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2008-10-20unevictable lru: add event counting with statisticsLee Schermerhorn
Fix to unevictable-lru-page-statistics.patch Add unevictable lru infrastructure vm events to the statistics patch. Rename the "NORECL_" and "noreclaim_" symbols and text strings to "UNEVICTABLE_" and "unevictable_", respectively. Currently, both the infrastructure and the mlocked pages event are added by a single patch later in the series. This makes it difficult to add or rework the incremental patches. The events actually "belong" with the stats, so pull them up to here. Also, restore the event counting to putback_lru_page(). This was removed from previous patch in series where it was "misplaced". The actual events weren't defined that early. Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Rik van Riel <riel@redhat.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> 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>
2008-10-20Unevictable LRU InfrastructureLee Schermerhorn
When the system contains lots of mlocked or otherwise unevictable pages, the pageout code (kswapd) can spend lots of time scanning over these pages. Worse still, the presence of lots of unevictable pages can confuse kswapd into thinking that more aggressive pageout modes are required, resulting in all kinds of bad behaviour. Infrastructure to manage pages excluded from reclaim--i.e., hidden from vmscan. Based on a patch by Larry Woodman of Red Hat. Reworked to maintain "unevictable" pages on a separate per-zone LRU list, to "hide" them from vmscan. Kosaki Motohiro added the support for the memory controller unevictable lru list. Pages on the unevictable list have both PG_unevictable and PG_lru set. Thus, PG_unevictable is analogous to and mutually exclusive with PG_active--it specifies which LRU list the page is on. The unevictable infrastructure is enabled by a new mm Kconfig option [CONFIG_]UNEVICTABLE_LRU. A new function 'page_evictable(page, vma)' in vmscan.c tests whether or not a page may be evictable. Subsequent patches will add the various !evictable tests. We'll want to keep these tests light-weight for use in shrink_active_list() and, possibly, the fault path. To avoid races between tasks putting pages [back] onto an LRU list and tasks that might be moving the page from non-evictable to evictable state, the new function 'putback_lru_page()' -- inverse to 'isolate_lru_page()' -- tests the "evictability" of a page after placing it on the LRU, before dropping the reference. If the page has become unevictable, putback_lru_page() will redo the 'putback', thus moving the page to the unevictable list. This way, we avoid "stranding" evictable pages on the unevictable list. [akpm@linux-foundation.org: fix fallout from out-of-order merge] [riel@redhat.com: fix UNEVICTABLE_LRU and !PROC_PAGE_MONITOR build] [nishimura@mxp.nes.nec.co.jp: remove redundant mapping check] [kosaki.motohiro@jp.fujitsu.com: unevictable-lru-infrastructure: putback_lru_page()/unevictable page handling rework] [kosaki.motohiro@jp.fujitsu.com: kill unnecessary lock_page() in vmscan.c] [kosaki.motohiro@jp.fujitsu.com: revert migration change of unevictable lru infrastructure] [kosaki.motohiro@jp.fujitsu.com: revert to unevictable-lru-infrastructure-kconfig-fix.patch] [kosaki.motohiro@jp.fujitsu.com: restore patch failure of vmstat-unevictable-and-mlocked-pages-vm-events.patch] Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Debugged-by: Benjamin Kidwell <benjkidwell@yahoo.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20more aggressively use lumpy reclaimRik van Riel
During an AIM7 run on a 16GB system, fork started failing around 32000 threads, despite the system having plenty of free swap and 15GB of pageable memory. This was on x86-64, so 8k stacks. If a higher order allocation fails, we can either: - keep evicting pages off the end of the LRUs and hope that we eventually create a contiguous region; this is somewhat unlikely if the system is under enough stress by new allocations - after trying normal eviction for a bit, use lumpy reclaim This patch switches the system to lumpy reclaim if the VM is having trouble freeing enough pages, using the same threshold for detection as used by pageout congestion wait. Signed-off-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>
2008-10-20vmscan: add newly swapped in pages to the inactive listRik van Riel
Swapin_readahead can read in a lot of data that the processes in memory never need. Adding swap cache pages to the inactive list prevents them from putting too much pressure on the working set. This has the potential to help the programs that are already in memory, but it could also be a disadvantage to processes that are trying to get swapped in. Signed-off-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>
2008-10-20vmscan: fix pagecache reclaim referenced bit checkRik van Riel
Moving referenced pages back to the head of the active list creates a huge scalability problem, because by the time a large memory system finally runs out of free memory, every single page in the system will have been referenced. Not only do we not have the time to scan every single page on the active list, but since they have will all have the referenced bit set, that bit conveys no useful information. A more scalable solution is to just move every page that hits the end of the active list to the inactive list. We clear the referenced bit off of mapped pages, which need just one reference to be moved back onto the active list. Unmapped pages will be moved back to the active list after two references (see mark_page_accessed). We preserve the PG_referenced flag on unmapped pages to preserve accesses that were made while the page was on the active list. Signed-off-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>
2008-10-20vmscan: second chance replacement for anonymous pagesRik van Riel
We avoid evicting and scanning anonymous pages for the most part, but under some workloads we can end up with most of memory filled with anonymous pages. At that point, we suddenly need to clear the referenced bits on all of memory, which can take ages on very large memory systems. We can reduce the maximum number of pages that need to be scanned by not taking the referenced state into account when deactivating an anonymous page. After all, every anonymous page starts out referenced, so why check? If an anonymous page gets referenced again before it reaches the end of the inactive list, we move it back to the active list. To keep the maximum amount of necessary work reasonable, we scale the active to inactive ratio with the size of memory, using the formula active:inactive ratio = sqrt(memory in GB * 10). Kswapd CPU use now seems to scale by the amount of pageout bandwidth, instead of by the amount of memory present in the system. [kamezawa.hiroyu@jp.fujitsu.com: fix OOM with memcg] [kamezawa.hiroyu@jp.fujitsu.com: memcg: lru scan fix] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20vmscan: split LRU lists into anon & file setsRik van Riel
Split the LRU lists in two, one set for pages that are backed by real file systems ("file") and one for pages that are backed by memory and swap ("anon"). The latter includes tmpfs. The advantage of doing this is that the VM will not have to scan over lots of anonymous pages (which we generally do not want to swap out), just to find the page cache pages that it should evict. This patch has the infrastructure and a basic policy to balance how much we scan the anon lists and how much we scan the file lists. The big policy changes are in separate patches. [lee.schermerhorn@hp.com: collect lru meminfo statistics from correct offset] [kosaki.motohiro@jp.fujitsu.com: prevent incorrect oom under split_lru] [kosaki.motohiro@jp.fujitsu.com: fix pagevec_move_tail() doesn't treat unevictable page] [hugh@veritas.com: memcg swapbacked pages active] [hugh@veritas.com: splitlru: BDI_CAP_SWAP_BACKED] [akpm@linux-foundation.org: fix /proc/vmstat units] [nishimura@mxp.nes.nec.co.jp: memcg: fix handling of shmem migration] [kosaki.motohiro@jp.fujitsu.com: adjust Quicklists field of /proc/meminfo] [kosaki.motohiro@jp.fujitsu.com: fix style issue of get_scan_ratio()] Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20define page_file_cache() functionRik van Riel
Define page_file_cache() function to answer the question: is page backed by a file? Originally part of Rik van Riel's split-lru patch. Extracted to make available for other, independent reclaim patches. Moved inline function to linux/mm_inline.h where it will be needed by subsequent "split LRU" and "noreclaim" patches. Unfortunately this needs to use a page flag, since the PG_swapbacked state needs to be preserved all the way to the point where the page is last removed from the LRU. Trying to derive the status from other info in the page resulted in wrong VM statistics in earlier split VM patchsets. The total number of page flags in use on a 32 bit machine after this patch is 19. [akpm@linux-foundation.org: fix up out-of-order merge fallout] [hugh@veritas.com: splitlru: shmem_getpage SetPageSwapBacked sooner[ Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: MinChan Kim <minchan.kim@gmail.com> Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20vmscan: free swap space on swap-in/activationRik van Riel
If vm_swap_full() (swap space more than 50% full), the system will free swap space at swapin time. With this patch, the system will also free the swap space in the pageout code, when we decide that the page is not a candidate for swapout (and just wasting swap space). Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: MinChan Kim <minchan.kim@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20swap: use an array for the LRU pagevecsKOSAKI Motohiro
Turn the pagevecs into an array just like the LRUs. This significantly cleans up the source code and reduces the size of the kernel by about 13kB after all the LRU lists have been created further down in the split VM patch series. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20vmscan: Use an indexed array for LRU variablesChristoph Lameter
Currently we are defining explicit variables for the inactive and active list. An indexed array can be more generic and avoid repeating similar code in several places in the reclaim code. We are saving a few bytes in terms of code size: Before: text data bss dec hex filename 4097753 573120 4092484 8763357 85b7dd vmlinux After: text data bss dec hex filename 4097729 573120 4092484 8763333 85b7c5 vmlinux Having an easy way to add new lru lists may ease future work on the reclaim code. Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com> Signed-off-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20vmscan: move isolate_lru_page() to vmscan.cNick Piggin
On large memory systems, the VM can spend way too much time scanning through pages that it cannot (or should not) evict from memory. Not only does it use up CPU time, but it also provokes lock contention and can leave large systems under memory presure in a catatonic state. This patch series improves VM scalability by: 1) putting filesystem backed, swap backed and unevictable pages onto their own LRUs, so the system only scans the pages that it can/should evict from memory 2) switching to two handed clock replacement for the anonymous LRUs, so the number of pages that need to be scanned when the system starts swapping is bound to a reasonable number 3) keeping unevictable pages off the LRU completely, so the VM does not waste CPU time scanning them. ramfs, ramdisk, SHM_LOCKED shared memory segments and mlock()ed VMA pages are keept on the unevictable list. This patch: isolate_lru_page logically belongs to be in vmscan.c than migrate.c. It is tough, because we don't need that function without memory migration so there is a valid argument to have it in migrate.c. However a subsequent patch needs to make use of it in the core mm, so we can happily move it to vmscan.c. Also, make the function a little more generic by not requiring that it adds an isolated page to a given list. Callers can do that. Note that we now have '__isolate_lru_page()', that does something quite different, visible outside of vmscan.c for use with memory controller. Methinks we need to rationalize these names/purposes. --lts [akpm@linux-foundation.org: fix mm/memory_hotplug.c build] Signed-off-by: Nick Piggin <npiggin@suse.de> Signed-off-by: Rik van Riel <riel@redhat.com> Signed-off-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-20mm: cleanup to make remove_memory() arch-neutralBadari Pulavarty
There is nothing architecture specific about remove_memory(). remove_memory() function is common for all architectures which support hotplug memory remove. Instead of duplicating it in every architecture, collapse them into arch neutral function. [akpm@linux-foundation.org: fix the export] Signed-off-by: Badari Pulavarty <pbadari@us.ibm.com> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: Gary Hade <garyhade@us.ibm.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Yasunori Goto <y-goto@jp.fujitsu.com> Cc: "Luck, Tony" <tony.luck@intel.com> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Paul Mackerras <paulus@samba.org> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-19anon_vma_prepare: properly lock even newly allocated entriesLinus Torvalds
The anon_vma code is very subtle, and we end up doing optimistic lookups of anon_vmas under RCU in page_lock_anon_vma() with no locking. Other CPU's can also see the newly allocated entry immediately after we've exposed it by setting "vma->anon_vma" to the new value. We protect against the anon_vma being destroyed by having the SLAB marked as SLAB_DESTROY_BY_RCU, so the RCU lookup can depend on the allocation not being destroyed - but it might still be free'd and re-allocated here to a new vma. As a result, we should not do the anon_vma list ops on a newly allocated vma without proper locking. Acked-by: Nick Piggin <npiggin@suse.de> Acked-by: Hugh Dickins <hugh@veritas.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-17Merge branch 'drm-next' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6 * 'drm-next' of git://git.kernel.org/pub/scm/linux/kernel/git/airlied/drm-2.6: (44 commits) drm/i915: fix ioremap of a user address for non-root (CVE-2008-3831) drm: make CONFIG_DRM depend on CONFIG_SHMEM. radeon: fix PCI bus mastering support enables. radeon: add RS400 family support. drm/radeon: add support for RS740 IGP chipsets. i915: GM45 has GM965-style MCH setup. i915: Don't run retire work handler while suspended i915: Map status page cached for chips with GTT-based HWS location. i915: Fix up ring initialization to cover G45 oddities i915: Use non-reserved status page index for breadcrumb drm: Increment dev_priv->irq_received so i915_gem_interrupts count works. drm: kill drm_device->irq drm: wbinvd is cache coherent. i915: add missing return in error path. i915: fixup permissions on gem ioctls. drm: Clean up many sparse warnings in i915. drm: Use ioremap_wc in i915_driver instead of ioremap, since we always want WC. drm: G33-class hardware has a newer 965-style MCH (no DCC register). drm: Avoid oops in GEM execbuffers with bad arguments. DRM: Return -EBADF on bad object in flink, and return curent name if it exists. ...
2008-10-18Export shmem_file_setup for DRM-GEMKeith Packard
GEM needs to create shmem files to back buffer objects. Though currently creation of files for objects could have been driven from userland, the modesetting work will require allocation of buffer objects before userland is running, for boot-time message display. Signed-off-by: Eric Anholt <eric@anholt.net> Cc: Nick Piggin <npiggin@suse.de> Signed-off-by: Dave Airlie <airlied@redhat.com>
2008-10-16Merge branch 'core-v28-for-linus' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'core-v28-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() fails softirq, warning fix: correct a format to avoid a warning softirqs, debug: preemption check x86, pci-hotplug, calgary / rio: fix EBDA ioremap() IO resources, x86: ioremap sanity check to catch mapping requests exceeding, fix IO resources, x86: ioremap sanity check to catch mapping requests exceeding the BAR sizes softlockup: Documentation/sysctl/kernel.txt: fix softlockup_thresh description dmi scan: warn about too early calls to dmi_check_system() generic: redefine resource_size_t as phys_addr_t generic: make PFN_PHYS explicitly return phys_addr_t generic: add phys_addr_t for holding physical addresses softirq: allocate less vectors IO resources: fix/remove printk printk: robustify printk, update comment printk: robustify printk, fix #2 printk: robustify printk, fix printk: robustify printk Fixed up conflicts in: arch/powerpc/include/asm/types.h arch/powerpc/platforms/Kconfig.cputype manually.
2008-10-16Remove Andrew Morton's old email accountsFrancois Cami
People can use the real name an an index into MAINTAINERS to find the current email address. Signed-off-by: Francois Cami <francois.cami@free.fr> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16Kconfig: eliminate "def_bool n" constructsJan Beulich
Using "def_bool n" is pointless, simply using bool here appears more appropriate. Further, retaining such options that don't have a prompt and aren't selected by anything seems also at least questionable. Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Tony Luck <tony.luck@intel.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16misc: replace __FUNCTION__ with __func__Harvey Harrison
__FUNCTION__ is gcc-specific, use __func__ Signed-off-by: Harvey Harrison <harvey.harrison@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16mm: do_generic_file_read() never gets a NULL 'filp' argumentKrishna Kumar
The 'filp' argument to do_generic_file_read() is never NULL. Signed-off-by: Krishna Kumar <krkumar2@in.ibm.com> Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16hugetlb: handle updating of ACCESSED and DIRTY in hugetlb_fault()David Gibson
The page fault path for normal pages, if the fault is neither a no-page fault nor a write-protect fault, will update the DIRTY and ACCESSED bits in the page table appropriately. The hugepage fault path, however, does not do this, handling only no-page or write-protect type faults. It assumes that either the ACCESSED and DIRTY bits are irrelevant for hugepages (usually true, since they are never swapped) or that they are handled by the arch code. This is inconvenient for some software-loaded TLB architectures, where the _PAGE_ACCESSED (_PAGE_DIRTY) bits need to be set to enable read (write) access to the page at the TLB miss. This could be worked around in the arch TLB miss code, but the TLB miss fast path can be made simple more easily if the hugetlb_fault() path handles this, as the normal page fault path does. Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Cc: William Lee Irwin III <wli@holomorphy.com> Cc: Hugh Dickins <hugh@veritas.com> Cc: Adam Litke <agl@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-16mm/page_alloc.c:free_area_init_nodes() fix inappropriate use of enumAndrew Morton
Local variable `i' is a) misleadingly-named for an `enum zone_type' and b) used for indexing zones as well as nodes as well as node_maps. Make it an `int'. Reported-by: Frans Pop <elendil@planet.nl> 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>
2008-10-16vfs: Add no_nrwrite_index_update writeback control flagAneesh Kumar K.V
If no_nrwrite_index_update is set we don't update nr_to_write and address space writeback_index in write_cache_pages. This change enables a file system to skip these updates in write_cache_pages and do them in the writepages() callback. This patch will be followed by an ext4 patch that make use of these new flags. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> CC: linux-fsdevel@vger.kernel.org
2008-10-16Introduce is_vmalloc_or_module_addr() and use with DEBUG_VIRTUALLinus Torvalds
Impact: crash on module insertion with CONFIG_DEBUG_VIRTUAL We would incorrectly BUG due to: VIRTUAL_BUG_ON(!is_vmalloc_addr(vmalloc_addr) && !is_module_address(addr)); ... because, at least on x86-64, is_module_address() doesn't do what it should. This patch introduces is_vmalloc_or_module_addr(), which is what we really want anyway, and uses it instead. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
2008-10-15Merge branches 'core/softlockup', 'core/softirq', 'core/resources', ↵Ingo Molnar
'core/printk' and 'core/misc' into core-v28-for-linus
2008-10-14do_generic_file_read: s/EINTR/EIO/ if lock_page_killable() failsOleg Nesterov
If lock_page_killable() fails because the task was killed by SIGKILL or any other fatal signal, do_generic_file_read() returns -EIO. This seems to be OK, because in fact the userspace won't see this error, the task will dequeue SIGKILL and exit. However, /sbin/init is different, it will dequeue SIGKILL, ignore it, and return to the user-space with the bogus -EIO. Change the code to return the error code from lock_page_killable(), -EINTR. This doesn't fix the bug, but perhaps makes sense anyway. Imho, with this change the code looks a bit more logical, and the "good" init should handle the spurious EINTR or short read. Afaics we can also change lock_page_killable() to return -ERESTARTNOINTR, but this can't prevent the short reads. Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-10-14vfs: Remove the range_cont writeback mode.Aneesh Kumar K.V
Ext4 was the only user of range_cont writeback mode and ext4 switched to a different method. So remove the range_cont mode which is not used in the kernel. Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> CC: linux-fsdevel@vger.kernel.org
2008-10-13integrity: special fs magicMimi Zohar
Discussion on the mailing list questioned the use of these magic values in userspace, concluding these values are already exported to userspace via statfs and their correct/incorrect usage is left up to the userspace application. - Move special fs magic number definitions to magic.h - Add magic.h include Signed-off-by: Mimi Zohar <zohar@us.ibm.com> Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: James Morris <jmorris@namei.org>
2008-10-12Merge branches 'x86/xen', 'x86/build', 'x86/microcode', 'x86/mm-debug-v2', ↵Ingo Molnar
'x86/memory-corruption-check', 'x86/early-printk', 'x86/xsave', 'x86/ptrace-v2', 'x86/quirks', 'x86/setup', 'x86/spinlocks' and 'x86/signal' into x86/core-v2
2008-10-11Merge phase #2 (PAT updates) of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip * 'x86-v28-for-linus-phase2-B' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (27 commits) x86, cpa: make the kernel physical mapping initialization a two pass sequence, fix x86, pat: cleanups x86: fix pagetable init 64-bit breakage x86: track memtype for RAM in page struct x86, cpa: srlz cpa(), global flush tlb after splitting big page and before doing cpa x86, cpa: remove cpa pool code x86, cpa: no need to check alias for __set_pages_p/__set_pages_np x86, cpa: dont use large pages for kernel identity mapping with DEBUG_PAGEALLOC x86, cpa: make the kernel physical mapping initialization a two pass sequence x86, cpa: remove USER permission from the very early identity mapping attribute x86, cpa: rename PTE attribute macros for kernel direct mapping in early boot x86: make sure the CPA test code's use of _PAGE_UNUSED1 is obvious linux-next: fix x86 tree build failure x86: have set_memory_array_{uc,wb} coalesce memtypes, fix agp: enable optimized agp_alloc_pages methods x86: have set_memory_array_{uc,wb} coalesce memtypes. x86: {reverve,free}_memtype() take a physical address x86: fix pageattr-test agp: add agp_generic_destroy_pages() agp: generic_alloc_pages() ...
2008-10-10Merge branch 'for-2.6.28' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-2.6.28' of git://git.kernel.dk/linux-2.6-block: (132 commits) doc/cdrom: Trvial documentation error, file not present block_dev: fix kernel-doc in new functions block: add some comments around the bio read-write flags block: mark bio_split_pool static block: Find bio sector offset given idx and offset block: gendisk integrity wrapper block: Switch blk_integrity_compare from bdev to gendisk block: Fix double put in blk_integrity_unregister block: Introduce integrity data ownership flag block: revert part of d7533ad0e132f92e75c1b2eb7c26387b25a583c1 bio.h: Remove unused conditional code block: remove end_{queued|dequeued}_request() block: change elevator to use __blk_end_request() gdrom: change to use __blk_end_request() memstick: change to use __blk_end_request() virtio_blk: change to use __blk_end_request() blktrace: use BLKTRACE_BDEV_SIZE as the name size for setup structure block: add lld busy state exporting interface block: Fix blk_start_queueing() to not kick a stopped queue include blktrace_api.h in headers_install ...
2008-10-10Merge branch 'linus' into x86/pat2Ingo Molnar
Conflicts: arch/x86/mm/init_64.c
2008-10-09SLOB: fix bogus ksize calculation fixMatt Mackall
This fixes the previous fix, which was completely wrong on closer inspection. This version has been manually tested with a user-space test harness and generates sane values. A nearly identical patch has been boot-tested. The problem arose from changing how kmalloc/kfree handled alignment padding without updating ksize to match. This brings it in sync. Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-09highmem: use bio_has_data() in the bounce pathJens Axboe
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2008-10-07SLOB: fix bogus ksize calculationMatt Mackall
SLOB's ksize calculation was braindamaged and generally harmlessly underreported the allocation size. But for very small buffers, it could in fact overreport them, leading code depending on krealloc to overrun the allocation and trample other data. Signed-off-by: Matt Mackall <mpm@selenic.com> Tested-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-02mm: handle initialising compound pages at orders greater than MAX_ORDERAndy Whitcroft
When we initialise a compound page we initialise the page flags and head page pointer for all base pages spanned by that page. When we initialise a gigantic page (a page of order greater than or equal to MAX_ORDER) we have to initialise more than MAX_ORDER_NR_PAGES pages. Currently we assume that all elements of the mem_map in this page are contigious in memory. However this is only guarenteed out to MAX_ORDER_NR_PAGES pages, and with SPARSEMEM enabled they will not be contigious. This leads us to walk off the end of the first section and scribble on everything which follows, BAD. When we reach a MAX_ORDER_NR_PAGES boundary we much locate the next section of the mem_map. As gigantic pages can only be maximally aligned we know this will occur at exact multiple of MAX_ORDER_NR_PAGES pages from the start of the page. This is a bug fix for the gigantic page support in hugetlbfs. Credit to Mel Gorman for spotting the issue. Signed-off-by: Andy Whitcroft <apw@shadowen.org> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Jon Tollefson <kniht@linux.vnet.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-02mm: tiny-shmem nommu fixNick Piggin
The previous patch db203d53d474aa068984e409d807628f5841da1b ("mm: tiny-shmem fix lock ordering: mmap_sem vs i_mutex") to fix the lock ordering in tiny-shmem breaks shared anonymous and IPC memory on NOMMU architectures because it was using the expanding truncate to signal ramfs to allocate a physically contiguous RAM backing the inode (otherwise it is unusable for "memory mapping" it to userspace). However do_truncate is what caused the lock ordering error, due to it taking i_mutex. In this case, we can actually just call ramfs directly to allocate memory for the mapping, rather than go via truncate. Acked-by: David Howells <dhowells@redhat.com> Acked-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Nick Piggin <npiggin@suse.de> Cc: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-10-02memory hotplug: missing zone->lock in test_pages_isolated()Gerald Schaefer
__test_page_isolated_in_pageblock() in mm/page_isolation.c has a comment saying that the caller must hold zone->lock. But the only caller of that function, test_pages_isolated(), does not hold zone->lock and the lock is also not acquired anywhere before. This patch adds the missing zone->lock to test_pages_isolated(). We reproducibly run into BUG_ON(!PageBuddy(page)) in __offline_isolated_pages() during memory hotplug stress test, see trace below. This patch fixes that problem, it would be good if we could have it in 2.6.27. kernel BUG at /home/autobuild/BUILD/linux-2.6.26-20080909/mm/page_alloc.c:4561! illegal operation: 0001 [#1] PREEMPT SMP Modules linked in: dm_multipath sunrpc bonding qeth_l3 dm_mod qeth ccwgroup vmur CPU: 1 Not tainted 2.6.26-29.x.20080909-s390default #1 Process memory_loop_all (pid: 10025, task: 2f444028, ksp: 2b10dd28) Krnl PSW : 040c0000 801727ea (__offline_isolated_pages+0x18e/0x1c4) R:0 T:1 IO:0 EX:0 Key:0 M:1 W:0 P:0 AS:0 CC:0 PM:0 Krnl GPRS: 00000000 7e27fc00 00000000 7e27fc00 00000000 00000400 00014000 7e27fc01 00606f00 7e27fc00 00013fe0 2b10dd28 00000005 80172662 801727b2 2b10dd28 Krnl Code: 801727de: 5810900c l %r1,12(%r9) 801727e2: a7f4ffb3 brc 15,80172748 801727e6: a7f40001 brc 15,801727e8 >801727ea: a7f4ffbc brc 15,80172762 801727ee: a7f40001 brc 15,801727f0 801727f2: a7f4ffaf brc 15,80172750 801727f6: 0707 bcr 0,%r7 801727f8: 0017 unknown Call Trace: ([<0000000000172772>] __offline_isolated_pages+0x116/0x1c4) [<00000000001953a2>] offline_isolated_pages_cb+0x22/0x34 [<000000000013164c>] walk_memory_resource+0xcc/0x11c [<000000000019520e>] offline_pages+0x36a/0x498 [<00000000001004d6>] remove_memory+0x36/0x44 [<000000000028fb06>] memory_block_change_state+0x112/0x150 [<000000000028ffb8>] store_mem_state+0x90/0xe4 [<0000000000289c00>] sysdev_store+0x34/0x40 [<00000000001ee048>] sysfs_write_file+0xd0/0x178 [<000000000019b1a8>] vfs_write+0x74/0x118 [<000000000019b9ae>] sys_write+0x46/0x7c [<000000000011160e>] sysc_do_restart+0x12/0x16 [<0000000077f3e8ca>] 0x77f3e8ca Signed-off-by: Gerald Schaefer <gerald.schaefer@de.ibm.com> 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>
2008-09-29mm owner: fix race between swapoff and exitBalbir Singh
There's a race between mm->owner assignment and swapoff, more easily seen when task slab poisoning is turned on. The condition occurs when try_to_unuse() runs in parallel with an exiting task. A similar race can occur with callers of get_task_mm(), such as /proc/<pid>/<mmstats> or ptrace or page migration. CPU0 CPU1 try_to_unuse looks at mm = task0->mm increments mm->mm_users task 0 exits mm->owner needs to be updated, but no new owner is found (mm_users > 1, but no other task has task->mm = task0->mm) mm_update_next_owner() leaves mmput(mm) decrements mm->mm_users task0 freed dereferencing mm->owner fails The fix is to notify the subsystem via mm_owner_changed callback(), if no new owner is found, by specifying the new task as NULL. Jiri Slaby: mm->owner was set to NULL prior to calling cgroup_mm_owner_callbacks(), but must be set after that, so as not to pass NULL as old owner causing oops. Daisuke Nishimura: mm_update_next_owner() may set mm->owner to NULL, but mem_cgroup_from_task() and its callers need to take account of this situation to avoid oops. Hugh Dickins: Lockdep warning and hang below exec_mmap() when testing these patches. exit_mm() up_reads mmap_sem before calling mm_update_next_owner(), so exec_mmap() now needs to do the same. And with that repositioning, there's now no point in mm_need_new_owner() allowing for NULL mm. Reported-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com> Signed-off-by: Jiri Slaby <jirislaby@gmail.com> Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Signed-off-by: Hugh Dickins <hugh@veritas.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Paul Menage <menage@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-23memcg: check under limit at shrink_usageDaisuke Nishimura
Current memory cgroup(both in mainline and -mm) doesn't account swap caches as memory(swap cache support is dropped temporarily now). So try_to_free_mem_cgroup_pages doesn't reflect the count of pages that have been moved to swap cache. But this makes mem_cgroup_shrink_usage fail easily if most of the pages are anon/shmem, and then shmem_getpage returns -ENOMEM and the process will be killed. This patch adds res_counter_check_under_limit to avoid these cases. BTW, even if swap cache support is enabled again, if a process is moved to another cgroup, which has been just made, between precharge and shrink_usage in shmem_getpage, shrink_usage may fail just because there is no pages to reclaim. So this change would make sense anyway. Signed-off-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Balbir Singh <balbir@in.ibm.com> Cc: Pavel Emelyanov <xemul@openvz.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-23mm: tiny-shmem fix lock ordering: mmap_sem vs i_mutexNick Piggin
tiny-shmem calls do_truncate in shmem_file_setup. do_truncate takes i_mutex, and shmem_file_setup is called with mmap_sem held. However i_mutex nests outside mmap_sem. Copy the code in shmem.c to avoid this problem. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Nick Piggin <npiggin@suse.de> Reported-and-tested-by: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Matt Mackall <mpm@selenic.com> Cc: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-15slub: fixed uninitialized counter in struct kmem_cache_nodeSalman Qazi
Initialized total objects atomic for the node in init_kmem_cache_node. The uninitialized value was ruining the stats in /proc/slabinfo. Acked-by: Christoph Lameter <cl@linux-foundation.org> Signed-off-by: Salman Qazi <sqazi@google.com> Signed-off-by: Pekka Enberg <penberg@cs.helsinki.fi>
2008-09-14Merge commit 'v2.6.27-rc6' into x86/patIngo Molnar
2008-09-14generic: add phys_addr_t for holding physical addressesJeremy Fitzhardinge
Add a kernel-wide "phys_addr_t" which is guaranteed to be able to hold any physical address. By default it equals the word size of the architecture, but a 32-bit architecture can set ARCH_PHYS_ADDR_T_64BIT if it needs a 64-bit phys_addr_t. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
2008-09-13mm: mark the correct zone as full when scanning zonelistsMel Gorman
The iterator for_each_zone_zonelist() uses a struct zoneref *z cursor when scanning zonelists to keep track of where in the zonelist it is. The zoneref that is returned corresponds to the the next zone that is to be scanned, not the current one. It was intended to be treated as an opaque list. When the page allocator is scanning a zonelist, it marks elements in the zonelist corresponding to zones that are temporarily full. As the zonelist is being updated, it uses the cursor here; if (NUMA_BUILD) zlc_mark_zone_full(zonelist, z); This is intended to prevent rescanning in the near future but the zoneref cursor does not correspond to the zone that has been found to be full. This is an easy misunderstanding to make so this patch corrects the problem by changing zoneref cursor to be the current zone being scanned instead of the next one. Signed-off-by: Mel Gorman <mel@csn.ul.ie> Cc: Andy Whitcroft <apw@shadowen.org> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: <stable@kernel.org> [2.6.26.x] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-03mmap: fix petty bug in anonymous shared mmap offset handlingTejun Heo
Anonymous mappings should ignore offset but shared anonymous mapping forgot to clear it and makes the following legit test program trigger SIGBUS. #include <sys/mman.h> #include <stdio.h> #include <errno.h> #define PAGE_SIZE 4096 int main(void) { char *p; int i; p = mmap(NULL, 2 * PAGE_SIZE, PROT_READ|PROT_WRITE, MAP_SHARED|MAP_ANONYMOUS, -1, PAGE_SIZE); if (p == MAP_FAILED) { perror("mmap"); return 1; } for (i = 0; i < 2; i++) { printf("page %d\n", i); p[i * 4096] = i; } return 0; } Fix it. Signed-off-by: Tejun Heo <tj@kernel.org> Acked-by: Hugh Dickins <hugh@veritas.com> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-02mm: size of quicklists shouldn't be proportional to the number of CPUsKOSAKI Motohiro
Quicklists store pages for each CPU as caches. (Each CPU can cache node_free_pages/16 pages) It is used for page table cache. exit() will increase the cache size, while fork() consumes it. So for example if an apache-style application runs (one parent and many child model), one CPU process will fork() while another CPU will process the middleware work and exit(). At that time, the CPU on which the parent runs doesn't have page table cache at all. Others (on which children runs) have maximum caches. QList_max = (#ofCPUs - 1) x Free / 16 => QList_max / (Free + QList_max) = (#ofCPUs - 1) / (16 + #ofCPUs - 1) So, How much quicklist memory is used in the maximum case? This is proposional to # of CPUs because the limit of per cpu quicklist cache doesn't see the number of cpus. Above calculation mean Number of CPUs per node 2 4 8 16 ============================== ==================== QList_max / (Free + QList_max) 5.8% 16% 30% 48% Wow! Quicklist can spend about 50% memory at worst case. My demonstration program is here -------------------------------------------------------------------------------- #define _GNU_SOURCE #include <stdio.h> #include <errno.h> #include <stdlib.h> #include <string.h> #include <sched.h> #include <unistd.h> #include <sys/mman.h> #include <sys/wait.h> #define BUFFSIZE 512 int max_cpu(void) /* get max number of logical cpus from /proc/cpuinfo */ { FILE *fd; char *ret, buffer[BUFFSIZE]; int cpu = 1; fd = fopen("/proc/cpuinfo", "r"); if (fd == NULL) { perror("fopen(/proc/cpuinfo)"); exit(EXIT_FAILURE); } while (1) { ret = fgets(buffer, BUFFSIZE, fd); if (ret == NULL) break; if (!strncmp(buffer, "processor", 9)) cpu = atoi(strchr(buffer, ':') + 2); } fclose(fd); return cpu; } void cpu_bind(int cpu) /* bind current process to one cpu */ { cpu_set_t mask; int ret; CPU_ZERO(&mask); CPU_SET(cpu, &mask); ret = sched_setaffinity(0, sizeof(mask), &mask); if (ret == -1) { perror("sched_setaffinity()"); exit(EXIT_FAILURE); } sched_yield(); /* not necessary */ } #define MMAP_SIZE (10 * 1024 * 1024) /* 10 MB */ #define FORK_INTERVAL 1 /* 1 second */ main(int argc, char *argv[]) { int cpu_max, nextcpu; long pagesize; pid_t pid; /* set max number of logical cpu */ if (argc > 1) cpu_max = atoi(argv[1]) - 1; else cpu_max = max_cpu(); /* get the page size */ pagesize = sysconf(_SC_PAGESIZE); if (pagesize == -1) { perror("sysconf(_SC_PAGESIZE)"); exit(EXIT_FAILURE); } /* prepare parent process */ cpu_bind(0); nextcpu = cpu_max; loop: /* select destination cpu for child process by round-robin rule */ if (++nextcpu > cpu_max) nextcpu = 1; pid = fork(); if (pid == 0) { /* child action */ char *p; int i; /* consume page tables */ p = mmap(0, MMAP_SIZE, PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, 0, 0); i = MMAP_SIZE / pagesize; while (i-- > 0) { *p = 1; p += pagesize; } /* move to other cpu */ cpu_bind(nextcpu); /* printf("a child moved to cpu%d after mmap().\n", nextcpu); fflush(stdout); */ /* back page tables to pgtable_quicklist */ exit(0); } else if (pid > 0) { /* parent action */ sleep(FORK_INTERVAL); waitpid(pid, NULL, WNOHANG); } goto loop; } ---------------------------------------- When above program which does task migration runs, my 8GB box spends 800MB of memory for quicklist. This is not memory leak but doesn't seem good. % cat /proc/meminfo MemTotal: 7701568 kB MemFree: 4724672 kB (snip) Quicklists: 844800 kB because - My machine spec is number of numa node: 2 number of cpus: 8 (4CPU x2 node) total mem: 8GB (4GB x2 node) free mem: about 5GB - Then, 4.7GB x 16% ~= 880MB. So, Quicklist can use 800MB. So, if following spec machine run that program CPUs: 64 (8cpu x 8node) Mem: 1TB (128GB x8node) Then, quicklist can waste 300GB (= 1TB x 30%). It is too large. So, I don't like cache policies which is proportional to # of cpus. My patch changes the number of caches from: per-cpu-cache-amount = memory_on_node / 16 to per-cpu-cache-amount = memory_on_node / 16 / number_of_cpus_on_node. Signed-off-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: Keiichiro Tokunaga <tokunaga.keiich@jp.fujitsu.com> Acked-by: Christoph Lameter <cl@linux-foundation.org> Tested-by: David Miller <davem@davemloft.net> Acked-by: Mike Travis <travis@sgi.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-02mm/bootmem: silence section mismatch warning - ↵Marcin Slusarz
contig_page_data/bootmem_node_data WARNING: vmlinux.o(.data+0x1f5c0): Section mismatch in reference from the variable contig_page_data to the variable .init.data:bootmem_node_data The variable contig_page_data references the variable __initdata bootmem_node_data If the reference is valid then annotate the variable with __init* (see linux/init.h) or name the variable: *driver, *_template, *_timer, *_sht, *_ops, *_probe, *_probe_one, *_console, Signed-off-by: Marcin Slusarz <marcin.slusarz@gmail.com> Cc: Johannes Weiner <hannes@saeurebad.de> Cc: Sean MacLennan <smaclennan@pikatech.com> Cc: Sam Ravnborg <sam@ravnborg.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-09-02VFS: fix dio write returning EIO when try_to_release_page failsHisashi Hifumi
Dio write returns EIO when try_to_release_page fails because bh is still referenced. The patch commit 3f31fddfa26b7594b44ff2b34f9a04ba409e0f91 Author: Mingming Cao <cmm@us.ibm.com> Date: Fri Jul 25 01:46:22 2008 -0700 jbd: fix race between free buffer and commit transaction was merged into 2.6.27-rc1, but I noticed that this patch is not enough to fix the race. I did fsstress test heavily to 2.6.27-rc1, and found that dio write still sometimes got EIO through this test. The patch above fixed race between freeing buffer(dio) and committing transaction(jbd) but I discovered that there is another race, freeing buffer(dio) and ext3/4_ordered_writepage. : background_writeout() ->write_cache_pages() ->ext3_ordered_writepage() walk_page_buffers() -> take a bh ref block_write_full_page() -> unlock_page : <- end_page_writeback : <- race! (dio write->try_to_release_page fails) walk_page_buffers() ->release a bh ref ext3_ordered_writepage holds bh ref and does unlock_page remaining taking a bh ref, so this causes the race and failure of try_to_release_page. To fix this race, I used the approach of falling back to buffered writes if try_to_release_page() fails on a page. [akpm@linux-foundation.org: cleanups] Signed-off-by: Hisashi Hifumi <hifumi.hisashi@oss.ntt.co.jp> Cc: Chris Mason <chris.mason@oracle.com> Cc: Jan Kara <jack@suse.cz> Cc: Mingming Cao <cmm@us.ibm.com> Cc: Zach Brown <zach.brown@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>