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  1. 30 Jul, 2009 1 commit
    • Xiao Guangrong's avatar
      This patch can remove spinlock from struct call_function_data, the · 4de930a4
      Xiao Guangrong authored 
      reasons are below:

1: add a new interface for cpumask named cpumask_test_and_clear_cpu(),
   it can atomically test and clear specific cpu, we can use it instead
   of cpumask_test_cpu() and cpumask_clear_cpu() and no need data->lock
   to protect those in generic_smp_call_function_interrupt().

2: in smp_call_function_many(), after csd_lock() return, the current's
   cfd_data is deleted from call_function list, so it not have race
   between other cpus, then cfs_data is only used in
   smp_call_function_many() that must disable preemption and not from
   a hardware interrupthandler or from a bottom half handler to call,
   only the correspond cpu can use it, so it not have race in current
   cpu, no need cfs_data->lock to protect it.

3: after 1 and 2, cfs_data->lock is only use to protect cfs_data->refs in
   generic_smp_call_function_interrupt(), so we can define cfs_data->refs
   to atomic_t, and no need cfs_data->lock any more.
Signed-off-by: default avatarXiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: default avatarRusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      4de930a4
  3. 24 Jul, 2009 1 commit
  5. 23 Jul, 2009 1 commit
  7. 24 Aug, 2009 1 commit
    • Neil Horman's avatar
      The user mode helper code has a race in it. call_usermodehelper_exec() · 75b80f4d
      Neil Horman authored 
      takes an allocated subprocess_info structure, which it passes to a
workqueue, and then passes it to a kernel thread which it creates, after
which it calls complete to signal to the caller of
call_usermodehelper_exec() that it can free the subprocess_info struct.

But since we use that structure in the created thread, we can't call
complete from __call_usermodehelper(), which is where we create the kernel
thread.  We need to call complete() from within the kernel thread and then
not use subprocess_info afterward in the case of UMH_WAIT_EXEC.  Tested
successfully by me.
Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      75b80f4d
  9. 29 Jun, 2009 2 commits
  11. 24 Aug, 2009 7 commits
  13. 13 Aug, 2009 1 commit
  15. 23 Jul, 2009 1 commit
  17. 13 Aug, 2009 1 commit
  19. 23 Jul, 2009 1 commit
  21. 13 Aug, 2009 1 commit
  23. 23 Jul, 2009 1 commit
  25. 13 Jul, 2009 1 commit
  27. 13 Aug, 2009 1 commit
  29. 12 Aug, 2009 1 commit
  31. 31 Jul, 2009 1 commit
  33. 23 Jul, 2009 1 commit
  35. 13 Aug, 2009 1 commit
  37. 04 Aug, 2009 1 commit
  39. 23 Jul, 2009 1 commit
  41. 13 Aug, 2009 1 commit
  43. 14 Feb, 2009 2 commits
  45. 09 Sep, 2009 10 commits
    • Hugh Dickins's avatar
      CONFIG_SHMEM off gives you (ramfs masquerading as) tmpfs, even when · 991ce3ef
      Hugh Dickins authored 
      CONFIG_TMPFS is off: that's a little anomalous, and I'd intended to make
more sense of it by removing CONFIG_TMPFS altogether, always enabling its
code when CONFIG_SHMEM; but so many defconfigs have CONFIG_SHMEM on
CONFIG_TMPFS off that we'd better leave that as is.

But there is no point in asking for CONFIG_TMPFS if CONFIG_SHMEM is off:
make TMPFS depend on SHMEM, which also prevents TMPFS_POSIX_ACL
shmem_acl.o being pointlessly built into the kernel when SHMEM is off.

And a selfish change, to prevent the world from being rebuilt when I
switch between CONFIG_SHMEM on and off: the only CONFIG_SHMEM in the
header files is mm.h shmem_lock() - give that a shmem.c stub instead.
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: default avatarMatt Mackall <mpm@selenic.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      991ce3ef
    • Huang Shijie's avatar
      If (flags & MAP_LOCKED) is true, it means vm_flags has already contained · 47b7b6a1
      Huang Shijie authored 
      the bit VM_LOCKED which is set by calc_vm_flag_bits().

So there is no need to reset it again, just remove it.
Signed-off-by: default avatarHuang Shijie <shijie8@gmail.com>
Acked-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      47b7b6a1
    • Hugh Dickins's avatar
      __get_user_pages() has been taking its own GUP flags, then processing · fdf2984f
      Hugh Dickins authored 
      them into FOLL flags for follow_page().  Though oddly named, the FOLL
flags are more widely used, so pass them to __get_user_pages() now.
Sorry, VM flags, VM_FAULT flags and FAULT_FLAGs are still distinct.

(The patch to __get_user_pages() looks peculiar, with both gup_flags
and foll_flags: the gup_flags remain constant; but as before there's
an exceptional case, out of scope of the patch, in which foll_flags
per page have FOLL_WRITE masked off.)
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: Rik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      fdf2984f
    • Hugh Dickins's avatar
      KAMEZAWA Hiroyuki has observed customers of earlier kernels taking · f671a4e8
      Hugh Dickins authored 
      advantage of the ZERO_PAGE: which we stopped do_anonymous_page() from
using in 2.6.24.  And there were a couple of regression reports on LKML.

Following suggestions from Linus, reinstate do_anonymous_page() use of
the ZERO_PAGE; but this time avoid dirtying its struct page cacheline
with (map)count updates - let vm_normal_page() regard it as abnormal.

Use it only on arches which __HAVE_ARCH_PTE_SPECIAL (x86, s390, sh32,
most powerpc): that's not essential, but minimizes additional branches
(keeping them in the unlikely pte_special case); and incidentally
excludes mips (some models of which needed eight colours of ZERO_PAGE
to avoid costly exceptions).

Don't be fanatical about avoiding ZERO_PAGE updates: get_user_pages()
callers won't want to make exceptions for it, so increment its count
there.  Changes to mlock and migration? happily seems not needed.

In most places it's quicker to check pfn than struct page address:
prepare a __read_mostly zero_pfn for that.  Does get_dump_page()
still need its ZERO_PAGE check? probably not, but keep it anyway.
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      f671a4e8
    • Hugh Dickins's avatar
      do_anonymous_page() has been wrong to dirty the pte regardless. · 1e9bc722
      Hugh Dickins authored 
      If it's not going to mark the pte writable, then it won't help
to mark it dirty here, and clogs up memory with pages which will
need swap instead of being thrown away.  Especially wrong if no
overcommit is chosen, and this vma is not yet VM_ACCOUNTed -
we could exceed the limit and OOM despite no overcommit.
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      1e9bc722
    • Hugh Dickins's avatar
      follow_hugetlb_page() shouldn't be guessing about the coredump case · 7dc46b63
      Hugh Dickins authored 
      either: pass the foll_flags down to it, instead of just the write bit.

Remove that obscure huge_zeropage_ok() test.  The decision is easy,
though unlike the non-huge case - here vm_ops->fault is always set.
But we know that a fault would serve up zeroes, unless there's
already a hugetlbfs pagecache page to back the range.

(Alternatively, since hugetlb pages aren't swapped out under pressure,
you could save more dump space by arguing that a page not yet faulted
into this process cannot be relevant to the dump; but that would be
more surprising.)
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      7dc46b63
    • Hugh Dickins's avatar
      The "FOLL_ANON optimization" and its use_zero_page() test have caused · c2b1bd26
      Hugh Dickins authored 
      confusion and bugs: why does it test VM_SHARED? for the very good but
unsatisfying reason that VMware crashed without.  As we look to maybe
reinstating anonymous use of the ZERO_PAGE, we need to sort this out.

Easily done: it's silly for __get_user_pages() and follow_page() to
be guessing whether it's safe to assume that they're being used for
a coredump (which can take a shortcut snapshot where other uses must
handle a fault) - just tell them with GUP_FLAGS_DUMP and FOLL_DUMP.

get_dump_page() doesn't even want a ZERO_PAGE: an error suits fine.
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      c2b1bd26
    • Hugh Dickins's avatar
      In preparation for the next patch, add a simple get_dump_page(addr) · e35e64ad
      Hugh Dickins authored 
      interface for the CONFIG_ELF_CORE dumpers to use, instead of calling
get_user_pages() directly.  They're not interested in errors: they
just want to use holes as much as possible, to save space and make
sure that the data is aligned where the headers said it would be.

Oh, and don't use that horrid DUMP_SEEK(off) macro!
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      e35e64ad
    • Hugh Dickins's avatar
      GUP_FLAGS_IGNORE_VMA_PERMISSIONS and GUP_FLAGS_IGNORE_SIGKILL were · 94e9f60b
      Hugh Dickins authored 
      flags added solely to prevent __get_user_pages() from doing some of
what it usually does, in the munlock case: we can now remove them.
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Minchan Kim <minchan.kim@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      94e9f60b
    • Hugh Dickins's avatar
      Hiroaki Wakabayashi points out that when mlock() has been interrupted · 70da9180
      Hugh Dickins authored 
      by SIGKILL, the subsequent munlock() takes unnecessarily long because
its use of __get_user_pages() insists on faulting in all the pages
which mlock() never reached.

It's worse than slowness if mlock() is terminated by Out Of Memory kill:
the munlock_vma_pages_all() in exit_mmap() insists on faulting in all the
pages which mlock() could not find memory for; so innocent bystanders are
killed too, and perhaps the system hangs.

__get_user_pages() does a lot that's silly for munlock(): so remove the
munlock option from __mlock_vma_pages_range(), and use a simple loop of
follow_page()s in munlock_vma_pages_range() instead; ignoring absent
pages, and not marking present pages as accessed or dirty.

(Change munlock() to only go so far as mlock() reached?  That does not
work out, given the convention that mlock() claims complete success even
when it has to give up early - in part so that an underlying file can be
extended later, and those pages locked which earlier would give SIGBUS.)
Signed-off-by: default avatarHugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <stable@kernel.org>
Acked-by: default avatarRik van Riel <riel@redhat.com>
Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Hiroaki Wakabayashi <primulaelatior@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      70da9180