1. 01 7月, 2006 6 次提交
    • C
      [PATCH] zoned vm counters: basic ZVC (zoned vm counter) implementation · 2244b95a
      Christoph Lameter 提交于
      Per zone counter infrastructure
      
      The counters that we currently have for the VM are split per processor.  The
      processor however has not much to do with the zone these pages belong to.  We
      cannot tell f.e.  how many ZONE_DMA pages are dirty.
      
      So we are blind to potentially inbalances in the usage of memory in various
      zones.  F.e.  in a NUMA system we cannot tell how many pages are dirty on a
      particular node.  If we knew then we could put measures into the VM to balance
      the use of memory between different zones and different nodes in a NUMA
      system.  For example it would be possible to limit the dirty pages per node so
      that fast local memory is kept available even if a process is dirtying huge
      amounts of pages.
      
      Another example is zone reclaim.  We do not know how many unmapped pages exist
      per zone.  So we just have to try to reclaim.  If it is not working then we
      pause and try again later.  It would be better if we knew when it makes sense
      to reclaim unmapped pages from a zone.  This patchset allows the determination
      of the number of unmapped pages per zone.  We can remove the zone reclaim
      interval with the counters introduced here.
      
      Futhermore the ability to have various usage statistics available will allow
      the development of new NUMA balancing algorithms that may be able to improve
      the decision making in the scheduler of when to move a process to another node
      and hopefully will also enable automatic page migration through a user space
      program that can analyse the memory load distribution and then rebalance
      memory use in order to increase performance.
      
      The counter framework here implements differential counters for each processor
      in struct zone.  The differential counters are consolidated when a threshold
      is exceeded (like done in the current implementation for nr_pageache), when
      slab reaping occurs or when a consolidation function is called.
      
      Consolidation uses atomic operations and accumulates counters per zone in the
      zone structure and also globally in the vm_stat array.  VM functions can
      access the counts by simply indexing a global or zone specific array.
      
      The arrangement of counters in an array also simplifies processing when output
      has to be generated for /proc/*.
      
      Counters can be updated by calling inc/dec_zone_page_state or
      _inc/dec_zone_page_state analogous to *_page_state.  The second group of
      functions can be called if it is known that interrupts are disabled.
      
      Special optimized increment and decrement functions are provided.  These can
      avoid certain checks and use increment or decrement instructions that an
      architecture may provide.
      
      We also add a new CONFIG_DMA_IS_NORMAL that signifies that an architecture can
      do DMA to all memory and therefore ZONE_NORMAL will not be populated.  This is
      only currently set for IA64 SGI SN2 and currently only affects
      node_page_state().  In the best case node_page_state can be reduced to
      retrieving a single counter for the one zone on the node.
      
      [akpm@osdl.org: cleanups]
      [akpm@osdl.org: export vm_stat[] for filesystems]
      Signed-off-by: NChristoph Lameter <clameter@sgi.com>
      Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      2244b95a
    • C
      [PATCH] zoned vm counters: create vmstat.c/.h from page_alloc.c/.h · f6ac2354
      Christoph Lameter 提交于
      NOTE: ZVC are *not* the lightweight event counters.  ZVCs are reliable whereas
      event counters do not need to be.
      
      Zone based VM statistics are necessary to be able to determine what the state
      of memory in one zone is.  In a NUMA system this can be helpful for local
      reclaim and other memory optimizations that may be able to shift VM load in
      order to get more balanced memory use.
      
      It is also useful to know how the computing load affects the memory
      allocations on various zones.  This patchset allows the retrieval of that data
      from userspace.
      
      The patchset introduces a framework for counters that is a cross between the
      existing page_stats --which are simply global counters split per cpu-- and the
      approach of deferred incremental updates implemented for nr_pagecache.
      
      Small per cpu 8 bit counters are added to struct zone.  If the counter exceeds
      certain thresholds then the counters are accumulated in an array of
      atomic_long in the zone and in a global array that sums up all zone values.
      The small 8 bit counters are next to the per cpu page pointers and so they
      will be in high in the cpu cache when pages are allocated and freed.
      
      Access to VM counter information for a zone and for the whole machine is then
      possible by simply indexing an array (Thanks to Nick Piggin for pointing out
      that approach).  The access to the total number of pages of various types does
      no longer require the summing up of all per cpu counters.
      
      Benefits of this patchset right now:
      
      - Ability for UP and SMP configuration to determine how memory
        is balanced between the DMA, NORMAL and HIGHMEM zones.
      
      - loops over all processors are avoided in writeback and
        reclaim paths. We can avoid caching the writeback information
        because the needed information is directly accessible.
      
      - Special handling for nr_pagecache removed.
      
      - zone_reclaim_interval vanishes since VM stats can now determine
        when it is worth to do local reclaim.
      
      - Fast inline per node page state determination.
      
      - Accurate counters in /sys/devices/system/node/node*/meminfo. Current
        counters are counting simply which processor allocated a page somewhere
        and guestimate based on that. So the counters were not useful to show
        the actual distribution of page use on a specific zone.
      
      - The swap_prefetch patch requires per node statistics in order to
        figure out when processors of a node can prefetch. This patch provides
        some of the needed numbers.
      
      - Detailed VM counters available in more /proc and /sys status files.
      
      References to earlier discussions:
      V1 http://marc.theaimsgroup.com/?l=linux-kernel&m=113511649910826&w=2
      V2 http://marc.theaimsgroup.com/?l=linux-kernel&m=114980851924230&w=2
      V3 http://marc.theaimsgroup.com/?l=linux-kernel&m=115014697910351&w=2
      V4 http://marc.theaimsgroup.com/?l=linux-kernel&m=115024767318740&w=2
      
      Performance tests with AIM7 did not show any regressions.  Seems to be a tad
      faster even.  Tested on ia64/NUMA.  Builds fine on i386, SMP / UP.  Includes
      fixes for s390/arm/uml arch code.
      
      This patch:
      
      Move counter code from page_alloc.c/page-flags.h to vmstat.c/h.
      
      Create vmstat.c/vmstat.h by separating the counter code and the proc
      functions.
      
      Move the vm_stat_text array before zoneinfo_show.
      
      [akpm@osdl.org: s390 build fix]
      [akpm@osdl.org: HOTPLUG_CPU build fix]
      Signed-off-by: NChristoph Lameter <clameter@sgi.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      f6ac2354
    • A
      [PATCH] fix ISTALLION=y · 672b2714
      Adrian Bunk 提交于
      drivers/char/istallion.c: In function ‘stli_initbrds’:
      drivers/char/istallion.c:4150: error: implicit declaration of function ‘stli_parsebrd’
      drivers/char/istallion.c:4150: error: ‘stli_brdsp’ undeclared (first use in this function)
      drivers/char/istallion.c:4150: error: (Each undeclared identifier is reported only once
      drivers/char/istallion.c:4150: error: for each function it appears in.)
      drivers/char/istallion.c:4164: error: implicit declaration of function ‘stli_argbrds’
      
      While I was at it, I also removed the #ifdef MODULE around the initialation
      code to allow it to perhaps work when built into the kernel and made a
      needlessly global function static.
      Signed-off-by: NAdrian Bunk <bunk@stusta.de>
      Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      672b2714
    • A
      [PATCH] msr.c: use register_hotcpu_notifier() · e09793bb
      Andrew Morton 提交于
      register_cpu_notifier() cannot do anything in a module, in a
      !CONFIG_HOTPLUG_CPU kernel.
      
      Cc: Chandra Seetharaman <sekharan@us.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      e09793bb
    • I
      [PATCH] fix platform_device_put/del mishaps · 1017f6af
      Ingo Molnar 提交于
      This fixes drivers/char/pc8736x_gpio.c and drivers/char/scx200_gpio.c to
      use the platform_device_del/put ops correctly.
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      Cc: Jim Cromie <jim.cromie@gmail.com>
      Cc: Greg KH <greg@kroah.com>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      1017f6af
    • I
      [PATCH] fix drivers/video/imacfb.c compilation · 491d525f
      Ingo Molnar 提交于
      Fix build error on x86_64.  There's nothing even remotely close to
      imacmp_seg in the kernel, so I removed the whole line.
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      Cc: Edgar Hucek <hostmaster@ed-soft.at>
      Cc: Antonino Daplas <adaplas@pol.net>
      Signed-off-by: NAndrew Morton <akpm@osdl.org>
      Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
      491d525f
  2. 30 6月, 2006 34 次提交