1. 25 May, 2010 1 commit
  2. 30 Mar, 2010 1 commit
    • Tejun Heo's avatar
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking... · 5a0e3ad6
      Tejun Heo authored
      include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h
      
      percpu.h is included by sched.h and module.h and thus ends up being
      included when building most .c files.  percpu.h includes slab.h which
      in turn includes gfp.h making everything defined by the two files
      universally available and complicating inclusion dependencies.
      
      percpu.h -> slab.h dependency is about to be removed.  Prepare for
      this change by updating users of gfp and slab facilities include those
      headers directly instead of assuming availability.  As this conversion
      needs to touch large number of source files, the following script is
      used as the basis of conversion.
      
        http://userweb.kernel.org/~tj/misc/slabh-sweep.py
      
      The script does the followings.
      
      * Scan files for gfp and slab usages and update includes such that
        only the necessary includes are there.  ie. if only gfp is used,
        gfp.h, if slab is used, slab.h.
      
      * When the script inserts a new include, it looks at the include
        blocks and try to put the new include such that its order conforms
        to its surrounding.  It's put in the include block which contains
        core kernel includes, in the same order that the rest are ordered -
        alphabetical, Christmas tree, rev-Xmas-tree or at the end if there
        doesn't seem to be any matching order.
      
      * If the script can't find a place to put a new include (mostly
        because the file doesn't have fitting include block), it prints out
        an error message indicating which .h file needs to be added to the
        file.
      
      The conversion was done in the following steps.
      
      1. The initial automatic conversion of all .c files updated slightly
         over 4000 files, deleting around 700 includes and adding ~480 gfp.h
         and ~3000 slab.h inclusions.  The script emitted errors for ~400
         files.
      
      2. Each error was manually checked.  Some didn't need the inclusion,
         some needed manual addition while adding it to implementation .h or
         embedding .c file was more appropriate for others.  This step added
         inclusions to around 150 files.
      
      3. The script was run again and the output was compared to the edits
         from #2 to make sure no file was left behind.
      
      4. Several build tests were done and a couple of problems were fixed.
         e.g. lib/decompress_*.c used malloc/free() wrappers around slab
         APIs requiring slab.h to be added manually.
      
      5. The script was run on all .h files but without automatically
         editing them as sprinkling gfp.h and slab.h inclusions around .h
         files could easily lead to inclusion dependency hell.  Most gfp.h
         inclusion directives were ignored as stuff from gfp.h was usually
         wildly available and often used in preprocessor macros.  Each
         slab.h inclusion directive was examined and added manually as
         necessary.
      
      6. percpu.h was updated not to include slab.h.
      
      7. Build test were done on the following configurations and failures
         were fixed.  CONFIG_GCOV_KERNEL was turned off for all tests (as my
         distributed build env didn't work with gcov compiles) and a few
         more options had to be turned off depending on archs to make things
         build (like ipr on powerpc/64 which failed due to missing writeq).
      
         * x86 and x86_64 UP and SMP allmodconfig and a custom test config.
         * powerpc and powerpc64 SMP allmodconfig
         * sparc and sparc64 SMP allmodconfig
         * ia64 SMP allmodconfig
         * s390 SMP allmodconfig
         * alpha SMP allmodconfig
         * um on x86_64 SMP allmodconfig
      
      8. percpu.h modifications were reverted so that it could be applied as
         a separate patch and serve as bisection point.
      
      Given the fact that I had only a couple of failures from tests on step
      6, I'm fairly confident about the coverage of this conversion patch.
      If there is a breakage, it's likely to be something in one of the arch
      headers which should be easily discoverable easily on most builds of
      the specific arch.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Guess-its-ok-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      5a0e3ad6
  3. 06 Mar, 2010 1 commit
  4. 05 Jan, 2010 2 commits
    • Christoph Lameter's avatar
      this_cpu: Remove pageset_notifier · ad596925
      Christoph Lameter authored
      Remove the pageset notifier since it only marks that a processor
      exists on a specific node. Move that code into the vmstat notifier.
      Signed-off-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      ad596925
    • Christoph Lameter's avatar
      this_cpu: Page allocator conversion · 99dcc3e5
      Christoph Lameter authored
      Use the per cpu allocator functionality to avoid per cpu arrays in struct zone.
      
      This drastically reduces the size of struct zone for systems with large
      amounts of processors and allows placement of critical variables of struct
      zone in one cacheline even on very large systems.
      
      Another effect is that the pagesets of one processor are placed near one
      another. If multiple pagesets from different zones fit into one cacheline
      then additional cacheline fetches can be avoided on the hot paths when
      allocating memory from multiple zones.
      
      Bootstrap becomes simpler if we use the same scheme for UP, SMP, NUMA. #ifdefs
      are reduced and we can drop the zone_pcp macro.
      
      Hotplug handling is also simplified since cpu alloc can bring up and
      shut down cpu areas for a specific cpu as a whole. So there is no need to
      allocate or free individual pagesets.
      
      V7-V8:
      - Explain chicken egg dilemmna with percpu allocator.
      
      V4-V5:
      - Fix up cases where per_cpu_ptr is called before irq disable
      - Integrate the bootstrap logic that was separate before.
      
      tj: Build failure in pageset_cpuup_callback() due to missing ret
          variable fixed.
      Reviewed-by: default avatarMel Gorman <mel@csn.ul.ie>
      Signed-off-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      99dcc3e5
  5. 15 Dec, 2009 2 commits
    • KOSAKI Motohiro's avatar
      vmscan: stop kswapd waiting on congestion when the min watermark is not being met · bb3ab596
      KOSAKI Motohiro authored
      If reclaim fails to make sufficient progress, the priority is raised.
      Once the priority is higher, kswapd starts waiting on congestion.
      However, if the zone is below the min watermark then kswapd needs to
      continue working without delay as there is a danger of an increased rate
      of GFP_ATOMIC allocation failure.
      
      This patch changes the conditions under which kswapd waits on congestion
      by only going to sleep if the min watermarks are being met.
      
      [mel@csn.ul.ie: add stats to track how relevant the logic is]
      [mel@csn.ul.ie: make kswapd only check its own zones and rename the relevant counters]
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Reviewed-by: default avatarRik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bb3ab596
    • Mel Gorman's avatar
      vmscan: have kswapd sleep for a short interval and double check it should be asleep · f50de2d3
      Mel Gorman authored
      After kswapd balances all zones in a pgdat, it goes to sleep.  In the
      event of no IO congestion, kswapd can go to sleep very shortly after the
      high watermark was reached.  If there are a constant stream of allocations
      from parallel processes, it can mean that kswapd went to sleep too quickly
      and the high watermark is not being maintained for sufficient length time.
      
      This patch makes kswapd go to sleep as a two-stage process.  It first
      tries to sleep for HZ/10.  If it is woken up by another process or the
      high watermark is no longer met, it's considered a premature sleep and
      kswapd continues work.  Otherwise it goes fully to sleep.
      
      This adds more counters to distinguish between fast and slow breaches of
      watermarks.  A "fast" premature sleep is one where the low watermark was
      hit in a very short time after kswapd going to sleep.  A "slow" premature
      sleep indicates that the high watermark was breached after a very short
      interval.
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Cc: Frans Pop <elendil@planet.nl>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f50de2d3
  6. 29 Oct, 2009 1 commit
    • Tejun Heo's avatar
      percpu: make percpu symbols under kernel/ and mm/ unique · 1871e52c
      Tejun Heo authored
      This patch updates percpu related symbols under kernel/ and mm/ such
      that percpu symbols are unique and don't clash with local symbols.
      This serves two purposes of decreasing the possibility of global
      percpu symbol collision and allowing dropping per_cpu__ prefix from
      percpu symbols.
      
      * kernel/lockdep.c: s/lock_stats/cpu_lock_stats/
      
      * kernel/sched.c: s/init_rq_rt/init_rt_rq_var/	(any better idea?)
        		  s/sched_group_cpus/sched_groups/
      
      * kernel/softirq.c: s/ksoftirqd/run_ksoftirqd/a
      
      * kernel/softlockup.c: s/(*)_timestamp/softlockup_\1_ts/
        		       s/watchdog_task/softlockup_watchdog/
      		       s/timestamp/ts/ for local variables
      
      * kernel/time/timer_stats: s/lookup_lock/tstats_lookup_lock/
      
      * mm/slab.c: s/reap_work/slab_reap_work/
        	     s/reap_node/slab_reap_node/
      
      * mm/vmstat.c: local variable changed to avoid collision with vmstat_work
      
      Partly based on Rusty Russell's "alloc_percpu: rename percpu vars
      which cause name clashes" patch.
      Signed-off-by: default avatarTejun Heo <tj@kernel.org>
      Acked-by: default avatar(slab/vmstat) Christoph Lameter <cl@linux-foundation.org>
      Reviewed-by: default avatarChristoph Lameter <cl@linux-foundation.org>
      Cc: Rusty Russell <rusty@rustcorp.com.au>
      Cc: Ingo Molnar <mingo@redhat.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Nick Piggin <npiggin@suse.de>
      1871e52c
  7. 22 Sep, 2009 3 commits
  8. 17 Jun, 2009 5 commits
  9. 18 May, 2009 1 commit
    • Mel Gorman's avatar
      [ARM] Double check memmap is actually valid with a memmap has unexpected holes V2 · eb33575c
      Mel Gorman authored
      pfn_valid() is meant to be able to tell if a given PFN has valid memmap
      associated with it or not. In FLATMEM, it is expected that holes always
      have valid memmap as long as there is valid PFNs either side of the hole.
      In SPARSEMEM, it is assumed that a valid section has a memmap for the
      entire section.
      
      However, ARM and maybe other embedded architectures in the future free
      memmap backing holes to save memory on the assumption the memmap is never
      used. The page_zone linkages are then broken even though pfn_valid()
      returns true. A walker of the full memmap must then do this additional
      check to ensure the memmap they are looking at is sane by making sure the
      zone and PFN linkages are still valid. This is expensive, but walkers of
      the full memmap are extremely rare.
      
      This was caught before for FLATMEM and hacked around but it hits again for
      SPARSEMEM because the page_zone linkages can look ok where the PFN linkages
      are totally screwed. This looks like a hatchet job but the reality is that
      any clean solution would end up consumning all the memory saved by punching
      these unexpected holes in the memmap. For example, we tried marking the
      memmap within the section invalid but the section size exceeds the size of
      the hole in most cases so pfn_valid() starts returning false where valid
      memmap exists. Shrinking the size of the section would increase memory
      consumption offsetting the gains.
      
      This patch identifies when an architecture is punching unexpected holes
      in the memmap that the memory model cannot automatically detect and sets
      ARCH_HAS_HOLES_MEMORYMODEL. At the moment, this is restricted to EP93xx
      which is the model sub-architecture this has been reported on but may expand
      later. When set, walkers of the full memmap must call memmap_valid_within()
      for each PFN and passing in what it expects the page and zone to be for
      that PFN. If it finds the linkages to be broken, it assumes the memmap is
      invalid for that PFN.
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      eb33575c
  10. 03 Apr, 2009 1 commit
  11. 01 Apr, 2009 1 commit
  12. 30 Mar, 2009 1 commit
  13. 31 Dec, 2008 1 commit
  14. 23 Oct, 2008 4 commits
  15. 20 Oct, 2008 7 commits
  16. 27 Aug, 2008 1 commit
    • Mel Gorman's avatar
      [ARM] Skip memory holes in FLATMEM when reading /proc/pagetypeinfo · e80d6a24
      Mel Gorman authored
      Ordinarily, memory holes in flatmem still have a valid memmap and is safe
      to use. However, an architecture (ARM) frees up the memmap backing memory
      holes on the assumption it is never used. /proc/pagetypeinfo reads the
      whole range of pages in a zone believing that the memmap is valid and that
      pfn_valid will return false if it is not. On ARM, freeing the memmap breaks
      the page->zone linkages even though pfn_valid() returns true and the kernel
      can oops shortly afterwards due to accessing a bogus struct zone *.
      
      This patch lets architectures say when FLATMEM can have holes in the
      memmap. Rather than an expensive check for valid memory, /proc/pagetypeinfo
      will confirm that the page linkages are still valid by checking page->zone
      is still the expected zone. The lookup of page_zone is safe as there is a
      limited range of memory that is accessed when calling page_zone.  Even if
      page_zone happens to return the correct zone, the impact is that the counters
      in /proc/pagetypeinfo are slightly off but fragmentation monitoring is
      unlikely to be relevant on an embedded system.
      Reported-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Tested-by: default avatarH Hartley Sweeten <hsweeten@visionengravers.com>
      Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
      e80d6a24
  17. 24 Jul, 2008 1 commit
  18. 23 May, 2008 1 commit
  19. 13 May, 2008 1 commit
  20. 30 Apr, 2008 2 commits
  21. 28 Apr, 2008 2 commits