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* ratelimit: add comment warning people off printk_ratelimit()Andrew Morton2010-10-271-0/+5
| | | | | | | | printk_ratelimit() was a bad idea - we don't want subsytem A causing ratelimiting of subsystem B's messages. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* printk: declare printk_ratelimit_state in ratelimit.hNamhyung Kim2010-10-271-0/+2
| | | | | | | | | | | | | Adding declaration of printk_ratelimit_state in ratelimit.h removes potential build breakage and following sparse warning: kernel/printk.c:1426:1: warning: symbol 'printk_ratelimit_state' was not declared. Should it be static? [akpm@linux-foundation.org: remove unneeded ifdef] Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel: remove PF_FLUSHERPeter Zijlstra2010-10-271-1/+0Star
| | | | | | | | | PF_FLUSHER is only ever set, not tested, remove it. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* fs: allow for more than 2^31 filesEric Dumazet2010-10-271-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Robin Holt tried to boot a 16TB system and found af_unix was overflowing a 32bit value : <quote> We were seeing a failure which prevented boot. The kernel was incapable of creating either a named pipe or unix domain socket. This comes down to a common kernel function called unix_create1() which does: atomic_inc(&unix_nr_socks); if (atomic_read(&unix_nr_socks) > 2 * get_max_files()) goto out; The function get_max_files() is a simple return of files_stat.max_files. files_stat.max_files is a signed integer and is computed in fs/file_table.c's files_init(). n = (mempages * (PAGE_SIZE / 1024)) / 10; files_stat.max_files = n; In our case, mempages (total_ram_pages) is approx 3,758,096,384 (0xe0000000). That leaves max_files at approximately 1,503,238,553. This causes 2 * get_max_files() to integer overflow. </quote> Fix is to let /proc/sys/fs/file-nr & /proc/sys/fs/file-max use long integers, and change af_unix to use an atomic_long_t instead of atomic_t. get_max_files() is changed to return an unsigned long. get_nr_files() is changed to return a long. unix_nr_socks is changed from atomic_t to atomic_long_t, while not strictly needed to address Robin problem. Before patch (on a 64bit kernel) : # echo 2147483648 >/proc/sys/fs/file-max # cat /proc/sys/fs/file-max -18446744071562067968 After patch: # echo 2147483648 >/proc/sys/fs/file-max # cat /proc/sys/fs/file-max 2147483648 # cat /proc/sys/fs/file-nr 704 0 2147483648 Reported-by: Robin Holt <holt@sgi.com> Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Acked-by: David Miller <davem@davemloft.net> Reviewed-by: Robin Holt <holt@sgi.com> Tested-by: Robin Holt <holt@sgi.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* drivers/misc: driver for APDS990X ALS and proximity sensorsSamu Onkalo2010-10-271-0/+79
| | | | | | | | | | | | | | This is a driver for Avago APDS990X combined ALS and proximity sensor. Interface is sysfs based. The driver uses interrupts to provide new data. The driver supports pm_runtime and regulator frameworks. See Documentation/misc-devices/apds990x.txt for details Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com> Acked-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* drivers/misc: driver for bh1770glc / sfh7770 ALS and proximity sensorSamu Onkalo2010-10-271-0/+53
| | | | | | | | | | | | | | | This is a driver for ROHM BH1770GLC and OSRAM SFH7770 combined ALS and proximity sensor. Interface is sysfs based. The driver uses interrupts to provide new data. The driver supports pm_runtime and regulator frameworks. See Documentation/misc-devices/bh1770glc.txt for details Signed-off-by: Samu Onkalo <samu.p.onkalo@nokia.com> Acked-by: Jonathan Cameron <jic23@cam.ac.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* workqueues: s/ON_STACK/ONSTACK/Andrew Morton2010-10-271-3/+3
| | | | | | | | | | | | | | | Silly though it is, completions and wait_queue_heads use foo_ONSTACK (COMPLETION_INITIALIZER_ONSTACK, DECLARE_COMPLETION_ONSTACK, __WAIT_QUEUE_HEAD_INIT_ONSTACK and DECLARE_WAIT_QUEUE_HEAD_ONSTACK) so I guess workqueues should do the same thing. s/INIT_WORK_ON_STACK/INIT_WORK_ONSTACK/ s/INIT_DELAYED_WORK_ON_STACK/INIT_DELAYED_WORK_ONSTACK/ Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmlinux.lds.h: lower init ramfs alignment to 4Mike Frysinger2010-10-271-1/+1
| | | | | | | | | | | | | | | | | | | The new init ramfs format (cpio based) requires an alignment of 4 (per the documentation and per the source files themselves). As for compressed sources, the decompressors can all deal with unaligned buffers. The cpio source is also found in the __init sections of the kernel, so once they are read and expanded into a tmpfs, the source is freed. That means there is no need to force page alignment here either. This has been used on Blackfin systems for many releases without issue. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmlinux.lds.h: gather .data..shared_aligned sections in DATA_DATAMike Frysinger2010-10-271-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | With the recent change "net: remove time limit in process_backlog()", the softnet_data variable changed from "DEFINE_PER_CPU()" to "DEFINE_PER_CPU_ALIGNED()" which moved it from the .data section to the .data.shared_align section. I'm not saying this patch is wrong, just that is what caused me to notice this larger problem. No one else in the kernel is using this aligned macro variant, so I imagine that's why no one has noticed yet. Since .data..shared_align isn't declared in any vmlinux files that I can see, the linker just places it last. This "just works" for most people, but when building a ROM kernel on Blackfin systems, it causes section overlap errors: bfin-uclinux-ld.real: section .init.data [00000000202e06b8 -> 00000000202e48b7] overlaps section .data.shared_aligned [00000000202e06b8 -> 00000000202e0723] I imagine other arches which support the ROM config option and thus do funky placement would see similar issues ... On x86, it is stuck in a dedicated section at the end: [8] .data PROGBITS ffffffff810ec000 2ec0000303a8 00 WA 0 0 4096 [9] .data.shared_alig PROGBITS ffffffff8111c3c0 31c3c00000c8 00 WA 0 0 64 So make sure we include this section in the DATA_DATA macro so that it is placed in the right location. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Sam Ravnborg <sam@ravnborg.org> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Alan Jenkins <alan-jenkins@tuffmail.co.uk> Cc: Greg Ungerer <gerg@snapgear.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* modules: no need to align .modinfo stringsJan Beulich2010-10-271-2/+2
| | | | | | | | | | | | | gcc aligns strings as a performance consideration for those cases where strings are being used a lot. Their use is not performance critical, and hence it seems better to save some space. Signed-off-by: Jan Beulich <jbeulich@novell.com> Acked-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* include/linux/kernel.h: add __must_check to strict_strto*()Andrew Morton2010-10-271-4/+4
| | | | | | | | | The whole point to using the strict functions is to check the return value. If you don't, strict_strto*() will return you uninitialised garbage. Offenders have been observed in the wild. Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kernel.h: add {min,max}3 macrosHagen Paul Pfeifer2010-10-271-0/+18
| | | | | | | | | | | | | | | | | | | | | Introduce two additional min/max macros to compare three operands. This will save some cycles as well as some bytes on the stack and last but not least more pleasing as macro nesting. [akpm@linux-foundation.org: fix warnings] Signed-off-by: Hagen Paul Pfeifer <hagen@jauu.net> Cc: Joe Perches <joe@perches.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Hartley Sweeten <hsweeten@visionengravers.com> Cc: Russell King <linux@arm.linux.org.uk> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Roland Dreier <rolandd@cisco.com> Cc: Sean Hefty <sean.hefty@intel.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: add vzalloc() and vzalloc_node() helpersDave Young2010-10-271-0/+2
| | | | | | | | | | | | | | Add vzalloc() and vzalloc_node() to encapsulate the vmalloc-then-memset-zero operation. Use __GFP_ZERO to zero fill the allocated memory. Signed-off-by: Dave Young <hidave.darkstar@gmail.com> Cc: Christoph Lameter <cl@linux-foundation.org> Acked-by: Greg Ungerer <gerg@snapgear.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix sparse warnings on GFP_ZONE_TABLE/BADNamhyung Kim2010-10-271-42/+63
| | | | | | | | | | | | Introduce ___GFP_* masks in order for gfp_t to not be mixed with plain integers which causes a lot of warnings like the following: warning: restricted gfp_t degrades to integer Signed-off-by: Namhyung Kim <namhyung@gmail.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: declare some external symbolsNamhyung Kim2010-10-272-0/+3
| | | | | | | | | | | | Declare 'bdi_pending_list' and 'tag_pages_for_writeback()' to remove following sparse warnings: mm/backing-dev.c:46:1: warning: symbol 'bdi_pending_list' was not declared. Should it be static? mm/page-writeback.c:825:6: warning: symbol 'tag_pages_for_writeback' was not declared. Should it be static? Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rmap: wrap page_check_address() using __cond_lock()Namhyung Kim2010-10-271-1/+12
| | | | | | | | | | | | | | | The page_check_address() conditionally grabs *@ptlp in case of returning non-NULL. Rename and wrap it using __cond_lock() removes following warnings from sparse: mm/rmap.c:472:9: warning: context imbalance in 'page_mapped_in_vma' - unexpected unlock mm/rmap.c:524:9: warning: context imbalance in 'page_referenced_one' - unexpected unlock mm/rmap.c:706:9: warning: context imbalance in 'page_mkclean_one' - unexpected unlock mm/rmap.c:1066:9: warning: context imbalance in 'try_to_unmap_one' - unexpected unlock Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* rmap: annotate lock context change on page_[un]lock_anon_vma()Namhyung Kim2010-10-271-1/+14
| | | | | | | | | | The page_lock_anon_vma() conditionally grabs RCU and anon_vma lock but page_unlock_anon_vma() releases them unconditionally. This leads sparse to complain about context imbalance. Annotate them. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: wrap get_locked_pte() using __cond_lock()Namhyung Kim2010-10-271-1/+9
| | | | | | | | | | The get_locked_pte() conditionally grabs 'ptl' in case of returning non-NULL. This leads sparse to complain about context imbalance. Rename and wrap it using __cond_lock() to make sparse happy. Signed-off-by: Namhyung Kim <namhyung@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: retry page fault when blocking on disk transferMichel Lespinasse2010-10-272-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This change reduces mmap_sem hold times that are caused by waiting for disk transfers when accessing file mapped VMAs. It introduces the VM_FAULT_ALLOW_RETRY flag, which indicates that the call site wants mmap_sem to be released if blocking on a pending disk transfer. In that case, filemap_fault() returns the VM_FAULT_RETRY status bit and do_page_fault() will then re-acquire mmap_sem and retry the page fault. It is expected that the retry will hit the same page which will now be cached, and thus it will complete with a low mmap_sem hold time. Tests: - microbenchmark: thread A mmaps a large file and does random read accesses to the mmaped area - achieves about 55 iterations/s. Thread B does mmap/munmap in a loop at a separate location - achieves 55 iterations/s before, 15000 iterations/s after. - We are seeing related effects in some applications in house, which show significant performance regressions when running without this change. [akpm@linux-foundation.org: fix warning & crash] Signed-off-by: Michel Lespinasse <walken@google.com> Acked-by: Rik van Riel <riel@redhat.com> Acked-by: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nick Piggin <nickpiggin@yahoo.com.au> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Ying Han <yinghan@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Acked-by: "H. Peter Anvin" <hpa@zytor.com> Cc: <linux-arch@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: remove alignment padding from anon_vma on (some) 64 bit buildsRichard Kennedy2010-10-271-1/+1
| | | | | | | | | | | | | | | | Reorder structure anon_vma to remove alignment padding on 64 builds when (CONFIG_KSM || CONFIG_MIGRATION). This will shrink the size of the anon_vma structure from 40 to 32 bytes & allow more objects per slab in its kmem_cache. Under slub the objects in the anon_vma kmem_cache will then be 40 bytes with 102 objects per slab. (On v2.6.36 without this patch,the size is 48 bytes and 85 objects/slab.) Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk> Reviewed-by: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: stack based kmap_atomic()Peter Zijlstra2010-10-272-30/+45
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Keep the current interface but ignore the KM_type and use a stack based approach. The advantage is that we get rid of crappy code like: #define __KM_PTE \ (in_nmi() ? KM_NMI_PTE : \ in_irq() ? KM_IRQ_PTE : \ KM_PTE0) and in general can stop worrying about what context we're in and what kmap slots might be appropriate for that. The downside is that FRV kmap_atomic() gets more expensive. For now we use a CPP trick suggested by Andrew: #define kmap_atomic(page, args...) __kmap_atomic(page) to avoid having to touch all kmap_atomic() users in a single patch. [ not compiled on: - mn10300: the arch doesn't actually build with highmem to begin with ] [akpm@linux-foundation.org: coding-style fixes] [akpm@linux-foundation.org: fix up drivers/gpu/drm/i915/intel_overlay.c] Acked-by: Rik van Riel <riel@redhat.com> Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Cc: David Howells <dhowells@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Miller <davem@davemloft.net> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Dave Airlie <airlied@linux.ie> Cc: Li Zefan <lizf@cn.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: strictly nested kmap_atomic()Peter Zijlstra2010-10-271-2/+2
| | | | | | | | | | | | | | | | | | | | | Ensure kmap_atomic() usage is strictly nested Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Chris Metcalf <cmetcalf@tilera.com> Cc: David Howells <dhowells@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Russell King <rmk@arm.linux.org.uk> Cc: Ralf Baechle <ralf@linux-mips.org> Cc: David Miller <davem@davemloft.net> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* writeback: do not sleep on the congestion queue if there are no congested ↵Mel Gorman2010-10-273-1/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | BDIs or if significant congestion is not being encountered in the current zone If congestion_wait() is called with no BDI congested, the caller will sleep for the full timeout and this may be an unnecessary sleep. This patch adds a wait_iff_congested() that checks congestion and only sleeps if a BDI is congested else, it calls cond_resched() to ensure the caller is not hogging the CPU longer than its quota but otherwise will not sleep. This is aimed at reducing some of the major desktop stalls reported during IO. For example, while kswapd is operating, it calls congestion_wait() but it could just have been reclaiming clean page cache pages with no congestion. Without this patch, it would sleep for a full timeout but after this patch, it'll just call schedule() if it has been on the CPU too long. Similar logic applies to direct reclaimers that are not making enough progress. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* vmscan: narrow the scenarios in whcih lumpy reclaim uses synchrounous reclaimKOSAKI Motohiro2010-10-271-3/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | shrink_page_list() can decide to give up reclaiming a page under a number of conditions such as 1. trylock_page() failure 2. page is unevictable 3. zone reclaim and page is mapped 4. PageWriteback() is true 5. page is swapbacked and swap is full 6. add_to_swap() failure 7. page is dirty and gfpmask don't have GFP_IO, GFP_FS 8. page is pinned 9. IO queue is congested 10. pageout() start IO, but not finished With lumpy reclaim, failures result in entering synchronous lumpy reclaim but this can be unnecessary. In cases (2), (3), (5), (6), (7) and (8), there is no point retrying. This patch causes lumpy reclaim to abort when it is known it will fail. Case (9) is more interesting. current behavior is, 1. start shrink_page_list(async) 2. found queue_congested() 3. skip pageout write 4. still start shrink_page_list(sync) 5. wait on a lot of pages 6. again, found queue_congested() 7. give up pageout write again So, it's useless time wasting. However, just skipping page reclaim is also notgood as x86 allocating a huge page needs 512 pages for example. It can have more dirty pages than queue congestion threshold (~=128). After this patch, pageout() behaves as follows; - If order > PAGE_ALLOC_COSTLY_ORDER Ignore queue congestion always. - If order <= PAGE_ALLOC_COSTLY_ORDER skip write page and disable lumpy reclaim. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* writeback: account for time spent congestion_waitedMel Gorman2010-10-271-0/+28
| | | | | | | | | | | | | | | | | There is strong evidence to indicate a lot of time is being spent in congestion_wait(), some of it unnecessarily. This patch adds a tracepoint for congestion_wait to record when congestion_wait() was called, how long the timeout was for and how long it actually slept. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Minchan Kim <minchan.kim@gmail.com> Reviewed-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* tracing, vmscan: add trace events for LRU list shrinkingMel Gorman2010-10-271-0/+42
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | There have been numerous reports of stalls that pointed at the problem being somewhere in the VM. There are multiple roots to the problems which means dealing with any of the root problems in isolation is tricky to justify on their own and they would still need integration testing. This patch series puts together two different patch sets which in combination should tackle some of the root causes of latency problems being reported. Patch 1 adds a tracepoint for shrink_inactive_list. For this series, the most important results is being able to calculate the scanning/reclaim ratio as a measure of the amount of work being done by page reclaim. Patch 2 accounts for time spent in congestion_wait. Patches 3-6 were originally developed by Kosaki Motohiro but reworked for this series. It has been noted that lumpy reclaim is far too aggressive and trashes the system somewhat. As SLUB uses high-order allocations, a large cost incurred by lumpy reclaim will be noticeable. It was also reported during transparent hugepage support testing that lumpy reclaim was trashing the system and these patches should mitigate that problem without disabling lumpy reclaim. Patch 7 adds wait_iff_congested() and replaces some callers of congestion_wait(). wait_iff_congested() only sleeps if there is a BDI that is currently congested. Patch 8 notes that any BDI being congested is not necessarily a problem because there could be multiple BDIs of varying speeds and numberous zones. It attempts to track when a zone being reclaimed contains many pages backed by a congested BDI and if so, reclaimers wait on the congestion queue. I ran a number of tests with monitoring on X86, X86-64 and PPC64. Each machine had 3G of RAM and the CPUs were X86: Intel P4 2-core X86-64: AMD Phenom 4-core PPC64: PPC970MP Each used a single disk and the onboard IO controller. Dirty ratio was left at 20. I'm just going to report for X86-64 and PPC64 in a vague attempt to keep this report short. Four kernels were tested each based on v2.6.36-rc4 traceonly-v2r2: Patches 1 and 2 to instrument vmscan reclaims and congestion_wait lowlumpy-v2r3: Patches 1-6 to test if lumpy reclaim is better waitcongest-v2r3: Patches 1-7 to only wait on congestion waitwriteback-v2r4: Patches 1-8 to detect when a zone is congested nocongest-v1r5: Patches 1-3 for testing wait_iff_congestion nodirect-v1r5: Patches 1-10 to disable filesystem writeback for better IO The tests run were as follows kernbench compile-based benchmark. Smoke test performance sysbench OLTP read-only benchmark. Will be re-run in the future as read-write micro-mapped-file-stream This is a micro-benchmark from Johannes Weiner that accesses a large sparse-file through mmap(). It was configured to run in only single-CPU mode but can be indicative of how well page reclaim identifies suitable pages. stress-highalloc Tries to allocate huge pages under heavy load. kernbench, iozone and sysbench did not report any performance regression on any machine. sysbench did pressure the system lightly and there was reclaim activity but there were no difference of major interest between the kernels. X86-64 micro-mapped-file-stream traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3 waitwriteback-v2r4 pgalloc_dma 1639.00 ( 0.00%) 667.00 (-145.73%) 1167.00 ( -40.45%) 578.00 (-183.56%) pgalloc_dma32 2842410.00 ( 0.00%) 2842626.00 ( 0.01%) 2843043.00 ( 0.02%) 2843014.00 ( 0.02%) pgalloc_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) pgsteal_dma 729.00 ( 0.00%) 85.00 (-757.65%) 609.00 ( -19.70%) 125.00 (-483.20%) pgsteal_dma32 2338721.00 ( 0.00%) 2447354.00 ( 4.44%) 2429536.00 ( 3.74%) 2436772.00 ( 4.02%) pgsteal_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) pgscan_kswapd_dma 1469.00 ( 0.00%) 532.00 (-176.13%) 1078.00 ( -36.27%) 220.00 (-567.73%) pgscan_kswapd_dma32 4597713.00 ( 0.00%) 4503597.00 ( -2.09%) 4295673.00 ( -7.03%) 3891686.00 ( -18.14%) pgscan_kswapd_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) pgscan_direct_dma 71.00 ( 0.00%) 134.00 ( 47.01%) 243.00 ( 70.78%) 352.00 ( 79.83%) pgscan_direct_dma32 305820.00 ( 0.00%) 280204.00 ( -9.14%) 600518.00 ( 49.07%) 957485.00 ( 68.06%) pgscan_direct_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) pageoutrun 16296.00 ( 0.00%) 21254.00 ( 23.33%) 18447.00 ( 11.66%) 20067.00 ( 18.79%) allocstall 443.00 ( 0.00%) 273.00 ( -62.27%) 513.00 ( 13.65%) 1568.00 ( 71.75%) These are based on the raw figures taken from /proc/vmstat. It's a rough measure of reclaim activity. Note that allocstall counts are higher because we are entering direct reclaim more often as a result of not sleeping in congestion. In itself, it's not necessarily a bad thing. It's easier to get a view of what happened from the vmscan tracepoint report. FTrace Reclaim Statistics: vmscan traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3 waitwriteback-v2r4 Direct reclaims 443 273 513 1568 Direct reclaim pages scanned 305968 280402 600825 957933 Direct reclaim pages reclaimed 43503 19005 30327 117191 Direct reclaim write file async I/O 0 0 0 0 Direct reclaim write anon async I/O 0 3 4 12 Direct reclaim write file sync I/O 0 0 0 0 Direct reclaim write anon sync I/O 0 0 0 0 Wake kswapd requests 187649 132338 191695 267701 Kswapd wakeups 3 1 4 1 Kswapd pages scanned 4599269 4454162 4296815 3891906 Kswapd pages reclaimed 2295947 2428434 2399818 2319706 Kswapd reclaim write file async I/O 1 0 1 1 Kswapd reclaim write anon async I/O 59 187 41 222 Kswapd reclaim write file sync I/O 0 0 0 0 Kswapd reclaim write anon sync I/O 0 0 0 0 Time stalled direct reclaim (seconds) 4.34 2.52 6.63 2.96 Time kswapd awake (seconds) 11.15 10.25 11.01 10.19 Total pages scanned 4905237 4734564 4897640 4849839 Total pages reclaimed 2339450 2447439 2430145 2436897 %age total pages scanned/reclaimed 47.69% 51.69% 49.62% 50.25% %age total pages scanned/written 0.00% 0.00% 0.00% 0.00% %age file pages scanned/written 0.00% 0.00% 0.00% 0.00% Percentage Time Spent Direct Reclaim 29.23% 19.02% 38.48% 20.25% Percentage Time kswapd Awake 78.58% 78.85% 76.83% 79.86% What is interesting here for nocongest in particular is that while direct reclaim scans more pages, the overall number of pages scanned remains the same and the ratio of pages scanned to pages reclaimed is more or less the same. In other words, while we are sleeping less, reclaim is not doing more work and as direct reclaim and kswapd is awake for less time, it would appear to be doing less work. FTrace Reclaim Statistics: congestion_wait Direct number congest waited 87 196 64 0 Direct time congest waited 4604ms 4732ms 5420ms 0ms Direct full congest waited 72 145 53 0 Direct number conditional waited 0 0 324 1315 Direct time conditional waited 0ms 0ms 0ms 0ms Direct full conditional waited 0 0 0 0 KSwapd number congest waited 20 10 15 7 KSwapd time congest waited 1264ms 536ms 884ms 284ms KSwapd full congest waited 10 4 6 2 KSwapd number conditional waited 0 0 0 0 KSwapd time conditional waited 0ms 0ms 0ms 0ms KSwapd full conditional waited 0 0 0 0 The vanilla kernel spent 8 seconds asleep in direct reclaim and no time at all asleep with the patches. MMTests Statistics: duration User/Sys Time Running Test (seconds) 10.51 10.73 10.6 11.66 Total Elapsed Time (seconds) 14.19 13.00 14.33 12.76 Overall, the tests completed faster. It is interesting to note that backing off further when a zone is congested and not just a BDI was more efficient overall. PPC64 micro-mapped-file-stream pgalloc_dma 3024660.00 ( 0.00%) 3027185.00 ( 0.08%) 3025845.00 ( 0.04%) 3026281.00 ( 0.05%) pgalloc_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) pgsteal_dma 2508073.00 ( 0.00%) 2565351.00 ( 2.23%) 2463577.00 ( -1.81%) 2532263.00 ( 0.96%) pgsteal_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) pgscan_kswapd_dma 4601307.00 ( 0.00%) 4128076.00 ( -11.46%) 3912317.00 ( -17.61%) 3377165.00 ( -36.25%) pgscan_kswapd_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) pgscan_direct_dma 629825.00 ( 0.00%) 971622.00 ( 35.18%) 1063938.00 ( 40.80%) 1711935.00 ( 63.21%) pgscan_direct_normal 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) 0.00 ( 0.00%) pageoutrun 27776.00 ( 0.00%) 20458.00 ( -35.77%) 18763.00 ( -48.04%) 18157.00 ( -52.98%) allocstall 977.00 ( 0.00%) 2751.00 ( 64.49%) 2098.00 ( 53.43%) 5136.00 ( 80.98%) Similar trends to x86-64. allocstalls are up but it's not necessarily bad. FTrace Reclaim Statistics: vmscan Direct reclaims 977 2709 2098 5136 Direct reclaim pages scanned 629825 963814 1063938 1711935 Direct reclaim pages reclaimed 75550 242538 150904 387647 Direct reclaim write file async I/O 0 0 0 2 Direct reclaim write anon async I/O 0 10 0 4 Direct reclaim write file sync I/O 0 0 0 0 Direct reclaim write anon sync I/O 0 0 0 0 Wake kswapd requests 392119 1201712 571935 571921 Kswapd wakeups 3 2 3 3 Kswapd pages scanned 4601307 4128076 3912317 3377165 Kswapd pages reclaimed 2432523 2318797 2312673 2144616 Kswapd reclaim write file async I/O 20 1 1 1 Kswapd reclaim write anon async I/O 57 132 11 121 Kswapd reclaim write file sync I/O 0 0 0 0 Kswapd reclaim write anon sync I/O 0 0 0 0 Time stalled direct reclaim (seconds) 6.19 7.30 13.04 10.88 Time kswapd awake (seconds) 21.73 26.51 25.55 23.90 Total pages scanned 5231132 5091890 4976255 5089100 Total pages reclaimed 2508073 2561335 2463577 2532263 %age total pages scanned/reclaimed 47.95% 50.30% 49.51% 49.76% %age total pages scanned/written 0.00% 0.00% 0.00% 0.00% %age file pages scanned/written 0.00% 0.00% 0.00% 0.00% Percentage Time Spent Direct Reclaim 18.89% 20.65% 32.65% 27.65% Percentage Time kswapd Awake 72.39% 80.68% 78.21% 77.40% Again, a similar trend that the congestion_wait changes mean that direct reclaim scans more pages but the overall number of pages scanned while slightly reduced, are very similar. The ratio of scanning/reclaimed remains roughly similar. The downside is that kswapd and direct reclaim was awake longer and for a larger percentage of the overall workload. It's possible there were big differences in the amount of time spent reclaiming slab pages between the different kernels which is plausible considering that the micro tests runs after fsmark and sysbench. Trace Reclaim Statistics: congestion_wait Direct number congest waited 845 1312 104 0 Direct time congest waited 19416ms 26560ms 7544ms 0ms Direct full congest waited 745 1105 72 0 Direct number conditional waited 0 0 1322 2935 Direct time conditional waited 0ms 0ms 12ms 312ms Direct full conditional waited 0 0 0 3 KSwapd number congest waited 39 102 75 63 KSwapd time congest waited 2484ms 6760ms 5756ms 3716ms KSwapd full congest waited 20 48 46 25 KSwapd number conditional waited 0 0 0 0 KSwapd time conditional waited 0ms 0ms 0ms 0ms KSwapd full conditional waited 0 0 0 0 The vanilla kernel spent 20 seconds asleep in direct reclaim and only 312ms asleep with the patches. The time kswapd spent congest waited was also reduced by a large factor. MMTests Statistics: duration ser/Sys Time Running Test (seconds) 26.58 28.05 26.9 28.47 Total Elapsed Time (seconds) 30.02 32.86 32.67 30.88 With all patches applies, the completion times are very similar. X86-64 STRESS-HIGHALLOC traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3waitwriteback-v2r4 Pass 1 82.00 ( 0.00%) 84.00 ( 2.00%) 85.00 ( 3.00%) 85.00 ( 3.00%) Pass 2 90.00 ( 0.00%) 87.00 (-3.00%) 88.00 (-2.00%) 89.00 (-1.00%) At Rest 92.00 ( 0.00%) 90.00 (-2.00%) 90.00 (-2.00%) 91.00 (-1.00%) Success figures across the board are broadly similar. traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3waitwriteback-v2r4 Direct reclaims 1045 944 886 887 Direct reclaim pages scanned 135091 119604 109382 101019 Direct reclaim pages reclaimed 88599 47535 47863 46671 Direct reclaim write file async I/O 494 283 465 280 Direct reclaim write anon async I/O 29357 13710 16656 13462 Direct reclaim write file sync I/O 154 2 2 3 Direct reclaim write anon sync I/O 14594 571 509 561 Wake kswapd requests 7491 933 872 892 Kswapd wakeups 814 778 731 780 Kswapd pages scanned 7290822 15341158 11916436 13703442 Kswapd pages reclaimed 3587336 3142496 3094392 3187151 Kswapd reclaim write file async I/O 91975 32317 28022 29628 Kswapd reclaim write anon async I/O 1992022 789307 829745 849769 Kswapd reclaim write file sync I/O 0 0 0 0 Kswapd reclaim write anon sync I/O 0 0 0 0 Time stalled direct reclaim (seconds) 4588.93 2467.16 2495.41 2547.07 Time kswapd awake (seconds) 2497.66 1020.16 1098.06 1176.82 Total pages scanned 7425913 15460762 12025818 13804461 Total pages reclaimed 3675935 3190031 3142255 3233822 %age total pages scanned/reclaimed 49.50% 20.63% 26.13% 23.43% %age total pages scanned/written 28.66% 5.41% 7.28% 6.47% %age file pages scanned/written 1.25% 0.21% 0.24% 0.22% Percentage Time Spent Direct Reclaim 57.33% 42.15% 42.41% 42.99% Percentage Time kswapd Awake 43.56% 27.87% 29.76% 31.25% Scanned/reclaimed ratios again look good with big improvements in efficiency. The Scanned/written ratios also look much improved. With a better scanned/written ration, there is an expectation that IO would be more efficient and indeed, the time spent in direct reclaim is much reduced by the full series and kswapd spends a little less time awake. Overall, indications here are that allocations were happening much faster and this can be seen with a graph of the latency figures as the allocations were taking place http://www.csn.ul.ie/~mel/postings/vmscanreduce-20101509/highalloc-interlatency-hydra-mean.ps FTrace Reclaim Statistics: congestion_wait Direct number congest waited 1333 204 169 4 Direct time congest waited 78896ms 8288ms 7260ms 200ms Direct full congest waited 756 92 69 2 Direct number conditional waited 0 0 26 186 Direct time conditional waited 0ms 0ms 0ms 2504ms Direct full conditional waited 0 0 0 25 KSwapd number congest waited 4 395 227 282 KSwapd time congest waited 384ms 25136ms 10508ms 18380ms KSwapd full congest waited 3 232 98 176 KSwapd number conditional waited 0 0 0 0 KSwapd time conditional waited 0ms 0ms 0ms 0ms KSwapd full conditional waited 0 0 0 0 KSwapd full conditional waited 318 0 312 9 Overall, the time spent speeping is reduced. kswapd is still hitting congestion_wait() but that is because there are callers remaining where it wasn't clear in advance if they should be changed to wait_iff_congested() or not. Overall the sleep imes are reduced though - from 79ish seconds to about 19. MMTests Statistics: duration User/Sys Time Running Test (seconds) 3415.43 3386.65 3388.39 3377.5 Total Elapsed Time (seconds) 5733.48 3660.33 3689.41 3765.39 With the full series, the time to complete the tests are reduced by 30% PPC64 STRESS-HIGHALLOC traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3waitwriteback-v2r4 Pass 1 17.00 ( 0.00%) 34.00 (17.00%) 38.00 (21.00%) 43.00 (26.00%) Pass 2 25.00 ( 0.00%) 37.00 (12.00%) 42.00 (17.00%) 46.00 (21.00%) At Rest 49.00 ( 0.00%) 43.00 (-6.00%) 45.00 (-4.00%) 51.00 ( 2.00%) Success rates there are *way* up particularly considering that the 16MB huge pages on PPC64 mean that it's always much harder to allocate them. FTrace Reclaim Statistics: vmscan stress-highalloc stress-highalloc stress-highalloc stress-highalloc traceonly-v2r2 lowlumpy-v2r3 waitcongest-v2r3waitwriteback-v2r4 Direct reclaims 499 505 564 509 Direct reclaim pages scanned 223478 41898 51818 45605 Direct reclaim pages reclaimed 137730 21148 27161 23455 Direct reclaim write file async I/O 399 136 162 136 Direct reclaim write anon async I/O 46977 2865 4686 3998 Direct reclaim write file sync I/O 29 0 1 3 Direct reclaim write anon sync I/O 31023 159 237 239 Wake kswapd requests 420 351 360 326 Kswapd wakeups 185 294 249 277 Kswapd pages scanned 15703488 16392500 17821724 17598737 Kswapd pages reclaimed 5808466 2908858 3139386 3145435 Kswapd reclaim write file async I/O 159938 18400 18717 13473 Kswapd reclaim write anon async I/O 3467554 228957 322799 234278 Kswapd reclaim write file sync I/O 0 0 0 0 Kswapd reclaim write anon sync I/O 0 0 0 0 Time stalled direct reclaim (seconds) 9665.35 1707.81 2374.32 1871.23 Time kswapd awake (seconds) 9401.21 1367.86 1951.75 1328.88 Total pages scanned 15926966 16434398 17873542 17644342 Total pages reclaimed 5946196 2930006 3166547 3168890 %age total pages scanned/reclaimed 37.33% 17.83% 17.72% 17.96% %age total pages scanned/written 23.27% 1.52% 1.94% 1.43% %age file pages scanned/written 1.01% 0.11% 0.11% 0.08% Percentage Time Spent Direct Reclaim 44.55% 35.10% 41.42% 36.91% Percentage Time kswapd Awake 86.71% 43.58% 52.67% 41.14% While the scanning rates are slightly up, the scanned/reclaimed and scanned/written figures are much improved. The time spent in direct reclaim and with kswapd are massively reduced, mostly by the lowlumpy patches. FTrace Reclaim Statistics: congestion_wait Direct number congest waited 725 303 126 3 Direct time congest waited 45524ms 9180ms 5936ms 300ms Direct full congest waited 487 190 52 3 Direct number conditional waited 0 0 200 301 Direct time conditional waited 0ms 0ms 0ms 1904ms Direct full conditional waited 0 0 0 19 KSwapd number congest waited 0 2 23 4 KSwapd time congest waited 0ms 200ms 420ms 404ms KSwapd full congest waited 0 2 2 4 KSwapd number conditional waited 0 0 0 0 KSwapd time conditional waited 0ms 0ms 0ms 0ms KSwapd full conditional waited 0 0 0 0 Not as dramatic a story here but the time spent asleep is reduced and we can still see what wait_iff_congested is going to sleep when necessary. MMTests Statistics: duration User/Sys Time Running Test (seconds) 12028.09 3157.17 3357.79 3199.16 Total Elapsed Time (seconds) 10842.07 3138.72 3705.54 3229.85 The time to complete this test goes way down. With the full series, we are allocating over twice the number of huge pages in 30% of the time and there is a corresponding impact on the allocation latency graph available at. http://www.csn.ul.ie/~mel/postings/vmscanreduce-20101509/highalloc-interlatency-powyah-mean.ps This patch: Add a trace event for shrink_inactive_list() and updates the sample postprocessing script appropriately. It can be used to determine how many pages were reclaimed and for non-lumpy reclaim where exactly the pages were reclaimed from. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Minchan Kim <minchan.kim@gmail.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* mm: fix typo in mm.h when NODE_NOT_IN_PAGE_FLAGSWill Deacon2010-10-271-2/+2
| | | | | | | | | | | | | | | NODE_NOT_IN_PAGE_FLAGS is defined in mm.h when the node information is not stored in the page flags bitmap. Unfortunately, there's a typo in one of the checks for it. This patch fixes it (s/NODE_NOT_IN_PAGEFLAGS/NODE_NOT_IN_PAGE_FLAGS/). Since this has been around for ages, I doubt it's been causing any serious problems. Signed-off-by: Will Deacon <will.deacon@arm.com> Cc: Christoph Lameter <clameter@sgi.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>
* writeback: add nr_dirtied and nr_written to /proc/vmstatMichael Rubin2010-10-271-0/+2
| | | | | | | | | | | | | | | | | | | | To help developers and applications gain visibility into writeback behaviour adding two entries to vm_stat_items and /proc/vmstat. This will allow us to track the "written" and "dirtied" counts. # grep nr_dirtied /proc/vmstat nr_dirtied 3747 # grep nr_written /proc/vmstat nr_written 3618 Signed-off-by: Michael Rubin <mrubin@google.com> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.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: add account_page_writeback()Michael Rubin2010-10-271-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | To help developers and applications gain visibility into writeback behaviour this patch adds two counters to /proc/vmstat. # grep nr_dirtied /proc/vmstat nr_dirtied 3747 # grep nr_written /proc/vmstat nr_written 3618 These entries allow user apps to understand writeback behaviour over time and learn how it is impacting their performance. Currently there is no way to inspect dirty and writeback speed over time. It's not possible for nr_dirty/nr_writeback. These entries are necessary to give visibility into writeback behaviour. We have /proc/diskstats which lets us understand the io in the block layer. We have blktrace for more in depth understanding. We have e2fsprogs and debugsfs to give insight into the file systems behaviour, but we don't offer our users the ability understand what writeback is doing. There is no way to know how active it is over the whole system, if it's falling behind or to quantify it's efforts. With these values exported users can easily see how much data applications are sending through writeback and also at what rates writeback is processing this data. Comparing the rates of change between the two allow developers to see when writeback is not able to keep up with incoming traffic and the rate of dirty memory being sent to the IO back end. This allows folks to understand their io workloads and track kernel issues. Non kernel engineers at Google often use these counters to solve puzzling performance problems. Patch #4 adds a pernode vmstat file with nr_dirtied and nr_written Patch #5 add writeback thresholds to /proc/vmstat Currently these values are in debugfs. But they should be promoted to /proc since they are useful for developers who are writing databases and file servers and are not debugging the kernel. The output is as below: # grep threshold /proc/vmstat nr_pages_dirty_threshold 409111 nr_pages_dirty_background_threshold 818223 This patch: This allows code outside of the mm core to safely manipulate page writeback state and not worry about the other accounting. Not using these routines means that some code will lose track of the accounting and we get bugs. Modify nilfs2 to use interface. Signed-off-by: Michael Rubin <mrubin@google.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Reviewed-by: Wu Fengguang <fengguang.wu@intel.com> Cc: KONISHI Ryusuke <konishi.ryusuke@lab.ntt.co.jp> Cc: Jiro SEKIBA <jir@unicus.jp> Cc: Dave Chinner <david@fromorbit.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.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>
* memory hotplug: unify is_removable and offline detection codeKAMEZAWA Hiroyuki2010-10-271-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | Now, sysfs interface of memory hotplug shows whether the section is removable or not. But it checks only migrateype of pages and doesn't check details of cluster of pages. Next, memory hotplug's set_migratetype_isolate() has the same kind of check, too. This patch adds the function __count_unmovable_pages() and makes above 2 checks to use the same logic. Then, is_removable and hotremove code uses the same logic. No changes in the hotremove logic itself. TODO: need to find a way to check RECLAMABLE. But, considering bit, calling shrink_slab() against a range before starting memory hotremove sounds better. If so, this patch's logic doesn't need to be changed. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reported-by: Michal Hocko <mhocko@suse.cz> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Mel Gorman <mel@csn.ul.ie> 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: only build per-node scan_unevictable functions when NUMA is enabledThadeu Lima de Souza Cascardo2010-10-271-0/+10
| | | | | | | | | | | | Non-NUMA systems do never create these files anyway, since they are only created by driver subsystem when NUMA is configured. [akpm@linux-foundation.org: cleanup] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@holoscopio.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.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>
* include/linux/pageblock-flags.h: fix set_pageblock_flags() macro definitonzeal2010-10-271-2/+3
| | | | | | | | | The presently-unused macro was missing one parameter. Signed-off-by: zeal <zealcook@gmail.com> Acked-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>
* writeback: remove nonblocking/encountered_congestion referencesWu Fengguang2010-10-272-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This removes more dead code that was somehow missed by commit 0d99519efef (writeback: remove unused nonblocking and congestion checks). There are no behavior change except for the removal of two entries from one of the ext4 tracing interface. The nonblocking checks in ->writepages are no longer used because the flusher now prefer to block on get_request_wait() than to skip inodes on IO congestion. The latter will lead to more seeky IO. The nonblocking checks in ->writepage are no longer used because it's redundant with the WB_SYNC_NONE check. We no long set ->nonblocking in VM page out and page migration, because a) it's effectively redundant with WB_SYNC_NONE in current code b) it's old semantic of "Don't get stuck on request queues" is mis-behavior: that would skip some dirty inodes on congestion and page out others, which is unfair in terms of LRU age. Inspired by Christoph Hellwig. Thanks! Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Cc: Theodore Ts'o <tytso@mit.edu> Cc: David Howells <dhowells@redhat.com> Cc: Sage Weil <sage@newdream.net> Cc: Steve French <sfrench@samba.org> Cc: Chris Mason <chris.mason@oracle.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Christoph Hellwig <hch@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* oom: add per-mm oom disable countYing Han2010-10-271-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | It's pointless to kill a task if another thread sharing its mm cannot be killed to allow future memory freeing. A subsequent patch will prevent kills in such cases, but first it's necessary to have a way to flag a task that shares memory with an OOM_DISABLE task that doesn't incur an additional tasklist scan, which would make select_bad_process() an O(n^2) function. This patch adds an atomic counter to struct mm_struct that follows how many threads attached to it have an oom_score_adj of OOM_SCORE_ADJ_MIN. They cannot be killed by the kernel, so their memory cannot be freed in oom conditions. This only requires task_lock() on the task that we're operating on, it does not require mm->mmap_sem since task_lock() pins the mm and the operation is atomic. [rientjes@google.com: changelog and sys_unshare() code] [rientjes@google.com: protect oom_disable_count with task_lock in fork] [rientjes@google.com: use old_mm for oom_disable_count in exec] Signed-off-by: Ying Han <yinghan@google.com> Signed-off-by: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Rik van Riel <riel@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* kfifo: disable __kfifo_must_check_helper()Andrew Morton2010-10-271-5/+2Star
| | | | | | | | | | | | | | | | | | | This helper is wrong: it coerces signed values into unsigned ones, so code such as if (kfifo_alloc(...) < 0) { error } will fail to detect the error. So let's disable __kfifo_must_check_helper() for 2.6.36. Cc: Randy Dunlap <randy.dunlap@oracle.com> Cc: Stefani Seibold <stefani@seibold.net> Cc: <stable@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* types.h: move misplaced commentAndrew Morton2010-10-271-10/+10
| | | | | | | | | | | | This comment landed in the wrong place. Cc: Andi Kleen <andi@firstfloor.org> Cc: Arnd Bergmann <arnd@arndb.de> Cc: David Miller <davem@davemloft.net> Cc: Eric Paris <eparis@redhat.com> Cc: Jan Engelhardt <jengelh@medozas.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Merge git://git.infradead.org/battery-2.6Linus Torvalds2010-10-261-1/+5
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * git://git.infradead.org/battery-2.6: power_supply: Makefile cleanup bq27x00_battery: Add missing kfree(di->bus) in bq27x00_battery_remove() power_supply: Introduce maximum current property power_supply: Add types for USB chargers ds2782_battery: Fix units power_supply: Add driver for TWL4030/TPS65950 BCI charger bq20z75: Add support for more power supply properties wm831x_power: Add missing kfree(wm831x_power) in wm831x_power_remove() jz4740-battery: Add missing kfree(jz_battery) in jz_battery_remove() ds2760_battery: Add missing kfree(di) in ds2760_battery_remove() olpc_battery: Fix endian neutral breakage for s16 values ds2760_battery: Fix W1 and W1_SLAVE_DS2760 dependency pcf50633-charger: Add missing sysfs_remove_group() power_supply: Add driver for TI BQ20Z75 gas gauge IC wm831x_power: Remove duplicate chg mask omap: rx51: Add support for USB chargers power_supply: Add isp1704 charger detection driver
| * power_supply: Introduce maximum current propertyHeikki Krogerus2010-10-061-0/+1
| | | | | | | | | | | | | | USB only gives the maximum current allowed to draw. Signed-off-by: Heikki Krogerus <ext-heikki.krogerus@nokia.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
| * power_supply: Add types for USB chargersHeikki Krogerus2010-10-061-1/+4
| | | | | | | | | | | | | | | | This adds power supply types for USB chargers defined in Battery Charging Specification 1.1. Signed-off-by: Heikki Krogerus <ext-heikki.krogerus@nokia.com> Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>
* | Merge branch 'hwpoison' of ↵Linus Torvalds2010-10-264-5/+43
|\ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6 * 'hwpoison' of git://git.kernel.org/pub/scm/linux/kernel/git/ak/linux-mce-2.6: (22 commits) Add _addr_lsb field to ia64 siginfo Fix migration.c compilation on s390 HWPOISON: Remove retry loop for try_to_unmap HWPOISON: Turn addr_valid from bitfield into char HWPOISON: Disable DEBUG by default HWPOISON: Convert pr_debugs to pr_info HWPOISON: Improve comments in memory-failure.c x86: HWPOISON: Report correct address granuality for huge hwpoison faults Encode huge page size for VM_FAULT_HWPOISON errors Fix build error with !CONFIG_MIGRATION hugepage: move is_hugepage_on_freelist inside ifdef to avoid warning Clean up __page_set_anon_rmap HWPOISON, hugetlb: fix unpoison for hugepage HWPOISON, hugetlb: soft offlining for hugepage HWPOSION, hugetlb: recover from free hugepage error when !MF_COUNT_INCREASED hugetlb: move refcounting in hugepage allocation inside hugetlb_lock HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page() hugetlb: hugepage migration core hugetlb: redefine hugepage copy functions hugetlb: add allocate function for hugepage migration ...
| * \ Merge branch 'hwpoison-hugepages' into hwpoisonAndi Kleen2010-10-223-4/+41
| |\ \ | | | | | | | | | | | | | | | | Conflicts: mm/memory-failure.c
| | * | Encode huge page size for VM_FAULT_HWPOISON errorsAndi Kleen2010-10-082-2/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This fixes a problem introduced with the hugetlb hwpoison handling The user space SIGBUS signalling wants to know the size of the hugepage that caused a HWPOISON fault. Unfortunately the architecture page fault handlers do not have easy access to the struct page. Pass the information out in the fault error code instead. I added a separate VM_FAULT_HWPOISON_LARGE bit for this case and encode the hpage index in some free upper bits of the fault code. The small page hwpoison keeps stays with the VM_FAULT_HWPOISON name to minimize changes. Also add code to hugetlb.h to convert that index into a page shift. Will be used in a further patch. Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: fengguang.wu@intel.com Signed-off-by: Andi Kleen <ak@linux.intel.com>
| | * | Fix build error with !CONFIG_MIGRATIONNaoya Horiguchi2010-10-081-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | migrate_huge_page_move_mapping() is declared as "extern int ..." in include/linux/migrate.h for !CONFIG_MIGRATION, which causes the build error like below: mm/mprotect.o: In function `migrate_huge_page_move_mapping': mprotect.c:(.text+0x0): multiple definition of `migrate_huge_page_move_mapping' mm/shmem.o:shmem.c:(.text+0x0): first defined here mm/rmap.o: In function `migrate_huge_page_move_mapping': rmap.c:(.text+0x0): multiple definition of `migrate_huge_page_move_mapping' mm/shmem.o:shmem.c:(.text+0x0): first defined here Reported-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
| | * | HWPOISON, hugetlb: add free check to dequeue_hwpoison_huge_page()Naoya Horiguchi2010-10-081-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This check is necessary to avoid race between dequeue and allocation, which can cause a free hugepage to be dequeued twice and get kernel unstable. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Wu Fengguang <fengguang.wu@intel.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Christoph Lameter <cl@linux.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
| | * | hugetlb: hugepage migration coreNaoya Horiguchi2010-10-081-0/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch extends page migration code to support hugepage migration. One of the potential users of this feature is soft offlining which is triggered by memory corrected errors (added by the next patch.) Todo: - there are other users of page migration such as memory policy, memory hotplug and memocy compaction. They are not ready for hugepage support for now. ChangeLog since v4: - define migrate_huge_pages() - remove changes on isolation/putback_lru_page() ChangeLog since v2: - refactor isolate/putback_lru_page() to handle hugepage - add comment about race on unmap_and_move_huge_page() ChangeLog since v1: - divide migration code path for hugepage - define routine checking migration swap entry for hugetlb - replace "goto" with "if/else" in remove_migration_pte() Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Andi Kleen <ak@linux.intel.com>
| | * | hugetlb: redefine hugepage copy functionsNaoya Horiguchi2010-10-081-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch modifies hugepage copy functions to have only destination and source hugepages as arguments for later use. The old ones are renamed from copy_{gigantic,huge}_page() to copy_user_{gigantic,huge}_page(). This naming convention is consistent with that between copy_highpage() and copy_user_highpage(). ChangeLog since v4: - add blank line between local declaration and code - remove unnecessary might_sleep() ChangeLog since v2: - change copy_huge_page() from macro to inline dummy function to avoid compile warning when !CONFIG_HUGETLB_PAGE. Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Reviewed-by: Christoph Lameter <cl@linux.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
| | * | hugetlb: add allocate function for hugepage migrationNaoya Horiguchi2010-10-081-0/+3
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We can't use existing hugepage allocation functions to allocate hugepage for page migration, because page migration can happen asynchronously with the running processes and page migration users should call the allocation function with physical addresses (not virtual addresses) as arguments. ChangeLog since v3: - unify alloc_buddy_huge_page() and alloc_buddy_huge_page_node() ChangeLog since v2: - remove unnecessary get/put_mems_allowed() (thanks to David Rientjes) ChangeLog since v1: - add comment on top of alloc_huge_page_no_vma() Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Acked-by: Mel Gorman <mel@csn.ul.ie> Signed-off-by: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> Reviewed-by: Christoph Lameter <cl@linux.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
| * | | Merge branch 'hwpoison-fixes-2.6.37' into hwpoisonAndi Kleen2010-10-221-1/+2
| |\ \ \
| | * | | HWPOISON/signalfd: add support for addr_lsbHidetoshi Seto2010-10-081-1/+2
| | |/ / | | | | | | | | | | | | | | | | | | | | | | | | | | | | Similar change as to signal delivery: copy out the si_addr_lsb field to user space in signalfd Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> Signed-off-by: Andi Kleen <ak@linux.intel.com>
* | | | Merge branch 'for-2.6.37' of git://linux-nfs.org/~bfields/linuxLinus Torvalds2010-10-2610-75/+103
|\ \ \ \ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | * 'for-2.6.37' of git://linux-nfs.org/~bfields/linux: (99 commits) svcrpc: svc_tcp_sendto XPT_DEAD check is redundant svcrpc: no need for XPT_DEAD check in svc_xprt_enqueue svcrpc: assume svc_delete_xprt() called only once svcrpc: never clear XPT_BUSY on dead xprt nfsd4: fix connection allocation in sequence() nfsd4: only require krb5 principal for NFSv4.0 callbacks nfsd4: move minorversion to client nfsd4: delay session removal till free_client nfsd4: separate callback change and callback probe nfsd4: callback program number is per-session nfsd4: track backchannel connections nfsd4: confirm only on succesful create_session nfsd4: make backchannel sequence number per-session nfsd4: use client pointer to backchannel session nfsd4: move callback setup into session init code nfsd4: don't cache seq_misordered replies SUNRPC: Properly initialize sock_xprt.srcaddr in all cases SUNRPC: Use conventional switch statement when reclassifying sockets sunrpc/xprtrdma: clean up workqueue usage sunrpc: Turn list_for_each-s into the ..._entry-s ... Fix up trivial conflicts (two different deprecation notices added in separate branches) in Documentation/feature-removal-schedule.txt
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