1. 18 7月, 2011 1 次提交
    • O
      ptrace: mv send-SIGSTOP from do_fork() to ptrace_init_task() · dcace06c
      Oleg Nesterov 提交于
      If the new child is traced, do_fork() adds the pending SIGSTOP.
      It assumes that either it is traced because of auto-attach or the
      tracer attached later, in both cases sigaddset/set_thread_flag is
      correct even if SIGSTOP is already pending.
      
      Now that we have PTRACE_SEIZE this is no longer right in the latter
      case. If the tracer does PTRACE_SEIZE after copy_process() makes the
      child visible the queued SIGSTOP is wrong.
      
      We could check PT_SEIZED bit and change ptrace_attach() to set both
      PT_PTRACED and PT_SEIZED bits simultaneously but see the next patch,
      we need to know whether this child was auto-attached or not anyway.
      
      So this patch simply moves this code to ptrace_init_task(), this
      way we can never race with ptrace_attach().
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Acked-by: NTejun Heo <tj@kernel.org>
      dcace06c
  2. 08 7月, 2011 1 次提交
  3. 23 6月, 2011 2 次提交
    • T
      ptrace: kill clone/exec tracehooks · 4b9d33e6
      Tejun Heo 提交于
      At this point, tracehooks aren't useful to mainline kernel and mostly
      just add an extra layer of obfuscation.  Although they have comments,
      without actual in-kernel users, it is difficult to tell what are their
      assumptions and they're actually trying to achieve.  To mainline
      kernel, they just aren't worth keeping around.
      
      This patch kills the following clone and exec related tracehooks.
      
      	tracehook_prepare_clone()
      	tracehook_finish_clone()
      	tracehook_report_clone()
      	tracehook_report_clone_complete()
      	tracehook_unsafe_exec()
      
      The changes are mostly trivial - logic is moved to the caller and
      comments are merged and adjusted appropriately.
      
      The only exception is in check_unsafe_exec() where LSM_UNSAFE_PTRACE*
      are OR'd to bprm->unsafe instead of setting it, which produces the
      same result as the field is always zero on entry.  It also tests
      p->ptrace instead of (p->ptrace & PT_PTRACED) for consistency, which
      also gives the same result.
      
      This doesn't introduce any behavior change.
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      4b9d33e6
    • T
      ptrace: kill trivial tracehooks · a288eecc
      Tejun Heo 提交于
      At this point, tracehooks aren't useful to mainline kernel and mostly
      just add an extra layer of obfuscation.  Although they have comments,
      without actual in-kernel users, it is difficult to tell what are their
      assumptions and they're actually trying to achieve.  To mainline
      kernel, they just aren't worth keeping around.
      
      This patch kills the following trivial tracehooks.
      
      * Ones testing whether task is ptraced.  Replace with ->ptrace test.
      
      	tracehook_expect_breakpoints()
      	tracehook_consider_ignored_signal()
      	tracehook_consider_fatal_signal()
      
      * ptrace_event() wrappers.  Call directly.
      
      	tracehook_report_exec()
      	tracehook_report_exit()
      	tracehook_report_vfork_done()
      
      * ptrace_release_task() wrapper.  Call directly.
      
      	tracehook_finish_release_task()
      
      * noop
      
      	tracehook_prepare_release_task()
      	tracehook_report_death()
      
      This doesn't introduce any behavior change.
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Cc: Christoph Hellwig <hch@infradead.org>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      a288eecc
  4. 30 5月, 2011 1 次提交
    • L
      mm: Fix boot crash in mm_alloc() · 6345d24d
      Linus Torvalds 提交于
      Thomas Gleixner reports that we now have a boot crash triggered by
      CONFIG_CPUMASK_OFFSTACK=y:
      
          BUG: unable to handle kernel NULL pointer dereference at   (null)
          IP: [<c11ae035>] find_next_bit+0x55/0xb0
          Call Trace:
           [<c11addda>] cpumask_any_but+0x2a/0x70
           [<c102396b>] flush_tlb_mm+0x2b/0x80
           [<c1022705>] pud_populate+0x35/0x50
           [<c10227ba>] pgd_alloc+0x9a/0xf0
           [<c103a3fc>] mm_init+0xec/0x120
           [<c103a7a3>] mm_alloc+0x53/0xd0
      
      which was introduced by commit de03c72c ("mm: convert
      mm->cpu_vm_cpumask into cpumask_var_t"), and is due to wrong ordering of
      mm_init() vs mm_init_cpumask
      
      Thomas wrote a patch to just fix the ordering of initialization, but I
      hate the new double allocation in the fork path, so I ended up instead
      doing some more radical surgery to clean it all up.
      Reported-by: NThomas Gleixner <tglx@linutronix.de>
      Reported-by: NIngo Molnar <mingo@elte.hu>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6345d24d
  5. 27 5月, 2011 3 次提交
  6. 25 5月, 2011 3 次提交
    • K
      mm: convert mm->cpu_vm_cpumask into cpumask_var_t · de03c72c
      KOSAKI Motohiro 提交于
      cpumask_t is very big struct and cpu_vm_mask is placed wrong position.
      It might lead to reduce cache hit ratio.
      
      This patch has two change.
      1) Move the place of cpumask into last of mm_struct. Because usually cpumask
         is accessed only front bits when the system has cpu-hotplug capability
      2) Convert cpu_vm_mask into cpumask_var_t. It may help to reduce memory
         footprint if cpumask_size() will use nr_cpumask_bits properly in future.
      
      In addition, this patch change the name of cpu_vm_mask with cpu_vm_mask_var.
      It may help to detect out of tree cpu_vm_mask users.
      
      This patch has no functional change.
      
      [akpm@linux-foundation.org: build fix]
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: David Howells <dhowells@redhat.com>
      Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Chris Metcalf <cmetcalf@tilera.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      de03c72c
    • P
      mm: Convert i_mmap_lock to a mutex · 3d48ae45
      Peter Zijlstra 提交于
      Straightforward conversion of i_mmap_lock to a mutex.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: NHugh Dickins <hughd@google.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: David Miller <davem@davemloft.net>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: Richard Weinberger <richard@nod.at>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Nick Piggin <npiggin@kernel.dk>
      Cc: Namhyung Kim <namhyung@gmail.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3d48ae45
    • P
      mm: Remove i_mmap_lock lockbreak · 97a89413
      Peter Zijlstra 提交于
      Hugh says:
       "The only significant loser, I think, would be page reclaim (when
        concurrent with truncation): could spin for a long time waiting for
        the i_mmap_mutex it expects would soon be dropped? "
      
      Counter points:
       - cpu contention makes the spin stop (need_resched())
       - zap pages should be freeing pages at a higher rate than reclaim
         ever can
      
      I think the simplification of the truncate code is definitely worth it.
      
      Effectively reverts: 2aa15890 ("mm: prevent concurrent
      unmap_mapping_range() on the same inode") and takes out the code that
      caused its problem.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Reviewed-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
      Cc: David Miller <davem@davemloft.net>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Russell King <rmk@arm.linux.org.uk>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: Jeff Dike <jdike@addtoit.com>
      Cc: Richard Weinberger <richard@nod.at>
      Cc: Tony Luck <tony.luck@intel.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Nick Piggin <npiggin@kernel.dk>
      Cc: Namhyung Kim <namhyung@gmail.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      97a89413
  7. 12 5月, 2011 1 次提交
  8. 24 4月, 2011 1 次提交
  9. 24 3月, 2011 2 次提交
  10. 23 3月, 2011 4 次提交
  11. 18 3月, 2011 1 次提交
  12. 10 3月, 2011 1 次提交
    • J
      block: initial patch for on-stack per-task plugging · 73c10101
      Jens Axboe 提交于
      This patch adds support for creating a queuing context outside
      of the queue itself. This enables us to batch up pieces of IO
      before grabbing the block device queue lock and submitting them to
      the IO scheduler.
      
      The context is created on the stack of the process and assigned in
      the task structure, so that we can auto-unplug it if we hit a schedule
      event.
      
      The current queue plugging happens implicitly if IO is submitted to
      an empty device, yet callers have to remember to unplug that IO when
      they are going to wait for it. This is an ugly API and has caused bugs
      in the past. Additionally, it requires hacks in the vm (->sync_page()
      callback) to handle that logic. By switching to an explicit plugging
      scheme we make the API a lot nicer and can get rid of the ->sync_page()
      hack in the vm.
      Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
      73c10101
  13. 14 1月, 2011 4 次提交
    • A
      thp: khugepaged · ba76149f
      Andrea Arcangeli 提交于
      Add khugepaged to relocate fragmented pages into hugepages if new
      hugepages become available.  (this is indipendent of the defrag logic that
      will have to make new hugepages available)
      
      The fundamental reason why khugepaged is unavoidable, is that some memory
      can be fragmented and not everything can be relocated.  So when a virtual
      machine quits and releases gigabytes of hugepages, we want to use those
      freely available hugepages to create huge-pmd in the other virtual
      machines that may be running on fragmented memory, to maximize the CPU
      efficiency at all times.  The scan is slow, it takes nearly zero cpu time,
      except when it copies data (in which case it means we definitely want to
      pay for that cpu time) so it seems a good tradeoff.
      
      In addition to the hugepages being released by other process releasing
      memory, we have the strong suspicion that the performance impact of
      potentially defragmenting hugepages during or before each page fault could
      lead to more performance inconsistency than allocating small pages at
      first and having them collapsed into large pages later...  if they prove
      themselfs to be long lived mappings (khugepaged scan is slow so short
      lived mappings have low probability to run into khugepaged if compared to
      long lived mappings).
      Signed-off-by: NAndrea Arcangeli <aarcange@redhat.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>
      ba76149f
    • A
      thp: add pmd_huge_pte to mm_struct · e7a00c45
      Andrea Arcangeli 提交于
      This increase the size of the mm struct a bit but it is needed to
      preallocate one pte for each hugepage so that split_huge_page will not
      require a fail path.  Guarantee of success is a fundamental property of
      split_huge_page to avoid decrasing swapping reliability and to avoid
      adding -ENOMEM fail paths that would otherwise force the hugepage-unaware
      VM code to learn rolling back in the middle of its pte mangling operations
      (if something we need it to learn handling pmd_trans_huge natively rather
      being capable of rollback).  When split_huge_page runs a pte is needed to
      succeed the split, to map the newly splitted regular pages with a regular
      pte.  This way all existing VM code remains backwards compatible by just
      adding a split_huge_page* one liner.  The memory waste of those
      preallocated ptes is negligible and so it is worth it.
      Signed-off-by: NAndrea Arcangeli <aarcange@redhat.com>
      Acked-by: NRik van Riel <riel@redhat.com>
      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>
      e7a00c45
    • M
      oom: allow a non-CAP_SYS_RESOURCE proces to oom_score_adj down · dabb16f6
      Mandeep Singh Baines 提交于
      We'd like to be able to oom_score_adj a process up/down as it
      enters/leaves the foreground.  Currently, it is not possible to oom_adj
      down without CAP_SYS_RESOURCE.  This patch allows a task to decrease its
      oom_score_adj back to the value that a CAP_SYS_RESOURCE thread set it to
      or its inherited value at fork.  Assuming the thread that has forked it
      has oom_score_adj of 0, each process could decrease it back from 0 upon
      activation unless a CAP_SYS_RESOURCE thread elevated it to something
      higher.
      
      Alternative considered:
      
      * a setuid binary
      * a daemon with CAP_SYS_RESOURCE
      
      Since you don't wan't all processes to be able to reduce their oom_adj, a
      setuid or daemon implementation would be complex.  The alternatives also
      have much higher overhead.
      
      This patch updated from original patch based on feedback from David
      Rientjes.
      Signed-off-by: NMandeep Singh Baines <msb@chromium.org>
      Acked-by: NDavid Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Ying Han <yinghan@google.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      dabb16f6
    • D
      sched: remove long deprecated CLONE_STOPPED flag · 43bb40c9
      Dave Jones 提交于
      This warning was added in commit bdff746a ("clone: prepare to recycle
      CLONE_STOPPED") three years ago.  2.6.26 came and went.  As far as I know,
      no-one is actually using CLONE_STOPPED.
      Signed-off-by: NDave Jones <davej@redhat.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Tejun Heo <tj@kernel.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      43bb40c9
  14. 07 1月, 2011 1 次提交
  15. 04 1月, 2011 1 次提交
  16. 17 12月, 2010 1 次提交
  17. 09 12月, 2010 1 次提交
    • M
      Sched: fix skip_clock_update optimization · f26f9aff
      Mike Galbraith 提交于
      idle_balance() drops/retakes rq->lock, leaving the previous task
      vulnerable to set_tsk_need_resched().  Clear it after we return
      from balancing instead, and in setup_thread_stack() as well, so
      no successfully descheduled or never scheduled task has it set.
      
      Need resched confused the skip_clock_update logic, which assumes
      that the next call to update_rq_clock() will come nearly immediately
      after being set.  Make the optimization robust against the waking
      a sleeper before it sucessfully deschedules case by checking that
      the current task has not been dequeued before setting the flag,
      since it is that useless clock update we're trying to save, and
      clear unconditionally in schedule() proper instead of conditionally
      in put_prev_task().
      Signed-off-by: NMike Galbraith <efault@gmx.de>
      Reported-by: NBjoern B. Brandenburg <bbb.lst@gmail.com>
      Tested-by: NYong Zhang <yong.zhang0@gmail.com>
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: stable@kernel.org
      LKML-Reference: <1291802742.1417.9.camel@marge.simson.net>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      f26f9aff
  18. 30 11月, 2010 1 次提交
    • M
      sched: Add 'autogroup' scheduling feature: automated per session task groups · 5091faa4
      Mike Galbraith 提交于
      A recurring complaint from CFS users is that parallel kbuild has
      a negative impact on desktop interactivity.  This patch
      implements an idea from Linus, to automatically create task
      groups.  Currently, only per session autogroups are implemented,
      but the patch leaves the way open for enhancement.
      
      Implementation: each task's signal struct contains an inherited
      pointer to a refcounted autogroup struct containing a task group
      pointer, the default for all tasks pointing to the
      init_task_group.  When a task calls setsid(), a new task group
      is created, the process is moved into the new task group, and a
      reference to the preveious task group is dropped.  Child
      processes inherit this task group thereafter, and increase it's
      refcount.  When the last thread of a process exits, the
      process's reference is dropped, such that when the last process
      referencing an autogroup exits, the autogroup is destroyed.
      
      At runqueue selection time, IFF a task has no cgroup assignment,
      its current autogroup is used.
      
      Autogroup bandwidth is controllable via setting it's nice level
      through the proc filesystem:
      
        cat /proc/<pid>/autogroup
      
      Displays the task's group and the group's nice level.
      
        echo <nice level> > /proc/<pid>/autogroup
      
      Sets the task group's shares to the weight of nice <level> task.
      Setting nice level is rate limited for !admin users due to the
      abuse risk of task group locking.
      
      The feature is enabled from boot by default if
      CONFIG_SCHED_AUTOGROUP=y is selected, but can be disabled via
      the boot option noautogroup, and can also be turned on/off on
      the fly via:
      
        echo [01] > /proc/sys/kernel/sched_autogroup_enabled
      
      ... which will automatically move tasks to/from the root task group.
      Signed-off-by: NMike Galbraith <efault@gmx.de>
      Acked-by: NLinus Torvalds <torvalds@linux-foundation.org>
      Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Markus Trippelsdorf <markus@trippelsdorf.de>
      Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
      Cc: Paul Turner <pjt@google.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      [ Removed the task_group_path() debug code, and fixed !EVENTFD build failure. ]
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      LKML-Reference: <1290281700.28711.9.camel@maggy.simson.net>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      5091faa4
  19. 28 10月, 2010 1 次提交
  20. 27 10月, 2010 1 次提交
    • Y
      oom: add per-mm oom disable count · 3d5992d2
      Ying Han 提交于
      It's pointless to kill a task if another thread sharing its mm cannot be
      killed to allow future memory freeing.  A subsequent patch will prevent
      kills in such cases, but first it's necessary to have a way to flag a task
      that shares memory with an OOM_DISABLE task that doesn't incur an
      additional tasklist scan, which would make select_bad_process() an O(n^2)
      function.
      
      This patch adds an atomic counter to struct mm_struct that follows how
      many threads attached to it have an oom_score_adj of OOM_SCORE_ADJ_MIN.
      They cannot be killed by the kernel, so their memory cannot be freed in
      oom conditions.
      
      This only requires task_lock() on the task that we're operating on, it
      does not require mm->mmap_sem since task_lock() pins the mm and the
      operation is atomic.
      
      [rientjes@google.com: changelog and sys_unshare() code]
      [rientjes@google.com: protect oom_disable_count with task_lock in fork]
      [rientjes@google.com: use old_mm for oom_disable_count in exec]
      Signed-off-by: NYing Han <yinghan@google.com>
      Signed-off-by: NDavid Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3d5992d2
  21. 23 9月, 2010 1 次提交
  22. 21 8月, 2010 1 次提交
  23. 18 8月, 2010 1 次提交
    • N
      fs: fs_struct rwlock to spinlock · 2a4419b5
      Nick Piggin 提交于
      fs: fs_struct rwlock to spinlock
      
      struct fs_struct.lock is an rwlock with the read-side used to protect root and
      pwd members while taking references to them. Taking a reference to a path
      typically requires just 2 atomic ops, so the critical section is very small.
      Parallel read-side operations would have cacheline contention on the lock, the
      dentry, and the vfsmount cachelines, so the rwlock is unlikely to ever give a
      real parallelism increase.
      
      Replace it with a spinlock to avoid one or two atomic operations in typical
      path lookup fastpath.
      Signed-off-by: NNick Piggin <npiggin@kernel.dk>
      Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
      2a4419b5
  24. 10 8月, 2010 1 次提交
    • D
      oom: badness heuristic rewrite · a63d83f4
      David Rientjes 提交于
      This a complete rewrite of the oom killer's badness() heuristic which is
      used to determine which task to kill in oom conditions.  The goal is to
      make it as simple and predictable as possible so the results are better
      understood and we end up killing the task which will lead to the most
      memory freeing while still respecting the fine-tuning from userspace.
      
      Instead of basing the heuristic on mm->total_vm for each task, the task's
      rss and swap space is used instead.  This is a better indication of the
      amount of memory that will be freeable if the oom killed task is chosen
      and subsequently exits.  This helps specifically in cases where KDE or
      GNOME is chosen for oom kill on desktop systems instead of a memory
      hogging task.
      
      The baseline for the heuristic is a proportion of memory that each task is
      currently using in memory plus swap compared to the amount of "allowable"
      memory.  "Allowable," in this sense, means the system-wide resources for
      unconstrained oom conditions, the set of mempolicy nodes, the mems
      attached to current's cpuset, or a memory controller's limit.  The
      proportion is given on a scale of 0 (never kill) to 1000 (always kill),
      roughly meaning that if a task has a badness() score of 500 that the task
      consumes approximately 50% of allowable memory resident in RAM or in swap
      space.
      
      The proportion is always relative to the amount of "allowable" memory and
      not the total amount of RAM systemwide so that mempolicies and cpusets may
      operate in isolation; they shall not need to know the true size of the
      machine on which they are running if they are bound to a specific set of
      nodes or mems, respectively.
      
      Root tasks are given 3% extra memory just like __vm_enough_memory()
      provides in LSMs.  In the event of two tasks consuming similar amounts of
      memory, it is generally better to save root's task.
      
      Because of the change in the badness() heuristic's baseline, it is also
      necessary to introduce a new user interface to tune it.  It's not possible
      to redefine the meaning of /proc/pid/oom_adj with a new scale since the
      ABI cannot be changed for backward compatability.  Instead, a new tunable,
      /proc/pid/oom_score_adj, is added that ranges from -1000 to +1000.  It may
      be used to polarize the heuristic such that certain tasks are never
      considered for oom kill while others may always be considered.  The value
      is added directly into the badness() score so a value of -500, for
      example, means to discount 50% of its memory consumption in comparison to
      other tasks either on the system, bound to the mempolicy, in the cpuset,
      or sharing the same memory controller.
      
      /proc/pid/oom_adj is changed so that its meaning is rescaled into the
      units used by /proc/pid/oom_score_adj, and vice versa.  Changing one of
      these per-task tunables will rescale the value of the other to an
      equivalent meaning.  Although /proc/pid/oom_adj was originally defined as
      a bitshift on the badness score, it now shares the same linear growth as
      /proc/pid/oom_score_adj but with different granularity.  This is required
      so the ABI is not broken with userspace applications and allows oom_adj to
      be deprecated for future removal.
      Signed-off-by: NDavid Rientjes <rientjes@google.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Balbir Singh <balbir@in.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a63d83f4
  25. 09 6月, 2010 1 次提交
    • T
      sched: add hooks for workqueue · 21aa9af0
      Tejun Heo 提交于
      Concurrency managed workqueue needs to know when workers are going to
      sleep and waking up.  Using these two hooks, cmwq keeps track of the
      current concurrency level and throttles execution of new works if it's
      too high and wakes up another worker from the sleep hook if it becomes
      too low.
      
      This patch introduces PF_WQ_WORKER to identify workqueue workers and
      adds the following two hooks.
      
      * wq_worker_waking_up(): called when a worker is woken up.
      
      * wq_worker_sleeping(): called when a worker is going to sleep and may
        return a pointer to a local task which should be woken up.  The
        returned task is woken up using try_to_wake_up_local() which is
        simplified ttwu which is called under rq lock and can only wake up
        local tasks.
      
      Both hooks are currently defined as noop in kernel/workqueue_sched.h.
      Later cmwq implementation will replace them with proper
      implementation.
      
      These hooks are hard coded as they'll always be enabled.
      Signed-off-by: NTejun Heo <tj@kernel.org>
      Acked-by: NPeter Zijlstra <peterz@infradead.org>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Ingo Molnar <mingo@elte.hu>
      21aa9af0
  26. 31 5月, 2010 1 次提交
  27. 28 5月, 2010 2 次提交
    • O
      pids: fix fork_idle() to setup ->pids correctly · f106eee1
      Oleg Nesterov 提交于
      copy_process(pid => &init_struct_pid) doesn't do attach_pid/etc.
      
      It shouldn't, but this means that the idle threads run with the wrong
      pids copied from the caller's task_struct. In x86 case the caller is
      either kernel_init() thread or keventd.
      
      In particular, this means that after the series of cpu_up/cpu_down an
      idle thread (which never exits) can run with .pid pointing to nowhere.
      
      Change fork_idle() to initialize idle->pids[] correctly. We only set
      .pid = &init_struct_pid but do not add .node to list, INIT_TASK() does
      the same for the boot-cpu idle thread (swapper).
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Cc: Cedric Le Goater <clg@fr.ibm.com>
      Cc: Dave Hansen <haveblue@us.ibm.com>
      Cc: Eric Biederman <ebiederm@xmission.com>
      Cc: Herbert Poetzl <herbert@13thfloor.at>
      Cc: Mathias Krause <Mathias.Krause@secunet.com>
      Acked-by: NRoland McGrath <roland@redhat.com>
      Acked-by: NSerge Hallyn <serue@us.ibm.com>
      Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f106eee1
    • O
      proc: turn signal_struct->count into "int nr_threads" · b3ac022c
      Oleg Nesterov 提交于
      No functional changes, just s/atomic_t count/int nr_threads/.
      
      With the recent changes this counter has a single user, get_nr_threads()
      And, none of its callers need the really accurate number of threads, not
      to mention each caller obviously races with fork/exit.  It is only used to
      report this value to the user-space, except first_tid() uses it to avoid
      the unnecessary while_each_thread() loop in the unlikely case.
      
      It is a bit sad we need a word in struct signal_struct for this, perhaps
      we can change get_nr_threads() to approximate the number of threads using
      signal->live and kill ->nr_threads later.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Cc: Alexey Dobriyan <adobriyan@gmail.com>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Acked-by: NRoland McGrath <roland@redhat.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b3ac022c