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* mm: raise MemFree by reverting percpu_pagelist_fraction to 0Hugh Dickins2012-05-111-1/+1
| | | | | | | | | | | | | | | | | | | | | | Why is there less MemFree than there used to be? It perturbed a test, so I've just been bisecting linux-next, and now find the offender went upstream yesterday. Commit 93278814d359 "mm: fix division by 0 in percpu_pagelist_fraction()" mistakenly initialized percpu_pagelist_fraction to the sysctl's minimum 8, which leaves 1/8th of memory on percpu lists (on each cpu??); but most of us expect it to be left unset at 0 (and it's not then used as a divisor). MemTotal: 8061476kB 8061476kB 8061476kB 8061476kB 8061476kB 8061476kB Repetitive test with percpu_pagelist_fraction 8: MemFree: 6948420kB 6237172kB 6949696kB 6840692kB 6949048kB 6862984kB Same test with percpu_pagelist_fraction back to 0: MemFree: 7945000kB 7944908kB 7948568kB 7949060kB 7948796kB 7948812kB Signed-off-by: Hugh Dickins <hughd@google.com> [ We really should fix the crazy sysctl interface too, but that's a separate thing - Linus ] Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix division by 0 in percpu_pagelist_fraction()Sasha Levin2012-05-101-2/+2
| | | | | | | | | | | | | | percpu_pagelist_fraction_sysctl_handler() has only considered -EINVAL as a possible error from proc_dointvec_minmax(). If any other error is returned, it would proceed to divide by zero since percpu_pagelist_fraction wasn't getting initialized at any point. For example, writing 0 bytes into the proc file would trigger the issue. Signed-off-by: Sasha Levin <levinsasha928@gmail.com> Reviewed-by: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: only IPI CPUs to drain local pages if they existGilad Ben-Yossef2012-03-281-2/+38
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Calculate a cpumask of CPUs with per-cpu pages in any zone and only send an IPI requesting CPUs to drain these pages to the buddy allocator if they actually have pages when asked to flush. This patch saves 85%+ of IPIs asking to drain per-cpu pages in case of severe memory pressure that leads to OOM since in these cases multiple, possibly concurrent, allocation requests end up in the direct reclaim code path so when the per-cpu pages end up reclaimed on first allocation failure for most of the proceeding allocation attempts until the memory pressure is off (possibly via the OOM killer) there are no per-cpu pages on most CPUs (and there can easily be hundreds of them). This also has the side effect of shortening the average latency of direct reclaim by 1 or more order of magnitude since waiting for all the CPUs to ACK the IPI takes a long time. Tested by running "hackbench 400" on a 8 CPU x86 VM and observing the difference between the number of direct reclaim attempts that end up in drain_all_pages() and those were more then 1/2 of the online CPU had any per-cpu page in them, using the vmstat counters introduced in the next patch in the series and using proc/interrupts. In the test sceanrio, this was seen to save around 3600 global IPIs after trigerring an OOM on a concurrent workload: $ cat /proc/vmstat | tail -n 2 pcp_global_drain 0 pcp_global_ipi_saved 0 $ cat /proc/interrupts | grep CAL CAL: 1 2 1 2 2 2 2 2 Function call interrupts $ hackbench 400 [OOM messages snipped] $ cat /proc/vmstat | tail -n 2 pcp_global_drain 3647 pcp_global_ipi_saved 3642 $ cat /proc/interrupts | grep CAL CAL: 6 13 6 3 3 3 1 2 7 Function call interrupts Please note that if the global drain is removed from the direct reclaim path as a patch from Mel Gorman currently suggests this should be replaced with an on_each_cpu_cond invocation. Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Christoph Lameter <cl@linux.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Pekka Enberg <penberg@kernel.org> Cc: Rik van Riel <riel@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Acked-by: Michal Nazarewicz <mina86@mina86.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, coredump: fail allocations when coredumping instead of oom killingDavid Rientjes2012-03-281-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The size of coredump files is limited by RLIMIT_CORE, however, allocating large amounts of memory results in three negative consequences: - the coredumping process may be chosen for oom kill and quickly deplete all memory reserves in oom conditions preventing further progress from being made or tasks from exiting, - the coredumping process may cause other processes to be oom killed without fault of their own as the result of a SIGSEGV, for example, in the coredumping process, or - the coredumping process may result in a livelock while writing to the dump file if it needs memory to allocate while other threads are in the exit path waiting on the coredumper to complete. This is fixed by implying __GFP_NORETRY in the page allocator for coredumping processes when reclaim has failed so the allocations fail and the process continues to exit. Signed-off-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* page_alloc: remove unused find_zone_movable_pfns_for_nodes() argumentKautuk Consul2012-03-211-2/+2
| | | | | | | | | | find_zone_movable_pfns_for_nodes() does not use its argument. Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Cc: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* page_alloc.c: remove add_from_early_node_map()Kautuk Consul2012-03-211-12/+0
| | | | | | | | | add_from_early_node_map() is unused. Signed-off-by: Kautuk Consul <consul.kautuk@gmail.com> Acked-by: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* cpuset: mm: reduce large amounts of memory barrier related damage v3Mel Gorman2012-03-211-10/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c0ff7453bb5c ("cpuset,mm: fix no node to alloc memory when changing cpuset's mems") wins a super prize for the largest number of memory barriers entered into fast paths for one commit. [get|put]_mems_allowed is incredibly heavy with pairs of full memory barriers inserted into a number of hot paths. This was detected while investigating at large page allocator slowdown introduced some time after 2.6.32. The largest portion of this overhead was shown by oprofile to be at an mfence introduced by this commit into the page allocator hot path. For extra style points, the commit introduced the use of yield() in an implementation of what looks like a spinning mutex. This patch replaces the full memory barriers on both read and write sides with a sequence counter with just read barriers on the fast path side. This is much cheaper on some architectures, including x86. The main bulk of the patch is the retry logic if the nodemask changes in a manner that can cause a false failure. While updating the nodemask, a check is made to see if a false failure is a risk. If it is, the sequence number gets bumped and parallel allocators will briefly stall while the nodemask update takes place. In a page fault test microbenchmark, oprofile samples from __alloc_pages_nodemask went from 4.53% of all samples to 1.15%. The actual results were 3.3.0-rc3 3.3.0-rc3 rc3-vanilla nobarrier-v2r1 Clients 1 UserTime 0.07 ( 0.00%) 0.08 (-14.19%) Clients 2 UserTime 0.07 ( 0.00%) 0.07 ( 2.72%) Clients 4 UserTime 0.08 ( 0.00%) 0.07 ( 3.29%) Clients 1 SysTime 0.70 ( 0.00%) 0.65 ( 6.65%) Clients 2 SysTime 0.85 ( 0.00%) 0.82 ( 3.65%) Clients 4 SysTime 1.41 ( 0.00%) 1.41 ( 0.32%) Clients 1 WallTime 0.77 ( 0.00%) 0.74 ( 4.19%) Clients 2 WallTime 0.47 ( 0.00%) 0.45 ( 3.73%) Clients 4 WallTime 0.38 ( 0.00%) 0.37 ( 1.58%) Clients 1 Flt/sec/cpu 497620.28 ( 0.00%) 520294.53 ( 4.56%) Clients 2 Flt/sec/cpu 414639.05 ( 0.00%) 429882.01 ( 3.68%) Clients 4 Flt/sec/cpu 257959.16 ( 0.00%) 258761.48 ( 0.31%) Clients 1 Flt/sec 495161.39 ( 0.00%) 517292.87 ( 4.47%) Clients 2 Flt/sec 820325.95 ( 0.00%) 850289.77 ( 3.65%) Clients 4 Flt/sec 1020068.93 ( 0.00%) 1022674.06 ( 0.26%) MMTests Statistics: duration Sys Time Running Test (seconds) 135.68 132.17 User+Sys Time Running Test (seconds) 164.2 160.13 Total Elapsed Time (seconds) 123.46 120.87 The overall improvement is small but the System CPU time is much improved and roughly in correlation to what oprofile reported (these performance figures are without profiling so skew is expected). The actual number of page faults is noticeably improved. For benchmarks like kernel builds, the overall benefit is marginal but the system CPU time is slightly reduced. To test the actual bug the commit fixed I opened two terminals. The first ran within a cpuset and continually ran a small program that faulted 100M of anonymous data. In a second window, the nodemask of the cpuset was continually randomised in a loop. Without the commit, the program would fail every so often (usually within 10 seconds) and obviously with the commit everything worked fine. With this patch applied, it also worked fine so the fix should be functionally equivalent. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Miao Xie <miaox@cn.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: drain percpu lru add/rotate page-vectors on cpu hot-unplugKonstantin Khlebnikov2012-03-211-0/+1
| | | | | | | | | | | | | | | | | | | | | This cpu hotplug hook was accidentally removed in commit 00a62ce91e55 ("mm: fix Committed_AS underflow on large NR_CPUS environment") The visible effect of this accident: some pages are borrowed in per-cpu page-vectors. Truncate can deal with it, but these pages cannot be reused while this cpu is offline. So this is like a temporary memory leak. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Eric B Munson <ebmunson@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm, oom: force oom kill on sysrq+fDavid Rientjes2012-03-211-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | The oom killer chooses not to kill a thread if: - an eligible thread has already been oom killed and has yet to exit, and - an eligible thread is exiting but has yet to free all its memory and is not the thread attempting to currently allocate memory. SysRq+F manually invokes the global oom killer to kill a memory-hogging task. This is normally done as a last resort to free memory when no progress is being made or to test the oom killer itself. For both uses, we always want to kill a thread and never defer. This patch causes SysRq+F to always kill an eligible thread and can be used to force a kill even if another oom killed thread has failed to exit. Signed-off-by: David Rientjes <rientjes@google.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Pekka Enberg <penberg@kernel.org> Acked-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: only defer compaction for failed order and higherRik van Riel2012-03-211-2/+4
| | | | | | | | | | | | | | | | | | | | | Currently a failed order-9 (transparent hugepage) compaction can lead to memory compaction being temporarily disabled for a memory zone. Even if we only need compaction for an order 2 allocation, eg. for jumbo frames networking. The fix is relatively straightforward: keep track of the highest order at which compaction is succeeding, and only defer compaction for orders at which compaction is failing. Signed-off-by: Rik van Riel <riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vfs: fix panic in __d_lookup() with high dentry hashtable countsDimitri Sivanich2012-02-131-0/+1
| | | | | | | | | | | | | | When the number of dentry cache hash table entries gets too high (2147483648 entries), as happens by default on a 16TB system, use of a signed integer in the dcache_init() initialization loop prevents the dentry_hashtable from getting initialized, causing a panic in __d_lookup(). Fix this in dcache_init() and similar areas. Signed-off-by: Dimitri Sivanich <sivanich@sgi.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* mm: __count_immobile_pages(): make sure the node is onlineMichal Hocko2012-01-231-3/+10
| | | | | | | | | | | | | page_zone() requires an online node otherwise we are accessing NULL NODE_DATA. This is not an issue at the moment because node_zones are located at the structure beginning but this might change in the future so better be careful about that. Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix NULL ptr dereference in __count_immobile_pagesMichal Hocko2012-01-231-0/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Fix the following NULL ptr dereference caused by cat /sys/devices/system/memory/memory0/removable Pid: 13979, comm: sed Not tainted 3.0.13-0.5-default #1 IBM BladeCenter LS21 -[7971PAM]-/Server Blade RIP: __count_immobile_pages+0x4/0x100 Process sed (pid: 13979, threadinfo ffff880221c36000, task ffff88022e788480) Call Trace: is_pageblock_removable_nolock+0x34/0x40 is_mem_section_removable+0x74/0xf0 show_mem_removable+0x41/0x70 sysfs_read_file+0xfe/0x1c0 vfs_read+0xc7/0x130 sys_read+0x53/0xa0 system_call_fastpath+0x16/0x1b We are crashing because we are trying to dereference NULL zone which came from pfn=0 (struct page ffffea0000000000). According to the boot log this page is marked reserved: e820 update range: 0000000000000000 - 0000000000010000 (usable) ==> (reserved) and early_node_map confirms that: early_node_map[3] active PFN ranges 1: 0x00000010 -> 0x0000009c 1: 0x00000100 -> 0x000bffa3 1: 0x00100000 -> 0x00240000 The problem is that memory_present works in PAGE_SECTION_MASK aligned blocks so the reserved range sneaks into the the section as well. This also means that free_area_init_node will not take care of those reserved pages and they stay uninitialized. When we try to read the removable status we walk through all available sections and hope that the zone is valid for all pages in the section. But this is not true in this case as the zone and nid are not initialized. We have only one node in this particular case and it is marked as node=1 (rather than 0) and that made the problem visible because page_to_nid will return 0 and there are no zones on the node. Let's check that the zone is valid and that the given pfn falls into its boundaries and mark the section not removable. This might cause some false positives, probably, but we do not have any sane way to find out whether the page is reserved by the platform or it is just not used for whatever other reasons. Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: enum lru_list lruHugh Dickins2012-01-121-3/+3
| | | | | | | | | Mostly we use "enum lru_list lru": change those few "l"s to "lru"s. Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-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: page allocator: do not call direct reclaim for THP allocations while ↵Mel Gorman2012-01-121-10/+35
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | compaction is deferred If compaction is deferred, direct reclaim is used to try to free enough pages for the allocation to succeed. For small high-orders, this has a reasonable chance of success. However, if the caller has specified __GFP_NO_KSWAPD to limit the disruption to the system, it makes more sense to fail the allocation rather than stall the caller in direct reclaim. This patch skips direct reclaim if compaction is deferred and the caller specifies __GFP_NO_KSWAPD. Async compaction only considers a subset of pages so it is possible for compaction to be deferred prematurely and not enter direct reclaim even in cases where it should. To compensate for this, this patch also defers compaction only if sync compaction failed. Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Rik van Riel<riel@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Dave Jones <davej@redhat.com> Cc: Jan Kara <jack@suse.cz> Cc: Andy Isaacson <adi@hexapodia.org> Cc: Nai Xia <nai.xia@gmail.com> Cc: Johannes Weiner <jweiner@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* page_alloc: break early in check_for_regular_memory()Bob Liu2012-01-121-1/+3
| | | | | | | | | | | | | If there is a zone below ZONE_NORMAL has present_pages, we can set node state to N_NORMAL_MEMORY, no need to loop to end. Signed-off-by: Bob Liu <lliubbo@gmail.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Johannes Weiner <hannes@cmpxchg.org> Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.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>
* mm: collect LRU list heads into struct lruvecJohannes Weiner2012-01-121-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | Having a unified structure with a LRU list set for both global zones and per-memcg zones allows to keep that code simple which deals with LRU lists and does not care about the container itself. Once the per-memcg LRU lists directly link struct pages, the isolation function and all other list manipulations are shared between the memcg case and the global LRU case. Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Kirill A. Shutemov <kirill@shutemov.name> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <bsingharora@gmail.com> Cc: Ying Han <yinghan@google.com> Cc: Greg Thelen <gthelen@google.com> Cc: Michel Lespinasse <walken@google.com> Cc: Rik van Riel <riel@redhat.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: page_alloc: generalize order handling in __free_pages_bootmem()Johannes Weiner2012-01-101-21/+12
| | | | | | | | | | | | | | | | __free_pages_bootmem() used to special-case higher-order frees to save individual page checking with free_pages_bulk(). Nowadays, both zero order and non-zero order frees use free_pages(), which checks each individual page anyway, and so there is little point in making the distinction anymore. The higher-order loop will work just fine for zero order pages. Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix off-by-two in __zone_watermark_ok()Michal Hocko2012-01-101-1/+1
| | | | | | | | | | | | | Commit 88f5acf88ae6 ("mm: page allocator: adjust the per-cpu counter threshold when memory is low") changed the form how free_pages is calculated but it forgot that we used to do free_pages - ((1 << order) - 1) so we ended up with off-by-two when calculating free_pages. Reported-by: Wang Sheng-Hui <shhuiw@gmail.com> Signed-off-by: Michal Hocko <mhocko@suse.cz> Acked-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: try to distribute dirty pages fairly across zonesJohannes Weiner2012-01-101-0/+29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The maximum number of dirty pages that exist in the system at any time is determined by a number of pages considered dirtyable and a user-configured percentage of those, or an absolute number in bytes. This number of dirtyable pages is the sum of memory provided by all the zones in the system minus their lowmem reserves and high watermarks, so that the system can retain a healthy number of free pages without having to reclaim dirty pages. But there is a flaw in that we have a zoned page allocator which does not care about the global state but rather the state of individual memory zones. And right now there is nothing that prevents one zone from filling up with dirty pages while other zones are spared, which frequently leads to situations where kswapd, in order to restore the watermark of free pages, does indeed have to write pages from that zone's LRU list. This can interfere so badly with IO from the flusher threads that major filesystems (btrfs, xfs, ext4) mostly ignore write requests from reclaim already, taking away the VM's only possibility to keep such a zone balanced, aside from hoping the flushers will soon clean pages from that zone. Enter per-zone dirty limits. They are to a zone's dirtyable memory what the global limit is to the global amount of dirtyable memory, and try to make sure that no single zone receives more than its fair share of the globally allowed dirty pages in the first place. As the number of pages considered dirtyable excludes the zones' lowmem reserves and high watermarks, the maximum number of dirty pages in a zone is such that the zone can always be balanced without requiring page cleaning. As this is a placement decision in the page allocator and pages are dirtied only after the allocation, this patch allows allocators to pass __GFP_WRITE when they know in advance that the page will be written to and become dirty soon. The page allocator will then attempt to allocate from the first zone of the zonelist - which on NUMA is determined by the task's NUMA memory policy - that has not exceeded its dirty limit. At first glance, it would appear that the diversion to lower zones can increase pressure on them, but this is not the case. With a full high zone, allocations will be diverted to lower zones eventually, so it is more of a shift in timing of the lower zone allocations. Workloads that previously could fit their dirty pages completely in the higher zone may be forced to allocate from lower zones, but the amount of pages that "spill over" are limited themselves by the lower zones' dirty constraints, and thus unlikely to become a problem. For now, the problem of unfair dirty page distribution remains for NUMA configurations where the zones allowed for allocation are in sum not big enough to trigger the global dirty limits, wake up the flusher threads and remedy the situation. Because of this, an allocation that could not succeed on any of the considered zones is allowed to ignore the dirty limits before going into direct reclaim or even failing the allocation, until a future patch changes the global dirty throttling and flusher thread activation so that they take individual zone states into account. Test results 15M DMA + 3246M DMA32 + 504 Normal = 3765M memory 40% dirty ratio 16G USB thumb drive 10 runs of dd if=/dev/zero of=disk/zeroes bs=32k count=$((10 << 15)) seconds nr_vmscan_write (stddev) min| median| max xfs vanilla: 549.747( 3.492) 0.000| 0.000| 0.000 patched: 550.996( 3.802) 0.000| 0.000| 0.000 fuse-ntfs vanilla: 1183.094(53.178) 54349.000| 59341.000| 65163.000 patched: 558.049(17.914) 0.000| 0.000| 43.000 btrfs vanilla: 573.679(14.015) 156657.000| 460178.000| 606926.000 patched: 563.365(11.368) 0.000| 0.000| 1362.000 ext4 vanilla: 561.197(15.782) 0.000|2725438.000|4143837.000 patched: 568.806(17.496) 0.000| 0.000| 0.000 Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Michal Hocko <mhocko@suse.cz> Tested-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Rik van Riel <riel@redhat.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: exclude reserved pages from dirtyable memoryJohannes Weiner2012-01-101-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Per-zone dirty limits try to distribute page cache pages allocated for writing across zones in proportion to the individual zone sizes, to reduce the likelihood of reclaim having to write back individual pages from the LRU lists in order to make progress. This patch: The amount of dirtyable pages should not include the full number of free pages: there is a number of reserved pages that the page allocator and kswapd always try to keep free. The closer (reclaimable pages - dirty pages) is to the number of reserved pages, the more likely it becomes for reclaim to run into dirty pages: +----------+ --- | anon | | +----------+ | | | | | | -- dirty limit new -- flusher new | file | | | | | | | | | -- dirty limit old -- flusher old | | | +----------+ --- reclaim | reserved | +----------+ | kernel | +----------+ This patch introduces a per-zone dirty reserve that takes both the lowmem reserve as well as the high watermark of the zone into account, and a global sum of those per-zone values that is subtracted from the global amount of dirtyable pages. The lowmem reserve is unavailable to page cache allocations and kswapd tries to keep the high watermark free. We don't want to end up in a situation where reclaim has to clean pages in order to balance zones. Not treating reserved pages as dirtyable on a global level is only a conceptual fix. In reality, dirty pages are not distributed equally across zones and reclaim runs into dirty pages on a regular basis. But it is important to get this right before tackling the problem on a per-zone level, where the distance between reclaim and the dirty pages is mostly much smaller in absolute numbers. [akpm@linux-foundation.org: fix highmem build] Signed-off-by: Johannes Weiner <jweiner@redhat.com> Reviewed-by: Rik van Riel <riel@redhat.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Mel Gorman <mgorman@suse.de> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Christoph Hellwig <hch@infradead.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jan Kara <jack@suse.cz> Cc: Shaohua Li <shaohua.li@intel.com> Cc: Chris Mason <chris.mason@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: more intensive memory corruption debuggingStanislaw Gruszka2012-01-101-6/+69
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With CONFIG_DEBUG_PAGEALLOC configured, the CPU will generate an exception on access (read,write) to an unallocated page, which permits us to catch code which corrupts memory. However the kernel is trying to maximise memory usage, hence there are usually few free pages in the system and buggy code usually corrupts some crucial data. This patch changes the buddy allocator to keep more free/protected pages and to interlace free/protected and allocated pages to increase the probability of catching corruption. When the kernel is compiled with CONFIG_DEBUG_PAGEALLOC, debug_guardpage_minorder defines the minimum order used by the page allocator to grant a request. The requested size will be returned with the remaining pages used as guard pages. The default value of debug_guardpage_minorder is zero: no change from current behaviour. [akpm@linux-foundation.org: tweak documentation, s/flg/flag/] Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Rafael J. Wysocki" <rjw@sisk.pl> Cc: Christoph Lameter <cl@linux-foundation.org> 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: avoid livelock on !__GFP_FS allocationsMel Gorman2012-01-101-8/+22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Colin Cross reported; Under the following conditions, __alloc_pages_slowpath can loop forever: gfp_mask & __GFP_WAIT is true gfp_mask & __GFP_FS is false reclaim and compaction make no progress order <= PAGE_ALLOC_COSTLY_ORDER These conditions happen very often during suspend and resume, when pm_restrict_gfp_mask() effectively converts all GFP_KERNEL allocations into __GFP_WAIT. The oom killer is not run because gfp_mask & __GFP_FS is false, but should_alloc_retry will always return true when order is less than PAGE_ALLOC_COSTLY_ORDER. In his fix, he avoided retrying the allocation if reclaim made no progress and __GFP_FS was not set. The problem is that this would result in GFP_NOIO allocations failing that previously succeeded which would be very unfortunate. The big difference between GFP_NOIO and suspend converting GFP_KERNEL to behave like GFP_NOIO is that normally flushers will be cleaning pages and kswapd reclaims pages allowing GFP_NOIO to succeed after a short delay. The same does not necessarily apply during suspend as the storage device may be suspended. This patch special cases the suspend case to fail the page allocation if reclaim cannot make progress and adds some documentation on how gfp_allowed_mask is currently used. Failing allocations like this may cause suspend to abort but that is better than a livelock. [mgorman@suse.de: Rework fix to be suspend specific] [rientjes@google.com: Move suspended device check to should_alloc_retry] Reported-by: Colin Cross <ccross@android.com> Signed-off-by: Mel Gorman <mgorman@suse.de> Acked-by: David Rientjes <rientjes@google.com> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: reduce the amount of work done when updating min_free_kbytesMel Gorman2012-01-101-16/+24
| | | | | | | | | | | | | | | | | When min_free_kbytes is updated, some pageblocks are marked MIGRATE_RESERVE. Ordinarily, this work is unnoticable as it happens early in boot but on large machines with 1TB of memory, this has been reported to delay boot times, probably due to the NUMA distances involved. The bulk of the work is due to calling calling pageblock_is_reserved() an unnecessary amount of times and accessing far more struct page metadata than is necessary. This patch significantly reduces the amount of work done by setup_zone_migrate_reserve() improving boot times on 1TB machines. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Mel Gorman <mgorman@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm-tracepoint: rename page-free eventsKonstantin Khlebnikov2012-01-101-2/+2
| | | | | | | | | | | | | | | | | Rename mm_page_free_direct into mm_page_free and mm_pagevec_free into mm_page_free_batched Since v2.6.33-5426-gc475dab the kernel triggers mm_page_free_direct for all freed pages, not only for directly freed. So, let's name it properly. For pages freed via page-list we also trigger mm_page_free_batched event. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove unused pagevec_freeKonstantin Khlebnikov2012-01-101-10/+0
| | | | | | | | | | | | It not exported and now nobody uses it. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: add free_hot_cold_page_list() helperKonstantin Khlebnikov2012-01-101-0/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | This patch adds helper free_hot_cold_page_list() to free list of 0-order pages. It frees pages directly from list without temporary page-vector. It also calls trace_mm_pagevec_free() to simulate pagevec_free() behaviour. bloat-o-meter: add/remove: 1/1 grow/shrink: 1/3 up/down: 267/-295 (-28) function old new delta free_hot_cold_page_list - 264 +264 get_page_from_freelist 2129 2132 +3 __pagevec_free 243 239 -4 split_free_page 380 373 -7 release_pages 606 510 -96 free_page_list 188 - -188 Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by: Minchan Kim <minchan.kim@gmail.com> Acked-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge branch 'for-linus' of ↵Linus Torvalds2012-01-081-2/+2
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial * 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (53 commits) Kconfig: acpi: Fix typo in comment. misc latin1 to utf8 conversions devres: Fix a typo in devm_kfree comment btrfs: free-space-cache.c: remove extra semicolon. fat: Spelling s/obsolate/obsolete/g SCSI, pmcraid: Fix spelling error in a pmcraid_err() call tools/power turbostat: update fields in manpage mac80211: drop spelling fix types.h: fix comment spelling for 'architectures' typo fixes: aera -> area, exntension -> extension devices.txt: Fix typo of 'VMware'. sis900: Fix enum typo 'sis900_rx_bufer_status' decompress_bunzip2: remove invalid vi modeline treewide: Fix comment and string typo 'bufer' hyper-v: Update MAINTAINERS treewide: Fix typos in various parts of the kernel, and fix some comments. clockevents: drop unknown Kconfig symbol GENERIC_CLOCKEVENTS_MIGR gpio: Kconfig: drop unknown symbol 'CS5535_GPIO' leds: Kconfig: Fix typo 'D2NET_V2' sound: Kconfig: drop unknown symbol ARCH_CLPS7500 ... Fix up trivial conflicts in arch/powerpc/platforms/40x/Kconfig (some new kconfig additions, close to removed commented-out old ones)
| * mm: cleanup the comment for head/tail pages of compound pages in mm/page_alloc.cWang Sheng-Hui2011-11-171-2/+2
| | | | | | | | | | | | | | | | Only tail pages point at the head page using their ->first_page fields. Signed-off-by: Wang Sheng-Hui <shhuiw@gmail.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
* | Merge branch 'for-linus2' of ↵Linus Torvalds2012-01-081-1/+1
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs * 'for-linus2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (165 commits) reiserfs: Properly display mount options in /proc/mounts vfs: prevent remount read-only if pending removes vfs: count unlinked inodes vfs: protect remounting superblock read-only vfs: keep list of mounts for each superblock vfs: switch ->show_options() to struct dentry * vfs: switch ->show_path() to struct dentry * vfs: switch ->show_devname() to struct dentry * vfs: switch ->show_stats to struct dentry * switch security_path_chmod() to struct path * vfs: prefer ->dentry->d_sb to ->mnt->mnt_sb vfs: trim includes a bit switch mnt_namespace ->root to struct mount vfs: take /proc/*/mounts and friends to fs/proc_namespace.c vfs: opencode mntget() mnt_set_mountpoint() vfs: spread struct mount - remaining argument of next_mnt() vfs: move fsnotify junk to struct mount vfs: move mnt_devname vfs: move mnt_list to struct mount vfs: switch pnode.h macros to struct mount * ...
| * | switch debugfs to umode_tAl Viro2012-01-031-1/+1
| | | | | | | | | | | | Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
* | | Merge branch 'memblock-kill-early_node_map' of ↵Ingo Molnar2011-12-201-428/+80
|\ \ \ | |/ / |/| | | | | git://git.kernel.org/pub/scm/linux/kernel/git/tj/misc into core/memblock
| * | memblock: Kill early_node_map[]Tejun Heo2011-12-081-241/+18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now all ARCH_POPULATES_NODE_MAP archs select HAVE_MEBLOCK_NODE_MAP - there's no user of early_node_map[] left. Kill early_node_map[] and replace ARCH_POPULATES_NODE_MAP with HAVE_MEMBLOCK_NODE_MAP. Also, relocate for_each_mem_pfn_range() and helper from mm.h to memblock.h as page_alloc.c would no longer host an alternative implementation. This change is ultimately one to one mapping and shouldn't cause any observable difference; however, after the recent changes, there are some functions which now would fit memblock.c better than page_alloc.c and dependency on HAVE_MEMBLOCK_NODE_MAP instead of HAVE_MEMBLOCK doesn't make much sense on some of them. Further cleanups for functions inside HAVE_MEMBLOCK_NODE_MAP in mm.h would be nice. -v2: Fix compile bug introduced by mis-spelling CONFIG_HAVE_MEMBLOCK_NODE_MAP to CONFIG_MEMBLOCK_HAVE_NODE_MAP in mmzone.h. Reported by Stephen Rothwell. Signed-off-by: Tejun Heo <tj@kernel.org> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Yinghai Lu <yinghai@kernel.org> Cc: Tony Luck <tony.luck@intel.com> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Chen Liqin <liqin.chen@sunplusct.com> Cc: Paul Mundt <lethal@linux-sh.org> Cc: "David S. Miller" <davem@davemloft.net> Cc: "H. Peter Anvin" <hpa@zytor.com>
| * | Merge branch 'master' into x86/memblockTejun Heo2011-11-281-57/+78
| |\ \ | | |/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Conflicts & resolutions: * arch/x86/xen/setup.c dc91c728fd "xen: allow extra memory to be in multiple regions" 24aa07882b "memblock, x86: Replace memblock_x86_reserve/free..." conflicted on xen_add_extra_mem() updates. The resolution is trivial as the latter just want to replace memblock_x86_reserve_range() with memblock_reserve(). * drivers/pci/intel-iommu.c 166e9278a3f "x86/ia64: intel-iommu: move to drivers/iommu/" 5dfe8660a3d "bootmem: Replace work_with_active_regions() with..." conflicted as the former moved the file under drivers/iommu/. Resolved by applying the chnages from the latter on the moved file. * mm/Kconfig 6661672053a "memblock: add NO_BOOTMEM config symbol" c378ddd53f9 "memblock, x86: Make ARCH_DISCARD_MEMBLOCK a config option" conflicted trivially. Both added config options. Just letting both add their own options resolves the conflict. * mm/memblock.c d1f0ece6cdc "mm/memblock.c: small function definition fixes" ed7b56a799c "memblock: Remove memblock_memory_can_coalesce()" confliected. The former updates function removed by the latter. Resolution is trivial. Signed-off-by: Tejun Heo <tj@kernel.org>
| * | memblock: Add optional region->nidTejun Heo2011-07-141-19/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | From 83103b92f3234ec830852bbc5c45911bd6cbdb20 Mon Sep 17 00:00:00 2001 From: Tejun Heo <tj@kernel.org> Date: Thu, 14 Jul 2011 11:22:16 +0200 Add optional region->nid which can be enabled by arch using CONFIG_HAVE_MEMBLOCK_NODE_MAP. When enabled, memblock also carries NUMA node information and replaces early_node_map[]. Newly added memblocks have MAX_NUMNODES as nid. Arch can then call memblock_set_node() to set node information. memblock takes care of merging and node affine allocations w.r.t. node information. When MEMBLOCK_NODE_MAP is enabled, early_node_map[], related data structures and functions to manipulate and iterate it are disabled. memblock version of __next_mem_pfn_range() is provided such that for_each_mem_pfn_range() behaves the same and its users don't have to be updated. -v2: Yinghai spotted section mismatch caused by missing __init_memblock in memblock_set_node(). Fixed. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20110714094342.GF3455@htj.dyndns.org Cc: Yinghai Lu <yinghai@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | memblock, x86: Replace memblock_x86_find_in_range_node() with generic ↵Tejun Heo2011-07-141-67/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | memblock calls With the previous changes, generic NUMA aware memblock API has feature parity with memblock_x86_find_in_range_node(). There currently are two users - x86 setup_node_data() and __alloc_memory_core_early() in nobootmem.c. This patch converts the former to use memblock_alloc_nid() and the latter memblock_find_range_in_node(), and kills memblock_x86_find_in_range_node() and related functions including find_memory_early_core_early() in page_alloc.c. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/1310460395-30913-9-git-send-email-tj@kernel.org Cc: Yinghai Lu <yinghai@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | bootmem: Use for_each_mem_pfn_range() in page_alloc.cTejun Heo2011-07-141-109/+56
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The previous patch added for_each_mem_pfn_range() which is more versatile than for_each_active_range_index_in_nid(). This patch replaces for_each_active_range_index_in_nid() and open coded early_node_map[] walks with for_each_mem_pfn_range(). All conversions in this patch are straight-forward and shouldn't cause any functional difference. After the conversions, for_each_active_range_index_in_nid() doesn't have any user left and is removed. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/1310460395-30913-4-git-send-email-tj@kernel.org Cc: Yinghai Lu <yinghai@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | bootmem: Reimplement __absent_pages_in_range() using for_each_mem_pfn_range()Tejun Heo2011-07-141-42/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | __absent_pages_in_range() was needlessly complex. Reimplement it using for_each_mem_pfn_range(). Also, update zone_absent_pages_in_node() such that it doesn't call __absent_pages_in_range() with @zone_start_pfn which is larger than @zone_end_pfn. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/1310460395-30913-3-git-send-email-tj@kernel.org Cc: Yinghai Lu <yinghai@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | bootmem: Replace work_with_active_regions() with for_each_mem_pfn_range()Tejun Heo2011-07-141-12/+28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Callback based iteration is cumbersome and much less useful than for_each_*() iterator. This patch implements for_each_mem_pfn_range() which replaces work_with_active_regions(). All the current users of work_with_active_regions() are converted. This simplifies walking over early_node_map and will allow converting internal logics in page_alloc to use iterator instead of walking early_node_map directly, which in turn will enable moving node information to memblock. powerpc change is only compile tested. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/20110714074610.GD3455@htj.dyndns.org Cc: Yinghai Lu <yinghai@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | memblock: Kill MEMBLOCK_ERRORTejun Heo2011-07-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 25818f0f28 (memblock: Make MEMBLOCK_ERROR be 0) thankfully made MEMBLOCK_ERROR 0 and there already are codes which expect error return to be 0. There's no point in keeping MEMBLOCK_ERROR around. End its misery. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/1310457490-3356-6-git-send-email-tj@kernel.org Cc: Yinghai Lu <yinghai@kernel.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| * | bootmem: Fix __free_pages_bootmem() to use @order properlyTejun Heo2011-07-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | a226f6c899 (FRV: Clean up bootmem allocator's page freeing algorithm) separated out __free_pages_bootmem() from free_all_bootmem_core(). __free_pages_bootmem() takes @order argument but it assumes @order is either 0 or ilog2(BITS_PER_LONG). Note that all the current users match that assumption and this doesn't cause actual problems. Fix it by using 1 << order instead of BITS_PER_LONG. Signed-off-by: Tejun Heo <tj@kernel.org> Link: http://lkml.kernel.org/r/1310457490-3356-3-git-send-email-tj@kernel.org Cc: David Howells <dhowells@redhat.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
* | | mm: Ensure that pfn_valid() is called once per pageblock when reserving ↵Michal Hocko2011-12-091-1/+7
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | pageblocks setup_zone_migrate_reserve() expects that zone->start_pfn starts at pageblock_nr_pages aligned pfn otherwise we could access beyond an existing memblock resulting in the following panic if CONFIG_HOLES_IN_ZONE is not configured and we do not check pfn_valid: IP: [<c02d331d>] setup_zone_migrate_reserve+0xcd/0x180 *pdpt = 0000000000000000 *pde = f000ff53f000ff53 Oops: 0000 [#1] SMP Pid: 1, comm: swapper Not tainted 3.0.7-0.7-pae #1 VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform EIP: 0060:[<c02d331d>] EFLAGS: 00010006 CPU: 0 EIP is at setup_zone_migrate_reserve+0xcd/0x180 EAX: 000c0000 EBX: f5801fc0 ECX: 000c0000 EDX: 00000000 ESI: 000c01fe EDI: 000c01fe EBP: 00140000 ESP: f2475f58 DS: 007b ES: 007b FS: 00d8 GS: 0000 SS: 0068 Process swapper (pid: 1, ti=f2474000 task=f2472cd0 task.ti=f2474000) Call Trace: [<c02d389c>] __setup_per_zone_wmarks+0xec/0x160 [<c02d3a1f>] setup_per_zone_wmarks+0xf/0x20 [<c08a771c>] init_per_zone_wmark_min+0x27/0x86 [<c020111b>] do_one_initcall+0x2b/0x160 [<c086639d>] kernel_init+0xbe/0x157 [<c05cae26>] kernel_thread_helper+0x6/0xd Code: a5 39 f5 89 f7 0f 46 fd 39 cf 76 40 8b 03 f6 c4 08 74 32 eb 91 90 89 c8 c1 e8 0e 0f be 80 80 2f 86 c0 8b 14 85 60 2f 86 c0 89 c8 <2b> 82 b4 12 00 00 c1 e0 05 03 82 ac 12 00 00 8b 00 f6 c4 08 0f EIP: [<c02d331d>] setup_zone_migrate_reserve+0xcd/0x180 SS:ESP 0068:f2475f58 CR2: 00000000000012b4 We crashed in pageblock_is_reserved() when accessing pfn 0xc0000 because highstart_pfn = 0x36ffe. The issue was introduced in 3.0-rc1 by 6d3163ce ("mm: check if any page in a pageblock is reserved before marking it MIGRATE_RESERVE"). Make sure that start_pfn is always aligned to pageblock_nr_pages to ensure that pfn_valid s always called at the start of each pageblock. Architectures with holes in pageblocks will be correctly handled by pfn_valid_within in pageblock_is_reserved. Signed-off-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Mel Gorman <mgorman@suse.de> Tested-by: Dang Bo <bdang@vmware.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Arve Hjnnevg <arve@android.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: John Stultz <john.stultz@linaro.org> Cc: Dave Hansen <dave@linux.vnet.ibm.com> Cc: <stable@vger.kernel.org> [3.0+] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | | thp: set compound tail page _count to zeroYouquan Song2011-12-091-1/+1
| |/ |/| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 70b50f94f1644 ("mm: thp: tail page refcounting fix") keeps all page_tail->_count zero at all times. But the current kernel does not set page_tail->_count to zero if a 1GB page is utilized. So when an IOMMU 1GB page is used by KVM, it wil result in a kernel oops because a tail page's _count does not equal zero. kernel BUG at include/linux/mm.h:386! invalid opcode: 0000 [#1] SMP Call Trace: gup_pud_range+0xb8/0x19d get_user_pages_fast+0xcb/0x192 ? trace_hardirqs_off+0xd/0xf hva_to_pfn+0x119/0x2f2 gfn_to_pfn_memslot+0x2c/0x2e kvm_iommu_map_pages+0xfd/0x1c1 kvm_iommu_map_memslots+0x7c/0xbd kvm_iommu_map_guest+0xaa/0xbf kvm_vm_ioctl_assigned_device+0x2ef/0xa47 kvm_vm_ioctl+0x36c/0x3a2 do_vfs_ioctl+0x49e/0x4e4 sys_ioctl+0x5a/0x7c system_call_fastpath+0x16/0x1b RIP gup_huge_pud+0xf2/0x159 Signed-off-by: Youquan Song <youquan.song@intel.com> Reviewed-by: Andrea Arcangeli <aarcange@redhat.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: neaten warn_alloc_failedJoe Perches2011-10-311-5/+11
| | | | | | | | | | | | | | | | | | | | | | | | Add __attribute__((format (printf...) to the function to validate format and arguments. Use vsprintf extension %pV to avoid any possible message interleaving. Coalesce format string. Convert printks/pr_warning to pr_warn. [akpm@linux-foundation.org: use the __printf() macro] Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: output a list of loaded modules when we hit bad_page()Dave Jones2011-10-311-0/+1
| | | | | | | | | | | | | | | | | | When we get a bad_page bug report, it's useful to see what modules the user had loaded. Signed-off-by: Dave Jones <davej@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | fault-injection: add ability to export fault_attr in arbitrary directoryAkinobu Mita2011-08-031-8/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | init_fault_attr_dentries() is used to export fault_attr via debugfs. But it can only export it in debugfs root directory. Per Forlin is working on mmc_fail_request which adds support to inject data errors after a completed host transfer in MMC subsystem. The fault_attr for mmc_fail_request should be defined per mmc host and export it in debugfs directory per mmc host like /sys/kernel/debug/mmc0/mmc_fail_request. init_fault_attr_dentries() doesn't help for mmc_fail_request. So this introduces fault_create_debugfs_attr() which is able to create a directory in the arbitrary directory and replace init_fault_attr_dentries(). [akpm@linux-foundation.org: extraneous semicolon, per Randy] Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Tested-by: Per Forlin <per.forlin@linaro.org> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Lameter <cl@linux-foundation.org> Cc: Pekka Enberg <penberg@kernel.org> Cc: Matt Mackall <mpm@selenic.com> Cc: Randy Dunlap <rdunlap@xenotime.net> Cc: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | fail_page_alloc: simplify debugfs initializationAkinobu Mita2011-07-261-31/+16
| | | | | | | | | | | | | | | | | | | | Now cleanup_fault_attr_dentries() recursively removes a directory, So we can simplify the error handling in the initialization code and no need to hold dentry structs for each debugfs file. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | fault-injection: use debugfs_remove_recursiveAkinobu Mita2011-07-261-1/+1
| | | | | | | | | | | | | | | | | | Use debugfs_remove_recursive() to simplify initialization and deinitialization of fault injection debugfs files. Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: page allocator: reconsider zones for allocation after direct reclaimMel Gorman2011-07-251-0/+23
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With zone_reclaim_mode enabled, it's possible for zones to be considered full in the zonelist_cache so they are skipped in the future. If the process enters direct reclaim, the ZLC may still consider zones to be full even after reclaiming pages. Reconsider all zones for allocation if direct reclaim returns successfully. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* | mm: page allocator: initialise ZLC for first zone eligible for zone_reclaimMel Gorman2011-07-251-13/+22
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There have been a small number of complaints about significant stalls while copying large amounts of data on NUMA machines reported on a distribution bugzilla. In these cases, zone_reclaim was enabled by default due to large NUMA distances. In general, the complaints have not been about the workload itself unless it was a file server (in which case the recommendation was disable zone_reclaim). The stalls are mostly due to significant amounts of time spent scanning the preferred zone for pages to free. After a failure, it might fallback to another node (as zonelists are often node-ordered rather than zone-ordered) but stall quickly again when the next allocation attempt occurs. In bad cases, each page allocated results in a full scan of the preferred zone. Patch 1 checks the preferred zone for recent allocation failure which is particularly important if zone_reclaim has failed recently. This avoids rescanning the zone in the near future and instead falling back to another node. This may hurt node locality in some cases but a failure to zone_reclaim is more expensive than a remote access. Patch 2 clears the zlc information after direct reclaim. Otherwise, zone_reclaim can mark zones full, direct reclaim can reclaim enough pages but the zone is still not considered for allocation. This was tested on a 24-thread 2-node x86_64 machine. The tests were focused on large amounts of IO. All tests were bound to the CPUs on node-0 to avoid disturbances due to processes being scheduled on different nodes. The kernels tested are 3.0-rc6-vanilla Vanilla 3.0-rc6 zlcfirst Patch 1 applied zlcreconsider Patches 1+2 applied FS-Mark ./fs_mark -d /tmp/fsmark-10813 -D 100 -N 5000 -n 208 -L 35 -t 24 -S0 -s 524288 fsmark-3.0-rc6 3.0-rc6 3.0-rc6 vanilla zlcfirs zlcreconsider Files/s min 54.90 ( 0.00%) 49.80 (-10.24%) 49.10 (-11.81%) Files/s mean 100.11 ( 0.00%) 135.17 (25.94%) 146.93 (31.87%) Files/s stddev 57.51 ( 0.00%) 138.97 (58.62%) 158.69 (63.76%) Files/s max 361.10 ( 0.00%) 834.40 (56.72%) 802.40 (55.00%) Overhead min 76704.00 ( 0.00%) 76501.00 ( 0.27%) 77784.00 (-1.39%) Overhead mean 1485356.51 ( 0.00%) 1035797.83 (43.40%) 1594680.26 (-6.86%) Overhead stddev 1848122.53 ( 0.00%) 881489.88 (109.66%) 1772354.90 ( 4.27%) Overhead max 7989060.00 ( 0.00%) 3369118.00 (137.13%) 10135324.00 (-21.18%) MMTests Statistics: duration User/Sys Time Running Test (seconds) 501.49 493.91 499.93 Total Elapsed Time (seconds) 2451.57 2257.48 2215.92 MMTests Statistics: vmstat Page Ins 46268 63840 66008 Page Outs 90821596 90671128 88043732 Swap Ins 0 0 0 Swap Outs 0 0 0 Direct pages scanned 13091697 8966863 8971790 Kswapd pages scanned 0 1830011 1831116 Kswapd pages reclaimed 0 1829068 1829930 Direct pages reclaimed 13037777 8956828 8648314 Kswapd efficiency 100% 99% 99% Kswapd velocity 0.000 810.643 826.346 Direct efficiency 99% 99% 96% Direct velocity 5340.128 3972.068 4048.788 Percentage direct scans 100% 83% 83% Page writes by reclaim 0 3 0 Slabs scanned 796672 720640 720256 Direct inode steals 7422667 7160012 7088638 Kswapd inode steals 0 1736840 2021238 Test completes far faster with a large increase in the number of files created per second. Standard deviation is high as a small number of iterations were much higher than the mean. The number of pages scanned by zone_reclaim is reduced and kswapd is used for more work. LARGE DD 3.0-rc6 3.0-rc6 3.0-rc6 vanilla zlcfirst zlcreconsider download tar 59 ( 0.00%) 59 ( 0.00%) 55 ( 7.27%) dd source files 527 ( 0.00%) 296 (78.04%) 320 (64.69%) delete source 36 ( 0.00%) 19 (89.47%) 20 (80.00%) MMTests Statistics: duration User/Sys Time Running Test (seconds) 125.03 118.98 122.01 Total Elapsed Time (seconds) 624.56 375.02 398.06 MMTests Statistics: vmstat Page Ins 3594216 439368 407032 Page Outs 23380832 23380488 23377444 Swap Ins 0 0 0 Swap Outs 0 436 287 Direct pages scanned 17482342 69315973 82864918 Kswapd pages scanned 0 519123 575425 Kswapd pages reclaimed 0 466501 522487 Direct pages reclaimed 5858054 2732949 2712547 Kswapd efficiency 100% 89% 90% Kswapd velocity 0.000 1384.254 1445.574 Direct efficiency 33% 3% 3% Direct velocity 27991.453 184832.737 208171.929 Percentage direct scans 100% 99% 99% Page writes by reclaim 0 5082 13917 Slabs scanned 17280 29952 35328 Direct inode steals 115257 1431122 332201 Kswapd inode steals 0 0 979532 This test downloads a large tarfile and copies it with dd a number of times - similar to the most recent bug report I've dealt with. Time to completion is reduced. The number of pages scanned directly is still disturbingly high with a low efficiency but this is likely due to the number of dirty pages encountered. The figures could probably be improved with more work around how kswapd is used and how dirty pages are handled but that is separate work and this result is significant on its own. Streaming Mapped Writer MMTests Statistics: duration User/Sys Time Running Test (seconds) 124.47 111.67 112.64 Total Elapsed Time (seconds) 2138.14 1816.30 1867.56 MMTests Statistics: vmstat Page Ins 90760 89124 89516 Page Outs 121028340 120199524 120736696 Swap Ins 0 86 55 Swap Outs 0 0 0 Direct pages scanned 114989363 96461439 96330619 Kswapd pages scanned 56430948 56965763 57075875 Kswapd pages reclaimed 27743219 27752044 27766606 Direct pages reclaimed 49777 46884 36655 Kswapd efficiency 49% 48% 48% Kswapd velocity 26392.541 31363.631 30561.736 Direct efficiency 0% 0% 0% Direct velocity 53780.091 53108.759 51581.004 Percentage direct scans 67% 62% 62% Page writes by reclaim 385 122 1513 Slabs scanned 43008 39040 42112 Direct inode steals 0 10 8 Kswapd inode steals 733 534 477 This test just creates a large file mapping and writes to it linearly. Time to completion is again reduced. The gains are mostly down to two things. In many cases, there is less scanning as zone_reclaim simply gives up faster due to recent failures. The second reason is that memory is used more efficiently. Instead of scanning the preferred zone every time, the allocator falls back to another zone and uses it instead improving overall memory utilisation. This patch: initialise ZLC for first zone eligible for zone_reclaim. The zonelist cache (ZLC) is used among other things to record if zone_reclaim() failed for a particular zone recently. The intention is to avoid a high cost scanning extremely long zonelists or scanning within the zone uselessly. Currently the zonelist cache is setup only after the first zone has been considered and zone_reclaim() has been called. The objective was to avoid a costly setup but zone_reclaim is itself quite expensive. If it is failing regularly such as the first eligible zone having mostly mapped pages, the cost in scanning and allocation stalls is far higher than the ZLC initialisation step. This patch initialises ZLC before the first eligible zone calls zone_reclaim(). Once initialised, it is checked whether the zone failed zone_reclaim recently. If it has, the zone is skipped. As the first zone is now being checked, additional care has to be taken about zones marked full. A zone can be marked "full" because it should not have enough unmapped pages for zone_reclaim but this is excessive as direct reclaim or kswapd may succeed where zone_reclaim fails. Only mark zones "full" after zone_reclaim fails if it failed to reclaim enough pages after scanning. Signed-off-by: Mel Gorman <mgorman@suse.de> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Lameter <cl@linux.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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