- 22 Sep, 2009 40 commits
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Izik Eidus authored
KSM is a linux driver that allows dynamicly sharing identical memory pages between one or more processes. Unlike tradtional page sharing that is made at the allocation of the memory, ksm do it dynamicly after the memory was created. Memory is periodically scanned; identical pages are identified and merged. The sharing is made in a transparent way to the processes that use it. Ksm is highly important for hypervisors (kvm), where in production enviorments there might be many copys of the same data data among the host memory. This kind of data can be: similar kernels, librarys, cache, and so on. Even that ksm was wrote for kvm, any userspace application that want to use it to share its data can try it. Ksm may be useful for any application that might have similar (page aligment) data strctures among the memory, ksm will find this data merge it to one copy, and even if it will be changed and thereforew copy on writed, ksm will merge it again as soon as it will be identical again. Another reason to consider using ksm is the fact that it might simplify alot the userspace code of application that want to use shared private data, instead that the application will mange shared area, ksm will do this for the application, and even write to this data will be allowed without any synchinization acts from the application. Ksm was designed to be a loadable module that doesn't change the VM code of linux. This patch: The set_pte_at_notify() macro allows setting a pte in the shadow page table directly, instead of flushing the shadow page table entry and then getting vmexit to set it. It uses a new change_pte() callback to do so. set_pte_at_notify() is an optimization for kvm, and other users of mmu_notifiers, for COW pages. It is useful for kvm when ksm is used, because it allows kvm not to have to receive vmexit and only then map the ksm page into the shadow page table, but instead map it directly at the same time as Linux maps the page into the host page table. Users of mmu_notifiers who don't implement new mmu_notifier_change_pte() callback will just receive the mmu_notifier_invalidate_page() callback. Signed-off-by:
Izik Eidus <ieidus@redhat.com> Signed-off-by:
Chris Wright <chrisw@redhat.com> Signed-off-by:
Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Rik van Riel <riel@redhat.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Avi Kivity <avi@redhat.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org>
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Johannes Weiner authored
By the time PG_mlocked is cleared in the page freeing path, nobody else is looking at our page->flags anymore. It is thus safe to make the test-and-clear non-atomic and thereby removing an unnecessary and expensive operation from a hotpath. Signed-off-by:
Johannes Weiner <hannes@cmpxchg.org> Reviewed-by:
Christoph Lameter <cl@linux-foundation.org> Reviewed-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by:
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Figo.zhang authored
There is no need for double error checking. Signed-off-by:
Figo.zhang <figo1802@gmail.com> Acked-by:
Tejun Heo <tj@kernel.org> Signed-off-by:
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Akinobu Mita authored
__get_free_pages() with __GFP_HIGHMEM is not safe because the return address cannot represent a highmem page. get_zeroed_page() already has such a debug checking. Signed-off-by:
Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by:
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KOSAKI Motohiro authored
The pages in the list passed move_active_pages_to_lru() are already touched by shrink_active_list(). IOW the prefetch in move_active_pages_to_lru() don't populate any cache. it's pointless. This patch remove it. Signed-off-by:
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KOSAKI Motohiro authored
The page_lru() already evaluate PageActive() and PageSwapBacked(). We don't need to re-evaluate it. Signed-off-by:
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KOSAKI Motohiro authored
The move_active_pages_to_lru() function is called under irq disabled and ClearPageActive() doesn't need irq disabling. Then, this patch move it into shrink_active_list(). Signed-off-by:
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Minchan Kim authored
The VM already avoids attempting to reclaim anon pages in various places, But it doesn't avoid it for lumpy reclaim. It shuffles lru list unnecessary so that it is pointless. [akpm@linux-foundation.org: cleanup] Signed-off-by:
Minchan Kim <minchan.kim@gmail.com> Reviewed-by:
Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by:
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Wu Fengguang authored
global_lru_pages() / zone_lru_pages() can be used in two ways: - to estimate max reclaimable pages in determine_dirtyable_memory() - to calculate the slab scan ratio When swap is full or not present, the anon lru lists are not reclaimable and also won't be scanned. So the anon pages shall not be counted in both usage scenarios. Also rename to _reclaimable_pages: now they are counting the possibly reclaimable lru pages. It can greatly (and correctly) increase the slab scan rate under high memory pressure (when most file pages have been reclaimed and swap is full/absent), thus reduce false OOM kills. Acked-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by:
Wu Fengguang <fengguang.wu@intel.com> Acked-by:
Jesse Barnes <jbarnes@virtuousgeek.org> Cc: David Howells <dhowells@redhat.com> Cc: "Li, Ming Chun" <macli@brc.ubc.ca> Signed-off-by:
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Jan Kara authored
Reported-by:
Christian Thaeter <ct@pipapo.org> Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
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KOSAKI Motohiro authored
__add_zone_page_state() and __sub_zone_page_state() are unused. Signed-off-by:
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Rik van Riel authored
When way too many processes go into direct reclaim, it is possible for all of the pages to be taken off the LRU. One result of this is that the next process in the page reclaim code thinks there are no reclaimable pages left and triggers an out of memory kill. One solution to this problem is to never let so many processes into the page reclaim path that the entire LRU is emptied. Limiting the system to only having half of each inactive list isolated for reclaim should be safe. Signed-off-by:
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KOSAKI Motohiro authored
If the system is running a heavy load of processes then concurrent reclaim can isolate a large number of pages from the LRU. /proc/vmstat and the output generated for an OOM do not show how many pages were isolated. This has been observed during process fork bomb testing (mstctl11 in LTP). This patch shows the information about isolated pages. Reproduced via: ----------------------- % ./hackbench 140 process 1000 => OOM occur active_anon:146 inactive_anon:0 isolated_anon:49245 active_file:79 inactive_file:18 isolated_file:113 unevictable:0 dirty:0 writeback:0 unstable:0 buffer:39 free:370 slab_reclaimable:309 slab_unreclaimable:5492 mapped:53 shmem:15 pagetables:28140 bounce:0 Signed-off-by:
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KOSAKI Motohiro authored
If sc->isolate_pages() return 0, we don't need to call shrink_page_list(). In past days, shrink_inactive_list() handled it properly. But commit fb8d14e1 (three years ago commit!) breaked it. current shrink_inactive_list() always call shrink_page_list() although isolate_pages() return 0. This patch restore proper return value check. Requirements: o "nr_taken == 0" condition should stay before calling shrink_page_list(). o "nr_taken == 0" condition should stay after nr_scan related statistics modification. Cc: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by:
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KOSAKI Motohiro authored
Currently the pgmoved variable has two meanings. It causes harder reviewing. This patch separates it. Signed-off-by:
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David Rientjes authored
It is possible for the oom killer to select current as the task to kill. When this happens, alloc_flags needs to be updated accordingly to set ALLOC_NO_WATERMARKS so the subsequent allocation attempt may use memory reserves as the result of its thread having TIF_MEMDIE set if the allocation is not __GFP_NOMEMALLOC. Acked-by:
Mel Gorman <mel@csn.ul.ie> Signed-off-by:
David Rientjes <rientjes@google.com> Signed-off-by:
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KOSAKI Motohiro authored
Recently we encountered OOM problems due to memory use of the GEM cache. Generally a large amuont of Shmem/Tmpfs pages tend to create a memory shortage problem. We often use the following calculation to determine the amount of shmem pages: shmem = NR_ACTIVE_ANON + NR_INACTIVE_ANON - NR_ANON_PAGES however the expression does not consider isolated and mlocked pages. This patch adds explicit accounting for pages used by shmem and tmpfs. Signed-off-by:
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KOSAKI Motohiro authored
The amount of memory allocated to kernel stacks can become significant and cause OOM conditions. However, we do not display the amount of memory consumed by stacks. Add code to display the amount of memory used for stacks in /proc/meminfo. Signed-off-by:
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KOSAKI Motohiro authored
It is often useful to know the statistics for all pages that are handled like page cache pages when looking at OOM log output. Therefore show_free_areas() should also display buffer cache statistics. Signed-off-by:
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KOSAKI Motohiro authored
show_free_areas() displays only a limited amount of zone counters. This patch includes additional counters in the display to allow easier debugging. This may be especially useful if an OOM is due to running out of DMA memory. Signed-off-by:
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Andi Kleen authored
Remove some very outdated recommendations in Documentation/memory.txt Signed-off-by:
Andi Kleen <ak@linux.intel.com> Signed-off-by:
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KOSAKI Motohiro authored
If an OOM happens, we really want to know the number of remaining reclaimable pages. So the reclaimable slab and unreclaimable slab fields should not be combined for display. Signed-off-by:
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KOSAKI Motohiro authored
page_remove_rmap() has multiple PageAnon() tests and it has deep nesting. Clean this up. Signed-off-by:
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Lee Schermerhorn authored
I noticed that alloc_bootmem_huge_page() will only advance to the next node on failure to allocate a huge page, potentially filling nodes with huge-pages. I asked about this on linux-mm and linux-numa, cc'ing the usual huge page suspects. Mel Gorman responded: I strongly suspect that the same node being used until allocation failure instead of round-robin is an oversight and not deliberate at all. It appears to be a side-effect of a fix made way back in commit 63b4613c ["hugetlb: fix hugepage allocation with memoryless nodes"]. Prior to that patch it looked like allocations would always round-robin even when allocation was successful. This patch--factored out of my "hugetlb mempolicy" series--moves the advance of the hstate next node from which to allocate up before the test for success of the attempted allocation. Note that alloc_bootmem_huge_page() is only used for order > MAX_ORDER huge pages. I'll post a separate patch for mainline/stable, as the above mentioned "balance freeing" series renamed the next node to alloc function. Signed-off-by:
Lee Schermerhorn <lee.schermerhorn@hp.com> Reviewed-by:
Andy Whitcroft <apw@canonical.com> Reviewed-by:
Andi Kleen <andi@firstfloor.org> Signed-off-by:
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Lee Schermerhorn authored
Attempt to clarify huge page administration and usage, and updates the doucmentation to mention the balancing of huge pages across nodes when allocating and freeing. Signed-off-by:
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Lee Schermerhorn authored
Use the [modified] free_pool_huge_page() function to return unused surplus pages. This will help keep huge pages balanced across nodes between freeing of unused surplus pages and freeing of persistent huge pages [from set_max_huge_pages] by using the same node id "cursor". It also eliminates some code duplication. Signed-off-by:
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Lee Schermerhorn authored
Free huges pages from nodes in round robin fashion in an attempt to keep [persistent a.k.a static] hugepages balanced across nodes New function free_pool_huge_page() is modeled on and performs roughly the inverse of alloc_fresh_huge_page(). Replaces dequeue_huge_page() which now has no callers, so this patch removes it. Helper function hstate_next_node_to_free() uses new hstate member next_to_free_nid to distribute "frees" across all nodes with huge pages. Acked-by:
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Randy Dunlap authored
Ummark function as having kernel-doc notation, fixing the kernel-doc warning. Warning(mm/page_alloc.c:4519): No description found for parameter 'zone' Signed-off-by:
Randy Dunlap <randy.dunlap@oracle.com> Signed-off-by:
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Shaohua Li authored
In test, some pages in swap-cache can't be migrated, as they aren't rmap. unmap_and_move() ignores swap-cache page which is just read in and hasn't rmap (see the comments in the code), but swap_aops provides .migratepage. Better to migrate such pages instead of ignore them. Signed-off-by:
Shaohua Li <shaohua.li@intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Yakui Zhao <yakui.zhao@intel.com> Signed-off-by:
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Shaohua Li authored
To initialize hotadded node, some pages are allocated. At that time, the node hasn't memory, this makes the allocation always fail. In such case, let's allocate pages from other nodes. Signed-off-by:
Yakui Zhao <yakui.zhao@intel.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Signed-off-by:
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Shaohua Li authored
Pages on movable zone have two types, MIGRATE_MOVABLE and MIGRATE_RESERVE, both them can be movable, because only movable memory allocation can get pages from movable zone. This makes pages in movable zone always be able to migrate. Signed-off-by:
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Shaohua Li authored
Pages marked as isolated should not be allocated again. If such pages reside in pcp list, they can be allocated too, so there is a ping-pong memory offline frees some pages to pcp list and the pages get allocated and then memory offline frees them again, this loop will happen again and again. This should have no impact in normal code path, because in normal code path, pages in pcp list aren't isolated, and below loop will break in the first entry. Signed-off-by:
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Shaohua Li authored
In my test, 128M memory is hot added, but zone's pcp batch is 0, which is an obvious error. When pages are onlined, zone pcp should be updated accordingly. [akpm@linux-foundation.org: fix warnings] Signed-off-by:
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David Rientjes authored
When a cpuset's nodemask is updated, all attached tasks have their cached task->mems_allowed updated by a heap instead of requiring an explicit call to cpuset_update_task_memory_state(), which has since been removed in 58568d2a ("cpuset,mm: update tasks' mems_allowed in time"). Remove the obsoleted comment from the page allocator. Cc: Paul Menage <menage@google.com> Acked-by:
Miao Xie <miaox@cn.fujitsu.com> Signed-off-by:
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Johannes Weiner authored
Make use of the compiler's typechecking on !CONFIG_SWAP as well. [akpm@linux-foundation.org: build fix] Signed-off-by:
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Alexey Dobriyan authored
Signed-off-by:
Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by:
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Alexey Dobriyan authored
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Alexey Dobriyan authored
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Alexey Dobriyan authored
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Alexey Dobriyan authored
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