1. 31 Jul, 2012 2 commits
  2. 30 Jul, 2012 2 commits
  3. 24 Jul, 2012 1 commit
  4. 29 May, 2012 2 commits
  5. 20 Mar, 2012 1 commit
  6. 12 Jan, 2012 1 commit
  7. 10 Jan, 2012 1 commit
  8. 20 Dec, 2011 1 commit
  9. 09 Dec, 2011 1 commit
  10. 18 Nov, 2011 1 commit
    • Nicolas Pitre's avatar
      mm: add vm_area_add_early() · be9b7335
      Nicolas Pitre authored
      The existing vm_area_register_early() allows for early vmalloc space
      allocation.  However upcoming cleanups in the ARM architecture require
      that some fixed locations in the vmalloc area be reserved also very early.
      
      The name "vm_area_register_early" would have been a good name for the
      reservation part without the allocation.  Since it is already in use with
      different semantics, let's create vm_area_add_early() instead.
      
      Both vm_area_register_early() and vm_area_add_early() can be used together
      meaning that the former is now implemented using the later where it is
      ensured that no conflicting areas are added, but no attempt is made to
      make the allocation scheme in vm_area_register_early() more sophisticated.
      After all, you must know what you're doing when using those functions.
      Signed-off-by: default avatarNicolas Pitre <nicolas.pitre@linaro.org>
      Acked-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Cc: linux-mm@kvack.org
      be9b7335
  11. 16 Nov, 2011 1 commit
  12. 31 Oct, 2011 3 commits
  13. 14 Sep, 2011 1 commit
    • David Vrabel's avatar
      mm: sync vmalloc address space page tables in alloc_vm_area() · 461ae488
      David Vrabel authored
      Xen backend drivers (e.g., blkback and netback) would sometimes fail to
      map grant pages into the vmalloc address space allocated with
      alloc_vm_area().  The GNTTABOP_map_grant_ref would fail because Xen could
      not find the page (in the L2 table) containing the PTEs it needed to
      update.
      
      (XEN) mm.c:3846:d0 Could not find L1 PTE for address fbb42000
      
      netback and blkback were making the hypercall from a kernel thread where
      task->active_mm != &init_mm and alloc_vm_area() was only updating the page
      tables for init_mm.  The usual method of deferring the update to the page
      tables of other processes (i.e., after taking a fault) doesn't work as a
      fault cannot occur during the hypercall.
      
      This would work on some systems depending on what else was using vmalloc.
      
      Fix this by reverting ef691947 ("vmalloc: remove vmalloc_sync_all()
      from alloc_vm_area()") and add a comment to explain why it's needed.
      Signed-off-by: default avatarDavid Vrabel <david.vrabel@citrix.com>
      Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
      Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
      Cc: Ian Campbell <Ian.Campbell@citrix.com>
      Cc: Keir Fraser <keir.xen@gmail.com>
      Cc: <stable@kernel.org>		[3.0.x]
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      461ae488
  14. 14 Aug, 2011 1 commit
  15. 26 Jul, 2011 1 commit
  16. 20 Jul, 2011 2 commits
  17. 25 May, 2011 2 commits
    • Dave Hansen's avatar
      mm: print vmalloc() state after allocation failures · 22943ab1
      Dave Hansen authored
      I was tracking down a page allocation failure that ended up in vmalloc().
      Since vmalloc() uses 0-order pages, if somebody asks for an insane amount
      of memory, we'll still get a warning with "order:0" in it.  That's not
      very useful.
      
      During recovery, vmalloc() also nicely frees all of the memory that it got
      up to the point of the failure.  That is wonderful, but it also quickly
      hides any issues.  We have a much different sitation if vmalloc()
      repeatedly fails 10GB in to:
      
      	vmalloc(100 * 1<<30);
      
      versus repeatedly failing 4096 bytes in to a:
      
      	vmalloc(8192);
      
      This patch will print out messages that look like this:
      
      [   68.123503] vmalloc: allocation failure, allocated 6680576 of 13426688 bytes
      [   68.124218] bash: page allocation failure: order:0, mode:0xd2
      [   68.124811] Pid: 3770, comm: bash Not tainted 2.6.39-rc3-00082-g85f2e689-dirty #333
      [   68.125579] Call Trace:
      [   68.125853]  [<ffffffff810f6da6>] warn_alloc_failed+0x146/0x170
      [   68.126464]  [<ffffffff8107e05c>] ? printk+0x6c/0x70
      [   68.126791]  [<ffffffff8112b5d4>] ? alloc_pages_current+0x94/0xe0
      [   68.127661]  [<ffffffff8111ed37>] __vmalloc_node_range+0x237/0x290
      ...
      
      The 'order' variable is added for clarity when calling warn_alloc_failed()
      to avoid having an unexplained '0' as an argument.
      
      The 'tmp_mask' is because adding an open-coded '| __GFP_NOWARN' would take
      us over 80 columns for the alloc_pages_node() call.  If we are going to
      add a line, it might as well be one that makes the sucker easier to read.
      
      As a side issue, I also noticed that ctl_ioctl() does vmalloc() based
      solely on an unverified value passed in from userspace.  Granted, it's
      under CAP_SYS_ADMIN, but it still frightens me a bit.
      Signed-off-by: default avatarDave Hansen <dave@linux.vnet.ibm.com>
      Cc: Johannes Weiner <hannes@cmpxchg.org>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Michal Nazarewicz <mina86@mina86.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      22943ab1
    • Johannes Weiner's avatar
      mm/vmalloc: remove guard page from between vmap blocks · 248ac0e1
      Johannes Weiner authored
      The vmap allocator is used to, among other things, allocate per-cpu vmap
      blocks, where each vmap block is naturally aligned to its own size.
      Obviously, leaving a guard page after each vmap area forbids packing vmap
      blocks efficiently and can make the kernel run out of possible vmap blocks
      long before overall vmap space is exhausted.
      
      The new interface to map a user-supplied page array into linear vmalloc
      space (vm_map_ram) insists on allocating from a vmap block (instead of
      falling back to a custom area) when the area size is below a certain
      threshold.  With heavy users of this interface (e.g.  XFS) and limited
      vmalloc space on 32-bit, vmap block exhaustion is a real problem.
      
      Remove the guard page from the core vmap allocator.  vmalloc and the old
      vmap interface enforce a guard page on their own at a higher level.
      
      Note that without this patch, we had accidental guard pages after those
      vm_map_ram areas that happened to be at the end of a vmap block, but not
      between every area.  This patch removes this accidental guard page only.
      
      If we want guard pages after every vm_map_ram area, this should be done
      separately.  And just like with vmalloc and the old interface on a
      different level, not in the core allocator.
      
      Mel pointed out: "If necessary, the guard page could be reintroduced as a
      debugging-only option (CONFIG_DEBUG_PAGEALLOC?).  Otherwise it seems
      reasonable."
      Signed-off-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
      Cc: Nick Piggin <npiggin@kernel.dk>
      Cc: Dave Chinner <david@fromorbit.com>
      Acked-by: default avatarMel Gorman <mel@csn.ul.ie>
      Cc: Hugh Dickins <hughd@google.com>
      Cc: Christoph Hellwig <hch@infradead.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      248ac0e1
  18. 20 May, 2011 1 commit
  19. 22 Mar, 2011 2 commits
    • Namhyung Kim's avatar
      vmalloc: remove confusing comment on vwrite() · a42931bf
      Namhyung Kim authored
      KM_USER1 is never used for vwrite() path so the caller doesn't need to
      guarantee it is not used.  Only the caller should guarantee is KM_USER0
      and it is commented already.
      Signed-off-by: default avatarNamhyung Kim <namhyung@gmail.com>
      Acked-by: default avatarKAMEZAWA 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>
      a42931bf
    • Nick Piggin's avatar
      mm: vmap area cache · 89699605
      Nick Piggin authored
      Provide a free area cache for the vmalloc virtual address allocator, based
      on the algorithm used by the user virtual memory allocator.
      
      This reduces the number of rbtree operations and linear traversals over
      the vmap extents in order to find a free area, by starting off at the last
      point that a free area was found.
      
      The free area cache is reset if areas are freed behind it, or if we are
      searching for a smaller area or alignment than last time.  So allocation
      patterns are not changed (verified by corner-case and random test cases in
      userspace testing).
      
      This solves a regression caused by lazy vunmap TLB purging introduced in
      db64fe02 (mm: rewrite vmap layer).  That patch will leave extents in the
      vmap allocator after they are vunmapped, and until a significant number
      accumulate that can be flushed in a single batch.  So in a workload that
      vmalloc/vfree frequently, a chain of extents will build up from
      VMALLOC_START address, which have to be iterated over each time (giving an
      O(n) type of behaviour).
      
      After this patch, the search will start from where it left off, giving
      closer to an amortized O(1).
      
      This is verified to solve regressions reported Steven in GFS2, and Avi in
      KVM.
      
      Hugh's update:
      
      : I tried out the recent mmotm, and on one machine was fortunate to hit
      : the BUG_ON(first->va_start < addr) which seems to have been stalling
      : your vmap area cache patch ever since May.
      
      : I can get you addresses etc, I did dump a few out; but once I stared
      : at them, it was easier just to look at the code: and I cannot see how
      : you would be so sure that first->va_start < addr, once you've done
      : that addr = ALIGN(max(...), align) above, if align is over 0x1000
      : (align was 0x8000 or 0x4000 in the cases I hit: ioremaps like Steve).
      
      : I originally got around it by just changing the
      : 		if (first->va_start < addr) {
      : to
      : 		while (first->va_start < addr) {
      : without thinking about it any further; but that seemed unsatisfactory,
      : why would we want to loop here when we've got another very similar
      : loop just below it?
      
      : I am never going to admit how long I've spent trying to grasp your
      : "while (n)" rbtree loop just above this, the one with the peculiar
      : 		if (!first && tmp->va_start < addr + size)
      : in.  That's unfamiliar to me, I'm guessing it's designed to save a
      : subsequent rb_next() in a few circumstances (at risk of then setting
      : a wrong cached_hole_size?); but they did appear few to me, and I didn't
      : feel I could sign off something with that in when I don't grasp it,
      : and it seems responsible for extra code and mistaken BUG_ON below it.
      
      : I've reverted to the familiar rbtree loop that find_vma() does (but
      : with va_end >= addr as you had, to respect the additional guard page):
      : and then (given that cached_hole_size starts out 0) I don't see the
      : need for any complications below it.  If you do want to keep that loop
      : as you had it, please add a comment to explain what it's trying to do,
      : and where addr is relative to first when you emerge from it.
      
      : Aren't your tests "size <= cached_hole_size" and
      : "addr + size > first->va_start" forgetting the guard page we want
      : before the next area?  I've changed those.
      
      : I have not changed your many "addr + size - 1 < addr" overflow tests,
      : but have since come to wonder, shouldn't they be "addr + size < addr"
      : tests - won't the vend checks go wrong if addr + size is 0?
      
      : I have added a few comments - Wolfgang Wander's 2.6.13 description of
      : 1363c3cd Avoiding mmap fragmentation
      : helped me a lot, perhaps a pointer to that would be good too.  And I found
      : it easier to understand when I renamed cached_start slightly and moved the
      : overflow label down.
      
      : This patch would go after your mm-vmap-area-cache.patch in mmotm.
      : Trivially, nobody is going to get that BUG_ON with this patch, and it
      : appears to work fine on my machines; but I have not given it anything like
      : the testing you did on your original, and may have broken all the
      : performance you were aiming for.  Please take a look and test it out
      : integrate with yours if you're satisfied - thanks.
      
      [akpm@linux-foundation.org: add locking comment]
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Signed-off-by: default avatarHugh Dickins <hughd@google.com>
      Reviewed-by: default avatarMinchan Kim <minchan.kim@gmail.com>
      Reported-and-tested-by: default avatarSteven Whitehouse <swhiteho@redhat.com>
      Reported-and-tested-by: default avatarAvi Kivity <avi@redhat.com>
      Tested-by: default avatar"Barry J. Marson" <bmarson@redhat.com>
      Cc: Prarit Bhargava <prarit@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      89699605
  20. 13 Jan, 2011 5 commits
  21. 12 Jan, 2011 1 commit
    • Huang Ying's avatar
      ACPI, APEI, Generic Hardware Error Source POLL/IRQ/NMI notification type support · 81e88fdc
      Huang Ying authored
      Generic Hardware Error Source provides a way to report platform
      hardware errors (such as that from chipset). It works in so called
      "Firmware First" mode, that is, hardware errors are reported to
      firmware firstly, then reported to Linux by firmware. This way, some
      non-standard hardware error registers or non-standard hardware link
      can be checked by firmware to produce more valuable hardware error
      information for Linux.
      
      This patch adds POLL/IRQ/NMI notification types support.
      
      Because the memory area used to transfer hardware error information
      from BIOS to Linux can be determined only in NMI, IRQ or timer
      handler, but general ioremap can not be used in atomic context, so a
      special version of atomic ioremap is implemented for that.
      
      Known issue:
      
      - Error information can not be printed for recoverable errors notified
        via NMI, because printk is not NMI-safe. Will fix this via delay
        printing to IRQ context via irq_work or make printk NMI-safe.
      
      v2:
      
      - adjust printk format per comments.
      Signed-off-by: default avatarHuang Ying <ying.huang@intel.com>
      Reviewed-by: default avatarAndi Kleen <ak@linux.intel.com>
      Signed-off-by: default avatarLen Brown <len.brown@intel.com>
      81e88fdc
  22. 02 Dec, 2010 1 commit
    • Jeremy Fitzhardinge's avatar
      vmalloc: eagerly clear ptes on vunmap · 64141da5
      Jeremy Fitzhardinge authored
      On stock 2.6.37-rc4, running:
      
        # mount lilith:/export /mnt/lilith
        # find  /mnt/lilith/ -type f -print0 | xargs -0 file
      
      crashes the machine fairly quickly under Xen.  Often it results in oops
      messages, but the couple of times I tried just now, it just hung quietly
      and made Xen print some rude messages:
      
          (XEN) mm.c:2389:d80 Bad type (saw 7400000000000001 != exp
          3000000000000000) for mfn 1d7058 (pfn 18fa7)
          (XEN) mm.c:964:d80 Attempt to create linear p.t. with write perms
          (XEN) mm.c:2389:d80 Bad type (saw 7400000000000010 != exp
          1000000000000000) for mfn 1d2e04 (pfn 1d1fb)
          (XEN) mm.c:2965:d80 Error while pinning mfn 1d2e04
      
      Which means the domain tried to map a pagetable page RW, which would
      allow it to map arbitrary memory, so Xen stopped it.  This is because
      vm_unmap_ram() left some pages mapped in the vmalloc area after NFS had
      finished with them, and those pages got recycled as pagetable pages
      while still having these RW aliases.
      
      Removing those mappings immediately removes the Xen-visible aliases, and
      so it has no problem with those pages being reused as pagetable pages.
      Deferring the TLB flush doesn't upset Xen because it can flush the TLB
      itself as needed to maintain its invariants.
      
      When unmapping a region in the vmalloc space, clear the ptes
      immediately.  There's no point in deferring this because there's no
      amortization benefit.
      
      The TLBs are left dirty, and they are flushed lazily to amortize the
      cost of the IPIs.
      
      This specific motivation for this patch is an oops-causing regression
      since 2.6.36 when using NFS under Xen, triggered by the NFS client's use
      of vm_map_ram() introduced in 56e4ebf8 ("NFS: readdir with vmapped
      pages") .  XFS also uses vm_map_ram() and could cause similar problems.
      Signed-off-by: default avatarJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
      Cc: Nick Piggin <npiggin@kernel.dk>
      Cc: Bryan Schumaker <bjschuma@netapp.com>
      Cc: Trond Myklebust <Trond.Myklebust@netapp.com>
      Cc: Alex Elder <aelder@sgi.com>
      Cc: Dave Chinner <david@fromorbit.com>
      Cc: Christoph Hellwig <hch@lst.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      64141da5
  23. 26 Oct, 2010 3 commits
  24. 02 Oct, 2010 1 commit
  25. 17 Sep, 2010 1 commit
    • Cliff Wickman's avatar
      mm, x86: Saving vmcore with non-lazy freeing of vmas · 3ee48b6a
      Cliff Wickman authored
      During the reading of /proc/vmcore the kernel is doing
      ioremap()/iounmap() repeatedly. And the buildup of un-flushed
      vm_area_struct's is causing a great deal of overhead. (rb_next()
      is chewing up most of that time).
      
      This solution is to provide function set_iounmap_nonlazy(). It
      causes a subsequent call to iounmap() to immediately purge the
      vma area (with try_purge_vmap_area_lazy()).
      
      With this patch we have seen the time for writing a 250MB
      compressed dump drop from 71 seconds to 44 seconds.
      Signed-off-by: default avatarCliff Wickman <cpw@sgi.com>
      Cc: Andrew Morton <akpm@linux-foundation.org>
      Cc: kexec@lists.infradead.org
      Cc: <stable@kernel.org>
      LKML-Reference: <E1OwHZ4-0005WK-Tw@eag09.americas.sgi.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      3ee48b6a
  26. 08 Sep, 2010 1 commit