1. 28 Apr, 2008 40 commits
    • Yasunori Goto's avatar
      memory hotplug: make alloc_bootmem_section() · e70260aa
      Yasunori Goto authored
      
      
      alloc_bootmem_section() can allocate specified section's area.  This is used
      for usemap to keep same section with pgdat by later patch.
      Signed-off-by: default avatarYasunori Goto <y-goto@jp.fujitsu.com>
      Cc: Badari Pulavarty <pbadari@us.ibm.com>
      Cc: Yinghai Lu <yhlu.kernel@gmail.com>
      Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e70260aa
    • Yasunori Goto's avatar
      memory hotplug: align memmap to page size · 9d99217a
      Yasunori Goto authored
      
      
      To free memmap easier, this patch aligns it to page size.  Bootmem allocater
      may mix some objects in one pages.  It's not good for freeing memmap of memory
      hot-remove.
      Signed-off-by: default avatarYasunori Goto <y-goto@jp.fujitsu.com>
      Cc: Badari Pulavarty <pbadari@us.ibm.com>
      Cc: Yinghai Lu <yhlu.kernel@gmail.com>
      Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9d99217a
    • Yasunori Goto's avatar
      memory hotplug: register section/node id to free · 04753278
      Yasunori Goto authored
      
      
      This patch set is to free pages which is allocated by bootmem for
      memory-hotremove.  Some structures of memory management are allocated by
      bootmem.  ex) memmap, etc.
      
      To remove memory physically, some of them must be freed according to
      circumstance.  This patch set makes basis to free those pages, and free
      memmaps.
      
      Basic my idea is using remain members of struct page to remember information
      of users of bootmem (section number or node id).  When the section is
      removing, kernel can confirm it.  By this information, some issues can be
      solved.
      
        1) When the memmap of removing section is allocated on other
           section by bootmem, it should/can be free.
        2) When the memmap of removing section is allocated on the
           same section, it shouldn't be freed. Because the section has to be
           logical memory offlined already and all pages must be isolated against
           page allocater. If it is freed, page allocator may use it which will
           be removed physically soon.
        3) When removing section has other section's memmap,
           kernel will be able to show easily which section should be removed
           before it for user. (Not implemented yet)
        4) When the above case 2), the page isolation will be able to check and skip
           memmap's page when logical memory offline (offline_pages()).
           Current page isolation code fails in this case because this page is
           just reserved page and it can't distinguish this pages can be
           removed or not. But, it will be able to do by this patch.
           (Not implemented yet.)
        5) The node information like pgdat has similar issues. But, this
           will be able to be solved too by this.
           (Not implemented yet, but, remembering node id in the pages.)
      
      Fortunately, current bootmem allocator just keeps PageReserved flags,
      and doesn't use any other members of page struct. The users of
      bootmem doesn't use them too.
      
      This patch:
      
      This is to register information which is node or section's id.  Kernel can
      distinguish which node/section uses the pages allcated by bootmem.  This is
      basis for hot-remove sections or nodes.
      Signed-off-by: default avatarYasunori Goto <y-goto@jp.fujitsu.com>
      Cc: Badari Pulavarty <pbadari@us.ibm.com>
      Cc: Yinghai Lu <yhlu.kernel@gmail.com>
      Cc: Yasunori Goto <y-goto@jp.fujitsu.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      04753278
    • Gerald Schaefer's avatar
      hugetlbfs: common code update for s390 · 7f2e9525
      Gerald Schaefer authored
      
      
      Huge ptes have a special type on s390 and cannot be handled with the standard
      pte functions in certain cases, e.g.  because of a different location of the
      invalid bit.  This patch adds some new architecture- specific functions to
      hugetlb common code, as a prerequisite for the s390 large page support.
      
      This won't affect other architectures in functionality, but I need to add some
      new dummy inline functions to the headers.
      Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: "Luck, Tony" <tony.luck@intel.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "David S. Miller" <davem@davemloft.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7f2e9525
    • Gerald Schaefer's avatar
      hugetlbfs: add missing TLB flush to hugetlb_cow() · 8fe627ec
      Gerald Schaefer authored
      
      
      A cow break on a hugetlbfs page with page_count > 1 will set a new pte with
      set_huge_pte_at(), w/o any tlb flush operation.  The old pte will remain in
      the tlb and subsequent write access to the page will result in a page fault
      loop, for as long as it may take until the tlb is flushed from somewhere else.
       This patch introduces an architecture-specific huge_ptep_clear_flush()
      function, which is called before the the set_huge_pte_at() in hugetlb_cow().
      
      ATTENTION: This is just a nop on all architectures for now, the s390
      implementation will come with our large page patch later.  Other architectures
      should define their own huge_ptep_clear_flush() if needed.
      Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: "Luck, Tony" <tony.luck@intel.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "David S. Miller" <davem@davemloft.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      8fe627ec
    • Gerald Schaefer's avatar
      hugetlbfs: architecture header cleanup · 6d779079
      Gerald Schaefer authored
      
      
      This patch moves all architecture functions for hugetlb to architecture header
      files (include/asm-foo/hugetlb.h) and converts all macros to inline functions.
       It also removes (!) ARCH_HAS_HUGEPAGE_ONLY_RANGE,
      ARCH_HAS_HUGETLB_FREE_PGD_RANGE, ARCH_HAS_PREPARE_HUGEPAGE_RANGE,
      ARCH_HAS_SETCLEAR_HUGE_PTE and ARCH_HAS_HUGETLB_PREFAULT_HOOK.
      
      Getting rid of the ARCH_HAS_xxx #ifdef and macro fugliness should increase
      readability and maintainability, at the price of some code duplication.  An
      asm-generic common part would have reduced the loc, but we would end up with
      new ARCH_HAS_xxx defines eventually.
      Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarGerald Schaefer <gerald.schaefer@de.ibm.com>
      Cc: Paul Mundt <lethal@linux-sh.org>
      Cc: "Luck, Tony" <tony.luck@intel.com>
      Cc: Ingo Molnar <mingo@elte.hu>
      Cc: Thomas Gleixner <tglx@linutronix.de>
      Cc: "David S. Miller" <davem@davemloft.net>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6d779079
    • Lee Schermerhorn's avatar
      mempolicy: use struct mempolicy pointer in shmem_sb_info · 71fe804b
      Lee Schermerhorn authored
      
      
      This patch replaces the mempolicy mode, mode_flags, and nodemask in the
      shmem_sb_info struct with a struct mempolicy pointer, initialized to NULL.
      This removes dependency on the details of mempolicy from shmem.c and hugetlbfs
      inode.c and simplifies the interfaces.
      
      mpol_parse_str() in mempolicy.c is changed to return, via a pointer to a
      pointer arg, a struct mempolicy pointer on success.  For MPOL_DEFAULT, the
      returned pointer is NULL.  Further, mpol_parse_str() now takes a 'no_context'
      argument that causes the input nodemask to be stored in the w.user_nodemask of
      the created mempolicy for use when the mempolicy is installed in a tmpfs inode
      shared policy tree.  At that time, any cpuset contextualization is applied to
      the original input nodemask.  This preserves the previous behavior where the
      input nodemask was stored in the superblock.  We can think of the returned
      mempolicy as "context free".
      
      Because mpol_parse_str() is now calling mpol_new(), we can remove from
      mpol_to_str() the semantic checks that mpol_new() already performs.
      
      Add 'no_context' parameter to mpol_to_str() to specify that it should format
      the nodemask in w.user_nodemask for 'bind' and 'interleave' policies.
      
      Change mpol_shared_policy_init() to take a pointer to a "context free" struct
      mempolicy and to create a new, "contextualized" mempolicy using the mode,
      mode_flags and user_nodemask from the input mempolicy.
      
        Note: we know that the mempolicy passed to mpol_to_str() or
        mpol_shared_policy_init() from a tmpfs superblock is "context free".  This
        is currently the only instance thereof.  However, if we found more uses for
        this concept, and introduced any ambiguity as to whether a mempolicy was
        context free or not, we could add another internal mode flag to identify
        context free mempolicies.  Then, we could remove the 'no_context' argument
        from mpol_to_str().
      
      Added shmem_get_sbmpol() to return a reference counted superblock mempolicy,
      if one exists, to pass to mpol_shared_policy_init().  We must add the
      reference under the sb stat_lock to prevent races with replacement of the mpol
      by remount.  This reference is removed in mpol_shared_policy_init().
      
      [akpm@linux-foundation.org: build fix]
      [akpm@linux-foundation.org: another build fix]
      [akpm@linux-foundation.org: yet another build fix]
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      71fe804b
    • Lee Schermerhorn's avatar
      mempolicy: support mpol=local tmpfs mount option · 3f226aa1
      Lee Schermerhorn authored
      
      
      For tmpfs/shmem shared policies, MPOL_DEFAULT is not necessarily equivalent to
      "local allocation".  Because shared policies are at the same "scope" level
      [see Documentation/vm/numa_memory_policy.txt], as vma policies MPOL_DEFAULT
      means "fall back to current task policy".
      
      This patch extends the memory policy string parsing function to display
      "local" for MPOL_PREFERRED + MPOL_F_LOCAL.  This allows one to specify local
      allocation as the default policy for shared memory areas via the tmpfs mpol
      mount option, regardless of the current task's policy.
      
      Also, "local" is now displayed for this policy.  This patch allows us to
      accept the same input format as the display.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      3f226aa1
    • Lee Schermerhorn's avatar
      mempolicy: rework shmem mpol parsing and display · 095f1fc4
      Lee Schermerhorn authored
      
      
      mm/shmem.c currently contains functions to parse and display memory policy
      strings for the tmpfs 'mpol' mount option.  Move this to mm/mempolicy.c with
      the rest of the mempolicy support.  With subsequent patches, we'll be able to
      remove knowledge of the details [mode, flags, policy, ...] completely from
      shmem.c
      
      1) replace shmem_parse_mpol() in mm/shmem.c with mpol_parse_str() in
         mm/mempolicy.c.  Rework to use the policy_types[] array [used by
         mpol_to_str()] to look up mode by name.
      
      2) use mpol_to_str() to format policy for shmem_show_mpol().  mpol_to_str()
         expects a pointer to a struct mempolicy, so temporarily construct one.
         This will be replaced with a reference to a struct mempolicy in the tmpfs
         superblock in a subsequent patch.
      
         NOTE 1: I changed mpol_to_str() to use a colon ':' rather than an equal
         sign '=' as the nodemask delimiter to match mpol_parse_str() and the
         tmpfs/shmem mpol mount option formatting that now uses mpol_to_str().  This
         is a user visible change to numa_maps, but then the addition of the mode
         flags already changed the display.  It makes sense to me to have the mounts
         and numa_maps display the policy in the same format.  However, if anyone
         objects strongly, I can pass the desired nodemask delimeter as an arg to
         mpol_to_str().
      
         Note 2: Like show_numa_map(), I don't check the return code from
         mpol_to_str().  I do use a longer buffer than the one provided by
         show_numa_map(), which seems to have sufficed so far.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      095f1fc4
    • Lee Schermerhorn's avatar
      mempolicy: clean-up mpol-to-str() mempolicy formatting · 2291990a
      Lee Schermerhorn authored
      
      
      mpol-to-str() formats memory policies into printable strings.  Currently this
      is only used to display "numa_maps".  A subsequent patch will use
      mpol_to_str() for formatting tmpfs [shmem] mpol mount options, allowing us to
      remove essentially duplicate code in mm/shmem.c.  This patch cleans up
      mpol_to_str() generally and in preparation for that patch.
      
      1) show_numa_maps() is not checking the return code from mpol_to_str().
         There's not a lot we can do in this context if mpol_to_str() did return the
         error [insufficient space in buffer].  Proposed "solution": just check,
         under DEBUG_VM, that callers are providing sufficient buffer space for the
         policy, flags, and a few nodes.  This way, we'll get some display.
         show_numa_maps() is providing a 50-byte buffer, so it won't trip this
         check.  50-bytes should be sufficient unless one has a large number of
         nodes in a very sparse nodemask.
      
      2) The display of the new mode flags ["static" & "relative"] was set up to
         display multiple flags, separated by a "bar" '|'.  However, this support is
         incomplete--e.g., need_bar was never incremented; and currently, these two
         flags are mutually exclusive.  So remove the "bar" support, for now, and
         only display one flag.
      
      3) Use snprint() to format flags, so as not to overflow the buffer.  Not
         that it's ever happed, AFAIK.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      2291990a
    • Lee Schermerhorn's avatar
      mempolicy: use MPOL_F_LOCAL to Indicate Preferred Local Policy · fc36b8d3
      Lee Schermerhorn authored
      
      
      Now that we're using "preferred local" policy for system default, we need to
      make this as fast as possible.  Because of the variable size of the mempolicy
      structure [based on size of nodemasks], the preferred_node may be in a
      different cacheline from the mode.  This can result in accessing an extra
      cacheline in the normal case of system default policy.  Suspect this is the
      cause of an observed 2-3% slowdown in page fault testing relative to kernel
      without this patch series.
      
      To alleviate this, use an internal mode flag, MPOL_F_LOCAL in the mempolicy
      flags member which is guaranteed [?] to be in the same cacheline as the mode
      itself.
      
      Verified that reworked mempolicy now performs slightly better on 25-rc8-mm1
      for both anon and shmem segments with system default and vma [preferred local]
      policy.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      fc36b8d3
    • Lee Schermerhorn's avatar
      mempolicy: mPOL_PREFERRED cleanups for "local allocation" · 53f2556b
      Lee Schermerhorn authored
      
      
      Here are a couple of "cleanups" for MPOL_PREFERRED behavior when
      v.preferred_node < 0 -- i.e., "local allocation":
      
      1)  [do_]get_mempolicy() calls the now renamed get_policy_nodemask()
          to fetch the nodemask associated with a policy.  Currently,
          get_policy_nodemask() returns the set of nodes with memory, when
          the policy 'mode' is 'PREFERRED, and the preferred_node is < 0.
          Change to return an empty nodemask, as this is what was specified
          to achieve "local allocation".
      
      2)  When a task is moved into a [new] cpuset, mpol_rebind_policy() is
          called to adjust any task and vma policy nodes to be valid in the
          new cpuset.  However, when the policy is MPOL_PREFERRED, and the
          preferred_node is <0, no rebind is necessary.  The "local allocation"
          indication is valid in any cpuset.  Existing code will "do the right
          thing" because node_remap() will just return the argument node when
          it is outside of the valid range of node ids.  However, I think it is
          clearer and cleaner to skip the remap explicitly in this case.
      
      3)  mpol_to_str() produces a printable, "human readable" string from a
          struct mempolicy.  For MPOL_PREFERRED with preferred_node <0,  show
          "local", as this indicates local allocation, as the task migrates
          among nodes.  Note that this matches the usage of "local allocation"
          in libnuma() and numactl.  Without this change, I believe that node_set()
          [via set_bit()] will set bit 31, resulting in a misleading display.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      53f2556b
    • Lee Schermerhorn's avatar
      mempolicy: use MPOL_PREFERRED for system-wide default policy · bea904d5
      Lee Schermerhorn authored
      
      
      Currently, when one specifies MPOL_DEFAULT via a NUMA memory policy API
      [set_mempolicy(), mbind() and internal versions], the kernel simply installs a
      NULL struct mempolicy pointer in the appropriate context: task policy, vma
      policy, or shared policy.  This causes any use of that policy to "fall back"
      to the next most specific policy scope.
      
      The only use of MPOL_DEFAULT to mean "local allocation" is in the system
      default policy.  This requires extra checks/cases for MPOL_DEFAULT in many
      mempolicy.c functions.
      
      There is another, "preferred" way to specify local allocation via the APIs.
      That is using the MPOL_PREFERRED policy mode with an empty nodemask.
      Internally, the empty nodemask gets converted to a preferred_node id of '-1'.
      All internal usage of MPOL_PREFERRED will convert the '-1' to the id of the
      node local to the cpu where the allocation occurs.
      
      System default policy, except during boot, is hard-coded to "local
      allocation".  By using the MPOL_PREFERRED mode with a negative value of
      preferred node for system default policy, MPOL_DEFAULT will never occur in the
      'policy' member of a struct mempolicy.  Thus, we can remove all checks for
      MPOL_DEFAULT when converting policy to a node id/zonelist in the allocation
      paths.
      
      In slab_node() return local node id when policy pointer is NULL.  No need to
      set a pol value to take the switch default.  Replace switch default with
      BUG()--i.e., shouldn't happen.
      
      With this patch MPOL_DEFAULT is only used in the APIs, including internal
      calls to do_set_mempolicy() and in the display of policy in
      /proc/<pid>/numa_maps.  It always means "fall back" to the the next most
      specific policy scope.  This simplifies the description of memory policies
      quite a bit, with no visible change in behavior.
      
      get_mempolicy() continues to return MPOL_DEFAULT and an empty nodemask when
      the requested policy [task or vma/shared] is NULL.  These are the values one
      would supply via set_mempolicy() or mbind() to achieve that condition--default
      behavior.
      
      This patch updates Documentation to reflect this change.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      bea904d5
    • Lee Schermerhorn's avatar
      mempolicy: rework mempolicy Reference Counting [yet again] · 52cd3b07
      Lee Schermerhorn authored
      
      
      After further discussion with Christoph Lameter, it has become clear that my
      earlier attempts to clean up the mempolicy reference counting were a bit of
      overkill in some areas, resulting in superflous ref/unref in what are usually
      fast paths.  In other areas, further inspection reveals that I botched the
      unref for interleave policies.
      
      A separate patch, suitable for upstream/stable trees, fixes up the known
      errors in the previous attempt to fix reference counting.
      
      This patch reworks the memory policy referencing counting and, one hopes,
      simplifies the code.  Maybe I'll get it right this time.
      
      See the update to the numa_memory_policy.txt document for a discussion of
      memory policy reference counting that motivates this patch.
      
      Summary:
      
      Lookup of mempolicy, based on (vma, address) need only add a reference for
      shared policy, and we need only unref the policy when finished for shared
      policies.  So, this patch backs out all of the unneeded extra reference
      counting added by my previous attempt.  It then unrefs only shared policies
      when we're finished with them, using the mpol_cond_put() [conditional put]
      helper function introduced by this patch.
      
      Note that shmem_swapin() calls read_swap_cache_async() with a dummy vma
      containing just the policy.  read_swap_cache_async() can call alloc_page_vma()
      multiple times, so we can't let alloc_page_vma() unref the shared policy in
      this case.  To avoid this, we make a copy of any non-null shared policy and
      remove the MPOL_F_SHARED flag from the copy.  This copy occurs before reading
      a page [or multiple pages] from swap, so the overhead should not be an issue
      here.
      
      I introduced a new static inline function "mpol_cond_copy()" to copy the
      shared policy to an on-stack policy and remove the flags that would require a
      conditional free.  The current implementation of mpol_cond_copy() assumes that
      the struct mempolicy contains no pointers to dynamically allocated structures
      that must be duplicated or reference counted during copy.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      52cd3b07
    • Lee Schermerhorn's avatar
      mempolicy: document {set|get}_policy() vm_ops APIs · a6020ed7
      Lee Schermerhorn authored
      
      
      Document mempolicy return value reference semantics assumed by the rest of the
      mempolicy code for the set_ and get_policy vm_ops in <linux/mm.h>--where the
      prototypes are defined--to inform any future mempolicy vm_op writers what the
      rest of the subsystem expects of them.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a6020ed7
    • Lee Schermerhorn's avatar
      mempolicy: mark shared policies for unref · aab0b102
      Lee Schermerhorn authored
      
      
      As part of yet another rework of mempolicy reference counting, we want to be
      able to identify shared policies efficiently, because they have an extra ref
      taken on lookup that needs to be removed when we're finished using the policy.
      
        Note:  the extra ref is required because the policies are
        shared between tasks/processes and can be changed/freed
        by one task while another task is using them--e.g., for
        page allocation.
      
      Building on David Rientjes mempolicy "mode flags" enhancement, this patch
      indicates a "shared" policy by setting a new MPOL_F_SHARED flag in the flags
      member of the struct mempolicy added by David.  MPOL_F_SHARED, and any future
      "internal mode flags" are reserved from bit zero up, as they will never be
      passed in the upper bits of the mode argument of a mempolicy API.
      
      I set the MPOL_F_SHARED flag when the policy is installed in the shared policy
      rb-tree.  Don't need/want to clear the flag when removing from the tree as the
      mempolicy is freed [unref'd] internally to the sp_delete() function.  However,
      a task could hold another reference on this mempolicy from a prior lookup.  We
      need the MPOL_F_SHARED flag to stay put so that any tasks holding a ref will
      unref, eventually freeing, the mempolicy.
      
      A later patch in this series will introduce a function to conditionally unref
      [mpol_free] a policy.  The MPOL_F_SHARED flag is one reason [currently the
      only reason] to unref/free a policy via the conditional free.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      aab0b102
    • Lee Schermerhorn's avatar
      mempolicy: rename struct mempolicy 'policy' member to 'mode' · 45c4745a
      Lee Schermerhorn authored
      
      
      The terms 'policy' and 'mode' are both used in various places to describe the
      semantics of the value stored in the 'policy' member of struct mempolicy.
      Furthermore, the term 'policy' is used to refer to that member, to the entire
      struct mempolicy and to the more abstract concept of the tuple consisting of a
      "mode" and an optional node or set of nodes.  Recently, we have added "mode
      flags" that are passed in the upper bits of the 'mode' [or sometimes,
      'policy'] member of the numa APIs.
      
      I'd like to resolve this confusion, which perhaps only exists in my mind, by
      renaming the 'policy' member to 'mode' throughout, and fixing up the
      Documentation.  Man pages will be updated separately.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      45c4745a
    • Lee Schermerhorn's avatar
      mempolicy: fixup Fallback for Default Shmem Policy · ae4d8c16
      Lee Schermerhorn authored
      
      
      get_vma_policy() is not handling fallback to task policy correctly when the
      get_policy() vm_op returns NULL.  The NULL overwrites the 'pol' variable that
      was holding the fallback task mempolicy.  So, it was falling back directly to
      system default policy.
      
      Fix get_vma_policy() to use only non-NULL policy returned from the vma
      get_policy op.
      
      shm_get_policy() was falling back to current task's mempolicy if the "backing
      file system" [tmpfs vs hugetlbfs] does not support the get_policy vm_op and
      the vma policy is null.  This is incorrect for show_numa_maps() which is
      likely querying the numa_maps of some task other than current.  Remove this
      fallback.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ae4d8c16
    • Lee Schermerhorn's avatar
      mempolicy: write lock mmap_sem while changing task mempolicy · f4e53d91
      Lee Schermerhorn authored
      
      
      A read of /proc/<pid>/numa_maps holds the target task's mmap_sem for read
      while examining each vma's mempolicy.  A vma's mempolicy can fall back to the
      task's policy.  However, the task could be changing it's task policy and free
      the one that the show_numa_maps() is examining.
      
      To prevent this, grab the mmap_sem for write when updating task mempolicy.
      Pointed out to me by Christoph Lameter and extracted and reworked from
      Christoph's alternative mempol reference counting patch.
      
      This is analogous to the way that do_mbind() and do_get_mempolicy() prevent
      races between task's sharing an mm_struct [a.k.a.  threads] setting and
      querying a mempolicy for a particular address.
      
      Note: this is necessary, but not sufficient, to allow us to stop taking an
      extra reference on "other task's mempolicy" in get_vma_policy.  Subsequent
      patches will complete this update, allowing us to simplify the tests for
      whether we need to unref a mempolicy at various points in the code.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f4e53d91
    • Lee Schermerhorn's avatar
      mempolicy: rename mpol_copy to mpol_dup · 846a16bf
      Lee Schermerhorn authored
      
      
      This patch renames mpol_copy() to mpol_dup() because, well, that's what it
      does.  Like, e.g., strdup() for strings, mpol_dup() takes a pointer to an
      existing mempolicy, allocates a new one and copies the contents.
      
      In a later patch, I want to use the name mpol_copy() to copy the contents from
      one mempolicy to another like, e.g., strcpy() does for strings.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      846a16bf
    • Lee Schermerhorn's avatar
      mempolicy: rename mpol_free to mpol_put · f0be3d32
      Lee Schermerhorn authored
      
      
      This is a change that was requested some time ago by Mel Gorman.  Makes sense
      to me, so here it is.
      
      Note: I retain the name "mpol_free_shared_policy()" because it actually does
      free the shared_policy, which is NOT a reference counted object.  However, ...
      
      The mempolicy object[s] referenced by the shared_policy are reference counted,
      so mpol_put() is used to release the reference held by the shared_policy.  The
      mempolicy might not be freed at this time, because some task attached to the
      shared object associated with the shared policy may be in the process of
      allocating a page based on the mempolicy.  In that case, the task performing
      the allocation will hold a reference on the mempolicy, obtained via
      mpol_shared_policy_lookup().  The mempolicy will be freed when all tasks
      holding such a reference have called mpol_put() for the mempolicy.
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: David Rientjes <rientjes@google.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Andi Kleen <ak@suse.de>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f0be3d32
    • Adam Litke's avatar
      Subject: [PATCH] hugetlb: vmstat events for huge page allocations · 3b116300
      Adam Litke authored
      
      
      Allocating huge pages directly from the buddy allocator is not guaranteed to
      succeed.  Success depends on several factors (such as the amount of physical
      memory available and the level of fragmentation).  With the addition of
      dynamic hugetlb pool resizing, allocations can occur much more frequently.
      For these reasons it is desirable to keep track of huge page allocation
      successes and failures.
      
      Add two new vmstat entries to track huge page allocations that succeed and
      fail.  The presence of the two entries is contingent upon CONFIG_HUGETLB_PAGE
      being enabled.
      
      [akpm@linux-foundation.org: reduced ifdeffery]
      Signed-off-by: default avatarAdam Litke <agl@us.ibm.com>
      Signed-off-by: default avatarEric Munson <ebmunson@us.ibm.com>
      Tested-by: default avatarMel Gorman <mel@csn.ul.ie>
      Reviewed-by: default avatarAndy Whitcroft <apw@shadowen.org>
      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>
      3b116300
    • Ken'ichi Ohmichi's avatar
      vmcoreinfo: add page flags values · 122c7a59
      Ken'ichi Ohmichi authored
      Add some values of page flags to the vmcoreinfo data.
      
      The vmcoreinfo data has the minimum debugging information only for dump
      filtering.  makedumpfile (dump filtering command) gets it to distinguish
      unnecessary pages, and makedumpfile creates a small dumpfile.
      
      An old makedumpfile (v1.2.4 or before) had assumed some values of page flags
      internally, and this implementation could not follow the change of these
      values.  For example, Christoph Lameter is changing these values by the
      follwing patch: http://lkml.org/lkml/2008/2/29/463
      
      
      
      So a new makedumpfile (v1.2.5) came to need these values and I created this
      patch to let the kernel output them.
      Signed-off-by: default avatarKen'ichi Ohmichi <oomichi@mxs.nes.nec.co.jp>
      Cc: Christoph Lameter <clameter@sgi.com>
      Cc: "Eric W. Biederman" <ebiederm@xmission.com>
      Acked-by: default avatarVivek Goyal <vgoyal@redhat.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      122c7a59
    • Nick Piggin's avatar
      s390: implement pte special bit · a08cb629
      Nick Piggin authored
      
      
      Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for
      the user mappings.
      
      This requires the get_xip_page API to be changed to an address based one.
      Improve the API layering a little bit too, while we're here.
      
      This is required in order to support XIP filesystems on memory that isn't
      backed with struct page (but memory with struct page is still supported too).
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Acked-by: default avatarCarsten Otte <cotte@de.ibm.com>
      Cc: Jared Hulbert <jaredeh@gmail.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      a08cb629
    • Nick Piggin's avatar
      xip: support non-struct page backed memory · 70688e4d
      Nick Piggin authored
      
      
      Convert XIP to support non-struct page backed memory, using VM_MIXEDMAP for
      the user mappings.
      
      This requires the get_xip_page API to be changed to an address based one.
      Improve the API layering a little bit too, while we're here.
      
      This is required in order to support XIP filesystems on memory that isn't
      backed with struct page (but memory with struct page is still supported too).
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Acked-by: default avatarCarsten Otte <cotte@de.ibm.com>
      Cc: Jared Hulbert <jaredeh@gmail.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      70688e4d
    • Jared Hulbert's avatar
      return pfn from direct_access, for XIP · 30afcb4b
      Jared Hulbert authored
      
      
      Alter the block device ->direct_access() API to work with the new
      get_xip_mem() API (that requires both kaddr and pfn are returned).
      
      Some architectures will not do the right thing in their virt_to_page() for use
      by XIP (to translate from the kernel virtual address returned by
      direct_access(), to a user mappable pfn in XIP's page fault handler.
      
      However, we can't switch it to just return the pfn and not the kaddr, because
      we have no good way to get a kva from a pfn, and XIP requires the kva for its
      read(2) and write(2) handlers.  So we have to return both.
      Signed-off-by: default avatarJared Hulbert <jaredeh@gmail.com>
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Cc: Carsten Otte <cotte@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Cc: linux-mm@kvack.org
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      30afcb4b
    • Nick Piggin's avatar
      mm: add vm_insert_mixed · 423bad60
      Nick Piggin authored
      
      
      vm_insert_mixed will insert either a raw pfn or a refcounted struct page into
      the page tables, depending on whether vm_normal_page() will return the page or
      not.  With the introduction of the new pte bit, this is now a too tricky for
      drivers to be doing themselves.
      
      filemap_xip uses this in a subsequent patch.
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Cc: Jared Hulbert <jaredeh@gmail.com>
      Cc: Carsten Otte <cotte@de.ibm.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      423bad60
    • Nick Piggin's avatar
      mm: introduce pte_special pte bit · 7e675137
      Nick Piggin authored
      
      
      s390 for one, cannot implement VM_MIXEDMAP with pfn_valid, due to their memory
      model (which is more dynamic than most).  Instead, they had proposed to
      implement it with an additional path through vm_normal_page(), using a bit in
      the pte to determine whether or not the page should be refcounted:
      
      vm_normal_page()
      {
      	...
              if (unlikely(vma->vm_flags & (VM_PFNMAP|VM_MIXEDMAP))) {
                      if (vma->vm_flags & VM_MIXEDMAP) {
      #ifdef s390
      			if (!mixedmap_refcount_pte(pte))
      				return NULL;
      #else
                              if (!pfn_valid(pfn))
                                      return NULL;
      #endif
                              goto out;
                      }
      	...
      }
      
      This is fine, however if we are allowed to use a bit in the pte to determine
      refcountedness, we can use that to _completely_ replace all the vma based
      schemes.  So instead of adding more cases to the already complex vma-based
      scheme, we can have a clearly seperate and simple pte-based scheme (and get
      slightly better code generation in the process):
      
      vm_normal_page()
      {
      #ifdef s390
      	if (!mixedmap_refcount_pte(pte))
      		return NULL;
      	return pte_page(pte);
      #else
      	...
      #endif
      }
      
      And finally, we may rather make this concept usable by any architecture rather
      than making it s390 only, so implement a new type of pte state for this.
      Unfortunately the old vma based code must stay, because some architectures may
      not be able to spare pte bits.  This makes vm_normal_page a little bit more
      ugly than we would like, but the 2 cases are clearly seperate.
      
      So introduce a pte_special pte state, and use it in mm/memory.c.  It is
      currently a noop for all architectures, so this doesn't actually result in any
      compiled code changes to mm/memory.o.
      
      BTW:
      I haven't put vm_normal_page() into arch code as-per an earlier suggestion.
      The reason is that, regardless of where vm_normal_page is actually
      implemented, the *abstraction* is still exactly the same. Also, while it
      depends on whether the architecture has pte_special or not, that is the
      only two possible cases, and it really isn't an arch specific function --
      the role of the arch code should be to provide primitive functions and
      accessors with which to build the core code; pte_special does that. We do
      not want architectures to know or care about vm_normal_page itself, and
      we definitely don't want them being able to invent something new there
      out of sight of mm/ code. If we made vm_normal_page an arch function, then
      we have to make vm_insert_mixed (next patch) an arch function too. So I
      don't think moving it to arch code fundamentally improves any abstractions,
      while it does practically make the code more difficult to follow, for both
      mm and arch developers, and easier to misuse.
      
      [akpm@linux-foundation.org: build fix]
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Acked-by: default avatarCarsten Otte <cotte@de.ibm.com>
      Cc: Jared Hulbert <jaredeh@gmail.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      7e675137
    • Jared Hulbert's avatar
      mm: introduce VM_MIXEDMAP · b379d790
      Jared Hulbert authored
      
      
      This series introduces some important infrastructure work.  The overall result
      is that:
      
      1. We now support XIP backed filesystems using memory that have no
         struct page allocated to them. And patches 6 and 7 actually implement
         this for s390.
      
         This is pretty important in a number of cases. As far as I understand,
         in the case of virtualisation (eg. s390), each guest may mount a
         readonly copy of the same filesystem (eg. the distro). Currently,
         guests need to allocate struct pages for this image. So if you have
         100 guests, you already need to allocate more memory for the struct
         pages than the size of the image. I think. (Carsten?)
      
         For other (eg. embedded) systems, you may have a very large non-
         volatile filesystem. If you have to have struct pages for this, then
         your RAM consumption will go up proportionally to fs size. Even
         though it is just a small proportion, the RAM can be much more costly
         eg in terms of power, so every KB less that Linux uses makes it more
         attractive to a lot of these guys.
      
      2. VM_MIXEDMAP allows us to support mappings where you actually do want
         to refcount _some_ pages in the mapping, but not others, and support
         COW on arbitrary (non-linear) mappings. Jared needs this for his NVRAM
         filesystem in progress. Future iterations of this filesystem will
         most likely want to migrate pages between pagecache and XIP backing,
         which is where the requirement for mixed (some refcounted, some not)
         comes from.
      
      3. pte_special also has a peripheral usage that I need for my lockless
         get_user_pages patch. That was shown to speed up "oltp" on db2 by
         10% on a 2 socket system, which is kind of significant because they
         scrounge for months to try to find 0.1% improvement on these
         workloads. I'm hoping we might finally be faster than AIX on
         pSeries with this :). My reference to lockless get_user_pages is not
         meant to justify this patchset (which doesn't include lockless gup),
         but just to show that pte_special is not some s390 specific thing that
         should be hidden in arch code or xip code: I definitely want to use it
         on at least x86 and powerpc as well.
      
      This patch:
      
      Introduce a new type of mapping, VM_MIXEDMAP.  This is unlike VM_PFNMAP in
      that it can support COW mappings of arbitrary ranges including ranges without
      struct page *and* ranges with a struct page that we actually want to refcount
      (PFNMAP can only support COW in those cases where the un-COW-ed translations
      are mapped linearly in the virtual address, and can only support non
      refcounted ranges).
      
      VM_MIXEDMAP achieves this by refcounting all pfn_valid pages, and not
      refcounting !pfn_valid pages (which is not an option for VM_PFNMAP, because it
      needs to avoid refcounting pfn_valid pages eg.  for /dev/mem mappings).
      Signed-off-by: default avatarJared Hulbert <jaredeh@gmail.com>
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Acked-by: default avatarCarsten Otte <cotte@de.ibm.com>
      Cc: Jared Hulbert <jaredeh@gmail.com>
      Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
      Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      b379d790
    • Peter Zijlstra's avatar
      smaps: account swap entries · 214e471f
      Peter Zijlstra authored
      
      
      Show the amount of swap for each vma.  This can be used to see where all the
      swap goes.
      
      [akpm@linux-foundation.org: coding-style fixes]
      Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
      Acked-by: default avatarMatt Mackall <mpm@selenic.com>
      Acked-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>
      214e471f
    • Christoph Lameter's avatar
      PAGEFLAGS_EXTENDED and separate page flags for Head and Tail · e20b8cca
      Christoph Lameter authored
      
      
      Having separate page flags for the head and the tail of a compound page allows
      the compiler to use bitops instead of operations on a word to check for a tail
      page.  That is f.e.  important for virt_to_head_page() which is used in
      various critical code paths (kfree for example):
      
      Code for PageTail(page)
      
      Before:
      
       mov    (%rdi),%rdx		page->flags
       mov    %rdx,%rax		3 bytes
       and    $0x12000,%eax		5 bytes
       cmp    $0x12000,%rax		6 bytes
       je     897 <kfree+0xa7>
      
      After:
      
       mov    (%rdi),%rax
       test   $0x40,%ah			(3 bytes)
       jne    887 <kfree+0x97>
      
      So we go from 14 bytes to 3 bytes and from 3 instructions to one.  From the
      use of 2 registers we go to none.
      
      We can only use page flags for this if we have page flags available.  This
      patch introduces CONFIG_PAGEFLAGS_EXTENDED that is set if pageflags are not
      scarce due to SPARSEMEM using page flags for its sectionid on 32 bit NUMA
      platforms.
      
      Additional page flag definitions can be added to the CONFIG_PAGEFLAGS_EXTENDED
      section in page-flags.h if the functionality depends on PAGEFLAGS_EXTENDED or
      if more page flag overlapping tricks are used for the !PAGEFLAGS_EXTENDED
      fallback (the upcoming virtual compound patch may hook in here and Rik's/Lee's
      additional page flags to solve the reclaim issues could also be added there
      [hint...  hint...  where are these patchsets?]).
      
      Avoiding the overlaying of Pg_reclaim also clears the way for possible use of
      compound pages for the pagecache or on the LRU.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.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>
      e20b8cca
    • Christoph Lameter's avatar
      mm: Get rid of __ZONE_COUNT · 97965478
      Christoph Lameter authored
      
      
      It was used to compensate because MAX_NR_ZONES was not available to the
      #ifdefs.  Export MAX_NR_ZONES via the new mechanism and get rid of
      __ZONE_COUNT.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      97965478
    • Christoph Lameter's avatar
      page flags: add PAGEFLAGS_FALSE for flags that are always false · ec7cade8
      Christoph Lameter authored
      
      
      Turns out that there are a number of times that a flag is simply always
      returning 0.  Define a macro for that.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      ec7cade8
    • Christoph Lameter's avatar
      page flags: handle PG_uncached like all other flags · 602c4d11
      Christoph Lameter authored
      
      
      Remove the special setup for PG_uncached and simply make it part of the enum.
      The page flag will only be allocated when the kernel build includes the
      uncached allocator.
      Acked-by: default avatarDean Nelson <dcn@sgi.com>
      Cc: Jes Sorensen <jes@trained-monkey.org>
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      602c4d11
    • Christoph Lameter's avatar
      pageflags: eliminate PG_xxx aliases · 0a128b2b
      Christoph Lameter authored
      
      
      Remove aliases of PG_xxx.  We can easily drop those now and alias by
      specifying the PG_xxx flag in the macro that generates the functions.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Andy Whitcroft <apw@shadowen.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Jeremy Fitzhardinge <jeremy@goop.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      0a128b2b
    • Christoph Lameter's avatar
      pageflags: use proper page flag functions in Xen · d60cd46b
      Christoph Lameter authored
      
      
      Xen uses bitops to manipulate page flags.  Make it use proper page flag
      functions.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Andy Whitcroft <apw@shadowen.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Jeremy Fitzhardinge <jeremy@goop.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      d60cd46b
    • Christoph Lameter's avatar
      pageflags: convert to the use of new macros · 6a1e7f77
      Christoph Lameter authored
      
      
      Replace explicit definitions of page flags through the use of macros.
      Significantly reduces the size of the definitions and removes a lot of
      opportunity for errors.  Additonal page flags can typically be generated with
      a single line.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Andy Whitcroft <apw@shadowen.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Jeremy Fitzhardinge <jeremy@goop.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      6a1e7f77
    • Christoph Lameter's avatar
      pageflags: introduce macros to generate page flag functions · f94a62e9
      Christoph Lameter authored
      
      
      Introduce a set of macros that generate functions to handle page flags.
      
      A page flag function group typically starts with either
      
      	SETPAGEFLAG(<part of function name>,<part of PG_ flagname>)
      
      to create a set of page flag operations that are atomic. Or
      
      	__SETPAGEFLAG(<part of function name>,<part of PG_ flagname)
      
      to create a set of page flag operations that are not atomic.
      
      Then additional operations can be added using the following macros
      
      TESTSCFLAG		Create additional atomic test-and-set and
      			test-and-clear functions
      
      TESTSETFLAG		Create additional test and set function
      TESTCLEARFLAG		Create additional test and clear function
      SETPAGEFLAG		Create additional atomic set function
      CLEARPAGEFLAG		Create additional atomic clear function
      __TESTPAGEFLAG		Create additional non atomic set function
      __SETPAGEFLAG		Create additional non atomic clear function
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Andy Whitcroft <apw@shadowen.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Jeremy Fitzhardinge <jeremy@goop.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      f94a62e9
    • Christoph Lameter's avatar
      pageflags: get rid of FLAGS_RESERVED · 9223b419
      Christoph Lameter authored
      
      
      NR_PAGEFLAGS specifies the number of page flags we are using.  From that we
      can calculate the number of bits leftover that can be used for zone, node (and
      maybe the sections id).  There is no need anymore for FLAGS_RESERVED if we use
      NR_PAGEFLAGS.
      
      Use the new methods to make NR_PAGEFLAGS available via the preprocessor.
      NR_PAGEFLAGS is used to calculate field boundaries in the page flags fields.
      These field widths have to be available to the preprocessor.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: David Miller <davem@davemloft.net>
      Cc: Andy Whitcroft <apw@shadowen.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Jeremy Fitzhardinge <jeremy@goop.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      9223b419
    • Christoph Lameter's avatar
      pageflags: use an enum for the flags · e2683181
      Christoph Lameter authored
      
      
      Use an enum to ease the maintenance of page flags.  This is going to change
      the numbering from 0 to 18.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Andy Whitcroft <apw@shadowen.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
      Cc: Rik van Riel <riel@redhat.com>
      Cc: Mel Gorman <mel@csn.ul.ie>
      Cc: Jeremy Fitzhardinge <jeremy@goop.org>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      e2683181