f000944d
    • H
      tmpfs: move swap_state stats update · bb63be0a
      Hugh Dickins 提交于
      Both unionfs and memcgroups pose challenges to tmpfs and shmem.  To help fix,
      it's best to move the swap swizzling functions from swap_state.c to shmem.c.
      As a preliminary to that, move swap stats updating down into
      __add_to_swap_cache, which will remain internal to swap_state.c.
      
      Well, actually, just move down the incrementation of add_total: remove
      noent_race and exist_race completely, they are relics of my 2.4.11 testing.
      Alt-SysRq-m users will be thrilled if 2.6.25 is at last free of "race M+N"s.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      bb63be0a
    • H
      swapin needs gfp_mask for loop on tmpfs · 02098fea
      Hugh Dickins 提交于
      Building in a filesystem on a loop device on a tmpfs file can hang when
      swapping, the loop thread caught in that infamous throttle_vm_writeout.
      
      In theory this is a long standing problem, which I've either never seen in
      practice, or long ago suppressed the recollection, after discounting my load
      and my tmpfs size as unrealistically high.  But now, with the new aops, it has
      become easy to hang on one machine.
      
      Loop used to grab_cache_page before the old prepare_write to tmpfs, which
      seems to have been enough to free up some memory for any swapin needed; but
      the new write_begin lets tmpfs find or allocate the page (much nicer, since
      grab_cache_page missed tmpfs pages in swapcache).
      
      When allocating a fresh page, tmpfs respects loop's mapping_gfp_mask, which
      has __GFP_IO|__GFP_FS stripped off, and throttle_vm_writeout is designed to
      break out when __GFP_IO or GFP_FS is unset; but when tmfps swaps in,
      read_swap_cache_async allocates with GFP_HIGHUSER_MOVABLE regardless of the
      mapping_gfp_mask - hence the hang.
      
      So, pass gfp_mask down the line from shmem_getpage to shmem_swapin to
      swapin_readahead to read_swap_cache_async to add_to_swap_cache.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Acked-by: NRik van Riel <riel@redhat.com>
      Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      02098fea
    • H
      swapin_readahead: move and rearrange args · 46017e95
      Hugh Dickins 提交于
      swapin_readahead has never sat well in mm/memory.c: move it to mm/swap_state.c
      beside its kindred read_swap_cache_async.  Why were its args in a different
      order?  rearrange them.  And since it was always followed by a
      read_swap_cache_async of the target page, fold that in and return struct
      page*.  Then CONFIG_SWAP=n no longer needs valid_swaphandles and
      read_swap_cache_async stubs.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Acked-by: NRik van Riel <riel@redhat.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      46017e95
  9. 17 10月, 2007 1 次提交
  10. 18 7月, 2007 1 次提交
    • M
      Add __GFP_MOVABLE for callers to flag allocations from high memory that may be migrated · 769848c0
      Mel Gorman 提交于
      It is often known at allocation time whether a page may be migrated or not.
      This patch adds a flag called __GFP_MOVABLE and a new mask called
      GFP_HIGH_MOVABLE.  Allocations using the __GFP_MOVABLE can be either migrated
      using the page migration mechanism or reclaimed by syncing with backing
      storage and discarding.
      
      An API function very similar to alloc_zeroed_user_highpage() is added for
      __GFP_MOVABLE allocations called alloc_zeroed_user_highpage_movable().  The
      flags used by alloc_zeroed_user_highpage() are not changed because it would
      change the semantics of an existing API.  After this patch is applied there
      are no in-kernel users of alloc_zeroed_user_highpage() so it probably should
      be marked deprecated if this patch is merged.
      
      Note that this patch includes a minor cleanup to the use of __GFP_ZERO in
      shmem.c to keep all flag modifications to inode->mapping in the
      shmem_dir_alloc() helper function.  This clean-up suggestion is courtesy of
      Hugh Dickens.
      
      Additional credit goes to Christoph Lameter and Linus Torvalds for shaping the
      concept.  Credit to Hugh Dickens for catching issues with shmem swap vector
      and ramfs allocations.
      
      [akpm@linux-foundation.org: build fix]
      [hugh@veritas.com: __GFP_ZERO cleanup]
      Signed-off-by: NMel Gorman <mel@csn.ul.ie>
      Cc: Andy Whitcroft <apw@shadowen.org>
      Cc: Christoph Lameter <clameter@sgi.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      769848c0
  11. 17 7月, 2007 1 次提交
  12. 04 7月, 2006 1 次提交
  13. 01 7月, 2006 1 次提交
  14. 29 6月, 2006 1 次提交
  15. 01 4月, 2006 1 次提交
  16. 22 3月, 2006 1 次提交
    • C
      [PATCH] page migration reorg · b20a3503
      Christoph Lameter 提交于
      Centralize the page migration functions in anticipation of additional
      tinkering.  Creates a new file mm/migrate.c
      
      1. Extract buffer_migrate_page() from fs/buffer.c
      
      2. Extract central migration code from vmscan.c
      
      3. Extract some components from mempolicy.c
      
      4. Export pageout() and remove_from_swap() from vmscan.c
      
      5. Make it possible to configure NUMA systems without page migration
         and non-NUMA systems with page migration.
      
      I had to so some #ifdeffing in mempolicy.c that may need a cleanup.
      Signed-off-by: NChristoph Lameter <clameter@sgi.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b20a3503
  17. 02 2月, 2006 1 次提交
  18. 09 1月, 2006 1 次提交
  19. 07 1月, 2006 1 次提交
  20. 07 11月, 2005 1 次提交
  21. 30 10月, 2005 2 次提交
    • H
      [PATCH] mm: update comments to pte lock · b8072f09
      Hugh Dickins 提交于
      Updated several references to page_table_lock in common code comments.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      b8072f09
    • H
      [PATCH] mm: split page table lock · 4c21e2f2
      Hugh Dickins 提交于
      Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with
      a many-threaded application which concurrently initializes different parts of
      a large anonymous area.
      
      This patch corrects that, by using a separate spinlock per page table page, to
      guard the page table entries in that page, instead of using the mm's single
      page_table_lock.  (But even then, page_table_lock is still used to guard page
      table allocation, and anon_vma allocation.)
      
      In this implementation, the spinlock is tucked inside the struct page of the
      page table page: with a BUILD_BUG_ON in case it overflows - which it would in
      the case of 32-bit PA-RISC with spinlock debugging enabled.
      
      Splitting the lock is not quite for free: another cacheline access.  Ideally,
      I suppose we would use split ptlock only for multi-threaded processes on
      multi-cpu machines; but deciding that dynamically would have its own costs.
      So for now enable it by config, at some number of cpus - since the Kconfig
      language doesn't support inequalities, let preprocessor compare that with
      NR_CPUS.  But I don't think it's worth being user-configurable: for good
      testing of both split and unsplit configs, split now at 4 cpus, and perhaps
      change that to 8 later.
      
      There is a benefit even for singly threaded processes: kswapd can be attacking
      one part of the mm while another part is busy faulting.
      Signed-off-by: NHugh Dickins <hugh@veritas.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      4c21e2f2
  22. 09 10月, 2005 1 次提交
  23. 11 9月, 2005 1 次提交
  24. 05 9月, 2005 1 次提交
  25. 01 5月, 2005 1 次提交
  26. 17 4月, 2005 1 次提交
    • L
      Linux-2.6.12-rc2 · 1da177e4
      Linus Torvalds 提交于
      Initial git repository build. I'm not bothering with the full history,
      even though we have it. We can create a separate "historical" git
      archive of that later if we want to, and in the meantime it's about
      3.2GB when imported into git - space that would just make the early
      git days unnecessarily complicated, when we don't have a lot of good
      infrastructure for it.
      
      Let it rip!
      1da177e4