1. 31 Aug, 2007 1 commit
  2. 26 Jul, 2007 2 commits
  3. 17 Jul, 2007 1 commit
    • Mel Gorman's avatar
      Add __GFP_MOVABLE for callers to flag allocations from high memory that may be migrated · 769848c0
      Mel Gorman authored
      It is often known at allocation time whether a page may be migrated or not.
      This patch adds a flag called __GFP_MOVABLE and a new mask called
      GFP_HIGH_MOVABLE.  Allocations using the __GFP_MOVABLE can be either migrated
      using the page migration mechanism or reclaimed by syncing with backing
      storage and discarding.
      
      An API function very similar to alloc_zeroed_user_highpage() is added for
      __GFP_MOVABLE allocations called alloc_zeroed_user_highpage_movable().  The
      flags used by alloc_zeroed_user_highpage() are not changed because it would
      change the semantics of an existing API.  After this patch is applied there
      are no in-kernel users of alloc_zeroed_user_highpage() so it probably should
      be marked deprecated if this patch is merged.
      
      Note that this patch includes a minor cleanup to the use of __GFP_ZERO in
      shmem.c to keep all flag modifications to inode->mapping in the
      shmem_dir_alloc() helper function.  This clean-up suggestion is courtesy of
      Hugh Dickens.
      
      Additional credit goes to Christoph Lameter and Linus Torvalds for shaping the
      concept.  Credit to Hugh Dickens for catching issues with shmem swap vector
      and ramfs allocations.
      
      [akpm@linux-foundation.org: build fix]
      [hugh@veritas.com: __GFP_ZERO cleanup]
      Signed-off-by: default avatarMel Gorman <mel@csn.ul.ie>
      Cc: Andy Whitcroft <apw@shadowen.org>
      Cc: Christoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
      769848c0
  4. 24 Apr, 2007 1 commit
  5. 05 Mar, 2007 1 commit
  6. 07 Dec, 2006 1 commit
    • Nick Piggin's avatar
      [PATCH] radix-tree: RCU lockless readside · 7cf9c2c7
      Nick Piggin authored
      Make radix tree lookups safe to be performed without locks.  Readers are
      protected against nodes being deleted by using RCU based freeing.  Readers
      are protected against new node insertion by using memory barriers to ensure
      the node itself will be properly written before it is visible in the radix
      tree.
      
      Each radix tree node keeps a record of their height (above leaf nodes).
      This height does not change after insertion -- when the radix tree is
      extended, higher nodes are only inserted in the top.  So a lookup can take
      the pointer to what is *now* the root node, and traverse down it even if
      the tree is concurrently extended and this node becomes a subtree of a new
      root.
      
      "Direct" pointers (tree height of 0, where root->rnode points directly to
      the data item) are handled by using the low bit of the pointer to signal
      whether rnode is a direct pointer or a pointer to a radix tree node.
      
      When a reader wants to traverse the next branch, they will take a copy of
      the pointer.  This pointer will be either NULL (and the branch is empty) or
      non-NULL (and will point to a valid node).
      
      [akpm@osdl.org: cleanups]
      [Lee.Schermerhorn@hp.com: bugfixes, comments, simplifications]
      [clameter@sgi.com: build fix]
      Signed-off-by: default avatarNick Piggin <npiggin@suse.de>
      Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
      Signed-off-by: default avatarLee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Christoph Lameter <clameter@engr.sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      7cf9c2c7
  7. 03 Nov, 2006 1 commit
    • Stephen Rothwell's avatar
      [PATCH] Fix sys_move_pages when a NULL node list is passed · 8ce08464
      Stephen Rothwell authored
      sys_move_pages() uses vmalloc() to allocate an array of structures that is
      fills with information passed from user mode and then passes to
      do_stat_pages() (in the case the node list is NULL).  do_stat_pages()
      depends on a marker in the node field of the structure to decide how large
      the array is and this marker is correctly inserted into the last element of
      the array.  However, vmalloc() doesn't zero the memory it allocates and if
      the user passes NULL for the node list, then the node fields are not filled
      in (except for the end marker).  If the memory the vmalloc() returned
      happend to have a word with the marker value in it in just the right place,
      do_pages_stat will fail to fill the status field of part of the array and
      we will return (random) kernel data to user mode.
      Signed-off-by: default avatarStephen Rothwell <sfr@canb.auug.org.au>
      Cc: Christoph Lameter <clameter@engr.sgi.com>
      Cc: <stable@kernel.org>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      8ce08464
  8. 30 Sep, 2006 2 commits
    • David Howells's avatar
      [PATCH] BLOCK: Make it possible to disable the block layer [try #6] · 9361401e
      David Howells authored
      Make it possible to disable the block layer.  Not all embedded devices require
      it, some can make do with just JFFS2, NFS, ramfs, etc - none of which require
      the block layer to be present.
      
      This patch does the following:
      
       (*) Introduces CONFIG_BLOCK to disable the block layer, buffering and blockdev
           support.
      
       (*) Adds dependencies on CONFIG_BLOCK to any configuration item that controls
           an item that uses the block layer.  This includes:
      
           (*) Block I/O tracing.
      
           (*) Disk partition code.
      
           (*) All filesystems that are block based, eg: Ext3, ReiserFS, ISOFS.
      
           (*) The SCSI layer.  As far as I can tell, even SCSI chardevs use the
           	 block layer to do scheduling.  Some drivers that use SCSI facilities -
           	 such as USB storage - end up disabled indirectly from this.
      
           (*) Various block-based device drivers, such as IDE and the old CDROM
           	 drivers.
      
           (*) MTD blockdev handling and FTL.
      
           (*) JFFS - which uses set_bdev_super(), something it could avoid doing by
           	 taking a leaf out of JFFS2's book.
      
       (*) Makes most of the contents of linux/blkdev.h, linux/buffer_head.h and
           linux/elevator.h contingent on CONFIG_BLOCK being set.  sector_div() is,
           however, still used in places, and so is still available.
      
       (*) Also made contingent are the contents of linux/mpage.h, linux/genhd.h and
           parts of linux/fs.h.
      
       (*) Makes a number of files in fs/ contingent on CONFIG_BLOCK.
      
       (*) Makes mm/bounce.c (bounce buffering) contingent on CONFIG_BLOCK.
      
       (*) set_page_dirty() doesn't call __set_page_dirty_buffers() if CONFIG_BLOCK
           is not enabled.
      
       (*) fs/no-block.c is created to hold out-of-line stubs and things that are
           required when CONFIG_BLOCK is not set:
      
           (*) Default blockdev file operations (to give error ENODEV on opening).
      
       (*) Makes some /proc changes:
      
           (*) /proc/devices does not list any blockdevs.
      
           (*) /proc/diskstats and /proc/partitions are contingent on CONFIG_BLOCK.
      
       (*) Makes some compat ioctl handling contingent on CONFIG_BLOCK.
      
       (*) If CONFIG_BLOCK is not defined, makes sys_quotactl() return -ENODEV if
           given command other than Q_SYNC or if a special device is specified.
      
       (*) In init/do_mounts.c, no reference is made to the blockdev routines if
           CONFIG_BLOCK is not defined.  This does not prohibit NFS roots or JFFS2.
      
       (*) The bdflush, ioprio_set and ioprio_get syscalls can now be absent (return
           error ENOSYS by way of cond_syscall if so).
      
       (*) The seclvl_bd_claim() and seclvl_bd_release() security calls do nothing if
           CONFIG_BLOCK is not set, since they can't then happen.
      Signed-Off-By: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      9361401e
    • David Howells's avatar
      [PATCH] BLOCK: Stop fallback_migrate_page() from using page_has_buffers() [try #6] · b398f6bf
      David Howells authored
      Stop fallback_migrate_page() from using page_has_buffers() since that might not
      be available.  Use PagePrivate() instead since that's more general.
      Signed-Off-By: default avatarDavid Howells <dhowells@redhat.com>
      Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
      b398f6bf
  9. 26 Sep, 2006 2 commits
  10. 25 Jun, 2006 2 commits
    • Christoph Lameter's avatar
      [PATCH] Allow migration of mlocked pages · e6a1530d
      Christoph Lameter authored
      Hugh clarified the role of VM_LOCKED.  So we can now implement page
      migration for mlocked pages.
      
      Allow the migration of mlocked pages.  This means that try_to_unmap must
      unmap mlocked pages in the migration case.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Acked-by: default avatarHugh Dickins <hugh@veritas.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      e6a1530d
    • Christoph Lameter's avatar
      [PATCH] page migration: Support a vma migration function · 7b2259b3
      Christoph Lameter authored
      Hooks for calling vma specific migration functions
      
      With this patch a vma may define a vma->vm_ops->migrate function.  That
      function may perform page migration on its own (some vmas may not contain page
      structs and therefore cannot be handled by regular page migration.  Pages in a
      vma may require special preparatory treatment before migration is possible
      etc) .  Only mmap_sem is held when the migration function is called.  The
      migrate() function gets passed two sets of nodemasks describing the source and
      the target of the migration.  The flags parameter either contains
      
      MPOL_MF_MOVE	which means that only pages used exclusively by
      		the specified mm should be moved
      
      or
      
      MPOL_MF_MOVE_ALL which means that pages shared with other processes
      		should also be moved.
      
      The migration function returns 0 on success or an error condition.  An error
      condition will prevent regular page migration from occurring.
      
      On its own this patch cannot be included since there are no users for this
      functionality.  But it seems that the uncached allocator will need this
      functionality at some point.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: Andi Kleen <ak@muc.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      7b2259b3
  11. 23 Jun, 2006 16 commits
    • David Quigley's avatar
      [PATCH] SELinux: add security_task_movememory calls to mm code · 86c3a764
      David Quigley authored
      This patch inserts security_task_movememory hook calls into memory management
      code to enable security modules to mediate this operation between tasks.
      
      Since the last posting, the hook has been renamed following feedback from
      Christoph Lameter.
      Signed-off-by: default avatarDavid Quigley <dpquigl@tycho.nsa.gov>
      Acked-by: default avatarStephen Smalley <sds@tycho.nsa.gov>
      Signed-off-by: default avatarJames Morris <jmorris@namei.org>
      Cc: Andi Kleen <ak@muc.de>
      Acked-by: default avatarChristoph Lameter <clameter@sgi.com>
      Acked-by: default avatarChris Wright <chrisw@sous-sol.org>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      86c3a764
    • Christoph Lameter's avatar
      [PATCH] page migration: sys_move_pages(): support moving of individual pages · 742755a1
      Christoph Lameter authored
      move_pages() is used to move individual pages of a process. The function can
      be used to determine the location of pages and to move them onto the desired
      node. move_pages() returns status information for each page.
      
      long move_pages(pid, number_of_pages_to_move,
      		addresses_of_pages[],
      		nodes[] or NULL,
      		status[],
      		flags);
      
      The addresses of pages is an array of void * pointing to the
      pages to be moved.
      
      The nodes array contains the node numbers that the pages should be moved
      to. If a NULL is passed instead of an array then no pages are moved but
      the status array is updated. The status request may be used to determine
      the page state before issuing another move_pages() to move pages.
      
      The status array will contain the state of all individual page migration
      attempts when the function terminates. The status array is only valid if
      move_pages() completed successfullly.
      
      Possible page states in status[]:
      
      0..MAX_NUMNODES	The page is now on the indicated node.
      
      -ENOENT		Page is not present
      
      -EACCES		Page is mapped by multiple processes and can only
      		be moved if MPOL_MF_MOVE_ALL is specified.
      
      -EPERM		The page has been mlocked by a process/driver and
      		cannot be moved.
      
      -EBUSY		Page is busy and cannot be moved. Try again later.
      
      -EFAULT		Invalid address (no VMA or zero page).
      
      -ENOMEM		Unable to allocate memory on target node.
      
      -EIO		Unable to write back page. The page must be written
      		back in order to move it since the page is dirty and the
      		filesystem does not provide a migration function that
      		would allow the moving of dirty pages.
      
      -EINVAL		A dirty page cannot be moved. The filesystem does not provide
      		a migration function and has no ability to write back pages.
      
      The flags parameter indicates what types of pages to move:
      
      MPOL_MF_MOVE	Move pages that are only mapped by the process.
      
      MPOL_MF_MOVE_ALL Also move pages that are mapped by multiple processes.
      		Requires sufficient capabilities.
      
      Possible return codes from move_pages()
      
      -ENOENT		No pages found that would require moving. All pages
      		are either already on the target node, not present, had an
      		invalid address or could not be moved because they were
      		mapped by multiple processes.
      
      -EINVAL		Flags other than MPOL_MF_MOVE(_ALL) specified or an attempt
      		to migrate pages in a kernel thread.
      
      -EPERM		MPOL_MF_MOVE_ALL specified without sufficient priviledges.
      		or an attempt to move a process belonging to another user.
      
      -EACCES		One of the target nodes is not allowed by the current cpuset.
      
      -ENODEV		One of the target nodes is not online.
      
      -ESRCH		Process does not exist.
      
      -E2BIG		Too many pages to move.
      
      -ENOMEM		Not enough memory to allocate control array.
      
      -EFAULT		Parameters could not be accessed.
      
      A test program for move_pages() may be found with the patches
      on ftp.kernel.org:/pub/linux/kernel/people/christoph/pmig/patches-2.6.17-rc4-mm3
      
      From: Christoph Lameter <clameter@sgi.com>
      
        Detailed results for sys_move_pages()
      
        Pass a pointer to an integer to get_new_page() that may be used to
        indicate where the completion status of a migration operation should be
        placed.  This allows sys_move_pags() to report back exactly what happened to
        each page.
      
        Wish there would be a better way to do this. Looks a bit hacky.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: Jes Sorensen <jes@trained-monkey.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Andi Kleen <ak@muc.de>
      Cc: Michael Kerrisk <mtk-manpages@gmx.net>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      742755a1
    • Christoph Lameter's avatar
      [PATCH] page migration: use allocator function for migrate_pages() · 95a402c3
      Christoph Lameter authored
      Instead of passing a list of new pages, pass a function to allocate a new
      page.  This allows the correct placement of MPOL_INTERLEAVE pages during page
      migration.  It also further simplifies the callers of migrate pages.
      migrate_pages() becomes similar to migrate_pages_to() so drop
      migrate_pages_to().  The batching of new page allocations becomes unnecessary.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: Jes Sorensen <jes@trained-monkey.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Andi Kleen <ak@muc.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      95a402c3
    • Christoph Lameter's avatar
      [PATCH] page migration: handle freeing of pages in migrate_pages() · aaa994b3
      Christoph Lameter authored
      Do not leave pages on the lists passed to migrate_pages().  Seems that we will
      not need any postprocessing of pages.  This will simplify the handling of
      pages by the callers of migrate_pages().
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: Jes Sorensen <jes@trained-monkey.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Andi Kleen <ak@muc.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      aaa994b3
    • Christoph Lameter's avatar
      [PATCH] page migration: simplify migrate_pages() · e24f0b8f
      Christoph Lameter authored
      Currently migrate_pages() is mess with lots of goto.  Extract two functions
      from migrate_pages() and get rid of the gotos.
      
      Plus we can just unconditionally set the locked bit on the new page since we
      are the only one holding a reference.  Locking is to stop others from
      accessing the page once we establish references to the new page.
      
      Remove the list_del from move_to_lru in order to have finer control over list
      processing.
      
      [akpm@osdl.org: add debug check]
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Cc: Hugh Dickins <hugh@veritas.com>
      Cc: Jes Sorensen <jes@trained-monkey.org>
      Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
      Cc: Lee Schermerhorn <lee.schermerhorn@hp.com>
      Cc: Andi Kleen <ak@muc.de>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      e24f0b8f
    • Christoph Lameter's avatar
      [PATCH] More page migration: use migration entries for file pages · 04e62a29
      Christoph Lameter authored
      This implements the use of migration entries to preserve ptes of file backed
      pages during migration.  Processes can therefore be migrated back and forth
      without loosing their connection to pagecache pages.
      
      Note that we implement the migration entries only for linear mappings.
      Nonlinear mappings still require the unmapping of the ptes for migration.
      
      And another writepage() ugliness shows up.  writepage() can drop the page
      lock.  Therefore we have to remove migration ptes before calling writepages()
      in order to avoid having migration entries point to unlocked pages.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      04e62a29
    • Christoph Lameter's avatar
      [PATCH] More page migration: do not inc/dec rss counters · 442c9137
      Christoph Lameter authored
      If we install a migration entry then the rss not really decreases since the
      page is just moved somewhere else.  We can save ourselves the work of
      decrementing and later incrementing which will just eventually cause cacheline
      bouncing.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      442c9137
    • Christoph Lameter's avatar
      [PATCH] Swapless page migration: modify core logic · 6c5240ae
      Christoph Lameter authored
      Use the migration entries for page migration
      
      This modifies the migration code to use the new migration entries.  It now
      becomes possible to migrate anonymous pages without having to add a swap
      entry.
      
      We add a couple of new functions to replace migration entries with the proper
      ptes.
      
      We cannot take the tree_lock for migrating anonymous pages anymore.  However,
      we know that we hold the only remaining reference to the page when the page
      count reaches 1.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      6c5240ae
    • Christoph Lameter's avatar
      [PATCH] Swapless page migration: rip out swap based logic · d75a0fcd
      Christoph Lameter authored
      Rip the page migration logic out.
      
      Remove all code that has to do with swapping during page migration.
      
      This also guts the ability to migrate pages to swap.  No one used that so lets
      let it go for good.
      
      Page migration should be a bit broken after this patch.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      d75a0fcd
    • Christoph Lameter's avatar
      [PATCH] Swapless page migration: add R/W migration entries · 0697212a
      Christoph Lameter authored
      Implement read/write migration ptes
      
      We take the upper two swapfiles for the two types of migration ptes and define
      a series of macros in swapops.h.
      
      The VM is modified to handle the migration entries.  migration entries can
      only be encountered when the page they are pointing to is locked.  This limits
      the number of places one has to fix.  We also check in copy_pte_range and in
      mprotect_pte_range() for migration ptes.
      
      We check for migration ptes in do_swap_cache and call a function that will
      then wait on the page lock.  This allows us to effectively stop all accesses
      to apge.
      
      Migration entries are created by try_to_unmap if called for migration and
      removed by local functions in migrate.c
      
      From: Hugh Dickins <hugh@veritas.com>
      
        Several times while testing swapless page migration (I've no NUMA, just
        hacking it up to migrate recklessly while running load), I've hit the
        BUG_ON(!PageLocked(p)) in migration_entry_to_page.
      
        This comes from an orphaned migration entry, unrelated to the current
        correctly locked migration, but hit by remove_anon_migration_ptes as it
        checks an address in each vma of the anon_vma list.
      
        Such an orphan may be left behind if an earlier migration raced with fork:
        copy_one_pte can duplicate a migration entry from parent to child, after
        remove_anon_migration_ptes has checked the child vma, but before it has
        removed it from the parent vma.  (If the process were later to fault on this
        orphaned entry, it would hit the same BUG from migration_entry_wait.)
      
        This could be fixed by locking anon_vma in copy_one_pte, but we'd rather
        not.  There's no such problem with file pages, because vma_prio_tree_add
        adds child vma after parent vma, and the page table locking at each end is
        enough to serialize.  Follow that example with anon_vma: add new vmas to the
        tail instead of the head.
      
        (There's no corresponding problem when inserting migration entries,
        because a missed pte will leave the page count and mapcount high, which is
        allowed for.  And there's no corresponding problem when migrating via swap,
        because a leftover swap entry will be correctly faulted.  But the swapless
        method has no refcounting of its entries.)
      
      From: Ingo Molnar <mingo@elte.hu>
      
        pte_unmap_unlock() takes the pte pointer as an argument.
      
      From: Hugh Dickins <hugh@veritas.com>
      
        Several times while testing swapless page migration, gcc has tried to exec
        a pointer instead of a string: smells like COW mappings are not being
        properly write-protected on fork.
      
        The protection in copy_one_pte looks very convincing, until at last you
        realize that the second arg to make_migration_entry is a boolean "write",
        and SWP_MIGRATION_READ is 30.
      
        Anyway, it's better done like in change_pte_range, using
        is_write_migration_entry and make_migration_entry_read.
      
      From: Hugh Dickins <hugh@veritas.com>
      
        Remove unnecessary obfuscation from sys_swapon's range check on swap type,
        which blew up causing memory corruption once swapless migration made
        MAX_SWAPFILES no longer 2 ^ MAX_SWAPFILES_SHIFT.
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Acked-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
      Signed-off-by: default avatarHugh Dickins <hugh@veritas.com>
      Signed-off-by: default avatarChristoph Lameter <clameter@engr.sgi.com>
      Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
      From: Hugh Dickins <hugh@veritas.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      0697212a
    • Christoph Lameter's avatar
      [PATCH] page migration cleanup: move fallback handling into special function · 8351a6e4
      Christoph Lameter authored
      Move the fallback code into a new fallback function and make the function
      behave like any other migration function.  This requires retaking the lock if
      pageout() drops it.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      8351a6e4
    • Christoph Lameter's avatar
      [PATCH] page migration cleanup: pass "mapping" to migration functions · 2d1db3b1
      Christoph Lameter authored
      Change handling of address spaces.
      
      Pass a pointer to the address space in which the page is migrated to all
      migration function.  This avoids repeatedly having to retrieve the address
      space pointer from the page and checking it for validity.  The old page
      mapping will change once migration has gone to a certain step, so it is less
      confusing to have the pointer always available.
      
      Move the setting of the mapping and index for the new page into
      migrate_pages().
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      2d1db3b1
    • Christoph Lameter's avatar
      [PATCH] page migration cleanup: extract try_to_unmap from migration functions · c3fcf8a5
      Christoph Lameter authored
      Extract try_to_unmap and rename remove_references -> move_mapping
      
      try_to_unmap() may significantly change the page state by for example setting
      the dirty bit.  It is therefore best to unmap in migrate_pages() before
      calling any migration functions.
      
      migrate_page_remove_references() will then only move the new page in place of
      the old page in the mapping.  Rename the function to
      migrate_page_move_mapping().
      
      This allows us to get rid of the special unmapping for the fallback path.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      c3fcf8a5
    • Christoph Lameter's avatar
      [PATCH] page migration cleanup: drop nr_refs in remove_references() · 5b5c7120
      Christoph Lameter authored
      Drop nr_refs parameter from migrate_page_remove_references()
      
      The nr_refs parameter is not really useful since the number of remaining
      references is always
      
      1 for anonymous pages without a mapping
      2 for pages with a mapping
      3 for pages with a mapping and PagePrivate set.
      
      Remove the early check for the number of references since we are checking
      page_mapcount() earlier.  Ultimately only the refcount matters after the
      tree_lock has been obtained.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.coim>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      5b5c7120
    • Christoph Lameter's avatar
      [PATCH] page migration cleanup: remove useless definitions · e7340f73
      Christoph Lameter authored
      Remove the export for migrate_page_remove_references() and migrate_page_copy()
      that are unlikely to be used directly by filesystems implementing migration.
      The export was useful when buffer_migrate_page() lived in fs/buffer.c but it
      has now been moved to migrate.c in the migration reorg.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      e7340f73
    • Christoph Lameter's avatar
      [PATCH] page migration cleanup: group functions · 1d8b85cc
      Christoph Lameter authored
      Reorder functions in migrate.c.  Group all migration functions for struct
      address_space_operations together.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      1d8b85cc
  12. 01 May, 2006 1 commit
    • Christoph Lameter's avatar
      [PATCH] page migration: Fix fallback behavior for dirty pages · 4c28f811
      Christoph Lameter authored
      Currently we check PageDirty() in order to make the decision to swap out
      the page.  However, the dirty information may be only be contained in the
      ptes pointing to the page.  We need to first unmap the ptes before checking
      for PageDirty().  If unmap is successful then the page count of the page
      will also be decreased so that pageout() works properly.
      
      This is a fix necessary for 2.6.17.  Without this fix we may migrate dirty
      pages for filesystems without migration functions.  Filesystems may keep
      pointers to dirty pages.  Migration of dirty pages can result in the
      filesystem keeping pointers to freed pages.
      
      Unmapping is currently not be separated out from removing all the
      references to a page and moving the mapping.  Therefore try_to_unmap will
      be called again in migrate_page() if the writeout is successful.  However,
      it wont do anything since the ptes are already removed.
      
      The coming updates to the page migration code will restructure the code
      so that this is no longer necessary.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      4c28f811
  13. 11 Apr, 2006 2 commits
  14. 22 Mar, 2006 1 commit
    • Christoph Lameter's avatar
      [PATCH] page migration reorg · b20a3503
      Christoph Lameter authored
      Centralize the page migration functions in anticipation of additional
      tinkering.  Creates a new file mm/migrate.c
      
      1. Extract buffer_migrate_page() from fs/buffer.c
      
      2. Extract central migration code from vmscan.c
      
      3. Extract some components from mempolicy.c
      
      4. Export pageout() and remove_from_swap() from vmscan.c
      
      5. Make it possible to configure NUMA systems without page migration
         and non-NUMA systems with page migration.
      
      I had to so some #ifdeffing in mempolicy.c that may need a cleanup.
      Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
      Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
      Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
      b20a3503