kernel/linux.git/include/linux/rmap.h, branch linux-2.6.28.y

make mm/rmap.c:anon_vma_cachep static

2008-10-20T15:52:40+00:00

This patch makes the needlessly global anon_vma_cachep static. Signed-off-by: Adrian Bunk Reviewed-by: KOSAKI Motohiro Acked-by: Rik van Riel Acked-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

vmscan: unevictable LRU scan sysctl

2008-10-20T15:52:31+00:00

This patch adds a function to scan individual or all zones' unevictable lists and move any pages that have become evictable onto the respective zone's inactive list, where shrink_inactive_list() will deal with them. Adds sysctl to scan all nodes, and per node attributes to individual nodes' zones. Kosaki: If evictable page found in unevictable lru when write /proc/sys/vm/scan_unevictable_pages, print filename and file offset of these pages. [akpm@linux-foundation.org: fix one CONFIG_MMU=n build error] [kosaki.motohiro@jp.fujitsu.com: adapt vmscan-unevictable-lru-scan-sysctl.patch to new sysfs API] Signed-off-by: Lee Schermerhorn Signed-off-by: Rik van Riel Signed-off-by: KOSAKI Motohiro Signed-off-by: KOSAKI Motohiro Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mlock: mlocked pages are unevictable

2008-10-20T15:52:30+00:00

Make sure that mlocked pages also live on the unevictable LRU, so kswapd will not scan them over and over again. This is achieved through various strategies: 1) add yet another page flag--PG_mlocked--to indicate that the page is locked for efficient testing in vmscan and, optionally, fault path. This allows early culling of unevictable pages, preventing them from getting to page_referenced()/try_to_unmap(). Also allows separate accounting of mlock'd pages, as Nick's original patch did. Note: Nick's original mlock patch used a PG_mlocked flag. I had removed this in favor of the PG_unevictable flag + an mlock_count [new page struct member]. I restored the PG_mlocked flag to eliminate the new count field. 2) add the mlock/unevictable infrastructure to mm/mlock.c, with internal APIs in mm/internal.h. This is a rework of Nick's original patch to these files, taking into account that mlocked pages are now kept on unevictable LRU list. 3) update vmscan.c:page_evictable() to check PageMlocked() and, if vma passed in, the vm_flags. Note that the vma will only be passed in for new pages in the fault path; and then only if the "cull unevictable pages in fault path" patch is included. 4) add try_to_unlock() to rmap.c to walk a page's rmap and ClearPageMlocked() if no other vmas have it mlocked. Reuses as much of try_to_unmap() as possible. This effectively replaces the use of one of the lru list links as an mlock count. If this mechanism let's pages in mlocked vmas leak through w/o PG_mlocked set [I don't know that it does], we should catch them later in try_to_unmap(). One hopes this will be rare, as it will be relatively expensive. Original mm/internal.h, mm/rmap.c and mm/mlock.c changes: Signed-off-by: Nick Piggin splitlru: introduce __get_user_pages(): New munlock processing need to GUP_FLAGS_IGNORE_VMA_PERMISSIONS. because current get_user_pages() can't grab PROT_NONE pages theresore it cause PROT_NONE pages can't munlock. [akpm@linux-foundation.org: fix this for pagemap-pass-mm-into-pagewalkers.patch] [akpm@linux-foundation.org: untangle patch interdependencies] [akpm@linux-foundation.org: fix things after out-of-order merging] [hugh@veritas.com: fix page-flags mess] [lee.schermerhorn@hp.com: fix munlock page table walk - now requires 'mm'] [kosaki.motohiro@jp.fujitsu.com: build fix] [kosaki.motohiro@jp.fujitsu.com: fix truncate race and sevaral comments] [kosaki.motohiro@jp.fujitsu.com: splitlru: introduce __get_user_pages()] Signed-off-by: KOSAKI Motohiro Signed-off-by: Rik van Riel Signed-off-by: Lee Schermerhorn Cc: Nick Piggin Cc: Dave Hansen Cc: Matt Mackall Signed-off-by: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: dirty page tracking race fix

2008-08-20T22:40:32+00:00

There is a race with dirty page accounting where a page may not properly be accounted for. clear_page_dirty_for_io() calls page_mkclean; then TestClearPageDirty. page_mkclean walks the rmaps for that page, and for each one it cleans and write protects the pte if it was dirty. It uses page_check_address to find the pte. That function has a shortcut to avoid the ptl if the pte is not present. Unfortunately, the pte can be switched to not-present then back to present by other code while holding the page table lock -- this should not be a signal for page_mkclean to ignore that pte, because it may be dirty. For example, powerpc64's set_pte_at will clear a previously present pte before setting it to the desired value. There may also be other code in core mm or in arch which do similar things. The consequence of the bug is loss of data integrity due to msync, and loss of dirty page accounting accuracy. XIP's __xip_unmap could easily also be unreliable (depending on the exact XIP locking scheme), which can lead to data corruption. Fix this by having an option to always take ptl to check the pte in page_check_address. It's possible to retain this optimization for page_referenced and try_to_unmap. Signed-off-by: Nick Piggin Cc: Jared Hulbert Cc: Carsten Otte Cc: Hugh Dickins Acked-by: Peter Zijlstra Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mmu-notifiers: add mm_take_all_locks() operation

2008-07-28T23:30:21+00:00

mm_take_all_locks holds off reclaim from an entire mm_struct. This allows mmu notifiers to register into the mm at any time with the guarantee that no mmu operation is in progress on the mm. This operation locks against the VM for all pte/vma/mm related operations that could ever happen on a certain mm. This includes vmtruncate, try_to_unmap, and all page faults. The caller must take the mmap_sem in write mode before calling mm_take_all_locks(). The caller isn't allowed to release the mmap_sem until mm_drop_all_locks() returns. mmap_sem in write mode is required in order to block all operations that could modify pagetables and free pages without need of altering the vma layout (for example populate_range() with nonlinear vmas). It's also needed in write mode to avoid new anon_vmas to be associated with existing vmas. A single task can't take more than one mm_take_all_locks() in a row or it would deadlock. mm_take_all_locks() and mm_drop_all_locks are expensive operations that may have to take thousand of locks. mm_take_all_locks() can fail if it's interrupted by signals. When mmu_notifier_register returns, we must be sure that the driver is notified if some task is in the middle of a vmtruncate for the 'mm' where the mmu notifier was registered (mmu_notifier_invalidate_range_start/end is run around the vmtruncation but mmu_notifier_register can run after mmu_notifier_invalidate_range_start and before mmu_notifier_invalidate_range_end). Same problem for rmap paths. And we've to remove page pinning to avoid replicating the tlb_gather logic inside KVM (and GRU doesn't work well with page pinning regardless of needing tlb_gather), so without mm_take_all_locks when vmtruncate frees the page, kvm would have no way to notice that it mapped into sptes a page that is going into the freelist without a chance of any further mmu_notifier notification. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Andrea Arcangeli Acked-by: Linus Torvalds Cc: Christoph Lameter Cc: Jack Steiner Cc: Robin Holt Cc: Nick Piggin Cc: Peter Zijlstra Cc: Kanoj Sarcar Cc: Roland Dreier Cc: Steve Wise Cc: Avi Kivity Cc: Hugh Dickins Cc: Rusty Russell Cc: Anthony Liguori Cc: Chris Wright Cc: Marcelo Tosatti Cc: Eric Dumazet Cc: "Paul E. McKenney" Cc: Izik Eidus Cc: Anthony Liguori Cc: Rik van Riel Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Memory controller: make page_referenced() cgroup aware

2008-02-07T16:42:19+00:00

Make page_referenced() cgroup aware. Without this patch, page_referenced() can cause a page to be skipped while reclaiming pages. This patch ensures that other cgroups do not hold pages in a particular cgroup hostage. It is required to ensure that shared pages are freed from a cgroup when they are not actively referenced from the cgroup that brought them in Signed-off-by: Balbir Singh Cc: Pavel Emelianov Cc: Paul Menage Cc: Peter Zijlstra Cc: "Eric W. Biederman" Cc: Nick Piggin Cc: Kirill Korotaev Cc: Herbert Poetzl Cc: David Rientjes Cc: Vaidyanathan Srinivasan Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

mm: more rmap checking

2007-05-17T12:23:06+00:00

Re-introduce rmap verification patches that Hugh removed when he removed PG_map_lock. PG_map_lock actually isn't needed to synchronise access to anonymous pages, because PG_locked and PTL together already do. These checks were important in discovering and fixing a rare rmap corruption in SLES9. Signed-off-by: Nick Piggin Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] mm: more rmap debugging

2006-12-22T16:55:49+00:00

Add more debugging in the rmap code in an attempt to locate to source of the occasional "mapcount went negative" assertions. Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] slab: remove kmem_cache_t

2006-12-07T16:39:25+00:00

Replace all uses of kmem_cache_t with struct kmem_cache. The patch was generated using the following script: #!/bin/sh # # Replace one string by another in all the kernel sources. # set -e for file in `find * -name "*.c" -o -name "*.h"|xargs grep -l $1`; do quilt add $file sed -e "1,\$s/$1/$2/g" $file >/tmp/$$ mv /tmp/$$ $file quilt refresh done The script was run like this sh replace kmem_cache_t "struct kmem_cache" Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

[PATCH] slab: remove SLAB_KERNEL

2006-12-07T16:39:24+00:00

SLAB_KERNEL is an alias of GFP_KERNEL. Signed-off-by: Christoph Lameter Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds