1. 11 12月, 2012 11 次提交
    • L
      mm: mempolicy: Check for misplaced page · 771fb4d8
      Lee Schermerhorn 提交于
      This patch provides a new function to test whether a page resides
      on a node that is appropriate for the mempolicy for the vma and
      address where the page is supposed to be mapped.  This involves
      looking up the node where the page belongs.  So, the function
      returns that node so that it may be used to allocated the page
      without consulting the policy again.
      
      A subsequent patch will call this function from the fault path.
      Because of this, I don't want to go ahead and allocate the page, e.g.,
      via alloc_page_vma() only to have to free it if it has the correct
      policy.  So, I just mimic the alloc_page_vma() node computation
      logic--sort of.
      
      Note:  we could use this function to implement a MPOL_MF_STRICT
      behavior when migrating pages to match mbind() mempolicy--e.g.,
      to ensure that pages in an interleaved range are reinterleaved
      rather than left where they are when they reside on any page in
      the interleave nodemask.
      Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
      Reviewed-by: NRik van Riel <riel@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      [ Added MPOL_F_LAZY to trigger migrate-on-fault;
        simplified code now that we don't have to bother
        with special crap for interleaved ]
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      771fb4d8
    • L
      mm: mempolicy: Add MPOL_NOOP · d3a71033
      Lee Schermerhorn 提交于
      This patch augments the MPOL_MF_LAZY feature by adding a "NOOP" policy
      to mbind().  When the NOOP policy is used with the 'MOVE and 'LAZY
      flags, mbind() will map the pages PROT_NONE so that they will be
      migrated on the next touch.
      
      This allows an application to prepare for a new phase of operation
      where different regions of shared storage will be assigned to
      worker threads, w/o changing policy.  Note that we could just use
      "default" policy in this case.  However, this also allows an
      application to request that pages be migrated, only if necessary,
      to follow any arbitrary policy that might currently apply to a
      range of pages, without knowing the policy, or without specifying
      multiple mbind()s for ranges with different policies.
      
      [ Bug in early version of mpol_parse_str() reported by Fengguang Wu. ]
      Bug-Reported-by: NReported-by: Fengguang Wu <fengguang.wu@intel.com>
      Signed-off-by: NLee Schermerhorn <lee.schermerhorn@hp.com>
      Reviewed-by: NRik van Riel <riel@redhat.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      d3a71033
    • P
      mm: mempolicy: Make MPOL_LOCAL a real policy · 479e2802
      Peter Zijlstra 提交于
      Make MPOL_LOCAL a real and exposed policy such that applications that
      relied on the previous default behaviour can explicitly request it.
      Requested-by: NChristoph Lameter <cl@linux.com>
      Reviewed-by: NRik van Riel <riel@redhat.com>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      479e2802
    • M
      mm: numa: Create basic numa page hinting infrastructure · d10e63f2
      Mel Gorman 提交于
      Note: This patch started as "mm/mpol: Create special PROT_NONE
      	infrastructure" and preserves the basic idea but steals *very*
      	heavily from "autonuma: numa hinting page faults entry points" for
      	the actual fault handlers without the migration parts.	The end
      	result is barely recognisable as either patch so all Signed-off
      	and Reviewed-bys are dropped. If Peter, Ingo and Andrea are ok with
      	this version, I will re-add the signed-offs-by to reflect the history.
      
      In order to facilitate a lazy -- fault driven -- migration of pages, create
      a special transient PAGE_NUMA variant, we can then use the 'spurious'
      protection faults to drive our migrations from.
      
      The meaning of PAGE_NUMA depends on the architecture but on x86 it is
      effectively PROT_NONE. Actual PROT_NONE mappings will not generate these
      NUMA faults for the reason that the page fault code checks the permission on
      the VMA (and will throw a segmentation fault on actual PROT_NONE mappings),
      before it ever calls handle_mm_fault.
      
      [dhillf@gmail.com: Fix typo]
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      Reviewed-by: NRik van Riel <riel@redhat.com>
      d10e63f2
    • A
      mm: numa: Support NUMA hinting page faults from gup/gup_fast · 0b9d7052
      Andrea Arcangeli 提交于
      Introduce FOLL_NUMA to tell follow_page to check
      pte/pmd_numa. get_user_pages must use FOLL_NUMA, and it's safe to do
      so because it always invokes handle_mm_fault and retries the
      follow_page later.
      
      KVM secondary MMU page faults will trigger the NUMA hinting page
      faults through gup_fast -> get_user_pages -> follow_page ->
      handle_mm_fault.
      
      Other follow_page callers like KSM should not use FOLL_NUMA, or they
      would fail to get the pages if they use follow_page instead of
      get_user_pages.
      
      [ This patch was picked up from the AutoNUMA tree. ]
      Originally-by: NAndrea Arcangeli <aarcange@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Rik van Riel <riel@redhat.com>
      [ ported to this tree. ]
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      Reviewed-by: NRik van Riel <riel@redhat.com>
      0b9d7052
    • A
      mm: numa: pte_numa() and pmd_numa() · be3a7284
      Andrea Arcangeli 提交于
      Implement pte_numa and pmd_numa.
      
      We must atomically set the numa bit and clear the present bit to
      define a pte_numa or pmd_numa.
      
      Once a pte or pmd has been set as pte_numa or pmd_numa, the next time
      a thread touches a virtual address in the corresponding virtual range,
      a NUMA hinting page fault will trigger. The NUMA hinting page fault
      will clear the NUMA bit and set the present bit again to resolve the
      page fault.
      
      The expectation is that a NUMA hinting page fault is used as part
      of a placement policy that decides if a page should remain on the
      current node or migrated to a different node.
      Acked-by: NRik van Riel <riel@redhat.com>
      Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      be3a7284
    • M
      mm: compaction: Add scanned and isolated counters for compaction · 397487db
      Mel Gorman 提交于
      Compaction already has tracepoints to count scanned and isolated pages
      but it requires that ftrace be enabled and if that information has to be
      written to disk then it can be disruptive. This patch adds vmstat counters
      for compaction called compact_migrate_scanned, compact_free_scanned and
      compact_isolated.
      
      With these counters, it is possible to define a basic cost model for
      compaction. This approximates of how much work compaction is doing and can
      be compared that with an oprofile showing TLB misses and see if the cost of
      compaction is being offset by THP for example. Minimally a compaction patch
      can be evaluated in terms of whether it increases or decreases cost. The
      basic cost model looks like this
      
      Fundamental unit u:	a word	sizeof(void *)
      
      Ca  = cost of struct page access = sizeof(struct page) / u
      
      Cmc = Cost migrate page copy = (Ca + PAGE_SIZE/u) * 2
      Cmf = Cost migrate failure   = Ca * 2
      Ci  = Cost page isolation    = (Ca + Wi)
      	where Wi is a constant that should reflect the approximate
      	cost of the locking operation.
      
      Csm = Cost migrate scanning = Ca
      Csf = Cost free    scanning = Ca
      
      Overall cost =	(Csm * compact_migrate_scanned) +
      	      	(Csf * compact_free_scanned)    +
      	      	(Ci  * compact_isolated)	+
      		(Cmc * pgmigrate_success)	+
      		(Cmf * pgmigrate_failed)
      
      Where the values are read from /proc/vmstat.
      
      This is very basic and ignores certain costs such as the allocation cost
      to do a migrate page copy but any improvement to the model would still
      use the same vmstat counters.
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      Reviewed-by: NRik van Riel <riel@redhat.com>
      397487db
    • M
      mm: migrate: Add a tracepoint for migrate_pages · 7b2a2d4a
      Mel Gorman 提交于
      The pgmigrate_success and pgmigrate_fail vmstat counters tells the user
      about migration activity but not the type or the reason. This patch adds
      a tracepoint to identify the type of page migration and why the page is
      being migrated.
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      Reviewed-by: NRik van Riel <riel@redhat.com>
      7b2a2d4a
    • M
      mm: compaction: Move migration fail/success stats to migrate.c · 5647bc29
      Mel Gorman 提交于
      The compact_pages_moved and compact_pagemigrate_failed events are
      convenient for determining if compaction is active and to what
      degree migration is succeeding but it's at the wrong level. Other
      users of migration may also want to know if migration is working
      properly and this will be particularly true for any automated
      NUMA migration. This patch moves the counters down to migration
      with the new events called pgmigrate_success and pgmigrate_fail.
      The compact_blocks_moved counter is removed because while it was
      useful for debugging initially, it's worthless now as no meaningful
      conclusions can be drawn from its value.
      Signed-off-by: NMel Gorman <mgorman@suse.de>
      Reviewed-by: NRik van Riel <riel@redhat.com>
      5647bc29
    • P
      mm: Count the number of pages affected in change_protection() · 7da4d641
      Peter Zijlstra 提交于
      This will be used for three kinds of purposes:
      
       - to optimize mprotect()
      
       - to speed up working set scanning for working set areas that
         have not been touched
      
       - to more accurately scan per real working set
      
      No change in functionality from this patch.
      Suggested-by: NIngo Molnar <mingo@kernel.org>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Andrea Arcangeli <aarcange@redhat.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mgorman@suse.de>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      7da4d641
    • R
      x86/mm: Introduce pte_accessible() · 2c3cf556
      Rik van Riel 提交于
      We need pte_present to return true for _PAGE_PROTNONE pages, to indicate that
      the pte is associated with a page.
      
      However, for TLB flushing purposes, we would like to know whether the pte
      points to an actually accessible page.  This allows us to skip remote TLB
      flushes for pages that are not actually accessible.
      
      Fill in this method for x86 and provide a safe (but slower) method
      on other architectures.
      Signed-off-by: NRik van Riel <riel@redhat.com>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Fixed-by: NLinus Torvalds <torvalds@linux-foundation.org>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Link: http://lkml.kernel.org/n/tip-66p11te4uj23gevgh4j987ip@git.kernel.org
      [ Added Linus's review fixes. ]
      Signed-off-by: NIngo Molnar <mingo@kernel.org>
      2c3cf556
  2. 17 11月, 2012 4 次提交
    • A
      revert "mm: fix-up zone present pages" · 5576646f
      Andrew Morton 提交于
      Revert commit 7f1290f2 ("mm: fix-up zone present pages")
      
      That patch tried to fix a issue when calculating zone->present_pages,
      but it caused a regression on 32bit systems with HIGHMEM.  With that
      change, reset_zone_present_pages() resets all zone->present_pages to
      zero, and fixup_zone_present_pages() is called to recalculate
      zone->present_pages when the boot allocator frees core memory pages into
      buddy allocator.  Because highmem pages are not freed by bootmem
      allocator, all highmem zones' present_pages becomes zero.
      
      Various options for improving the situation are being discussed but for
      now, let's return to the 3.6 code.
      
      Cc: Jianguo Wu <wujianguo@huawei.com>
      Cc: Jiang Liu <jiang.liu@huawei.com>
      Cc: Petr Tesarik <ptesarik@suse.cz>
      Cc: "Luck, Tony" <tony.luck@intel.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Yinghai Lu <yinghai@kernel.org>
      Cc: Minchan Kim <minchan.kim@gmail.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Acked-by: NDavid Rientjes <rientjes@google.com>
      Tested-by: NChris Clayton <chris2553@googlemail.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      5576646f
    • R
      rapidio: fix kernel-doc warnings · 2ca3cb50
      Randy Dunlap 提交于
      Fix rapidio kernel-doc warnings:
      
        Warning(drivers/rapidio/rio.c:415): No description found for parameter 'local'
        Warning(drivers/rapidio/rio.c:415): Excess function parameter 'lstart' description in 'rio_map_inb_region'
        Warning(include/linux/rio.h:290): No description found for parameter 'switches'
        Warning(include/linux/rio.h:290): No description found for parameter 'destid_table'
      Signed-off-by: NRandy Dunlap <rdunlap@infradead.org>
      Cc: Matt Porter <mporter@kernel.crashing.org>
      Acked-by: NAlexandre Bounine <alexandre.bounine@idt.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      2ca3cb50
    • H
      memcg: fix hotplugged memory zone oops · bea8c150
      Hugh Dickins 提交于
      When MEMCG is configured on (even when it's disabled by boot option),
      when adding or removing a page to/from its lru list, the zone pointer
      used for stats updates is nowadays taken from the struct lruvec.  (On
      many configurations, calculating zone from page is slower.)
      
      But we have no code to update all the lruvecs (per zone, per memcg) when
      a memory node is hotadded.  Here's an extract from the oops which
      results when running numactl to bind a program to a newly onlined node:
      
        BUG: unable to handle kernel NULL pointer dereference at 0000000000000f60
        IP:  __mod_zone_page_state+0x9/0x60
        Pid: 1219, comm: numactl Not tainted 3.6.0-rc5+ #180 Bochs Bochs
        Process numactl (pid: 1219, threadinfo ffff880039abc000, task ffff8800383c4ce0)
        Call Trace:
          __pagevec_lru_add_fn+0xdf/0x140
          pagevec_lru_move_fn+0xb1/0x100
          __pagevec_lru_add+0x1c/0x30
          lru_add_drain_cpu+0xa3/0x130
          lru_add_drain+0x2f/0x40
         ...
      
      The natural solution might be to use a memcg callback whenever memory is
      hotadded; but that solution has not been scoped out, and it happens that
      we do have an easy location at which to update lruvec->zone.  The lruvec
      pointer is discovered either by mem_cgroup_zone_lruvec() or by
      mem_cgroup_page_lruvec(), and both of those do know the right zone.
      
      So check and set lruvec->zone in those; and remove the inadequate
      attempt to set lruvec->zone from lruvec_init(), which is called before
      NODE_DATA(node) has been allocated in such cases.
      
      Ah, there was one exceptionr.  For no particularly good reason,
      mem_cgroup_force_empty_list() has its own code for deciding lruvec.
      Change it to use the standard mem_cgroup_zone_lruvec() and
      mem_cgroup_get_lru_size() too.  In fact it was already safe against such
      an oops (the lru lists in danger could only be empty), but we're better
      proofed against future changes this way.
      
      I've marked this for stable (3.6) since we introduced the problem in 3.5
      (now closed to stable); but I have no idea if this is the only fix
      needed to get memory hotadd working with memcg in 3.6, and received no
      answer when I enquired twice before.
      Reported-by: NTang Chen <tangchen@cn.fujitsu.com>
      Signed-off-by: NHugh Dickins <hughd@google.com>
      Acked-by: NJohannes Weiner <hannes@cmpxchg.org>
      Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Konstantin Khlebnikov <khlebnikov@openvz.org>
      Cc: Wen Congyang <wency@cn.fujitsu.com>
      Cc: <stable@vger.kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      bea8c150
    • D
      mm, oom: reintroduce /proc/pid/oom_adj · fa0cbbf1
      David Rientjes 提交于
      This is mostly a revert of 01dc52eb ("oom: remove deprecated oom_adj")
      from Davidlohr Bueso.
      
      It reintroduces /proc/pid/oom_adj for backwards compatibility with earlier
      kernels.  It simply scales the value linearly when /proc/pid/oom_score_adj
      is written.
      
      The major difference is that its scheduled removal is no longer included
      in Documentation/feature-removal-schedule.txt.  We do warn users with a
      single printk, though, to suggest the more powerful and supported
      /proc/pid/oom_score_adj interface.
      Reported-by: NArtem S. Tashkinov <t.artem@lycos.com>
      Signed-off-by: NDavid Rientjes <rientjes@google.com>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fa0cbbf1
  3. 16 11月, 2012 1 次提交
    • I
      clk: remove inline usage from clk-provider.h · 93532c8a
      Igor Mazanov 提交于
      Users of GCC 4.7 have reported compiler errors due to having inline
      applied to function declarations in clk-provider.h.  The definitions
      exist in drivers/clk/clk.c.  An example error:
      
      In file included from arch/arm/mach-omap2/clockdomain.c:25:0:
      arch/arm/mach-omap2/clockdomain.c: In function ‘clkdm_clk_disable’:
      include/linux/clk-provider.h:338:12: error: inlining failed in call to always_inline ‘__clk_get_enable_count’: function body not available
      arch/arm/mach-omap2/clockdomain.c:1001:28: error: called from here
      make[1]: *** [arch/arm/mach-omap2/clockdomain.o] Error 1
      make: *** [arch/arm/mach-omap2] Error 2
      
      This patch removes the use of inline from include/linux/clk-provider.h
      but keeps the function definitions in drivers/clk/clk.c as inlined since
      they are one-liners.
      Signed-off-by: NIgor Mazanov <i.mazanov@gmail.com>
      Acked-by: NPaul Walmsley <paul@pwsan.com>
      Signed-off-by: NMike Turquette <mturquette@linaro.org>
      [mturquette@linaro.org: improved subject, added changelog]
      93532c8a
  4. 10 11月, 2012 1 次提交
    • A
      of/address: sparc: Declare of_address_to_resource() as an extern function for sparc again · 0bce04be
      Andreas Larsson 提交于
      This bug-fix makes sure that of_address_to_resource is defined extern for sparc
      so that the sparc-specific implementation of of_address_to_resource() is once
      again used when including include/linux/of_address.h in a sparc context. A
      number of drivers in mainline relies on this function working for sparc.
      
      The bug was introduced in a850a755, "of/address:
      add empty static inlines for !CONFIG_OF". Contrary to that commit title, the
      static inlines are added for !CONFIG_OF_ADDRESS, and CONFIG_OF_ADDRESS is never
      defined for sparc. This is good behavior for the other functions in
      include/linux/of_address.h, as the extern functions defined in
      drivers/of/address.c only gets linked when OF_ADDRESS is configured. However,
      for of_address_to_resource there exists a sparc-specific implementation in
      arch/sparc/arch/sparc/kernel/of_device_common.c
      
      Solution suggested by: Sam Ravnborg <sam@ravnborg.org>
      Signed-off-by: NAndreas Larsson <andreas@gaisler.com>
      Acked-by: NRob Herring <rob.herring@calxeda.com>
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      0bce04be
  5. 09 11月, 2012 1 次提交
    • A
      revert "epoll: support for disabling items, and a self-test app" · a80a6b85
      Andrew Morton 提交于
      Revert commit 03a7beb5 ("epoll: support for disabling items, and a
      self-test app") pending resolution of the issues identified by Michael
      Kerrisk, copied below.
      
      We'll revisit this for 3.8.
      
      : I've taken a look at this patch as it currently stands in 3.7-rc1, and
      : done a bit of testing. (By the way, the test program
      : tools/testing/selftests/epoll/test_epoll.c does not compile...)
      :
      : There are one or two places where the behavior seems a little strange,
      : so I have a question or two at the end of this mail. But other than
      : that, I want to check my understanding so that the interface can be
      : correctly documented.
      :
      : Just to go though my understanding, the problem is the following
      : scenario in a multithreaded application:
      :
      : 1. Multiple threads are performing epoll_wait() operations,
      :    and maintaining a user-space cache that contains information
      :    corresponding to each file descriptor being monitored by
      :    epoll_wait().
      :
      : 2. At some point, a thread wants to delete (EPOLL_CTL_DEL)
      :    a file descriptor from the epoll interest list, and
      :    delete the corresponding record from the user-space cache.
      :
      : 3. The problem with (2) is that some other thread may have
      :    previously done an epoll_wait() that retrieved information
      :    about the fd in question, and may be in the middle of using
      :    information in the cache that relates to that fd. Thus,
      :    there is a potential race.
      :
      : 4. The race can't solved purely in user space, because doing
      :    so would require applying a mutex across the epoll_wait()
      :    call, which would of course blow thread concurrency.
      :
      : Right?
      :
      : Your solution is the EPOLL_CTL_DISABLE operation. I want to
      : confirm my understanding about how to use this flag, since
      : the description that has accompanied the patches so far
      : has been a bit sparse
      :
      : 0. In the scenario you're concerned about, deleting a file
      :    descriptor means (safely) doing the following:
      :    (a) Deleting the file descriptor from the epoll interest list
      :        using EPOLL_CTL_DEL
      :    (b) Deleting the corresponding record in the user-space cache
      :
      : 1. It's only meaningful to use this EPOLL_CTL_DISABLE in
      :    conjunction with EPOLLONESHOT.
      :
      : 2. Using EPOLL_CTL_DISABLE without using EPOLLONESHOT in
      :    conjunction is a logical error.
      :
      : 3. The correct way to code multithreaded applications using
      :    EPOLL_CTL_DISABLE and EPOLLONESHOT is as follows:
      :
      :    a. All EPOLL_CTL_ADD and EPOLL_CTL_MOD operations should
      :       should EPOLLONESHOT.
      :
      :    b. When a thread wants to delete a file descriptor, it
      :       should do the following:
      :
      :       [1] Call epoll_ctl(EPOLL_CTL_DISABLE)
      :       [2] If the return status from epoll_ctl(EPOLL_CTL_DISABLE)
      :           was zero, then the file descriptor can be safely
      :           deleted by the thread that made this call.
      :       [3] If the epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY,
      :           then the descriptor is in use. In this case, the calling
      :           thread should set a flag in the user-space cache to
      :           indicate that the thread that is using the descriptor
      :           should perform the deletion operation.
      :
      : Is all of the above correct?
      :
      : The implementation depends on checking on whether
      : (events & ~EP_PRIVATE_BITS) == 0
      : This replies on the fact that EPOLL_CTL_AD and EPOLL_CTL_MOD always
      : set EPOLLHUP and EPOLLERR in the 'events' mask, and EPOLLONESHOT
      : causes those flags (as well as all others in ~EP_PRIVATE_BITS) to be
      : cleared.
      :
      : A corollary to the previous paragraph is that using EPOLL_CTL_DISABLE
      : is only useful in conjunction with EPOLLONESHOT. However, as things
      : stand, one can use EPOLL_CTL_DISABLE on a file descriptor that does
      : not have EPOLLONESHOT set in 'events' This results in the following
      : (slightly surprising) behavior:
      :
      : (a) The first call to epoll_ctl(EPOLL_CTL_DISABLE) returns 0
      :     (the indicator that the file descriptor can be safely deleted).
      : (b) The next call to epoll_ctl(EPOLL_CTL_DISABLE) fails with EBUSY.
      :
      : This doesn't seem particularly useful, and in fact is probably an
      : indication that the user made a logic error: they should only be using
      : epoll_ctl(EPOLL_CTL_DISABLE) on a file descriptor for which
      : EPOLLONESHOT was set in 'events'. If that is correct, then would it
      : not make sense to return an error to user space for this case?
      
      Cc: Michael Kerrisk <mtk.manpages@gmail.com>
      Cc: "Paton J. Lewis" <palewis@adobe.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a80a6b85
  6. 08 11月, 2012 4 次提交
  7. 07 11月, 2012 1 次提交
  8. 04 11月, 2012 1 次提交
  9. 03 11月, 2012 1 次提交
  10. 01 11月, 2012 2 次提交
    • X
      KVM: x86: fix vcpu->mmio_fragments overflow · 87da7e66
      Xiao Guangrong 提交于
      After commit b3356bf0 (KVM: emulator: optimize "rep ins" handling),
      the pieces of io data can be collected and write them to the guest memory
      or MMIO together
      
      Unfortunately, kvm splits the mmio access into 8 bytes and store them to
      vcpu->mmio_fragments. If the guest uses "rep ins" to move large data, it
      will cause vcpu->mmio_fragments overflow
      
      The bug can be exposed by isapc (-M isapc):
      
      [23154.818733] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC
      [ ......]
      [23154.858083] Call Trace:
      [23154.859874]  [<ffffffffa04f0e17>] kvm_get_cr8+0x1d/0x28 [kvm]
      [23154.861677]  [<ffffffffa04fa6d4>] kvm_arch_vcpu_ioctl_run+0xcda/0xe45 [kvm]
      [23154.863604]  [<ffffffffa04f5a1a>] ? kvm_arch_vcpu_load+0x17b/0x180 [kvm]
      
      Actually, we can use one mmio_fragment to store a large mmio access then
      split it when we pass the mmio-exit-info to userspace. After that, we only
      need two entries to store mmio info for the cross-mmio pages access
      Signed-off-by: NXiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
      Signed-off-by: NMarcelo Tosatti <mtosatti@redhat.com>
      87da7e66
    • K
      xen/mmu: Use Xen specific TLB flush instead of the generic one. · 95a7d768
      Konrad Rzeszutek Wilk 提交于
      As Mukesh explained it, the MMUEXT_TLB_FLUSH_ALL allows the
      hypervisor to do a TLB flush on all active vCPUs. If instead
      we were using the generic one (which ends up being xen_flush_tlb)
      we end up making the MMUEXT_TLB_FLUSH_LOCAL hypercall. But
      before we make that hypercall the kernel will IPI all of the
      vCPUs (even those that were asleep from the hypervisor
      perspective). The end result is that we needlessly wake them
      up and do a TLB flush when we can just let the hypervisor
      do it correctly.
      
      This patch gives around 50% speed improvement when migrating
      idle guest's from one host to another.
      
      Oracle-bug: 14630170
      
      CC: stable@vger.kernel.org
      Tested-by: NJingjie Jiang <jingjie.jiang@oracle.com>
      Suggested-by: NMukesh Rathor <mukesh.rathor@oracle.com>
      Signed-off-by: NKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      95a7d768
  11. 30 10月, 2012 1 次提交
  12. 29 10月, 2012 2 次提交
  13. 27 10月, 2012 1 次提交
    • J
      mac80211: verify that skb data is present · 9b395bc3
      Johannes Berg 提交于
      A number of places in the mesh code don't check that
      the frame data is present and in the skb header when
      trying to access. Add those checks and the necessary
      pskb_may_pull() calls. This prevents accessing data
      that doesn't actually exist.
      
      To do this, export ieee80211_get_mesh_hdrlen() to be
      able to use it in mac80211.
      
      Cc: stable@vger.kernel.org
      Signed-off-by: NJohannes Berg <johannes.berg@intel.com>
      9b395bc3
  14. 26 10月, 2012 1 次提交
  15. 25 10月, 2012 2 次提交
  16. 24 10月, 2012 2 次提交
  17. 23 10月, 2012 3 次提交
  18. 22 10月, 2012 1 次提交