1. 17 10月, 2007 7 次提交
    • D
      mm: test and set zone reclaim lock before starting reclaim · d773ed6b
      David Rientjes 提交于
      Introduces new zone flag interface for testing and setting flags:
      
      	int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag)
      
      Instead of setting and clearing ZONE_RECLAIM_LOCKED each time shrink_zone() is
      called, this flag is test and set before starting zone reclaim.  Zone reclaim
      starts in __alloc_pages() when a zone's watermark fails and the system is in
      zone_reclaim_mode.  If it's already in reclaim, there's no need to start again
      so it is simply considered full for that allocation attempt.
      
      There is a change of behavior with regard to concurrent zone shrinking.  It is
      now possible for try_to_free_pages() or kswapd to already be shrinking a
      particular zone when __alloc_pages() starts zone reclaim.  In this case, it is
      possible for two concurrent threads to invoke shrink_zone() for a single zone.
      
      This change forbids a zone to be in zone reclaim twice, which was always the
      behavior, but allows for concurrent try_to_free_pages() or kswapd shrinking
      when starting zone reclaim.
      
      Cc: Andrea Arcangeli <andrea@suse.de>
      Cc: Christoph Lameter <clameter@sgi.com>
      Signed-off-by: NDavid Rientjes <rientjes@google.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      d773ed6b
    • D
      oom: change all_unreclaimable zone member to flags · e815af95
      David Rientjes 提交于
      Convert the int all_unreclaimable member of struct zone to unsigned long
      flags.  This can now be used to specify several different zone flags such as
      all_unreclaimable and reclaim_in_progress, which can now be removed and
      converted to a per-zone flag.
      
      Flags are set and cleared as follows:
      
      	zone_set_flag(struct zone *zone, zone_flags_t flag)
      	zone_clear_flag(struct zone *zone, zone_flags_t flag)
      
      Defines the first zone flags, ZONE_ALL_UNRECLAIMABLE and ZONE_RECLAIM_LOCKED,
      which have the same semantics as the old zone->all_unreclaimable and
      zone->reclaim_in_progress, respectively.  Also converts all current users that
      set or clear either flag to use the new interface.
      
      Helper functions are defined to test the flags:
      
      	int zone_is_all_unreclaimable(const struct zone *zone)
      	int zone_is_reclaim_locked(const struct zone *zone)
      
      All flag operators are of the atomic variety because there are currently
      readers that are implemented that do not take zone->lock.
      
      [akpm@linux-foundation.org: add needed include]
      Cc: Andrea Arcangeli <andrea@suse.de>
      Acked-by: NChristoph Lameter <clameter@sgi.com>
      Signed-off-by: NDavid Rientjes <rientjes@google.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e815af95
    • A
      make swappiness safer to use · 4106f83a
      Andrea Arcangeli 提交于
      Swappiness isn't a safe sysctl.  Setting it to 0 for example can hang a
      system.  That's a corner case but even setting it to 10 or lower can waste
      enormous amounts of cpu without making much progress.  We've customers who
      wants to use swappiness but they can't because of the current
      implementation (if you change it so the system stops swapping it really
      stops swapping and nothing works sane anymore if you really had to swap
      something to make progress).
      
      This patch from Kurt Garloff makes swappiness safer to use (no more huge
      cpu usage or hangs with low swappiness values).
      
      I think the prev_priority can also be nuked since it wastes 4 bytes per
      zone (that would be an incremental patch but I wait the nr_scan_[in]active
      to be nuked first for similar reasons).  Clearly somebody at some point
      noticed how broken that thing was and they had to add min(priority,
      prev_priority) to give it some reliability, but they didn't go the last
      mile to nuke prev_priority too.  Calculating distress only in function of
      not-racy priority is correct and sure more than enough without having to
      add randomness into the equation.
      
      Patch is tested on older kernels but it compiles and it's quite simple
      so...
      
      Overall I'm not very satisified by the swappiness tweak, since it doesn't
      rally do anything with the dirty pagecache that may be inactive.  We need
      another kind of tweak that controls the inactive scan and tunes the
      can_writepage feature (not yet in mainline despite having submitted it a
      few times), not only the active one.  That new tweak will tell the kernel
      how hard to scan the inactive list for pure clean pagecache (something the
      mainline kernel isn't capable of yet).  We already have that feature
      working in all our enterprise kernels with the default reasonable tune, or
      they can't even run a readonly backup with tar without triggering huge
      write I/O.  I think it should be available also in mainline later.
      
      Cc: Nick Piggin <npiggin@suse.de>
      Signed-off-by: NKurt Garloff <garloff@suse.de>
      Signed-off-by: NAndrea Arcangeli <andrea@suse.de>
      Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4106f83a
    • Y
      Fix panic of cpu online with memory less node · 58c0a4a7
      Yasunori Goto 提交于
      When a cpu is onlined on memory-less-node box, kernel panics due to touch
      NULL pointer of pgdat->kswapd.  Current kswapd runs only nodes which have
      memory.  So, calling of set_cpus_allowed() is not necessary for memory-less
      node.
      
      This is fix for it.
      Signed-off-by: NYasunori Goto <y-goto@jp.fujitsu.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      58c0a4a7
    • C
      Memoryless nodes: Add N_CPU node state · 37c0708d
      Christoph Lameter 提交于
      We need the check for a node with cpu in zone reclaim.  Zone reclaim will not
      allow remote zone reclaim if a node has a cpu.
      
      [Lee.Schermerhorn@hp.com: Move setup of N_CPU node state mask]
      Signed-off-by: NChristoph Lameter <clameter@sgi.com>
      Tested-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
      Acked-by: NBob Picco <bob.picco@hp.com>
      Cc: Nishanth Aravamudan <nacc@us.ibm.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Mel Gorman <mel@skynet.ie>
      Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      37c0708d
    • C
      Memoryless nodes: No need for kswapd · 9422ffba
      Christoph Lameter 提交于
      A node without memory does not need a kswapd.  So use the memory map instead
      of the online map when starting kswapd.
      Signed-off-by: NChristoph Lameter <clameter@sgi.com>
      Acked-by: NNishanth Aravamudan <nacc@us.ibm.com>
      Tested-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
      Acked-by: NBob Picco <bob.picco@hp.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Mel Gorman <mel@skynet.ie>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      9422ffba
    • R
      mm: prevent kswapd from freeing excessive amounts of lowmem · 32a4330d
      Rik van Riel 提交于
      The current VM can get itself into trouble fairly easily on systems with a
      small ZONE_HIGHMEM, which is common on i686 computers with 1GB of memory.
      
      On one side, page_alloc() will allocate down to zone->pages_low, while on
      the other side, kswapd() and balance_pgdat() will try to free memory from
      every zone, until every zone has more free pages than zone->pages_high.
      
      Highmem can be filled up to zone->pages_low with page tables, ramfs,
      vmalloc allocations and other unswappable things quite easily and without
      many bad side effects, since we still have a huge ZONE_NORMAL to do future
      allocations from.
      
      However, as long as the number of free pages in the highmem zone is below
      zone->pages_high, kswapd will continue swapping things out from
      ZONE_NORMAL, too!
      
      Sami Farin managed to get his system into a stage where kswapd had freed
      about 700MB of low memory and was still "going strong".
      
      The attached patch will make kswapd stop paging out data from zones when
      there is more than enough memory free.  We do go above zone->pages_high in
      order to keep pressure between zones equal in normal circumstances, but the
      patch should prevent the kind of excesses that made Sami's computer totally
      unusable.
      Signed-off-by: NRik van Riel <riel@redhat.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      32a4330d
  2. 23 8月, 2007 2 次提交
    • A
      synchronous lumpy reclaim: wait for page writeback when directly reclaiming contiguous areas · c661b078
      Andy Whitcroft 提交于
      Lumpy reclaim works by selecting a lead page from the LRU list and then
      selecting pages for reclaim from the order-aligned area of pages.  In the
      situation were all pages in that region are inactive and not referenced by any
      process over time, it works well.
      
      In the situation where there is even light load on the system, the pages may
      not free quickly.  Out of a area of 1024 pages, maybe only 950 of them are
      freed when the allocation attempt occurs because lumpy reclaim returned early.
       This patch alters the behaviour of direct reclaim for large contiguous
      blocks.
      
      The first attempt to call shrink_page_list() is asynchronous but if it fails,
      the pages are submitted a second time and the calling process waits for the IO
      to complete.  This may stall allocators waiting for contiguous memory but that
      should be expected behaviour for high-order users.  It is preferable behaviour
      to potentially queueing unnecessary areas for IO.  Note that kswapd will not
      stall in this fashion.
      
      [apw@shadowen.org: update to version 2]
      [apw@shadowen.org: update to version 3]
      Signed-off-by: NMel Gorman <mel@csn.ul.ie>
      Signed-off-by: NAndy Whitcroft <apw@shadowen.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c661b078
    • A
      synchronous lumpy reclaim: ensure we count pages transitioning inactive via clear_active_flags · e9187bdc
      Andy Whitcroft 提交于
      As pointed out by Mel when reclaim is applied at higher orders a significant
      amount of IO may be started.  As this takes finite time to drain reclaim will
      consider more areas than ultimatly needed to satisfy the request.  This leads
      to more reclaim than strictly required and reduced success rates.
      
      I was able to confirm Mel's test results on systems locally.  These show that
      even under light load the success rates drop off far more than expected.
      Testing with a modified version of his patch (which follows) I was able to
      allocate almost all of ZONE_MOVABLE with a near idle system.  I ran 5 test
      passes sequentially following system boot (the system has 29 hugepages in
      ZONE_MOVABLE):
      
        2.6.23-rc1              11  8  6  7  7
        sync_lumpy              28 28 29 29 26
      
      These show that although hugely better than the near 0% success normally
      expected we can only allocate about a 1/4 of the zone.  Using synchronous
      reclaim for these allocations we get close to 100% as expected.
      
      I have also run our standard high order tests and these show no regressions in
      allocation success rates at rest, and some significant improvements under
      load.
      
      This patch:
      
      We are transitioning pages from active to inactive in clear_active_flags,
      those need counting as PGDEACTIVATE vm events.
      Signed-off-by: NAndy Whitcroft <apw@shadowen.org>
      Acked-by: NMel Gorman <mel@csn.ul.ie>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      e9187bdc
  3. 18 7月, 2007 3 次提交
    • R
      Freezer: make kernel threads nonfreezable by default · 83144186
      Rafael J. Wysocki 提交于
      Currently, the freezer treats all tasks as freezable, except for the kernel
      threads that explicitly set the PF_NOFREEZE flag for themselves.  This
      approach is problematic, since it requires every kernel thread to either
      set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
      care for the freezing of tasks at all.
      
      It seems better to only require the kernel threads that want to or need to
      be frozen to use some freezer-related code and to remove any
      freezer-related code from the other (nonfreezable) kernel threads, which is
      done in this patch.
      
      The patch causes all kernel threads to be nonfreezable by default (ie.  to
      have PF_NOFREEZE set by default) and introduces the set_freezable()
      function that should be called by the freezable kernel threads in order to
      unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
      threads call set_freezable(), so it shouldn't cause any (intentional)
      change of behaviour to appear.  Additionally, it updates documentation to
      describe the freezing of tasks more accurately.
      
      [akpm@linux-foundation.org: build fixes]
      Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      Acked-by: NNigel Cunningham <nigel@nigel.suspend2.net>
      Cc: Pavel Machek <pavel@ucw.cz>
      Cc: Oleg Nesterov <oleg@tv-sign.ru>
      Cc: Gautham R Shenoy <ego@in.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      83144186
    • R
      mm: clean up and kernelify shrinker registration · 8e1f936b
      Rusty Russell 提交于
      I can never remember what the function to register to receive VM pressure
      is called.  I have to trace down from __alloc_pages() to find it.
      
      It's called "set_shrinker()", and it needs Your Help.
      
      1) Don't hide struct shrinker.  It contains no magic.
      2) Don't allocate "struct shrinker".  It's not helpful.
      3) Call them "register_shrinker" and "unregister_shrinker".
      4) Call the function "shrink" not "shrinker".
      5) Reduce the 17 lines of waffly comments to 13, but document it properly.
      Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
      Cc: David Chinner <dgc@sgi.com>
      Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8e1f936b
    • A
      Lumpy Reclaim V4 · 5ad333eb
      Andy Whitcroft 提交于
      When we are out of memory of a suitable size we enter reclaim.  The current
      reclaim algorithm targets pages in LRU order, which is great for fairness at
      order-0 but highly unsuitable if you desire pages at higher orders.  To get
      pages of higher order we must shoot down a very high proportion of memory;
      >95% in a lot of cases.
      
      This patch set adds a lumpy reclaim algorithm to the allocator.  It targets
      groups of pages at the specified order anchored at the end of the active and
      inactive lists.  This encourages groups of pages at the requested orders to
      move from active to inactive, and active to free lists.  This behaviour is
      only triggered out of direct reclaim when higher order pages have been
      requested.
      
      This patch set is particularly effective when utilised with an
      anti-fragmentation scheme which groups pages of similar reclaimability
      together.
      
      This patch set is based on Peter Zijlstra's lumpy reclaim V2 patch which forms
      the foundation.  Credit to Mel Gorman for sanitity checking.
      
      Mel said:
      
        The patches have an application with hugepage pool resizing.
      
        When lumpy-reclaim is used used with ZONE_MOVABLE, the hugepages pool can
        be resized with greater reliability.  Testing on a desktop machine with 2GB
        of RAM showed that growing the hugepage pool with ZONE_MOVABLE on it's own
        was very slow as the success rate was quite low.  Without lumpy-reclaim,
        each attempt to grow the pool by 100 pages would yield 1 or 2 hugepages.
        With lumpy-reclaim, getting 40 to 70 hugepages on each attempt was typical.
      
      [akpm@osdl.org: ia64 pfn_to_nid fixes and loop cleanup]
      [bunk@stusta.de: static declarations for internal functions]
      [a.p.zijlstra@chello.nl: initial lumpy V2 implementation]
      Signed-off-by: NAndy Whitcroft <apw@shadowen.org>
      Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: NMel Gorman <mel@csn.ul.ie>
      Acked-by: NMel Gorman <mel@csn.ul.ie>
      Cc: Bob Picco <bob.picco@hp.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5ad333eb
  4. 10 5月, 2007 1 次提交
    • R
      Add suspend-related notifications for CPU hotplug · 8bb78442
      Rafael J. Wysocki 提交于
      Since nonboot CPUs are now disabled after tasks and devices have been
      frozen and the CPU hotplug infrastructure is used for this purpose, we need
      special CPU hotplug notifications that will help the CPU-hotplug-aware
      subsystems distinguish normal CPU hotplug events from CPU hotplug events
      related to a system-wide suspend or resume operation in progress.  This
      patch introduces such notifications and causes them to be used during
      suspend and resume transitions.  It also changes all of the
      CPU-hotplug-aware subsystems to take these notifications into consideration
      (for now they are handled in the same way as the corresponding "normal"
      ones).
      
      [oleg@tv-sign.ru: cleanups]
      Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      Cc: Gautham R Shenoy <ego@in.ibm.com>
      Cc: Pavel Machek <pavel@ucw.cz>
      Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8bb78442
  5. 09 5月, 2007 1 次提交
  6. 08 5月, 2007 1 次提交
  7. 02 3月, 2007 1 次提交
  8. 12 2月, 2007 1 次提交
    • C
      [PATCH] Use ZVC for inactive and active counts · c8785385
      Christoph Lameter 提交于
      The determination of the dirty ratio to determine writeback behavior is
      currently based on the number of total pages on the system.
      
      However, not all pages in the system may be dirtied.  Thus the ratio is always
      too low and can never reach 100%.  The ratio may be particularly skewed if
      large hugepage allocations, slab allocations or device driver buffers make
      large sections of memory not available anymore.  In that case we may get into
      a situation in which f.e.  the background writeback ratio of 40% cannot be
      reached anymore which leads to undesired writeback behavior.
      
      This patchset fixes that issue by determining the ratio based on the actual
      pages that may potentially be dirty.  These are the pages on the active and
      the inactive list plus free pages.
      
      The problem with those counts has so far been that it is expensive to
      calculate these because counts from multiple nodes and multiple zones will
      have to be summed up.  This patchset makes these counters ZVC counters.  This
      means that a current sum per zone, per node and for the whole system is always
      available via global variables and not expensive anymore to calculate.
      
      The patchset results in some other good side effects:
      
      - Removal of the various functions that sum up free, active and inactive
        page counts
      
      - Cleanup of the functions that display information via the proc filesystem.
      
      This patch:
      
      The use of a ZVC for nr_inactive and nr_active allows a simplification of some
      counter operations.  More ZVC functionality is used for sums etc in the
      following patches.
      
      [akpm@osdl.org: UP build fix]
      Signed-off-by: NChristoph Lameter <clameter@sgi.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c8785385
  9. 06 1月, 2007 1 次提交
  10. 31 12月, 2006 1 次提交
  11. 23 12月, 2006 1 次提交
  12. 14 12月, 2006 1 次提交
    • P
      [PATCH] cpuset: rework cpuset_zone_allowed api · 02a0e53d
      Paul Jackson 提交于
      Elaborate the API for calling cpuset_zone_allowed(), so that users have to
      explicitly choose between the two variants:
      
        cpuset_zone_allowed_hardwall()
        cpuset_zone_allowed_softwall()
      
      Until now, whether or not you got the hardwall flavor depended solely on
      whether or not you or'd in the __GFP_HARDWALL gfp flag to the gfp_mask
      argument.
      
      If you didn't specify __GFP_HARDWALL, you implicitly got the softwall
      version.
      
      Unfortunately, this meant that users would end up with the softwall version
      without thinking about it.  Since only the softwall version might sleep,
      this led to bugs with possible sleeping in interrupt context on more than
      one occassion.
      
      The hardwall version requires that the current tasks mems_allowed allows
      the node of the specified zone (or that you're in interrupt or that
      __GFP_THISNODE is set or that you're on a one cpuset system.)
      
      The softwall version, depending on the gfp_mask, might allow a node if it
      was allowed in the nearest enclusing cpuset marked mem_exclusive (which
      requires taking the cpuset lock 'callback_mutex' to evaluate.)
      
      This patch removes the cpuset_zone_allowed() call, and forces the caller to
      explicitly choose between the hardwall and the softwall case.
      
      If the caller wants the gfp_mask to determine this choice, they should (1)
      be sure they can sleep or that __GFP_HARDWALL is set, and (2) invoke the
      cpuset_zone_allowed_softwall() routine.
      
      This adds another 100 or 200 bytes to the kernel text space, due to the few
      lines of nearly duplicate code at the top of both cpuset_zone_allowed_*
      routines.  It should save a few instructions executed for the calls that
      turned into calls of cpuset_zone_allowed_hardwall, thanks to not having to
      set (before the call) then check (within the call) the __GFP_HARDWALL flag.
      
      For the most critical call, from get_page_from_freelist(), the same
      instructions are executed as before -- the old cpuset_zone_allowed()
      routine it used to call is the same code as the
      cpuset_zone_allowed_softwall() routine that it calls now.
      
      Not a perfect win, but seems worth it, to reduce this chance of hitting a
      sleeping with irq off complaint again.
      Signed-off-by: NPaul Jackson <pj@sgi.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      02a0e53d
  13. 08 12月, 2006 4 次提交
    • I
      [PATCH] hotplug CPU: clean up hotcpu_notifier() use · 02316067
      Ingo Molnar 提交于
      There was lots of #ifdef noise in the kernel due to hotcpu_notifier(fn,
      prio) not correctly marking 'fn' as used in the !HOTPLUG_CPU case, and thus
      generating compiler warnings of unused symbols, hence forcing people to add
      #ifdefs.
      
      the compiler can skip truly unused functions just fine:
      
          text    data     bss     dec     hex filename
       1624412  728710 3674856 6027978  5bfaca vmlinux.before
       1624412  728710 3674856 6027978  5bfaca vmlinux.after
      
      [akpm@osdl.org: topology.c fix]
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      02316067
    • N
      [PATCH] Add include/linux/freezer.h and move definitions from sched.h · 7dfb7103
      Nigel Cunningham 提交于
      Move process freezing functions from include/linux/sched.h to freezer.h, so
      that modifications to the freezer or the kernel configuration don't require
      recompiling just about everything.
      
      [akpm@osdl.org: fix ueagle driver]
      Signed-off-by: NNigel Cunningham <nigel@suspend2.net>
      Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
      Cc: Pavel Machek <pavel@ucw.cz>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      7dfb7103
    • R
      [PATCH] swsusp: Improve handling of highmem · 8357376d
      Rafael J. Wysocki 提交于
      Currently swsusp saves the contents of highmem pages by copying them to the
      normal zone which is quite inefficient (eg.  it requires two normal pages
      to be used for saving one highmem page).  This may be improved by using
      highmem for saving the contents of saveable highmem pages.
      
      Namely, during the suspend phase of the suspend-resume cycle we try to
      allocate as many free highmem pages as there are saveable highmem pages.
      If there are not enough highmem image pages to store the contents of all of
      the saveable highmem pages, some of them will be stored in the "normal"
      memory.  Next, we allocate as many free "normal" pages as needed to store
      the (remaining) image data.  We use a memory bitmap to mark the allocated
      free pages (ie.  highmem as well as "normal" image pages).
      
      Now, we use another memory bitmap to mark all of the saveable pages
      (highmem as well as "normal") and the contents of the saveable pages are
      copied into the image pages.  Then, the second bitmap is used to save the
      pfns corresponding to the saveable pages and the first one is used to save
      their data.
      
      During the resume phase the pfns of the pages that were saveable during the
      suspend are loaded from the image and used to mark the "unsafe" page
      frames.  Next, we try to allocate as many free highmem page frames as to
      load all of the image data that had been in the highmem before the suspend
      and we allocate so many free "normal" page frames that the total number of
      allocated free pages (highmem and "normal") is equal to the size of the
      image.  While doing this we have to make sure that there will be some extra
      free "normal" and "safe" page frames for two lists of PBEs constructed
      later.
      
      Now, the image data are loaded, if possible, into their "original" page
      frames.  The image data that cannot be written into their "original" page
      frames are loaded into "safe" page frames and their "original" kernel
      virtual addresses, as well as the addresses of the "safe" pages containing
      their copies, are stored in one of two lists of PBEs.
      
      One list of PBEs is for the copies of "normal" suspend pages (ie.  "normal"
      pages that were saveable during the suspend) and it is used in the same way
      as previously (ie.  by the architecture-dependent parts of swsusp).  The
      other list of PBEs is for the copies of highmem suspend pages.  The pages
      in this list are restored (in a reversible way) right before the
      arch-dependent code is called.
      Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl>
      Cc: Pavel Machek <pavel@ucw.cz>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      8357376d
    • A
      [PATCH] balance_pdgat() cleanup · e1dbeda6
      Andrew Morton 提交于
      Despaghettify balance_pdgat() a bit.
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      e1dbeda6
  14. 29 10月, 2006 2 次提交
    • M
      [PATCH] Use min of two prio settings in calculating distress for reclaim · bbdb396a
      Martin Bligh 提交于
      If try_to_free_pages / balance_pgdat are called with a gfp_mask specifying
      GFP_IO and/or GFP_FS, they will reclaim the requisite number of pages, and the
      reset prev_priority to DEF_PRIORITY (or to some other high (ie: unurgent)
      value).
      
      However, another reclaimer without those gfp_mask flags set (say, GFP_NOIO)
      may still be struggling to reclaim pages.  The concurrent overwrite of
      zone->prev_priority will cause this GFP_NOIO thread to unexpectedly cease
      deactivating mapped pages, thus causing reclaim difficulties.
      
      Fix this is to key the distress calculation not off zone->prev_priority, but
      also take into account the local caller's priority by using
      min(zone->prev_priority, sc->priority)
      Signed-off-by: NMartin J. Bligh <mbligh@google.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: <stable@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      bbdb396a
    • M
      [PATCH] vmscan: Fix temp_priority race · 3bb1a852
      Martin Bligh 提交于
      The temp_priority field in zone is racy, as we can walk through a reclaim
      path, and just before we copy it into prev_priority, it can be overwritten
      (say with DEF_PRIORITY) by another reclaimer.
      
      The same bug is contained in both try_to_free_pages and balance_pgdat, but
      it is fixed slightly differently.  In balance_pgdat, we keep a separate
      priority record per zone in a local array.  In try_to_free_pages there is
      no need to do this, as the priority level is the same for all zones that we
      reclaim from.
      
      Impact of this bug is that temp_priority is copied into prev_priority, and
      setting this artificially high causes reclaimers to set distress
      artificially low.  They then fail to reclaim mapped pages, when they are,
      in fact, under severe memory pressure (their priority may be as low as 0).
      This causes the OOM killer to fire incorrectly.
      
      From: Andrew Morton <akpm@osdl.org>
      
      __zone_reclaim() isn't modifying zone->prev_priority.  But zone->prev_priority
      is used in the decision whether or not to bring mapped pages onto the inactive
      list.  Hence there's a risk here that __zone_reclaim() will fail because
      zone->prev_priority ir large (ie: low urgency) and lots of mapped pages end up
      stuck on the active list.
      
      Fix that up by decreasing (ie making more urgent) zone->prev_priority as
      __zone_reclaim() scans the zone's pages.
      
      This bug perhaps explains why ZONE_RECLAIM_PRIORITY was created.  It should be
      possible to remove that now, and to just start out at DEF_PRIORITY?
      
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <clameter@engr.sgi.com>
      Cc: <stable@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      3bb1a852
  15. 21 10月, 2006 1 次提交
    • A
      [PATCH] separate bdi congestion functions from queue congestion functions · 3fcfab16
      Andrew Morton 提交于
      Separate out the concept of "queue congestion" from "backing-dev congestion".
      Congestion is a backing-dev concept, not a queue concept.
      
      The blk_* congestion functions are retained, as wrappers around the core
      backing-dev congestion functions.
      
      This proper layering is needed so that NFS can cleanly use the congestion
      functions, and so that CONFIG_BLOCK=n actually links.
      
      Cc: "Thomas Maier" <balagi@justmail.de>
      Cc: "Jens Axboe" <jens.axboe@oracle.com>
      Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Peter Osterlund <petero2@telia.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      3fcfab16
  16. 17 10月, 2006 1 次提交
  17. 27 9月, 2006 2 次提交
  18. 26 9月, 2006 9 次提交