1. 06 Jan, 2009 40 commits
    • Cyrill Gorcunov's avatar
      mm: hugetlb: remove redundant `if' operation · 91f47662
      Cyrill Gorcunov authored
      
      
      At this point we already know that 'addr' is not NULL so get rid of
      redundant 'if'.  Probably gcc eliminate it by optimization pass.
      
      [akpm@linux-foundation.org: use __weak, too]
      Signed-off-by: default avatarCyrill Gorcunov <gorcunov@openvz.org>
      Reviewed-by: default avatarIngo Molnar <mingo@elte.hu>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      91f47662
    • KOSAKI Motohiro's avatar
      mm: stop kswapd's infinite loop at high order allocation · 73ce02e9
      KOSAKI Motohiro authored
      
      
      Wassim Dagash reported following kswapd infinite loop problem.
      
        kswapd runs in some infinite loop trying to swap until order 10 of zone
        highmem is OK.... kswapd will continue to try to balance order 10 of zone
        highmem forever (or until someone release a very large chunk of highmem).
      
      For non order-0 allocations, the system may never be balanced due to
      fragmentation but kswapd should not infinitely loop as a result.
      
      Instead, recheck all watermarks at order-0 as they are the most important.
      If watermarks are ok, kswapd will go back to sleep.
      
      [akpm@linux-foundation.org: fix comment]
      Reported-by: default avatarwassim dagash <wassim.dagash@gmail.com>
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      73ce02e9
    • Johannes Weiner's avatar
      bootmem: print request details before BUG_ON(them) · 594fe1a0
      Johannes Weiner authored
      
      
      Moving the request details print-out before the sanity checks that
      might panic() enables us to analyse invalid requests without having
      access to the line information of the stack dump.
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      594fe1a0
    • Johannes Weiner's avatar
      mm: check for no mmaps in exit_mmap() · dcd4a049
      Johannes Weiner authored
      
      
      When dup_mmap() ooms we can end up with mm->mmap == NULL.  The error
      path does mmput() and unmap_vmas() gets a NULL vma which it
      dereferences.
      
      In exit_mmap() there is nothing to do at all for this case, we can
      cancel the callpath right there.
      
      [akpm@linux-foundation.org: add sorely-needed comment]
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Reported-by: default avatarAkinobu Mita <akinobu.mita@gmail.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Hugh Dickins <hugh@veritas.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      dcd4a049
    • KOSAKI Motohiro's avatar
      mm: kill page_queue_congested() · 084f71ae
      KOSAKI Motohiro authored
      
      
      page_queue_congested() was introduced in 2002, but it was never used
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Peter Zijlstra <peterz@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      084f71ae
    • KOSAKI Motohiro's avatar
      mm: remove CONFIG_OUT_OF_LINE_PFN_TO_PAGE · 9f572e3f
      KOSAKI Motohiro authored
      
      
      No architectures use CONFIG_OUT_OF_LINE_PFN_TO_PAGE - it can be removed.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9f572e3f
    • Oleg Nesterov's avatar
      mm: introduce get_mm_hiwater_xxx(), fix taskstats->hiwater_xxx accounting · 901608d9
      Oleg Nesterov authored
      
      
      xacct_add_tsk() relies on do_exit()->update_hiwater_xxx() and uses
      mm->hiwater_xxx directly, this leads to 2 problems:
      
      - taskstats_user_cmd() can call fill_pid()->xacct_add_tsk() at any
        moment before the task exits, so we should check the current values of
        rss/vm anyway.
      
      - do_exit()->update_hiwater_xxx() calls are racy.  An exiting thread can
        be preempted right before mm->hiwater_xxx = new_val, and another thread
        can use A_LOT of memory and exit in between.  When the first thread
        resumes it can be the last thread in the thread group, in that case we
        report the wrong hiwater_xxx values which do not take A_LOT into
        account.
      
      Introduce get_mm_hiwater_rss() and get_mm_hiwater_vm() helpers and change
      xacct_add_tsk() to use them.  The first helper will also be used by
      rusage->ru_maxrss accounting.
      
      Kill do_exit()->update_hiwater_xxx() calls.  Unless we are going to
      decrease rss/vm there is no point to update mm->hiwater_xxx, and nobody
      can look at this mm_struct when exit_mmap() actually unmaps the memory.
      Signed-off-by: default avatarOleg Nesterov <oleg@redhat.com>
      Acked-by: default avatarHugh Dickins <hugh@veritas.com>
      Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Acked-by: default avatarBalbir Singh <balbir@linux.vnet.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      901608d9
    • Nick Piggin's avatar
      mm: pagecache gfp flags fix · 67d58ac4
      Nick Piggin authored
      
      
      Frustratingly, gfp_t is really divided into two classes of flags.  One are
      the context dependent ones (can we sleep?  can we enter filesystem?  block
      subsystem?  should we use some extra reserves, etc.).  The other ones are
      the type of memory required and depend on how the algorithm is implemented
      rather than the point at which the memory is allocated (highmem?  dma
      memory?  etc).
      
      Some of the functions which allocate a page and add it to page cache take
      a gfp_t, but sometimes those functions or their callers aren't really
      doing the right thing: when allocating pagecache page, the memory type
      should be mapping_gfp_mask(mapping).  When allocating radix tree nodes,
      the memory type should be kernel mapped (not highmem) memory.  The gfp_t
      argument should only really be needed for context dependent options.
      
      This patch doesn't really solve that tangle in a nice way, but it does
      attempt to fix a couple of bugs.
      
      - find_or_create_page changes its radix-tree allocation to only include
        the main context dependent flags in order so the pagecache page may be
        allocated from arbitrary types of memory without affecting the
        radix-tree.  In practice, slab allocations don't come from highmem
        anyway, and radix-tree only uses slab allocations.  So there isn't a
        practical change (unless some fs uses GFP_DMA for pages).
      
      - grab_cache_page_nowait() is changed to allocate radix-tree nodes with
        GFP_NOFS, because it is not supposed to reenter the filesystem.  This
        bug could cause lock recursion if a filesystem is not expecting the
        function to reenter the fs (as-per documentation).
      
      Filesystems should be careful about exactly what semantics they want and
      what they get when fiddling with gfp_t masks to allocate pagecache.  One
      should be as liberal as possible with the type of memory that can be used,
      and same for the the context specific flags.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      67d58ac4
    • Nick Piggin's avatar
      fs: sys_sync fix · 856bf4d7
      Nick Piggin authored
      
      
      s_syncing livelock avoidance was breaking data integrity guarantee of
      sys_sync, by allowing sys_sync to skip writing or waiting for superblocks
      if there is a concurrent sys_sync happening.
      
      This livelock avoidance is much less important now that we don't have the
      get_super_to_sync() call after every sb that we sync.  This was replaced
      by __put_super_and_need_restart.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      856bf4d7
    • Nick Piggin's avatar
      fs: sync_sb_inodes fix · 38f21977
      Nick Piggin authored
      
      
      Fix data integrity semantics required by sys_sync, by iterating over all
      inodes and waiting for any writeback pages after the initial writeout.
      Comments explain the exact problem.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      38f21977
    • Nick Piggin's avatar
      fs: remove WB_SYNC_HOLD · 4f5a99d6
      Nick Piggin authored
      
      
      Remove WB_SYNC_HOLD.  The primary motiviation is the design of my
      anti-starvation code for fsync.  It requires taking an inode lock over the
      sync operation, so we could run into lock ordering problems with multiple
      inodes.  It is possible to take a single global lock to solve the ordering
      problem, but then that would prevent a future nice implementation of "sync
      multiple inodes" based on lock order via inode address.
      
      Seems like a backward step to remove this, but actually it is busted
      anyway: we can't use the inode lists for data integrity wait: an inode can
      be taken off the dirty lists but still be under writeback.  In order to
      satisfy data integrity semantics, we should wait for it to finish
      writeback, but if we only search the dirty lists, we'll miss it.
      
      It would be possible to have a "writeback" list, for sys_sync, I suppose.
      But why complicate things by prematurely optimise?  For unmounting, we
      could avoid the "livelock avoidance" code, which would be easier, but
      again premature IMO.
      
      Fixing the existing data integrity problem will come next.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4f5a99d6
    • Artem Bityutskiy's avatar
      UBIFS: do not use WB_SYNC_HOLD · e8ea1759
      Artem Bityutskiy authored
      
      
      WB_SYNC_HOLD is going to be zapped so we should not use it. Use
      %WB_SYNC_NONE instead. Here is what akpm said:
      
      "I think I'll just switch that to WB_SYNC_NONE.  The `wait==0' mode is
      just an advisory thing to help the fs shove lots of data into the
      queues.  If some gets missed then it'll be picked up on the second
      ->sync_fs call, with wait==1."
      
      Thanks to Randy Dunlap for catching this.
      Signed-off-by: default avatarArtem Bityutskiy <Artem.Bityutskiy@nokia.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Randy Dunlap <randy.dunlap@oracle.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e8ea1759
    • Nick Piggin's avatar
      mm: direct IO starvation improvement · 48b47c56
      Nick Piggin authored
      
      
      Direct IO can invalidate and sync a lot of pagecache pages in the mapping.
       A 4K direct IO will actually try to sync and/or invalidate the pagecache
      of the entire file, for example (which might be many GB or TB large).
      
      Improve this by doing range syncs.  Also, memory no longer has to be
      unmapped to catch the dirty bits for syncing, as dirty bits would remain
      coherent due to dirty mmap accounting.
      
      This fixes the immediate DM deadlocks when doing direct IO reads to block
      device with a mounted filesystem, if only by papering over the problem
      somewhat rather than addressing the fsync starvation cases.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Reviewed-by: default avatarJeff Moyer <jmoyer@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      48b47c56
    • ZhenwenXu's avatar
      mm/mmap.c: fix coding style · 48aae425
      ZhenwenXu authored
      
      
      Fix a little of the coding style in mm/mmap.c
      
      [akpm@linux-foundation.org: cleanup]
      Signed-off-by: default avatarZhenwenXu <helight.xu@gmail.com>
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      48aae425
    • Matt Mackall's avatar
      shmem: unify regular and tiny shmem · 853ac43a
      Matt Mackall authored
      
      
      tiny-shmem shares most of its 130 lines of code with shmem and tends to
      break when particular bits of shmem get modified.  Unifying saves code and
      makes keeping these two in sync much easier.
      
      before:
        14367	    392	     24	  14783	   39bf	mm/shmem.o
          396      72       8     476	    1dc	mm/tiny-shmem.o
      
      after:
        14367	    392	     24	  14783	   39bf	mm/shmem.o
          412	     72       8     492	    1ec	mm/shmem.o tiny
      Signed-off-by: default avatarMatt Mackall <mpm@selenic.com>
      Acked-by: default avatarHugh Dickins <hugh@veritas.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      853ac43a
    • Franck Bui-Huu's avatar
    • Ying Han's avatar
      mm: make get_user_pages() interruptible · 4779280d
      Ying Han authored
      
      
      The initial implementation of checking TIF_MEMDIE covers the cases of OOM
      killing.  If the process has been OOM killed, the TIF_MEMDIE is set and it
      return immediately.  This patch includes:
      
      1.  add the case that the SIGKILL is sent by user processes.  The
         process can try to get_user_pages() unlimited memory even if a user
         process has sent a SIGKILL to it(maybe a monitor find the process
         exceed its memory limit and try to kill it).  In the old
         implementation, the SIGKILL won't be handled until the get_user_pages()
         returns.
      
      2.  change the return value to be ERESTARTSYS.  It makes no sense to
         return ENOMEM if the get_user_pages returned by getting a SIGKILL
         signal.  Considering the general convention for a system call
         interrupted by a signal is ERESTARTNOSYS, so the current return value
         is consistant to that.
      
      Lee:
      
      An unfortunate side effect of "make-get_user_pages-interruptible" is that
      it prevents a SIGKILL'd task from munlock-ing pages that it had mlocked,
      resulting in freeing of mlocked pages.  Freeing of mlocked pages, in
      itself, is not so bad.  We just count them now--altho' I had hoped to
      remove this stat and add PG_MLOCKED to the free pages flags check.
      
      However, consider pages in shared libraries mapped by more than one task
      that a task mlocked--e.g., via mlockall().  If the task that mlocked the
      pages exits via SIGKILL, these pages would be left mlocked and
      unevictable.
      
      Proposed fix:
      
      Add another GUP flag to ignore sigkill when calling get_user_pages from
      munlock()--similar to Kosaki Motohiro's 'IGNORE_VMA_PERMISSIONS flag for
      the same purpose.  We are not actually allocating memory in this case,
      which "make-get_user_pages-interruptible" intends to avoid.  We're just
      munlocking pages that are already resident and mapped, and we're reusing
      get_user_pages() to access those pages.
      
      ??  Maybe we should combine 'IGNORE_VMA_PERMISSIONS and '_IGNORE_SIGKILL
      into a single flag: GUP_FLAGS_MUNLOCK ???
      
      [Lee.Schermerhorn@hp.com: ignore sigkill in get_user_pages during munlock]
      Signed-off-by: default avatarPaul Menage <menage@google.com>
      Signed-off-by: default avatarYing Han <yinghan@google.com>
      Reviewed-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Reviewed-by: default avatarPekka Enberg <penberg@cs.helsinki.fi>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: Oleg Nesterov <oleg@tv-sign.ru>
      Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Rohit Seth <rohitseth@google.com>
      Cc: David Rientjes <rientjes@google.com>
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      4779280d
    • Roel Kluin's avatar
      hugetlb: unsigned ret cannot be negative · 91bf189c
      Roel Kluin authored
      
      
      unsigned long ret cannot be negative, but ret can get -EFAULT.
      Signed-off-by: default avatarRoel Kluin <roel.kluin@gmail.com>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: Adam Litke <agl@us.ibm.com>
      Cc: David Gibson <david@gibson.dropbear.id.au>
      Cc: Ken Chen <kenchen@google.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      91bf189c
    • Andrew Morton's avatar
      vmscan: shrink_active_list(): reduce lru_lock hold time · b555749a
      Andrew Morton authored
      
      
      These three statements manipulate local variables and do not need the lock
      coverage.
      
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
      Cc: Rik van Riel <riel@redhat.com
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b555749a
    • Hugh Dickins's avatar
      badpage: KERN_ALERT BUG instead of KERN_EMERG · 1e9e6365
      Hugh Dickins authored
      
      
      bad_page() and rmap Eeek messages have said KERN_EMERG for a few years,
      which I've followed in print_bad_pte().  These are serious system errors,
      on a par with BUGs, but they're not quite emergencies, and we do our best
      to carry on: say KERN_ALERT "BUG: " like the x86 oops does.
      
      And remove the "Trying to fix it up, but a reboot is needed" line: it's
      not untrue, but I hope the KERN_ALERT "BUG: " conveys as much.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      1e9e6365
    • Hugh Dickins's avatar
      badpage: ratelimit print_bad_pte and bad_page · d936cf9b
      Hugh Dickins authored
      
      
      print_bad_pte() and bad_page() might each need ratelimiting - especially
      for their dump_stacks, almost never of interest, yet not quite
      dispensible.  Correlating corruption across neighbouring entries can be
      very helpful, so allow a burst of 60 reports before keeping quiet for the
      remainder of that minute (or allow a steady drip of one report per
      second).
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d936cf9b
    • Hugh Dickins's avatar
      badpage: remove vma from page_remove_rmap · edc315fd
      Hugh Dickins authored
      
      
      Remove page_remove_rmap()'s vma arg, which was only for the Eeek message.
      And remove the BUG_ON(page_mapcount(page) == 0) from CONFIG_DEBUG_VM's
      page_dup_rmap(): we're trying to be more resilient about that than BUGs.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      edc315fd
    • Hugh Dickins's avatar
      badpage: zap print_bad_pte on swap and file · 2509ef26
      Hugh Dickins authored
      
      
      Complete zap_pte_range()'s coverage of bad pagetable entries by calling
      print_bad_pte() on a pte_file in a linear vma and on a bad swap entry.
      That needs free_swap_and_cache() to tell it, which will also have shown
      one of those "swap_free" errors (but with much less information).
      
      Similar checks in fork's copy_one_pte()?  No, that would be more noisy
      than helpful: we'll see them when parent and child exec or exit.
      
      Where do_nonlinear_fault() calls print_bad_pte(): omit !VM_CAN_NONLINEAR
      case, that could only be a bug in sys_remap_file_pages(), not a bad pte.
      VM_FAULT_OOM rather than VM_FAULT_SIGBUS?  Well, okay, that is consistent
      with what happens if do_swap_page() operates a bad swap entry; but don't
      we have patches to be more careful about killing when VM_FAULT_OOM?
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2509ef26
    • Hugh Dickins's avatar
      badpage: vm_normal_page use print_bad_pte · 22b31eec
      Hugh Dickins authored
      
      
      print_bad_pte() is so far being called only when zap_pte_range() finds
      negative page_mapcount, or there's a fault on a pte_file where it does not
      belong.  That's weak coverage when we suspect pagetable corruption.
      
      Originally, it was called when vm_normal_page() found an invalid pfn: but
      pfn_valid is expensive on some architectures and configurations, so 2.6.24
      put that under CONFIG_DEBUG_VM (which doesn't help in the field), then
      2.6.26 replaced it by a VM_BUG_ON (likewise).
      
      Reinstate the print_bad_pte() in vm_normal_page(), but use a cheaper test
      than pfn_valid(): memmap_init_zone() (used in bootup and hotplug) keep a
      __read_mostly note of the highest_memmap_pfn, vm_normal_page() then check
      pfn against that.  We could call this pfn_plausible() or pfn_sane(), but I
      doubt we'll need it elsewhere: of course it's not reliable, but gives much
      stronger pagetable validation on many boxes.
      
      Also use print_bad_pte() when the pte_special bit is found outside a
      VM_PFNMAP or VM_MIXEDMAP area, instead of VM_BUG_ON.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      22b31eec
    • Hugh Dickins's avatar
      badpage: replace page_remove_rmap Eeek and BUG · 3dc14741
      Hugh Dickins authored
      
      
      Now that bad pages are kept out of circulation, there is no need for the
      infamous page_remove_rmap() BUG() - once that page is freed, its negative
      mapcount will issue a "Bad page state" message and the page won't be
      freed.  Removing the BUG() allows more info, on subsequent pages, to be
      gathered.
      
      We do have more info about the page at this point than bad_page() can know
      - notably, what the pmd is, which might pinpoint something like low 64kB
      corruption - but page_remove_rmap() isn't given the address to find that.
      
      In practice, there is only one call to page_remove_rmap() which has ever
      reported anything, that from zap_pte_range() (usually on exit, sometimes
      on munmap).  It has all the info, so remove page_remove_rmap()'s "Eeek"
      message and leave it all to zap_pte_range().
      
      mm/memory.c already has a hardly used print_bad_pte() function, showing
      some of the appropriate info: extend it to show what we want for the rmap
      case: pte info, page info (when there is a page) and vma info to compare.
      zap_pte_range() already knows the pmd, but print_bad_pte() is easier to
      use if it works that out for itself.
      
      Some of this info is also shown in bad_page()'s "Bad page state" message.
      Keep them separate, but adjust them to match each other as far as
      possible.  Say "Bad page map" in print_bad_pte(), and add a TAINT_BAD_PAGE
      there too.
      
      print_bad_pte() show current->comm unconditionally (though it should get
      repeated in the usually irrelevant stack trace): sorry, I misled Nick
      Piggin to make it conditional on vm_mm == current->mm, but current->mm is
      already NULL in the exit case.  Usually current->comm is good, though
      exceptionally it may not be that of the mm (when "swapoff" for example).
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3dc14741
    • Hugh Dickins's avatar
      badpage: keep any bad page out of circulation · 8cc3b392
      Hugh Dickins authored
      
      
      Until now the bad_page() checkers have special-cased PageReserved, keeping
      those pages out of circulation thereafter.  Now extend the special case to
      all: we want to keep ANY page with bad state out of circulation - the
      "free" page may well be in use by something.
      
      Leave the bad state of those pages untouched, for examination by
      debuggers; except for PageBuddy - leaving that set would risk bringing the
      page back.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8cc3b392
    • Hugh Dickins's avatar
      badpage: simplify page_alloc flag check+clear · 79f4b7bf
      Hugh Dickins authored
      
      
      Simplify the PAGE_FLAGS checking and clearing when freeing and allocating
      a page: check the same flags as before when freeing, clear ALL the flags
      (unless PageReserved) when freeing, check ALL flags off when allocating.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Christoph Lameter <cl@linux-foundation.org>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Rik van Riel <riel@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      79f4b7bf
    • Dmitri Monakhov's avatar
      fs: truncate blocks outside i_size after O_DIRECT write error · 0f64415d
      Dmitri Monakhov authored
      
      
      In case of error extending write may have instantiated a few blocks
      outside i_size.  We need to trim these blocks.  We have to do it
      *regardless* to blocksize.  At least ext2, ext3 and reiserfs interpret
      (i_size < biggest block) condition as error.  Fsck will complain about
      wrong i_size.  Then fsck will fix the error by changing i_size according
      to the biggest block.  This is bad because this blocks contain garbage
      from previous write attempt.  And result in data corruption.
      
      ####TESTCASE_BEGIN
      $touch /mnt/test/BIG_FILE
      ## at this moment /mnt/test/BIG_FILE size and blocks equal to zero
      open("/mnt/test/BIG_FILE", O_WRONLY|O_CREAT|O_DIRECT, 0666) = 3
      write(3, "aaaaaaaaaaaa"..., 104857600) = -1 ENOSPC (No space left on device)
      ## size and block sould't be changed because write op failed.
      $stat /mnt/test/BIG_FILE
      File: `/mnt/test/BIG_FILE'
      Size: 0 Blocks: 110896 IO Block: 1024 regular empty file
      <<<<<<<<^^^^^^^^^^^^^^^^^^^^^^^^^^^^^file size is less than biggest block idx
      Device: fe07h/65031d Inode: 14 Links: 1
      Access: (0644/-rw-r--r--) Uid: ( 0/ root) Gid: ( 0/ root)
      Access: 2007-01-24 20:03:38.000000000 +0300
      Modify: 2007-01-24 20:03:38.000000000 +0300
      Change: 2007-01-24 20:03:39.000000000 +0300
      
      #fsck.ext3 -f /dev/VG/test
      e2fsck 1.39 (29-May-2006)
      Pass 1: Checking inodes, blocks, and sizes
      Inode 14, i_size is 0, should be 56556544. Fix<y>? yes
      Pass 2: Checking directory structure
      ....
      #####TESTCASE_ENDdiff --git a/fs/direct-io.c b/fs/direct-io.c
      index af0558d..4e88bea 100644
      
      [akpm@linux-foundation.org: use i_size_read()]
      Signed-off-by: default avatarDmitri Monakhov <dmonakhov@openvz.org>
      Cc: Zach Brown <zach.brown@oracle.com>
      Cc: Nick Piggin <npiggin@suse.de>
      Cc: Badari Pulavarty <pbadari@us.ibm.com>
      Cc: Chris Mason <chris.mason@oracle.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0f64415d
    • KOSAKI Motohiro's avatar
      mm: kill zone_is_near_oom() · 09f445e7
      KOSAKI Motohiro authored
      
      
      zone_is_near_oom() is unused.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      09f445e7
    • KOSAKI Motohiro's avatar
      vmscan: improve reclaim throughput to bail out patch · 01dbe5c9
      KOSAKI Motohiro authored
      
      
      The vmscan bail out patch move nr_reclaimed variable to struct
      scan_control.  Unfortunately, indirect access can easily happen cache
      miss.
      
      if heavy memory pressure happend, that's ok.
      cache miss already plenty. it is not observable.
      
      but, if memory pressure is lite, performance degression is obserbable.
      
      I compared following three pattern (it was mesured 10 times each)
      
      hackbench 125 process 3000
      hackbench 130 process 3000
      hackbench 135 process 3000
      
                  2.6.28-rc6                       bail-out
      
      	125	130	135		125	130	135
            ==============================================================
      	71.866	75.86	81.274		93.414	73.254	193.382
      	74.145	78.295	77.27		74.897	75.021	80.17
      	70.305	77.643	75.855		70.134	77.571	79.896
      	74.288	73.986	75.955		77.222	78.48	80.619
      	72.029	79.947	78.312		75.128	82.172	79.708
      	71.499	77.615	77.042		74.177	76.532	77.306
      	76.188	74.471	83.562		73.839	72.43	79.833
      	73.236	75.606	78.743		76.001	76.557	82.726
      	69.427	77.271	76.691		76.236	79.371	103.189
      	72.473	76.978	80.643		69.128	78.932	75.736
      
      avg	72.545	76.767	78.534		76.017	77.03	93.256
      std	1.89	1.71	2.41		6.29	2.79	34.16
      min	69.427	73.986	75.855		69.128	72.43	75.736
      max	76.188	79.947	83.562		93.414	82.172	193.382
      
      about 4-5% degression.
      
      Then, this patch introduces a temporary local variable.
      
      result:
      
                  2.6.28-rc6                       this patch
      
      num	125	130	135		125	130	135
            ==============================================================
      	71.866	75.86	81.274		67.302	68.269	77.161
      	74.145	78.295	77.27   	72.616	72.712	79.06
      	70.305	77.643	75.855  	72.475	75.712	77.735
      	74.288	73.986	75.955  	69.229	73.062	78.814
      	72.029	79.947	78.312  	71.551	74.392	78.564
      	71.499	77.615	77.042  	69.227	74.31	78.837
      	76.188	74.471	83.562  	70.759	75.256	76.6
      	73.236	75.606	78.743  	69.966	76.001	78.464
      	69.427	77.271	76.691  	69.068	75.218	80.321
      	72.473	76.978	80.643  	72.057	77.151	79.068
      
      avg	72.545	76.767	78.534 		70.425	74.2083	78.462
      std 	1.89	1.71	2.41    	1.66	2.34	1.00
      min 	69.427	73.986	75.855  	67.302	68.269	76.6
      max 	76.188	79.947	83.562  	72.616	77.151	80.321
      
      OK. the degression is disappeared.
      Signed-off-by: default avatarKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Acked-by: default avatarRik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      01dbe5c9
    • Rik van Riel's avatar
      vmscan: bail out of direct reclaim after swap_cluster_max pages · a79311c1
      Rik van Riel authored
      When the VM is under pressure, it can happen that several direct reclaim
      processes are in the pageout code simultaneously.  It also happens that
      the reclaiming processes run into mostly referenced, mapped and dirty
      pages in the first round.
      
      This results in multiple direct reclaim processes having a lower
      pageout priority, which corresponds to a higher target of pages to
      scan.
      
      This in turn can result in each direct reclaim process freeing
      many pages.  Together, they can end up freeing way too many pages.
      
      This kicks useful data out of memory (in some cases more than half
      of all memory is swapped out).  It also impacts performance by
      keeping tasks stuck in the pageout code for too long.
      
      A 30% improvement in hackbench has been observed with this patch.
      
      The fix is relatively simple: in shrink_zone() we can check how many
      pages we have already freed, direct reclaim tasks break out of the
      scanning loop if they have already freed enough pages and have reached
      a lower priority level.
      
      We do not break out of shrink_zone() when priority == DEF_PRIORITY,
      to ensure that equal pressure is applied to every zone in the common
      case.
      
      However, in order to do this we do need to know how many pages we already
      freed, so move nr_reclaimed into scan_control.
      
      akpm: a historical interlude...
      
      We tried this in 2004:
      
      :commit e468e46a9bea3297011d5918663ce6d19094cf87
      :Author: akpm <akpm>
      :Date:   Thu Jun 24 15:53:52 2004 +0000
      :
      :[PATCH] vmscan.c: dont reclaim too many pages
      :
      :    The shrink_zone() logic can, under some circumstances, cause far too many
      :    pages to be reclaimed.  Say, we're scanning at high priority and suddenly hit
      :    a large number of reclaimable pages on the LRU.
      :    Change things so we bale out when SWAP_CLUSTER_MAX pages have been reclaimed.
      
      And we reverted it in 2006:
      
      :commit 210fe530
      
      
      :Author: Andrew Morton <akpm@osdl.org>
      :Date:   Fri Jan 6 00:11:14 2006 -0800
      :
      :    [PATCH] vmscan: balancing fix
      :
      :    Revert a patch which went into 2.6.8-rc1.  The changelog for that patch was:
      :
      :      The shrink_zone() logic can, under some circumstances, cause far too many
      :      pages to be reclaimed.  Say, we're scanning at high priority and suddenly
      :      hit a large number of reclaimable pages on the LRU.
      :
      :      Change things so we bale out when SWAP_CLUSTER_MAX pages have been
      :      reclaimed.
      :
      :    Problem is, this change caused significant imbalance in inter-zone scan
      :    balancing by truncating scans of larger zones.
      :
      :    Suppose, for example, ZONE_HIGHMEM is 10x the size of ZONE_NORMAL.  The zone
      :    balancing algorithm would require that if we're scanning 100 pages of
      :    ZONE_HIGHMEM, we should scan 10 pages of ZONE_NORMAL.  But this logic will
      :    cause the scanning of ZONE_HIGHMEM to bale out after only 32 pages are
      :    reclaimed.  Thus effectively causing smaller zones to be scanned relatively
      :    harder than large ones.
      :
      :    Now I need to remember what the workload was which caused me to write this
      :    patch originally, then fix it up in a different way...
      
      And we haven't demonstrated that whatever problem caused that reversion is
      not being reintroduced by this change in 2008.
      Signed-off-by: default avatarRik van Riel <riel@redhat.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a79311c1
    • Hannes Eder's avatar
      hugetlb: fix sparse warnings · ebdd4aea
      Hannes Eder authored
      
      
      Fix the following sparse warnings:
      
        mm/hugetlb.c:375:3: warning: returning void-valued expression
        mm/hugetlb.c:408:3: warning: returning void-valued expression
      Signed-off-by: default avatarHannes Eder <hannes@hanneseder.net>
      Acked-by: default avatarNishanth Aravamudan <nacc@us.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ebdd4aea
    • Hugh Dickins's avatar
      swapfile: let others seed random · f0d7a4b3
      Hugh Dickins authored
      
      
      Remove the srandom32((u32)get_seconds()) from non-rotational swapon:
      there's been a coincidental discussion of earlier randomization, assume
      that goes ahead, let swapon be a client rather than stirring for itself.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Donjun Shin <djshin90@gmail.com>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Jens Axboe <jens.axboe@oracle.com>
      Cc: Joern Engel <joern@logfs.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: Tejun Heo <teheo@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f0d7a4b3
    • Hugh Dickins's avatar
      swapfile: change discard pgoff_t to sector_t · 858a2990
      Hugh Dickins authored
      
      
      Change pgoff_t nr_blocks in discard_swap() and discard_swap_cluster() to
      sector_t: given the constraints on swap offsets (in particular, the 5 bits
      of swap type accommodated in the same unsigned long), pgoff_t was actually
      safe as is, but it certainly looked worrying when shifted left.
      
      [akpm@linux-foundation.org: fix shift overflow]
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Jens Axboe <jens.axboe@oracle.com>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Joern Engel <joern@logfs.org>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Donjun Shin <djshin90@gmail.com>
      Cc: Tejun Heo <teheo@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      858a2990
    • Hugh Dickins's avatar
      swapfile: swap allocation cycle if nonrot · c60aa176
      Hugh Dickins authored
      
      
      Though attempting to find free clusters (Andrea), swap allocation has
      always restarted its searches from the beginning of the swap area (sct),
      to reduce seek times between swap pages, by not scattering them all over
      the partition.
      
      But on a solidstate swap device, seeks are cheap, and block remapping to
      level the wear may be limited by zones: in that case it's better to cycle
      around the whole partition.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Jens Axboe <jens.axboe@oracle.com>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Joern Engel <joern@logfs.org>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Donjun Shin <djshin90@gmail.com>
      Cc: Tejun Heo <teheo@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      c60aa176
    • Hugh Dickins's avatar
      swapfile: swapon randomize if nonrot · 20137a49
      Hugh Dickins authored
      
      
      Swap allocation has always started from the beginning of the swap area;
      but if we're dealing with a solidstate swap device which can only remap
      blocks within limited zones, that would sooner wear out the first zone.
      
      Therefore sys_swapon() test whether blk_queue is non-rotational, and if so
      randomize the cluster_next starting position for allocation.
      
      If blk_queue is nonrot, note SWP_SOLIDSTATE for later use, and report it
      with an "SS" at the right end of the kernel's "Adding ...  swap" message
      (so that if it's both nonrot and discardable, "SSD" will be shown there).
      Perhaps something should be shown in /proc/swaps (swapon -s), but we have
      to be more cautious before making any addition to that format.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Jens Axboe <jens.axboe@oracle.com>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Joern Engel <joern@logfs.org>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Donjun Shin <djshin90@gmail.com>
      Cc: Tejun Heo <teheo@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      20137a49
    • Hugh Dickins's avatar
      swapfile: swap allocation use discard · 7992fde7
      Hugh Dickins authored
      
      
      When scan_swap_map() finds a free cluster of swap pages to allocate,
      discard the old contents of the cluster if the device supports discard.
      But don't bother when swap is so fragmented that we allocate single pages.
      
      Be careful about racing allocations made while we're scanning for a
      cluster; and hold up allocations made while we're discarding.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Jens Axboe <jens.axboe@oracle.com>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Joern Engel <joern@logfs.org>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Donjun Shin <djshin90@gmail.com>
      Cc: Tejun Heo <teheo@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7992fde7
    • Hugh Dickins's avatar
      swapfile: swapon use discard (trim) · 6a6ba831
      Hugh Dickins authored
      
      
      When adding swap, all the old data on swap can be forgotten: sys_swapon()
      discard all but the header page of the swap partition (or every extent but
      the header of the swap file), to give a solidstate swap device the
      opportunity to optimize its wear-levelling.
      
      If that succeeds, note SWP_DISCARDABLE for later use, and report it with a
      "D" at the right end of the kernel's "Adding ...  swap" message.  Perhaps
      something should be shown in /proc/swaps (swapon -s), but we have to be
      more cautious before making any addition to that format.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Cc: David Woodhouse <dwmw2@infradead.org>
      Cc: Jens Axboe <jens.axboe@oracle.com>
      Cc: Matthew Wilcox <matthew@wil.cx>
      Cc: Joern Engel <joern@logfs.org>
      Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
      Cc: Donjun Shin <djshin90@gmail.com>
      Cc: Tejun Heo <teheo@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6a6ba831
    • Hugh Dickins's avatar
      swapfile: rearrange scan and swap_info · ebebbbe9
      Hugh Dickins authored
      
      
      Before making functional changes, rearrange scan_swap_map() to simplify
      subsequent diffs.  Actually, there is one functional change in there:
      leave cluster_nr negative while scanning for a new cluster - resetting it
      early increased the likelihood that when we have difficulty finding a free
      cluster, another task may come in and try doing exactly the same - just a
      waste of cpu.
      
      Before making functional changes, rearrange struct swap_info_struct
      slightly: flags will be needed as an unsigned long (for wait_on_bit), next
      is a good int to pair with prio, old_block_size is uninteresting so shift
      it to the end.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ebebbbe9
    • Hugh Dickins's avatar
      swapfile: remove v0 SWAP-SPACE message · 81e33971
      Hugh Dickins authored
      
      
      The kernel has not supported v0 SWAP-SPACE since 2.5.22: I think we can
      now safely drop its "version 0 swap is no longer supported" message - just
      say "Unable to find swap-space signature" as usual.  This removes one
      level of indentation from a stretch of sys_swapon().
      
      I'd have liked to be specific, saying "Unable to find SWAPSPACE2
      signature", but it's just too confusing that the version 1 signature shows
      the number 2.
      
      Irrelevant nearby cleanup: kmap(page) already gives page_address(page).
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Nick Piggin <nickpiggin@yahoo.com.au>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      81e33971