1. 10 9月, 2009 4 次提交
  2. 06 9月, 2009 2 次提交
    • O
      exec: do not sleep in TASK_TRACED under ->cred_guard_mutex · a2a8474c
      Oleg Nesterov 提交于
      Tom Horsley reports that his debugger hangs when it tries to read
      /proc/pid_of_tracee/maps, this happens since
      
      	"mm_for_maps: take ->cred_guard_mutex to fix the race with exec"
      	04b836cbf19e885f8366bccb2e4b0474346c02d
      
      commit in 2.6.31.
      
      But the root of the problem lies in the fact that do_execve() path calls
      tracehook_report_exec() which can stop if the tracer sets PT_TRACE_EXEC.
      
      The tracee must not sleep in TASK_TRACED holding this mutex.  Even if we
      remove ->cred_guard_mutex from mm_for_maps() and proc_pid_attr_write(),
      another task doing PTRACE_ATTACH should not hang until it is killed or the
      tracee resumes.
      
      With this patch do_execve() does not use ->cred_guard_mutex directly and
      we do not hold it throughout, instead:
      
      	- introduce prepare_bprm_creds() helper, it locks the mutex
      	  and calls prepare_exec_creds() to initialize bprm->cred.
      
      	- install_exec_creds() drops the mutex after commit_creds(),
      	  and thus before tracehook_report_exec()->ptrace_stop().
      
      	  or, if exec fails,
      
      	  free_bprm() drops this mutex when bprm->cred != NULL which
      	  indicates install_exec_creds() was not called.
      Reported-by: NTom Horsley <tom.horsley@att.net>
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Acked-by: NDavid Howells <dhowells@redhat.com>
      Cc: Roland McGrath <roland@redhat.com>
      Cc: James Morris <jmorris@namei.org>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      a2a8474c
    • O
      workqueues: introduce __cancel_delayed_work() · 4e49627b
      Oleg Nesterov 提交于
      cancel_delayed_work() has to use del_timer_sync() to guarantee the timer
      function is not running after return.  But most users doesn't actually
      need this, and del_timer_sync() has problems: it is not useable from
      interrupt, and it depends on every lock which could be taken from irq.
      
      Introduce __cancel_delayed_work() which calls del_timer() instead.
      
      The immediate reason for this patch is
      http://bugzilla.kernel.org/show_bug.cgi?id=13757
      but hopefully this helper makes sense anyway.
      
      As for 13757 bug, actually we need requeue_delayed_work(), but its
      semantics are not yet clear.
      
      Merge this patch early to resolves cross-tree interdependencies between
      input and infiniband.
      Signed-off-by: NOleg Nesterov <oleg@redhat.com>
      Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
      Cc: Roland Dreier <rdreier@cisco.com>
      Cc: Stefan Richter <stefanr@s5r6.in-berlin.de>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4e49627b
  3. 05 9月, 2009 2 次提交
    • J
      dm log: userspace add luid to distinguish between concurrent log instances · 7ec23d50
      Jonathan Brassow 提交于
      Device-mapper userspace logs (like the clustered log) are
      identified by a universally unique identifier (UUID).  This
      identifier is used to associate requests from the kernel to
      a specific log in userspace.  The UUID must be unique everywhere,
      since multiple machines may use this identifier when communicating
      about a particular log, as is the case for cluster logs.
      
      Sometimes, device-mapper/LVM may re-use a UUID.  This is the
      case during pvmoves, when moving from one segment of an LV
      to another, or when resizing a mirror, etc.  In these cases,
      a new log is created with the same UUID and loaded in the
      "inactive" slot.  When a device-mapper "resume" is issued,
      the "live" table is deactivated and the new "inactive" table
      becomes "live".  (The "inactive" table can also be removed
      via a device-mapper 'clear' command.)
      
      The above two issues were colliding.  More than one log was being
      created with the same UUID, and there was no way to distinguish
      between them.  So, sometimes the wrong log would be swapped
      out during the exchange.
      
      The solution is to create a locally unique identifier,
      'luid', to go along with the UUID.  This new identifier is used
      to determine exactly which log is being referenced by the kernel
      when the log exchange is made.  The identifier is not
      universally safe, but it does not need to be, since
      create/destroy/suspend/resume operations are bound to a specific
      machine; and these are the operations that make up the exchange.
      Signed-off-by: NJonathan Brassow <jbrassow@redhat.com>
      Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      7ec23d50
    • M
      dm stripe: expose correct io hints · 40bea431
      Mike Snitzer 提交于
      Set sensible I/O hints for striped DM devices in the topology
      infrastructure added for 2.6.31 for userspace tools to
      obtain via sysfs.
      
      Add .io_hints to 'struct target_type' to allow the I/O hints portion
      (io_min and io_opt) of the 'struct queue_limits' to be set by each
      target and implement this for dm-stripe.
      Signed-off-by: NMike Snitzer <snitzer@redhat.com>
      Signed-off-by: NAlasdair G Kergon <agk@redhat.com>
      40bea431
  4. 02 9月, 2009 1 次提交
    • D
      pkt_sched: Revert tasklet_hrtimer changes. · 2fbd3da3
      David S. Miller 提交于
      These are full of unresolved problems, mainly that conversions don't
      work 1-1 from hrtimers to tasklet_hrtimers because unlike hrtimers
      tasklets can't be killed from softirq context.
      
      And when a qdisc gets reset, that's exactly what we need to do here.
      
      We'll work this out in the net-next-2.6 tree and if warranted we'll
      backport that work to -stable.
      
      This reverts the following 3 changesets:
      
      a2cb6a4d
      ("pkt_sched: Fix bogon in tasklet_hrtimer changes.")
      
      38acce2d
      ("pkt_sched: Convert CBQ to tasklet_hrtimer.")
      
      ee5f9757
      ("pkt_sched: Convert qdisc_watchdog to tasklet_hrtimer")
      Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      2fbd3da3
  5. 01 9月, 2009 1 次提交
  6. 29 8月, 2009 1 次提交
  7. 27 8月, 2009 3 次提交
  8. 25 8月, 2009 1 次提交
    • H
      mm: fix hugetlb bug due to user_shm_unlock call · 353d5c30
      Hugh Dickins 提交于
      2.6.30's commit 8a0bdec1 removed
      user_shm_lock() calls in hugetlb_file_setup() but left the
      user_shm_unlock call in shm_destroy().
      
      In detail:
      Assume that can_do_hugetlb_shm() returns true and hence user_shm_lock()
      is not called in hugetlb_file_setup(). However, user_shm_unlock() is
      called in any case in shm_destroy() and in the following
      atomic_dec_and_lock(&up->__count) in free_uid() is executed and if
      up->__count gets zero, also cleanup_user_struct() is scheduled.
      
      Note that sched_destroy_user() is empty if CONFIG_USER_SCHED is not set.
      However, the ref counter up->__count gets unexpectedly non-positive and
      the corresponding structs are freed even though there are live
      references to them, resulting in a kernel oops after a lots of
      shmget(SHM_HUGETLB)/shmctl(IPC_RMID) cycles and CONFIG_USER_SCHED set.
      
      Hugh changed Stefan's suggested patch: can_do_hugetlb_shm() at the
      time of shm_destroy() may give a different answer from at the time
      of hugetlb_file_setup().  And fixed newseg()'s no_id error path,
      which has missed user_shm_unlock() ever since it came in 2.6.9.
      Reported-by: NStefan Huber <shuber2@gmail.com>
      Signed-off-by: NHugh Dickins <hugh.dickins@tiscali.co.uk>
      Tested-by: NStefan Huber <shuber2@gmail.com>
      Cc: stable@kernel.org
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      353d5c30
  9. 24 8月, 2009 1 次提交
  10. 23 8月, 2009 1 次提交
  11. 22 8月, 2009 1 次提交
    • L
      Make bitmask 'and' operators return a result code · f4b0373b
      Linus Torvalds 提交于
      When 'and'ing two bitmasks (where 'andnot' is a variation on it), some
      cases want to know whether the result is the empty set or not.  In
      particular, the TLB IPI sending code wants to do cpumask operations and
      determine if there are any CPU's left in the final set.
      
      So this just makes the bitmask (and cpumask) functions return a boolean
      for whether the result has any bits set.
      
      Cc: stable@kernel.org (2.6.30, needed by TLB shootdown fix)
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      f4b0373b
  12. 21 8月, 2009 3 次提交
  13. 19 8月, 2009 1 次提交
    • K
      mm: revert "oom: move oom_adj value" · 0753ba01
      KOSAKI Motohiro 提交于
      The commit 2ff05b2b (oom: move oom_adj value) moveed the oom_adj value to
      the mm_struct.  It was a very good first step for sanitize OOM.
      
      However Paul Menage reported the commit makes regression to his job
      scheduler.  Current OOM logic can kill OOM_DISABLED process.
      
      Why? His program has the code of similar to the following.
      
      	...
      	set_oom_adj(OOM_DISABLE); /* The job scheduler never killed by oom */
      	...
      	if (vfork() == 0) {
      		set_oom_adj(0); /* Invoked child can be killed */
      		execve("foo-bar-cmd");
      	}
      	....
      
      vfork() parent and child are shared the same mm_struct.  then above
      set_oom_adj(0) doesn't only change oom_adj for vfork() child, it's also
      change oom_adj for vfork() parent.  Then, vfork() parent (job scheduler)
      lost OOM immune and it was killed.
      
      Actually, fork-setting-exec idiom is very frequently used in userland program.
      We must not break this assumption.
      
      Then, this patch revert commit 2ff05b2b and related commit.
      
      Reverted commit list
      ---------------------
      - commit 2ff05b2b (oom: move oom_adj value from task_struct to mm_struct)
      - commit 4d8b9135 (oom: avoid unnecessary mm locking and scanning for OOM_DISABLE)
      - commit 81236810 (oom: only oom kill exiting tasks with attached memory)
      - commit 933b787b (mm: copy over oom_adj value at fork time)
      Signed-off-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Paul Menage <menage@google.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Linus Torvalds <torvalds@linux-foundation.org>
      Cc: Oleg Nesterov <oleg@redhat.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      0753ba01
  14. 18 8月, 2009 1 次提交
  15. 17 8月, 2009 4 次提交
  16. 13 8月, 2009 2 次提交
    • P
      perf: Rework/fix the whole read vs group stuff · 3dab77fb
      Peter Zijlstra 提交于
      Replace PERF_SAMPLE_GROUP with PERF_SAMPLE_READ and introduce
      PERF_FORMAT_GROUP to deal with group reads in a more generic
      way.
      
      This allows you to get group reads out of read() as well.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Corey J Ashford <cjashfor@us.ibm.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: stephane eranian <eranian@googlemail.com>
      LKML-Reference: <20090813103655.117411814@chello.nl>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3dab77fb
    • I
      perf_counter: Provide hw_perf_counter_setup_online() APIs · 28402971
      Ingo Molnar 提交于
      Provide weak aliases for hw_perf_counter_setup_online(). This is
      used by the BTS patches (for v2.6.32), but it interacts with
      fixes so propagate this upstream. (it has no effect as of yet)
      
      Also export perf_counter_output() to architecture code.
      
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      LKML-Reference: <new-submission>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      28402971
  17. 12 8月, 2009 1 次提交
  18. 10 8月, 2009 4 次提交
    • F
      perf_counter: Zero dead bytes from ftrace raw samples size alignment · 1853db0e
      Frederic Weisbecker 提交于
      After aligning the ftrace raw samples, there are dead bytes storing
      random data from the stack. We don't want to leak these to userspace,
      then zero these out.
      
      Before:
      
      	0x2de88 [0x50]: event: 9
      	.
      	. ... raw event: size 80 bytes
      	.  0000:  09 00 00 00 01 00 50 00 d0 c7 00 81 ff ff ff ff  ......P........
      	.  0010:  68 01 00 00 68 01 00 00 2c 00 00 00 00 00 00 00  h...h...,......
      	.  0020:  2c 00 00 00 2b 00 01 02 68 01 00 00 68 01 00 00  ,...+...h...h..
      	.  0030:  6b 6f 6e 64 65 6d 61 6e 64 2f 30 00 00 00 00 00  kondemand/0....
      	.  0040:  68 01 00 00 40 7f 46 81 ff ff ff ff 00 10 1b 7f  h...@.F........
                                                            ^  ^  ^  ^
                                                               Leak
      
      After:
      
      	0x2d318 [0x50]: event: 9
      	.
      	. ... raw event: size 80 bytes
      	.  0000:  09 00 00 00 01 00 50 00 d0 c7 00 81 ff ff ff ff  ......P........
      	.  0010:  68 01 00 00 68 01 00 00 68 14 00 00 00 00 00 00  h...h...h......
      	.  0020:  2c 00 00 00 2b 00 01 02 68 01 00 00 68 01 00 00  ,...+...h...h..
      	.  0030:  6b 6f 6e 64 65 6d 61 6e 64 2f 30 00 00 00 00 00  kondemand/0....
      	.  0040:  68 01 00 00 a0 80 46 81 ff ff ff ff 00 00 00 00  h.....F........
                                                            ^  ^  ^  ^
      							 Fixed
      Reported-by: NPeter Zijlstra <peterz@infradead.org>
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      LKML-Reference: <1249915116-5210-1-git-send-email-fweisbec@gmail.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      1853db0e
    • F
      perf_counter: Subtract the buffer size field from the event record size · 304703ab
      Frederic Weisbecker 提交于
      We compute the perf raw sample size by aligning the raw ftrace
      event size plus the buffer size field itself. We do that
      instead of aligning only the perf raw sample size, so that we
      might economize some in some cases.
      
      But this buffer size field is not stored in the perf raw
      sample, we must then substract its size from the buffer once we
      computed the alignment unless we may get a useless u32 field in
      the buffer.
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Acked-by: NPeter Zijlstra <peterz@infradead.org>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      LKML-Reference: <20090810141129.GA5124@nowhere>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      304703ab
    • P
      locking, sched: Give waitqueue spinlocks their own lockdep classes · 2fc39111
      Peter Zijlstra 提交于
      Give waitqueue spinlocks their own lockdep classes when they
      are initialised from init_waitqueue_head().  This means that
      struct wait_queue::func functions can operate other waitqueues.
      
      This is used by CacheFiles to catch the page from a backing fs
      being unlocked and to wake up another thread to take a copy of
      it.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Signed-off-by: NDavid Howells <dhowells@redhat.com>
      Tested-by: NTakashi Iwai <tiwai@suse.de>
      Cc: linux-cachefs@redhat.com
      Cc: torvalds@osdl.org
      Cc: akpm@linux-foundation.org
      LKML-Reference: <20090810113305.17284.81508.stgit@warthog.procyon.org.uk>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      2fc39111
    • P
      perf_counter: Correct PERF_SAMPLE_RAW output · a044560c
      Peter Zijlstra 提交于
      PERF_SAMPLE_* output switches should unconditionally output the
      correct format, as they are the only way to unambiguously parse
      the PERF_EVENT_SAMPLE data.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      LKML-Reference: <1249896447.17467.74.camel@twins>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      a044560c
  19. 09 8月, 2009 3 次提交
    • F
      perf_counter: Fix tracepoint sampling to be part of generic sampling · 3a43ce68
      Frederic Weisbecker 提交于
      Based on Peter's comments, make tracepoint sampling generic
      just like all the other sampling bits are. This is a rename
      with no code changes:
      
      - PERF_SAMPLE_TP_RECORD to PERF_SAMPLE_RAW
      - struct perf_tracepoint_record to perf_raw_record
      
      We want the system in place that transport tracepoints raw
      samples events into the perf ring buffer to be generalized and
      usable by any type of counter.
      
      Reported-by; Peter Zijlstra <peterz@infradead.org>
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Paul Mackerras <paulus@samba.org>
      LKML-Reference: <1249698400-5441-4-git-send-email-fweisbec@gmail.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3a43ce68
    • F
      perf_counter: Fix/complete ftrace event records sampling · f413cdb8
      Frederic Weisbecker 提交于
      This patch implements the kernel side support for ftrace event
      record sampling.
      
      A new counter sampling attribute is added:
      
         PERF_SAMPLE_TP_RECORD
      
      which requests ftrace events record sampling. In this case
      if a PERF_TYPE_TRACEPOINT counter is active and a tracepoint
      fires, we emit the tracepoint binary record to the
      perfcounter event buffer, as a sample.
      
      Result, after setting PERF_SAMPLE_TP_RECORD attribute from perf
      record:
      
       perf record -f -F 1 -a -e workqueue:workqueue_execution
       perf report -D
      
       0x21e18 [0x48]: event: 9
       .
       . ... raw event: size 72 bytes
       .  0000:  09 00 00 00 01 00 48 00 d0 c7 00 81 ff ff ff ff  ......H........
       .  0010:  0a 00 00 00 0a 00 00 00 21 00 00 00 00 00 00 00  ........!......
       .  0020:  2b 00 01 02 0a 00 00 00 0a 00 00 00 65 76 65 6e  +...........eve
       .  0030:  74 73 2f 31 00 00 00 00 00 00 00 00 0a 00 00 00  ts/1...........
       .  0040:  e0 b1 31 81 ff ff ff ff                          .......
      .
      0x21e18 [0x48]: PERF_EVENT_SAMPLE (IP, 1): 10: 0xffffffff8100c7d0 period: 33
      
      The raw ftrace binary record starts at offset 0020.
      
      Translation:
      
       struct trace_entry {
      	type		= 0x2b = 43;
      	flags		= 1;
      	preempt_count	= 2;
      	pid		= 0xa = 10;
      	tgid		= 0xa = 10;
       }
      
       thread_comm = "events/1"
       thread_pid  = 0xa = 10;
       func	    = 0xffffffff8131b1e0 = flush_to_ldisc()
      
      What will come next?
      
       - Userspace support ('perf trace'), 'flight data recorder' mode
         for perf trace, etc.
      
       - The unconditional copy from the profiling callback brings
         some costs however if someone wants no such sampling to
         occur, and needs to be fixed in the future. For that we need
         to have an instant access to the perf counter attribute.
         This is a matter of a flag to add in the struct ftrace_event.
      
       - Take care of the events recursivity! Don't ever try to record
         a lock event for example, it seems some locking is used in
         the profiling fast path and lead to a tracing recursivity.
         That will be fixed using raw spinlock or recursivity
         protection.
      
       - [...]
      
       - Profit! :-)
      Signed-off-by: NFrederic Weisbecker <fweisbec@gmail.com>
      Cc: Li Zefan <lizf@cn.fujitsu.com>
      Cc: Tom Zanussi <tzanussi@gmail.com>
      Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Mike Galbraith <efault@gmx.de>
      Cc: Steven Rostedt <rostedt@goodmis.org>
      Cc: Paul Mackerras <paulus@samba.org>
      Cc: Pekka Enberg <penberg@cs.helsinki.fi>
      Cc: Gabriel Munteanu <eduard.munteanu@linux360.ro>
      Cc: Lai Jiangshan <laijs@cn.fujitsu.com>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      f413cdb8
    • P
      perf_counter, ftrace: Fix perf_counter integration · 3a659305
      Peter Zijlstra 提交于
      Adds possible second part to the assign argument of TP_EVENT().
      
        TP_perf_assign(
      	__perf_count(foo);
      	__perf_addr(bar);
        )
      
      Which, when specified make the swcounter increment with @foo instead
      of the usual 1, and report @bar for PERF_SAMPLE_ADDR (data address
      associated with the event) when this triggers a counter overflow.
      Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: NSteven Rostedt <rostedt@goodmis.org>
      Cc: Frederic Weisbecker <fweisbec@gmail.com>
      Cc: Jason Baron <jbaron@redhat.com>
      Cc: Paul Mackerras <paulus@samba.org>
      Signed-off-by: NIngo Molnar <mingo@elte.hu>
      3a659305
  20. 08 8月, 2009 3 次提交
    • P
      bzip2/lzma/gzip: fix comments describing decompressor API · daeb6b6f
      Phillip Lougher 提交于
      Fix and improve comments in decompress/generic.h that describe the
      decompressor API.  Also remove an unused definition, and rename INBUF_LEN
      in lib/decompress_inflate.c to conform to bzip2/lzma naming.
      Signed-off-by: NPhillip Lougher <phillip@lougher.demon.co.uk>
      Cc: "H. Peter Anvin" <hpa@zytor.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      daeb6b6f
    • K
      mm: make set_mempolicy(MPOL_INTERLEAV) N_HIGH_MEMORY aware · 4bfc4495
      KAMEZAWA Hiroyuki 提交于
      At first, init_task's mems_allowed is initialized as this.
       init_task->mems_allowed == node_state[N_POSSIBLE]
      
      And cpuset's top_cpuset mask is initialized as this
       top_cpuset->mems_allowed = node_state[N_HIGH_MEMORY]
      
      Before 2.6.29:
      policy's mems_allowed is initialized as this.
      
        1. update tasks->mems_allowed by its cpuset->mems_allowed.
        2. policy->mems_allowed = nodes_and(tasks->mems_allowed, user's mask)
      
      Updating task's mems_allowed in reference to top_cpuset's one.
      cpuset's mems_allowed is aware of N_HIGH_MEMORY, always.
      
      In 2.6.30: After commit 58568d2a
      ("cpuset,mm: update tasks' mems_allowed in time"), policy's mems_allowed
      is initialized as this.
      
        1. policy->mems_allowd = nodes_and(task->mems_allowed, user's mask)
      
      Here, if task is in top_cpuset, task->mems_allowed is not updated from
      init's one.  Assume user excutes command as #numactrl --interleave=all
      ,....
      
        policy->mems_allowd = nodes_and(N_POSSIBLE, ALL_SET_MASK)
      
      Then, policy's mems_allowd can includes a possible node, which has no pgdat.
      
      MPOL's INTERLEAVE just scans nodemask of task->mems_allowd and access this
      directly.
      
        NODE_DATA(nid)->zonelist even if NODE_DATA(nid)==NULL
      
      Then, what's we need is making policy->mems_allowed be aware of
      N_HIGH_MEMORY.  This patch does that.  But to do so, extra nodemask will
      be on statck.  Because I know cpumask has a new interface of
      CPUMASK_ALLOC(), I added it to node.
      
      This patch stands on old behavior.  But I feel this fix itself is just a
      Band-Aid.  But to do fundametal fix, we have to take care of memory
      hotplug and it takes time.  (task->mems_allowd should be N_HIGH_MEMORY, I
      think.)
      
      mpol_set_nodemask() should be aware of N_HIGH_MEMORY and policy's nodemask
      should be includes only online nodes.
      
      In old behavior, this is guaranteed by frequent reference to cpuset's
      code.  Now, most of them are removed and mempolicy has to check it by
      itself.
      
      To do check, a few nodemask_t will be used for calculating nodemask.  But,
      size of nodemask_t can be big and it's not good to allocate them on stack.
      
      Now, cpumask_t has CPUMASK_ALLOC/FREE an easy code for get scratch area.
      NODEMASK_ALLOC/FREE shoudl be there.
      
      [akpm@linux-foundation.org: cleanups & tweaks]
      Tested-by: NKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Miao Xie <miaox@cn.fujitsu.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Paul Menage <menage@google.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
      Cc: Pekka Enberg <penberg@cs.helsinki.fi>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
      Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4bfc4495
    • C
      vfs: add __destroy_inode · 2e00c97e
      Christoph Hellwig 提交于
      When we want to tear down an inode that lost the add to the cache race
      in XFS we must not call into ->destroy_inode because that would delete
      the inode that won the race from the inode cache radix tree.
      
      This patch provides the __destroy_inode helper needed to fix this,
      the actual fix will be in th next patch.  As XFS was the only reason
      destroy_inode was exported we shift the export to the new __destroy_inode.
      Signed-off-by: NChristoph Hellwig <hch@lst.de>
      Reviewed-by: NEric Sandeen <sandeen@sandeen.net>
      2e00c97e