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* sysctl: remove "struct file *" argument of ->proc_handlerAlexey Dobriyan2009-09-24
| | | | | | | | | | | | | | | | | | | | | It's unused. It isn't needed -- read or write flag is already passed and sysctl shouldn't care about the rest. It _was_ used in two places at arch/frv for some reason. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Cc: David Howells <dhowells@redhat.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: "David S. Miller" <davem@davemloft.net> Cc: James Morris <jmorris@namei.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* page-allocator: split per-cpu list into one-list-per-migrate-typeMel Gorman2009-09-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The following two patches remove searching in the page allocator fast-path by maintaining multiple free-lists in the per-cpu structure. At the time the search was introduced, increasing the per-cpu structures would waste a lot of memory as per-cpu structures were statically allocated at compile-time. This is no longer the case. The patches are as follows. They are based on mmotm-2009-08-27. Patch 1 adds multiple lists to struct per_cpu_pages, one per migratetype that can be stored on the PCP lists. Patch 2 notes that the pcpu drain path check empty lists multiple times. The patch reduces the number of checks by maintaining a count of free lists encountered. Lists containing pages will then free multiple pages in batch The patches were tested with kernbench, netperf udp/tcp, hackbench and sysbench. The netperf tests were not bound to any CPU in particular and were run such that the results should be 99% confidence that the reported results are within 1% of the estimated mean. sysbench was run with a postgres background and read-only tests. Similar to netperf, it was run multiple times so that it's 99% confidence results are within 1%. The patches were tested on x86, x86-64 and ppc64 as x86: Intel Pentium D 3GHz with 8G RAM (no-brand machine) kernbench - No significant difference, variance well within noise netperf-udp - 1.34% to 2.28% gain netperf-tcp - 0.45% to 1.22% gain hackbench - Small variances, very close to noise sysbench - Very small gains x86-64: AMD Phenom 9950 1.3GHz with 8G RAM (no-brand machine) kernbench - No significant difference, variance well within noise netperf-udp - 1.83% to 10.42% gains netperf-tcp - No conclusive until buffer >= PAGE_SIZE 4096 +15.83% 8192 + 0.34% (not significant) 16384 + 1% hackbench - Small gains, very close to noise sysbench - 0.79% to 1.6% gain ppc64: PPC970MP 2.5GHz with 10GB RAM (it's a terrasoft powerstation) kernbench - No significant difference, variance well within noise netperf-udp - 2-3% gain for almost all buffer sizes tested netperf-tcp - losses on small buffers, gains on larger buffers possibly indicates some bad caching effect. hackbench - No significant difference sysbench - 2-4% gain This patch: Currently the per-cpu page allocator searches the PCP list for pages of the correct migrate-type to reduce the possibility of pages being inappropriate placed from a fragmentation perspective. This search is potentially expensive in a fast-path and undesirable. Splitting the per-cpu list into multiple lists increases the size of a per-cpu structure and this was potentially a major problem at the time the search was introduced. These problem has been mitigated as now only the necessary number of structures is allocated for the running system. This patch replaces a list search in the per-cpu allocator with one list per migrate type. The potential snag with this approach is when bulk freeing pages. We round-robin free pages based on migrate type which has little bearing on the cache hotness of the page and potentially checks empty lists repeatedly in the event the majority of PCP pages are of one type. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Nick Piggin <npiggin@suse.de> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: do batched scans for mem_cgroupWu Fengguang2009-09-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | For mem_cgroup, shrink_zone() may call shrink_list() with nr_to_scan=1, in which case shrink_list() _still_ calls isolate_pages() with the much larger SWAP_CLUSTER_MAX. It effectively scales up the inactive list scan rate by up to 32 times. For example, with 16k inactive pages and DEF_PRIORITY=12, (16k >> 12)=4. So when shrink_zone() expects to scan 4 pages in the active/inactive list, the active list will be scanned 4 pages, while the inactive list will be (over) scanned SWAP_CLUSTER_MAX=32 pages in effect. And that could break the balance between the two lists. It can further impact the scan of anon active list, due to the anon active/inactive ratio rebalance logic in balance_pgdat()/shrink_zone(): inactive anon list over scanned => inactive_anon_is_low() == TRUE => shrink_active_list() => active anon list over scanned So the end result may be - anon inactive => over scanned - anon active => over scanned (maybe not as much) - file inactive => over scanned - file active => under scanned (relatively) The accesses to nr_saved_scan are not lock protected and so not 100% accurate, however we can tolerate small errors and the resulted small imbalanced scan rates between zones. Cc: Rik van Riel <riel@redhat.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Balbir Singh <balbir@linux.vnet.ibm.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: vmstat: add isolate pagesKOSAKI Motohiro2009-09-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: oom analysis: add shmem vmstatKOSAKI Motohiro2009-09-22
| | | | | | | | | | | | | | | | | | | | | | | | 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: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Acked-by: Wu Fengguang <fengguang.wu@intel.com> Cc: David Rientjes <rientjes@google.com> Cc: Hugh Dickins <hugh.dickins@tiscali.co.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: oom analysis: Show kernel stack usage in /proc/meminfo and OOM log outputKOSAKI Motohiro2009-09-22
| | | | | | | | | | | | | | | | 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: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove CONFIG_UNEVICTABLE_LRU config optionKOSAKI Motohiro2009-06-16
| | | | | | | | | | | | | | | | Currently, nobody wants to turn UNEVICTABLE_LRU off. Thus this configurability is unnecessary. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Andi Kleen <andi@firstfloor.org> Acked-by: Minchan Kim <minchan.kim@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Rik van Riel <riel@redhat.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: cleanup the scan batching codeWu Fengguang2009-06-16
| | | | | | | | | | | | | | The vmscan batching logic is twisting. Move it into a standalone function nr_scan_try_batch() and document it. No behavior change. Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Nick Piggin <npiggin@suse.de> Cc: Christoph Lameter <cl@linux-foundation.org> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* page allocator: use allocation flags as an index to the zone watermarkMel Gorman2009-06-16
| | | | | | | | | | | | | | | | | | | | | | | ALLOC_WMARK_MIN, ALLOC_WMARK_LOW and ALLOC_WMARK_HIGH determin whether pages_min, pages_low or pages_high is used as the zone watermark when allocating the pages. Two branches in the allocator hotpath determine which watermark to use. This patch uses the flags as an array index into a watermark array that is indexed with WMARK_* defines accessed via helpers. All call sites that use zone->pages_* are updated to use the helpers for accessing the values and the array offsets for setting. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* page allocator: move check for disabled anti-fragmentation out of fastpathMel Gorman2009-06-16
| | | | | | | | | | | | | | | | | | | | On low-memory systems, anti-fragmentation gets disabled as there is nothing it can do and it would just incur overhead shuffling pages between lists constantly. Currently the check is made in the free page fast path for every page. This patch moves it to a slow path. On machines with low memory, there will be small amount of additional overhead as pages get shuffled between lists but it should quickly settle. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Christoph Lameter <cl@linux-foundation.org> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [ARM] Double check memmap is actually valid with a memmap has unexpected ↵Mel Gorman2009-05-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | holes V2 pfn_valid() is meant to be able to tell if a given PFN has valid memmap associated with it or not. In FLATMEM, it is expected that holes always have valid memmap as long as there is valid PFNs either side of the hole. In SPARSEMEM, it is assumed that a valid section has a memmap for the entire section. However, ARM and maybe other embedded architectures in the future free memmap backing holes to save memory on the assumption the memmap is never used. The page_zone linkages are then broken even though pfn_valid() returns true. A walker of the full memmap must then do this additional check to ensure the memmap they are looking at is sane by making sure the zone and PFN linkages are still valid. This is expensive, but walkers of the full memmap are extremely rare. This was caught before for FLATMEM and hacked around but it hits again for SPARSEMEM because the page_zone linkages can look ok where the PFN linkages are totally screwed. This looks like a hatchet job but the reality is that any clean solution would end up consumning all the memory saved by punching these unexpected holes in the memmap. For example, we tried marking the memmap within the section invalid but the section size exceeds the size of the hole in most cases so pfn_valid() starts returning false where valid memmap exists. Shrinking the size of the section would increase memory consumption offsetting the gains. This patch identifies when an architecture is punching unexpected holes in the memmap that the memory model cannot automatically detect and sets ARCH_HAS_HOLES_MEMORYMODEL. At the moment, this is restricted to EP93xx which is the model sub-architecture this has been reported on but may expand later. When set, walkers of the full memmap must call memmap_valid_within() for each PFN and passing in what it expects the page and zone to be for that PFN. If it finds the linkages to be broken, it assumes the memmap is invalid for that PFN. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* Merge git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumaskLinus Torvalds2009-04-05
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux-2.6-cpumask: (36 commits) cpumask: remove cpumask allocation from idle_balance, fix numa, cpumask: move numa_node_id default implementation to topology.h, fix cpumask: remove cpumask allocation from idle_balance x86: cpumask: x86 mmio-mod.c use cpumask_var_t for downed_cpus x86: cpumask: update 32-bit APM not to mug current->cpus_allowed x86: microcode: cleanup x86: cpumask: use work_on_cpu in arch/x86/kernel/microcode_core.c cpumask: fix CONFIG_CPUMASK_OFFSTACK=y cpu hotunplug crash numa, cpumask: move numa_node_id default implementation to topology.h cpumask: convert node_to_cpumask_map[] to cpumask_var_t cpumask: remove x86 cpumask_t uses. cpumask: use cpumask_var_t in uv_flush_tlb_others. cpumask: remove cpumask_t assignment from vector_allocation_domain() cpumask: make Xen use the new operators. cpumask: clean up summit's send_IPI functions cpumask: use new cpumask functions throughout x86 x86: unify cpu_callin_mask/cpu_callout_mask/cpu_initialized_mask/cpu_sibling_setup_mask cpumask: convert struct cpuinfo_x86's llc_shared_map to cpumask_var_t cpumask: convert node_to_cpumask_map[] to cpumask_var_t x86: unify 32 and 64-bit node_to_cpumask_map ...
| * numa, cpumask: move numa_node_id default implementation to topology.hRusty Russell2009-03-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Impact: cleanup, potential bugfix Not sure what changed to expose this, but clearly that numa_node_id() doesn't belong in mmzone.h (the inline in gfp.h is probably overkill, too). In file included from include/linux/topology.h:34, from arch/x86/mm/numa.c:2: /home/rusty/patches-cpumask/linux-2.6/arch/x86/include/asm/topology.h:64:1: warning: "numa_node_id" redefined In file included from include/linux/topology.h:32, from arch/x86/mm/numa.c:2: include/linux/mmzone.h:770:1: warning: this is the location of the previous definition Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: Mike Travis <travis@sgi.com> LKML-Reference: <200903132343.37661.rusty@rustcorp.com.au> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* | mm: introduce for_each_populated_zone() macroKOSAKI Motohiro2009-04-01
|/ | | | | | | | | | | | | | | | | | Impact: cleanup In almost cases, for_each_zone() is used with populated_zone(). It's because almost function doesn't need memoryless node information. Therefore, for_each_populated_zone() can help to make code simplify. This patch has no functional change. [akpm@linux-foundation.org: small cleanup] Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix memmap init for handling memory holeKAMEZAWA Hiroyuki2009-02-18
| | | | | | | | | | | | | | | | | | Now, early_pfn_in_nid(PFN, NID) may returns false if PFN is a hole. and memmap initialization was not done. This was a trouble for sparc boot. To fix this, the PFN should be initialized and marked as PG_reserved. This patch changes early_pfn_in_nid() return true if PFN is a hole. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reported-by: David Miller <davem@davemlloft.net> Tested-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: <stable@kernel.org> [2.6.25.x, 2.6.26.x, 2.6.27.x, 2.6.28.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: introduce zone_reclaim structKOSAKI Motohiro2009-01-08
| | | | | | | | | | | | | | | | Add zone_reclam_stat struct for later enhancement. A later patch uses this. This patch doesn't any behavior change (yet). Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Hugh Dickins <hugh@veritas.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memcg: allocate all page_cgroup at bootKAMEZAWA Hiroyuki2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Allocate all page_cgroup at boot and remove page_cgroup poitner from struct page. This patch adds an interface as struct page_cgroup *lookup_page_cgroup(struct page*) All FLATMEM/DISCONTIGMEM/SPARSEMEM and MEMORY_HOTPLUG is supported. Remove page_cgroup pointer reduces the amount of memory by - 4 bytes per PAGE_SIZE. - 8 bytes per PAGE_SIZE if memory controller is disabled. (even if configured.) On usual 8GB x86-32 server, this saves 8MB of NORMAL_ZONE memory. On my x86-64 server with 48GB of memory, this saves 96MB of memory. I think this reduction makes sense. By pre-allocation, kmalloc/kfree in charge/uncharge are removed. This means - we're not necessary to be afraid of kmalloc faiulre. (this can happen because of gfp_mask type.) - we can avoid calling kmalloc/kfree. - we can avoid allocating tons of small objects which can be fragmented. - we can know what amount of memory will be used for this extra-lru handling. I added printk message as "allocated %ld bytes of page_cgroup" "please try cgroup_disable=memory option if you don't want" maybe enough informative for users. Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Balbir Singh <balbir@linux.vnet.ibm.com> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmstat: mlocked pages statisticsNick Piggin2008-10-20
| | | | | | | | | | | | | | | | | Add NR_MLOCK zone page state, which provides a (conservative) count of mlocked pages (actually, the number of mlocked pages moved off the LRU). Reworked by lts to fit in with the modified mlock page support in the Reclaim Scalability series. [kosaki.motohiro@jp.fujitsu.com: fix incorrect Mlocked field of /proc/meminfo] [lee.schermerhorn@hp.com: mlocked-pages: add event counting with statistics] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Unevictable LRU InfrastructureLee Schermerhorn2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: second chance replacement for anonymous pagesRik van Riel2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We avoid evicting and scanning anonymous pages for the most part, but under some workloads we can end up with most of memory filled with anonymous pages. At that point, we suddenly need to clear the referenced bits on all of memory, which can take ages on very large memory systems. We can reduce the maximum number of pages that need to be scanned by not taking the referenced state into account when deactivating an anonymous page. After all, every anonymous page starts out referenced, so why check? If an anonymous page gets referenced again before it reaches the end of the inactive list, we move it back to the active list. To keep the maximum amount of necessary work reasonable, we scale the active to inactive ratio with the size of memory, using the formula active:inactive ratio = sqrt(memory in GB * 10). Kswapd CPU use now seems to scale by the amount of pageout bandwidth, instead of by the amount of memory present in the system. [kamezawa.hiroyu@jp.fujitsu.com: fix OOM with memcg] [kamezawa.hiroyu@jp.fujitsu.com: memcg: lru scan fix] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: split LRU lists into anon & file setsRik van Riel2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs. The advantage of doing this is that the VM will not have to scan over lots of anonymous pages (which we generally do not want to swap out), just to find the page cache pages that it should evict. This patch has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches. [lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset] [kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru] [kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page] [hugh@veritas.com: memcg swapbacked pages active] [hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED] [akpm@linux-foundation.org: fix /proc/vmstat units] [nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration] [kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo] [kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: Use an indexed array for LRU variablesChristoph Lameter2008-10-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently we are defining explicit variables for the inactive and active list. An indexed array can be more generic and avoid repeating similar code in several places in the reclaim code. We are saving a few bytes in terms of code size: Before: text data bss dec hex filename 4097753 573120 4092484 8763357 85b7dd vmlinux After: text data bss dec hex filename 4097729 573120 4092484 8763333 85b7c5 vmlinux Having an easy way to add new lru lists may ease future work on the reclaim code. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: mark the correct zone as full when scanning zonelistsMel Gorman2008-09-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | The iterator for_each_zone_zonelist() uses a struct zoneref *z cursor when scanning zonelists to keep track of where in the zonelist it is. The zoneref that is returned corresponds to the the next zone that is to be scanned, not the current one. It was intended to be treated as an opaque list. When the page allocator is scanning a zonelist, it marks elements in the zonelist corresponding to zones that are temporarily full. As the zonelist is being updated, it uses the cursor here; if (NUMA_BUILD) zlc_mark_zone_full(zonelist, z); This is intended to prevent rescanning in the near future but the zoneref cursor does not correspond to the zone that has been found to be full. This is an easy misunderstanding to make so this patch corrects the problem by changing zoneref cursor to be the current zone being scanned instead of the next one. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@kernel.org> [2.6.26.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* for_each_online_pgdat(): kerneldoc fixFernando Luis Vazquez Cao2008-05-24
| | | | | | | | | for_each_pgdat() was renamed to for_each_online_pgdat() and kerneldoc comments should be updated accordingly. Signed-off-by: Fernando Luis Vazquez Cao <fernando@oss.ntt.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove "#ifdef __KERNEL__" checks from unexported headersRobert P. J. Day2008-04-30
| | | | | | | | | | | | Remove the "#ifdef __KERNEL__" tests from unexported header files in linux/include whose entire contents are wrapped in that preprocessor test. Signed-off-by: Robert P. J. Day <rpjday@crashcourse.ca> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Add NR_WRITEBACK_TEMP counterMiklos Szeredi2008-04-30
| | | | | | | | | | | | | | | | | | | | Fuse will use temporary buffers to write back dirty data from memory mappings (normal writes are done synchronously). This is needed, because there cannot be any guarantee about the time in which a write will complete. By using temporary buffers, from the MM's point if view the page is written back immediately. If the writeout was due to memory pressure, this effectively migrates data from a full zone to a less full zone. This patch adds a new counter (NR_WRITEBACK_TEMP) for the number of pages used as temporary buffers. [Lee.Schermerhorn@hp.com: add vmstat_text for NR_WRITEBACK_TEMP] Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memory hotplug: register section/node id to freeYasunori Goto2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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: Yasunori 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: Get rid of __ZONE_COUNTChristoph Lameter2008-04-28
| | | | | | | | | | 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: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* pageflags: get rid of FLAGS_RESERVEDChristoph Lameter2008-04-28
| | | | | | | | | | | | | | | | | | | | | | 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: Christoph 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: make early_pfn_to_nid() a C functionAndrew Morton2008-04-28
| | | | | | | | | | | | | | | | | | | | | Fix this (sparc64) mm/sparse-vmemmap.c: In function `vmemmap_verify': mm/sparse-vmemmap.c:64: warning: unused variable `pfn' by switching to a C function which touches its arg. (reason 3,555 why macros are bad) Also, the `nid' arg was misnamed. Reviewed-by: Christoph Lameter <clameter@sgi.com> Acked-by: Andy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Andi Kleen <ak@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: filter based on a nodemask as well as a gfp_maskMel Gorman2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | The MPOL_BIND policy creates a zonelist that is used for allocations controlled by that mempolicy. As the per-node zonelist is already being filtered based on a zone id, this patch adds a version of __alloc_pages() that takes a nodemask for further filtering. This eliminates the need for MPOL_BIND to create a custom zonelist. A positive benefit of this is that allocations using MPOL_BIND now use the local node's distance-ordered zonelist instead of a custom node-id-ordered zonelist. I.e., pages will be allocated from the closest allowed node with available memory. [Lee.Schermerhorn@hp.com: Mempolicy: update stale documentation and comments] [Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask] [Lee.Schermerhorn@hp.com: Mempolicy: make dequeue_huge_page_vma() obey MPOL_BIND nodemask rework] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Hugh Dickins <hugh@veritas.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>
* mm: have zonelist contains structs with both a zone pointer and zone_idxMel Gorman2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Filtering zonelists requires very frequent use of zone_idx(). This is costly as it involves a lookup of another structure and a substraction operation. As the zone_idx is often required, it should be quickly accessible. The node idx could also be stored here if it was found that accessing zone->node is significant which may be the case on workloads where nodemasks are heavily used. This patch introduces a struct zoneref to store a zone pointer and a zone index. The zonelist then consists of an array of these struct zonerefs which are looked up as necessary. Helpers are given for accessing the zone index as well as the node index. [kamezawa.hiroyu@jp.fujitsu.com: Suggested struct zoneref instead of embedding information in pointers] [hugh@veritas.com: mm-have-zonelist: fix memcg ooms] [hugh@veritas.com: just return do_try_to_free_pages] [hugh@veritas.com: do_try_to_free_pages gfp_mask redundant] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: use two zonelist that are filtered by GFP maskMel Gorman2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | Currently a node has two sets of zonelists, one for each zone type in the system and a second set for GFP_THISNODE allocations. Based on the zones allowed by a gfp mask, one of these zonelists is selected. All of these zonelists consume memory and occupy cache lines. This patch replaces the multiple zonelists per-node with two zonelists. The first contains all populated zones in the system, ordered by distance, for fallback allocations when the target/preferred node has no free pages. The second contains all populated zones in the node suitable for GFP_THISNODE allocations. An iterator macro is introduced called for_each_zone_zonelist() that interates through each zone allowed by the GFP flags in the selected zonelist. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <clameter@sgi.com> Cc: Hugh Dickins <hugh@veritas.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>
* remove sparse warning for mmzone.hHarvey Harrison2008-04-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | include/linux/mmzone.h:640:22: warning: potentially expensive pointer subtraction Calculate the offset into the node_zones array rather than the index using casts to (char *) and comparing against the index * sizeof(struct zone). On X86_32 this saves a sar, but code size increases by one byte per is_highmem() use due to 32-bit cmps rather than 16 bit cmps. Before: 207: 2b 80 8c 07 00 00 sub 0x78c(%eax),%eax 20d: c1 f8 0b sar $0xb,%eax 210: 83 f8 02 cmp $0x2,%eax 213: 74 16 je 22b <kmap_atomic_prot+0x144> 215: 83 f8 03 cmp $0x3,%eax 218: 0f 85 8f 00 00 00 jne 2ad <kmap_atomic_prot+0x1c6> 21e: 83 3d 00 00 00 00 02 cmpl $0x2,0x0 225: 0f 85 82 00 00 00 jne 2ad <kmap_atomic_prot+0x1c6> 22b: 64 a1 00 00 00 00 mov %fs:0x0,%eax After: 207: 2b 80 8c 07 00 00 sub 0x78c(%eax),%eax 20d: 3d 00 10 00 00 cmp $0x1000,%eax 212: 74 18 je 22c <kmap_atomic_prot+0x145> 214: 3d 00 18 00 00 cmp $0x1800,%eax 219: 0f 85 8f 00 00 00 jne 2ae <kmap_atomic_prot+0x1c7> 21f: 83 3d 00 00 00 00 02 cmpl $0x2,0x0 226: 0f 85 82 00 00 00 jne 2ae <kmap_atomic_prot+0x1c7> 22c: 64 a1 00 00 00 00 mov %fs:0x0,%eax [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove unused MAX_NODES_SHIFTJohannes Weiner2008-04-21
| | | | | | | MAX_NODES_SHIFT is not referenced anywhere in the tree, so dump it. Signed-off-by: Johannes Weiner <hannes@saeurebad.de> Signed-off-by: Jesper Juhl <jesper.juhl@gmail.com>
* Page allocator: get rid of the list of cold pagesChristoph Lameter2008-02-05
| | | | | | | | | | | | | | | | | We have repeatedly discussed if the cold pages still have a point. There is one way to join the two lists: Use a single list and put the cold pages at the end and the hot pages at the beginning. That way a single list can serve for both types of allocations. The discussion of the RFC for this and Mel's measurements indicate that there may not be too much of a point left to having separate lists for hot and cold pages (see http://marc.info/?t=119492914200001&r=1&w=2). Signed-off-by: Christoph Lameter <clameter@sgi.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Martin Bligh <mbligh@mbligh.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: test and set zone reclaim lock before starting reclaimDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | Introduces new zone flag interface for testing and setting flags: int zone_test_and_set_flag(struct zone *zone, zone_flags_t flag) Instead of setting and clearing ZONE_RECLAIM_LOCKED each time shrink_zone() is called, this flag is test and set before starting zone reclaim. Zone reclaim starts in __alloc_pages() when a zone's watermark fails and the system is in zone_reclaim_mode. If it's already in reclaim, there's no need to start again so it is simply considered full for that allocation attempt. There is a change of behavior with regard to concurrent zone shrinking. It is now possible for try_to_free_pages() or kswapd to already be shrinking a particular zone when __alloc_pages() starts zone reclaim. In this case, it is possible for two concurrent threads to invoke shrink_zone() for a single zone. This change forbids a zone to be in zone reclaim twice, which was always the behavior, but allows for concurrent try_to_free_pages() or kswapd shrinking when starting zone reclaim. Cc: Andrea Arcangeli <andrea@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom: add per-zone lockingDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | OOM killer synchronization should be done with zone granularity so that memory policy and cpuset allocations may have their corresponding zones locked and allow parallel kills for other OOM conditions that may exist elsewhere in the system. DMA allocations can be targeted at the zone level, which would not be possible if locking was done in nodes or globally. Synchronization shall be done with a variation of "trylocks." The goal is to put the current task to sleep and restart the failed allocation attempt later if the trylock fails. Otherwise, the OOM killer is invoked. Each zone in the zonelist that __alloc_pages() was called with is checked for the newly-introduced ZONE_OOM_LOCKED flag. If any zone has this flag present, the "trylock" to serialize the OOM killer fails and returns zero. Otherwise, all the zones have ZONE_OOM_LOCKED set and the try_set_zone_oom() function returns non-zero. Cc: Andrea Arcangeli <andrea@suse.de> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom: change all_unreclaimable zone member to flagsDavid Rientjes2007-10-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the int all_unreclaimable member of struct zone to unsigned long flags. This can now be used to specify several different zone flags such as all_unreclaimable and reclaim_in_progress, which can now be removed and converted to a per-zone flag. Flags are set and cleared as follows: zone_set_flag(struct zone *zone, zone_flags_t flag) zone_clear_flag(struct zone *zone, zone_flags_t flag) Defines the first zone flags, ZONE_ALL_UNRECLAIMABLE and ZONE_RECLAIM_LOCKED, which have the same semantics as the old zone->all_unreclaimable and zone->reclaim_in_progress, respectively. Also converts all current users that set or clear either flag to use the new interface. Helper functions are defined to test the flags: int zone_is_all_unreclaimable(const struct zone *zone) int zone_is_reclaim_locked(const struct zone *zone) All flag operators are of the atomic variety because there are currently readers that are implemented that do not take zone->lock. [akpm@linux-foundation.org: add needed include] Cc: Andrea Arcangeli <andrea@suse.de> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* memory unplug: page isolationKAMEZAWA Hiroyuki2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Implement generic chunk-of-pages isolation method by using page grouping ops. This patch add MIGRATE_ISOLATE to MIGRATE_TYPES. By this - MIGRATE_TYPES increases. - bitmap for migratetype is enlarged. pages of MIGRATE_ISOLATE migratetype will not be allocated even if it is free. By this, you can isolated *freed* pages from users. How-to-free pages is not a purpose of this patch. You may use reclaim and migrate codes to free pages. If start_isolate_page_range(start,end) is called, - migratetype of the range turns to be MIGRATE_ISOLATE if its type is MIGRATE_MOVABLE. (*) this check can be updated if other memory reclaiming works make progress. - MIGRATE_ISOLATE is not on migratetype fallback list. - All free pages and will-be-freed pages are isolated. To check all pages in the range are isolated or not, use test_pages_isolated(), To cancel isolation, use undo_isolate_page_range(). Changes V6 -> V7 - removed unnecessary #ifdef There are HOLES_IN_ZONE handling codes...I'm glad if we can remove them.. Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Print out statistics in relation to fragmentation avoidance to ↵Mel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | /proc/pagetypeinfo This patch provides fragmentation avoidance statistics via /proc/pagetypeinfo. The information is collected only on request so there is no runtime overhead. The statistics are in three parts: The first part prints information on the size of blocks that pages are being grouped on and looks like Page block order: 10 Pages per block: 1024 The second part is a more detailed version of /proc/buddyinfo and looks like Free pages count per migrate type at order 0 1 2 3 4 5 6 7 8 9 10 Node 0, zone DMA, type Unmovable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Reclaimable 1 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Movable 0 0 0 0 0 0 0 0 0 0 0 Node 0, zone DMA, type Reserve 0 4 4 0 0 0 0 1 0 1 0 Node 0, zone Normal, type Unmovable 111 8 4 4 2 3 1 0 0 0 0 Node 0, zone Normal, type Reclaimable 293 89 8 0 0 0 0 0 0 0 0 Node 0, zone Normal, type Movable 1 6 13 9 7 6 3 0 0 0 0 Node 0, zone Normal, type Reserve 0 0 0 0 0 0 0 0 0 0 4 The third part looks like Number of blocks type Unmovable Reclaimable Movable Reserve Node 0, zone DMA 0 1 2 1 Node 0, zone Normal 3 17 94 4 To walk the zones within a node with interrupts disabled, walk_zones_in_node() is introduced and shared between /proc/buddyinfo, /proc/zoneinfo and /proc/pagetypeinfo to reduce code duplication. It seems specific to what vmstat.c requires but could be broken out as a general utility function in mmzone.c if there were other other potential users. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Do not depend on MAX_ORDER when grouping pages by mobilityMel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently mobility grouping works at the MAX_ORDER_NR_PAGES level. This makes sense for the majority of users where this is also the huge page size. However, on platforms like ia64 where the huge page size is runtime configurable it is desirable to group at a lower order. On x86_64 and occasionally on x86, the hugepage size may not always be MAX_ORDER_NR_PAGES. This patch groups pages together based on the value of HUGETLB_PAGE_ORDER. It uses a compile-time constant if possible and a variable where the huge page size is runtime configurable. It is assumed that grouping should be done at the lowest sensible order and that the user would not want to override this. If this is not true, page_block order could be forced to a variable initialised via a boot-time kernel parameter. One potential issue with this patch is that IA64 now parses hugepagesz with early_param() instead of __setup(). __setup() is called after the memory allocator has been initialised and the pageblock bitmaps already setup. In tests on one IA64 there did not seem to be any problem with using early_param() and in fact may be more correct as it guarantees the parameter is handled before the parsing of hugepages=. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Acked-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* don't group high order atomic allocationsMel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Grouping high-order atomic allocations together was intended to allow bursty users of atomic allocations to work such as e1000 in situations where their preallocated buffers were depleted. This did not work in at least one case with a wireless network adapter needing order-1 allocations frequently. To resolve that, the free pages used for min_free_kbytes were moved to separate contiguous blocks with the patch bias-the-location-of-pages-freed-for-min_free_kbytes-in-the-same-max_order_nr_pages-blocks. It is felt that keeping the free pages in the same contiguous blocks should be sufficient for bursty short-lived high-order atomic allocations to succeed, maybe even with the e1000. Even if there is a failure, increasing the value of min_free_kbytes will free pages as contiguous bloks in contrast to the standard buddy allocator which makes no attempt to keep the minimum number of free pages contiguous. This patch backs out grouping high order atomic allocations together to determine if it is really needed or not. If a new report comes in about high-order atomic allocations failing, the feature can be reintroduced to determine if it fixes the problem or not. As a side-effect, this patch reduces by 1 the number of bits required to track the mobility type of pages within a MAX_ORDER_NR_PAGES block. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* remove PAGE_GROUP_BY_MOBILITYMel Gorman2007-10-16
| | | | | | | | | | | | Grouping pages by mobility can be disabled at compile-time. This was considered undesirable by a number of people. However, in the current stack of patches, it is not a simple case of just dropping the configurable patch as it would cause merge conflicts. This patch backs out the configuration option. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Bias the location of pages freed for min_free_kbytes in the same ↵Mel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | MAX_ORDER_NR_PAGES blocks The standard buddy allocator always favours the smallest block of pages. The effect of this is that the pages free to satisfy min_free_kbytes tends to be preserved since boot time at the same location of memory ffor a very long time and as a contiguous block. When an administrator sets the reserve at 16384 at boot time, it tends to be the same MAX_ORDER blocks that remain free. This allows the occasional high atomic allocation to succeed up until the point the blocks are split. In practice, it is difficult to split these blocks but when they do split, the benefit of having min_free_kbytes for contiguous blocks disappears. Additionally, increasing min_free_kbytes once the system has been running for some time has no guarantee of creating contiguous blocks. On the other hand, CONFIG_PAGE_GROUP_BY_MOBILITY favours splitting large blocks when there are no free pages of the appropriate type available. A side-effect of this is that all blocks in memory tends to be used up and the contiguous free blocks from boot time are not preserved like in the vanilla allocator. This can cause a problem if a new caller is unwilling to reclaim or does not reclaim for long enough. A failure scenario was found for a wireless network device allocating order-1 atomic allocations but the allocations were not intense or frequent enough for a whole block of pages to be preserved for MIGRATE_HIGHALLOC. This was reproduced on a desktop by booting with mem=256mb, forcing the driver to allocate at order-1, running a bittorrent client (downloading a debian ISO) and building a kernel with -j2. This patch addresses the problem on the desktop machine booted with mem=256mb. It works by setting aside a reserve of MAX_ORDER_NR_PAGES blocks, the number of which depends on the value of min_free_kbytes. These blocks are only fallen back to when there is no other free pages. Then the smallest possible page is used just like the normal buddy allocator instead of the largest possible page to preserve contiguous pages The pages in free lists in the reserve blocks are never taken for another migrate type. The results is that even if min_free_kbytes is set to a low value, contiguous blocks will be preserved in the MIGRATE_RESERVE blocks. This works better than the vanilla allocator because if min_free_kbytes is increased, a new reserve block will be chosen based on the location of reclaimable pages and the block will free up as contiguous pages. In the vanilla allocator, no effort is made to target a block of pages to free as contiguous pages and min_free_kbytes pages are scattered randomly. This effect has been observed on the test machine. min_free_kbytes was set initially low but it was kept as a contiguous free block within MIGRATE_RESERVE. min_free_kbytes was then set to a higher value and over a period of time, the free blocks were within the reserve and coalescing. How long it takes to free up depends on how quickly LRU is rotating. Amusingly, this means that more activity will free the blocks faster. This mechanism potentially replaces MIGRATE_HIGHALLOC as it may be more effective than grouping contiguous free pages together. It all depends on whether the number of active atomic high allocations exceeds min_free_kbytes or not. If the number of active allocations exceeds min_free_kbytes, it's worth it but maybe in that situation, min_free_kbytes should be set higher. Once there are no more reports of allocation failures, a patch will be submitted that backs out MIGRATE_HIGHALLOC and see if the reports stay missing. Credit to Mariusz Kozlowski for discovering the problem, describing the failure scenario and testing patches and scenarios. [akpm@linux-foundation.org: cleanups] Signed-off-by: Mel Gorman <mel@csn.ul.ie> Acked-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Fix corruption of memmap on IA64 SPARSEMEM when mem_section is not a power of 2Mel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There are problems in the use of SPARSEMEM and pageblock flags that causes problems on ia64. The first part of the problem is that units are incorrect in SECTION_BLOCKFLAGS_BITS computation. This results in a map_section's section_mem_map being treated as part of a bitmap which isn't good. This was evident with an invalid virtual address when mem_init attempted to free bootmem pages while relinquishing control from the bootmem allocator. The second part of the problem occurs because the pageblock flags bitmap is be located with the mem_section. The SECTIONS_PER_ROOT computation using sizeof (mem_section) may not be a power of 2 depending on the size of the bitmap. This renders masks and other such things not power of 2 base. This issue was seen with SPARSEMEM_EXTREME on ia64. This patch moves the bitmap outside of mem_section and uses a pointer instead in the mem_section. The bitmaps are allocated when the section is being initialised. Note that sparse_early_usemap_alloc() does not use alloc_remap() like sparse_early_mem_map_alloc(). The allocation required for the bitmap on x86, the only architecture that uses alloc_remap is typically smaller than a cache line. alloc_remap() pads out allocations to the cache size which would be a needless waste. Credit to Bob Picco for identifying the original problem and effecting a fix for the SECTION_BLOCKFLAGS_BITS calculation. Credit to Andy Whitcroft for devising the best way of allocating the bitmaps only when required for the section. [wli@holomorphy.com: warning fix] Signed-off-by: Bob Picco <bob.picco@hp.com> Signed-off-by: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: "Luck, Tony" <tony.luck@intel.com> Signed-off-by: William Irwin <bill.irwin@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Group high-order atomic allocationsMel Gorman2007-10-16
| | | | | | | | | | | | | | | | In rare cases, the kernel needs to allocate a high-order block of pages without sleeping. For example, this is the case with e1000 cards configured to use jumbo frames. Migrating or reclaiming pages in this situation is not an option. This patch groups these allocations together as much as possible by adding a new MIGRATE_TYPE. The MIGRATE_HIGHATOMIC type are exactly what they sound like. Care is taken that pages of other migrate types do not use the same blocks as high-order atomic allocations. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Group short-lived and reclaimable kernel allocationsMel Gorman2007-10-16
| | | | | | | | | | | | | | | | | | This patch marks a number of allocations that are either short-lived such as network buffers or are reclaimable such as inode allocations. When something like updatedb is called, long-lived and unmovable kernel allocations tend to be spread throughout the address space which increases fragmentation. This patch groups these allocations together as much as possible by adding a new MIGRATE_TYPE. The MIGRATE_RECLAIMABLE type is for allocations that can be reclaimed on demand, but not moved. i.e. they can be migrated by deleting them and re-reading the information from elsewhere. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Add a configure option to group pages by mobilityMel Gorman2007-10-16
| | | | | | | | | | | | | | The grouping mechanism has some memory overhead and a more complex allocation path. This patch allows the strategy to be disabled for small memory systems or if it is known the workload is suffering because of the strategy. It also acts to show where the page groupings strategy interacts with the standard buddy allocator. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Joel Schopp <jschopp@austin.ibm.com> Cc: Andy Whitcroft <apw@shadowen.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Split the free lists for movable and unmovable allocationsMel Gorman2007-10-16
| | | | | | | | | | | This patch adds the core of the fragmentation reduction strategy. It works by grouping pages together based on their ability to migrate or be reclaimed. Basically, it works by breaking the list in zone->free_area list into MIGRATE_TYPES number of lists. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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