- 01 Aug, 2012 19 commits
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Minchan Kim authored
commit 39deaf85 upstream. Stable note: Not tracked in Bugzilla. THP and compaction disrupt the LRU list leading to poor reclaim decisions which has a variable performance impact. In async mode, compaction doesn't migrate dirty or writeback pages. So, it's meaningless to pick the page and re-add it to lru list. Of course, when we isolate the page in compaction, the page might be dirty or writeback but when we try to migrate the page, the page would be not dirty, writeback. So it could be migrated. But it's very unlikely as isolate and migration cycle is much faster than writeout. So, this patch helps cpu overhead and prevent unnecessary LRU churning. Signed-off-by:
Minchan Kim <minchan.kim@gmail.com> Acked-by:
Johannes Weiner <hannes@cmpxchg.org> Reviewed-by:
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Reviewed-by:
KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Acked-by:
Mel Gorman <mgorman@suse.de> Acked-by:
Rik van Riel <riel@redhat.com> Reviewed-by:
Michal Hocko <mhocko@suse.cz> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Minchan Kim authored
commit 4356f21d upstream. Stable note: Not tracked in Bugzilla. This patch makes later patches easier to apply but has no other impact. Change ISOLATE_XXX macro with bitwise isolate_mode_t type. Normally, macro isn't recommended as it's type-unsafe and making debugging harder as symbol cannot be passed throught to the debugger. Quote from Johannes " Hmm, it would probably be cleaner to fully convert the isolation mode into independent flags. INACTIVE, ACTIVE, BOTH is currently a tri-state among flags, which is a bit ugly." This patch moves isolate mode from swap.h to mmzone.h by memcontrol.h Signed-off-by:
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Minchan Kim authored
commit b9e84ac1 upstream. Stable note: Not tracked in Bugzilla. This patch makes later patches easier to apply but has no other impact. acct_isolated of compaction uses page_lru_base_type which returns only base type of LRU list so it never returns LRU_ACTIVE_ANON or LRU_ACTIVE_FILE. In addtion, cc->nr_[anon|file] is used in only acct_isolated so it doesn't have fields in conpact_control. This patch removes fields from compact_control and makes clear function of acct_issolated which counts the number of anon|file pages isolated. Signed-off-by:
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Mel Gorman authored
commit e0c23279 upstream. Stable note: Not tracked on Bugzilla. THP and compaction was found to aggressively reclaim pages and stall systems under different situations that was addressed piecemeal over time. If compaction can proceed, shrink_zones() stops doing any work but its callers still call shrink_slab() which raises the priority and potentially sleeps. This is unnecessary and wasteful so this patch aborts direct reclaim/compaction entirely if compaction can proceed. Signed-off-by:
Johannes Weiner <jweiner@redhat.com> Cc: Josh Boyer <jwboyer@redhat.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Signed-off-by:
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Rik van Riel authored
commit e0887c19 upstream. Stable note: Not tracked on Bugzilla. THP and compaction was found to aggressively reclaim pages and stall systems under different situations that was addressed piecemeal over time. Paragraph 3 of this changelog is the motivation for this patch. When suffering from memory fragmentation due to unfreeable pages, THP page faults will repeatedly try to compact memory. Due to the unfreeable pages, compaction fails. Needless to say, at that point page reclaim also fails to create free contiguous 2MB areas. However, that doesn't stop the current code from trying, over and over again, and freeing a minimum of 4MB (2UL << sc->order pages) at every single invocation. This resulted in my 12GB system having 2-3GB free memory, a corresponding amount of used swap and very sluggish response times. This can be avoided by having the direct reclaim code not reclaim from zones that already have plenty of free memory available for compaction. If compaction still fails due to unmovable memory, doing additional reclaim will only hurt the system, not help. [jweiner@redhat.com: change comment to explain the order check] Signed-off-by:
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Dave Chinner authored
commit 3567b59a upstream. Stable note: Not tracked in Bugzilla. This patch reduces excessive reclaim of slab objects reducing the amount of information that has to be brought back in from disk. The third and fourth paragram in the series describes the impact. When a shrinker returns -1 to shrink_slab() to indicate it cannot do any work given the current memory reclaim requirements, it adds the entire total_scan count to shrinker->nr. The idea ehind this is that whenteh shrinker is next called and can do work, it will do the work of the previously aborted shrinker call as well. However, if a filesystem is doing lots of allocation with GFP_NOFS set, then we get many, many more aborts from the shrinkers than we do successful calls. The result is that shrinker->nr winds up to it's maximum permissible value (twice the current cache size) and then when the next shrinker call that can do work is issued, it has enough scan count built up to free the entire cache twice over. This manifests itself in the cache going from full to empty in a matter of seconds, even when only a small part of the cache is needed to be emptied to free sufficient memory. Under metadata intensive workloads on ext4 and XFS, I'm seeing the VFS caches increase memory consumption up to 75% of memory (no page cache pressure) over a period of 30-60s, and then the shrinker empties them down to zero in the space of 2-3s. This cycle repeats over and over again, with the shrinker completely trashing the inode and dentry caches every minute or so the workload continues. This behaviour was made obvious by the shrink_slab tracepoints added earlier in the series, and made worse by the patch that corrected the concurrent accounting of shrinker->nr. To avoid this problem, stop repeated small increments of the total scan value from winding shrinker->nr up to a value that can cause the entire cache to be freed. We still need to allow it to wind up, so use the delta as the "large scan" threshold check - if the delta is more than a quarter of the entire cache size, then it is a large scan and allowed to cause lots of windup because we are clearly needing to free lots of memory. If it isn't a large scan then limit the total scan to half the size of the cache so that windup never increases to consume the whole cache. Reducing the total scan limit further does not allow enough wind-up to maintain the current levels of performance, whilst a higher threshold does not prevent the windup from freeing the entire cache under sustained workloads. Signed-off-by:
Dave Chinner <dchinner@redhat.com> Signed-off-by:
Al Viro <viro@zeniv.linux.org.uk> Signed-off-by:
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Dave Chinner authored
commit acf92b48 upstream. Stable note: Not tracked in Bugzilla. This patch reduces excessive reclaim of slab objects reducing the amount of information that has to be brought back in from disk. shrink_slab() allows shrinkers to be called in parallel so the struct shrinker can be updated concurrently. It does not provide any exclusio for such updates, so we can get the shrinker->nr value increasing or decreasing incorrectly. As a result, when a shrinker repeatedly returns a value of -1 (e.g. a VFS shrinker called w/ GFP_NOFS), the shrinker->nr goes haywire, sometimes updating with the scan count that wasn't used, sometimes losing it altogether. Worse is when a shrinker does work and that update is lost due to racy updates, which means the shrinker will do the work again! Fix this by making the total_scan calculations independent of shrinker->nr, and making the shrinker->nr updates atomic w.r.t. to other updates via cmpxchg loops. Signed-off-by:
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Dave Chinner authored
commit 09576073 upstream. Stable note: This patch makes later patches easier to apply but otherwise has little to justify it. It is a diagnostic patch that was part of a series addressing excessive slab shrinking after GFP_NOFS failures. There is detailed information on the series' motivation at https://lkml.org/lkml/2011/6/2/42 . It is impossible to understand what the shrinkers are actually doing without instrumenting the code, so add a some tracepoints to allow insight to be gained. Signed-off-by:
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Shaohua Li authored
commit 439423f6 upstream. Stable note: Not tracked in Bugzilla. kswapd is responsible for clearing ZONE_CONGESTED after it balances a zone and this patch fixes a bug where that was failing to happen. Without this patch, processes can stall in wait_iff_congested unnecessarily. For users, this can look like an interactivity stall but some workloads would see it as sudden drop in throughput. ZONE_CONGESTED is only cleared in kswapd, but pages can be freed in any task. It's possible ZONE_CONGESTED isn't cleared in some cases: 1. the zone is already balanced just entering balance_pgdat() for order-0 because concurrent tasks free memory. In this case, later check will skip the zone as it's balanced so the flag isn't cleared. 2. high order balance fallbacks to order-0. quote from Mel: At the end of balance_pgdat(), kswapd uses the following logic; If reclaiming at high order { for each zone { if all_unreclaimable skip if watermark is not met order = 0 loop again /* watermark is met */ clear congested } } i.e. it clears ZONE_CONGESTED if it the zone is balanced. if not, it restarts balancing at order-0. However, if the higher zones are balanced for order-0, kswapd will miss clearing ZONE_CONGESTED as that only happens after a zone is shrunk. This can mean that wait_iff_congested() stalls unnecessarily. This patch makes kswapd clear ZONE_CONGESTED during its initial highmem->dma scan for zones that are already balanced. Signed-off-by:
Shaohua Li <shaohua.li@intel.com> Acked-by:
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Johannes Weiner authored
commit a4d3e9e7 upstream. Stable note: Not tracked in Bugzilla. This patch augments an earlier commit that avoids scanning priority being artificially raised. The older fix was particularly important for small memcgs to avoid calling wait_iff_congested() unnecessarily. Without swap, anonymous pages are not scanned. As such, they should not count when considering force-scanning a small target if there is no swap. Otherwise, targets are not force-scanned even when their effective scan number is zero and the other conditions--kswapd/memcg--apply. This fixes 246e87a9 ("memcg: fix get_scan_count() for small targets"). [akpm@linux-foundation.org: fix comment] Signed-off-by:
Mel Gorman <mel@csn.ul.ie> Signed-off-by:
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Mel Gorman authored
commit 938929f1 upstream. Stable note: Fixes https://bugzilla.novell.com/show_bug.cgi?id=726210 . Large machines with 1TB or more of RAM take a long time to boot without this patch and may spew out soft lockup warnings. When min_free_kbytes is updated, some pageblocks are marked MIGRATE_RESERVE. Ordinarily, this work is unnoticable as it happens early in boot but on large machines with 1TB of memory, this has been reported to delay boot times, probably due to the NUMA distances involved. The bulk of the work is due to calling calling pageblock_is_reserved() an unnecessary amount of times and accessing far more struct page metadata than is necessary. This patch significantly reduces the amount of work done by setup_zone_migrate_reserve() improving boot times on 1TB machines. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
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Mel Gorman authored
commit 2bbcb878 upstream. Stable note: Fixes https://bugzilla.novell.com/show_bug.cgi?id=721039 . Without the patch, memory hot-add can fail for kernel configurations that do not set CONFIG_SPARSEMEM_VMEMMAP. (Resending as I am not seeing it in -next so maybe it got lost) mm: memory hotplug: Check if pages are correctly reserved on a per-section basis It is expected that memory being brought online is PageReserved similar to what happens when the page allocator is being brought up. Memory is onlined in "memory blocks" which consist of one or more sections. Unfortunately, the code that verifies PageReserved is currently assuming that the memmap backing all these pages is virtually contiguous which is only the case when CONFIG_SPARSEMEM_VMEMMAP is set. As a result, memory hot-add is failing on those configurations with the message; kernel: section number XXX page number 256 not reserved, was it already online? This patch updates the PageReserved check to lookup struct page once per section to guarantee the correct struct page is being checked. [Check pages within sections properly: rientjes@google.com] [original patch by: nfont@linux.vnet.ibm.com] Signed-off-by:
Nathan Fontenot <nfont@linux.vnet.ibm.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@suse.de>
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Dimitri Sivanich authored
commit a1cb2c60 upstream. Stable note: Not tracked on Bugzilla. This patch is known to make a big difference to tmpfs performance on larger machines. This was found to adversely affect tmpfs I/O performance. Tests run on a 640 cpu UV system. With 120 threads doing parallel writes, each to different tmpfs mounts: No patch: ~300 MB/sec With vm_stat alignment: ~430 MB/sec Signed-off-by:
Dimitri Sivanich <sivanich@sgi.com> Acked-by:
Christoph Lameter <cl@gentwo.org> Acked-by:
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Mikulas Patocka authored
commit 751f188d upstream. This patch fixes a crash when a discard request is sent during mirror recovery. Firstly, some background. Generally, the following sequence happens during mirror synchronization: - function do_recovery is called - do_recovery calls dm_rh_recovery_prepare - dm_rh_recovery_prepare uses a semaphore to limit the number simultaneously recovered regions (by default the semaphore value is 1, so only one region at a time is recovered) - dm_rh_recovery_prepare calls __rh_recovery_prepare, __rh_recovery_prepare asks the log driver for the next region to recover. Then, it sets the region state to DM_RH_RECOVERING. If there are no pending I/Os on this region, the region is added to quiesced_regions list. If there are pending I/Os, the region is not added to any list. It is added to the quiesced_regions list later (by dm_rh_dec function) when all I/Os finish. - when the region is on quiesced_regions list, there are no I/Os in flight on this region. The region is popped from the list in dm_rh_recovery_start function. Then, a kcopyd job is started in the recover function. - when the kcopyd job finishes, recovery_complete is called. It calls dm_rh_recovery_end. dm_rh_recovery_end adds the region to recovered_regions or failed_recovered_regions list (depending on whether the copy operation was successful or not). The above mechanism assumes that if the region is in DM_RH_RECOVERING state, no new I/Os are started on this region. When I/O is started, dm_rh_inc_pending is called, which increases reg->pending count. When I/O is finished, dm_rh_dec is called. It decreases reg->pending count. If the count is zero and the region was in DM_RH_RECOVERING state, dm_rh_dec adds it to the quiesced_regions list. Consequently, if we call dm_rh_inc_pending/dm_rh_dec while the region is in DM_RH_RECOVERING state, it could be added to quiesced_regions list multiple times or it could be added to this list when kcopyd is copying data (it is assumed that the region is not on any list while kcopyd does its jobs). This results in memory corruption and crash. There already exist bypasses for REQ_FLUSH requests: REQ_FLUSH requests do not belong to any region, so they are always added to the sync list in do_writes. dm_rh_inc_pending does not increase count for REQ_FLUSH requests. In mirror_end_io, dm_rh_dec is never called for REQ_FLUSH requests. These bypasses avoid the crash possibility described above. These bypasses were improperly implemented for REQ_DISCARD when the mirror target gained discard support in commit 5fc2ffea (dm raid1: support discard). In do_writes, REQ_DISCARD requests is always added to the sync queue and immediately dispatched (even if the region is in DM_RH_RECOVERING). However, dm_rh_inc and dm_rh_dec is called for REQ_DISCARD resusts. So it violates the rule that no I/Os are started on DM_RH_RECOVERING regions, and causes the list corruption described above. This patch changes it so that REQ_DISCARD requests follow the same path as REQ_FLUSH. This avoids the crash. Reference: https://bugzilla.redhat.com/837607Signed-off-by:
Mikulas Patocka <mpatocka@redhat.com> Signed-off-by:
Alasdair G Kergon <agk@redhat.com> Signed-off-by:
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Artem Bityutskiy authored
commit c6727932 upstream. UBIFS has a feature called "empty space fix-up" which is a quirk to work-around limitations of dumb flasher programs. Namely, of those flashers that are unable to skip NAND pages full of 0xFFs while flashing, resulting in empty space at the end of half-filled eraseblocks to be unusable for UBIFS. This feature is relatively new (introduced in v3.0). The fix-up routine (fixup_free_space()) is executed only once at the very first mount if the superblock has the 'space_fixup' flag set (can be done with -F option of mkfs.ubifs). It basically reads all the UBIFS data and metadata and writes it back to the same LEB. The routine assumes the image is pristine and does not have anything in the journal. There was a bug in 'fixup_free_space()' where it fixed up the log incorrectly. All but one LEB of the log of a pristine file-system are empty. And one contains just a commit start node. And 'fixup_free_space()' just unmapped this LEB, which resulted in wiping the commit start node. As a result, some users were unable to mount the file-system next time with the following symptom: UBIFS error (pid 1): replay_log_leb: first log node at LEB 3:0 is not CS node UBIFS error (pid 1): replay_log_leb: log error detected while replaying the log at LEB 3:0 The root-cause of this bug was that 'fixup_free_space()' wrongly assumed that the beginning of empty space in the log head (c->lhead_offs) was known on mount. However, it is not the case - it was always 0. UBIFS does not store in it the master node and finds out by scanning the log on every mount. The fix is simple - just pass commit start node size instead of 0 to 'fixup_leb()'. Signed-off-by:
Artem Bityutskiy <Artem.Bityutskiy@linux.intel.com> Reported-by:
Iwo Mergler <Iwo.Mergler@netcommwireless.com> Tested-by:
James Nute <newten82@gmail.com> Signed-off-by:
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David Daney authored
commit 7b1c0d26 upstream. Improper alignment can lead to unbootable systems and/or random crashes. [ralf@linux-mips.org: This is a lond standing bug since 6eb10bc9 (kernel.org) rsp. c422a10917f75fd19fa7fe070aaaa23e384dae6f (lmo) [MIPS: Clean up linker script using new linker script macros.] so dates back to 2.6.32.] Signed-off-by:
David Daney <david.daney@cavium.com> Cc: linux-mips@linux-mips.org Patchwork: https://patchwork.linux-mips.org/patch/3881/Signed-off-by:
Ralf Baechle <ralf@linux-mips.org> Signed-off-by:
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Aaditya Kumar authored
commit 1c7e7f6c upstream. Offlining memory may block forever, waiting for kswapd() to wake up because kswapd() does not check the event kthread->should_stop before sleeping. The proper pattern, from Documentation/memory-barriers.txt, is: --- waker --- event_indicated = 1; wake_up_process(event_daemon); --- sleeper --- for (;;) { set_current_state(TASK_UNINTERRUPTIBLE); if (event_indicated) break; schedule(); } set_current_state() may be wrapped by: prepare_to_wait(); In the kswapd() case, event_indicated is kthread->should_stop. === offlining memory (waker) === kswapd_stop() kthread_stop() kthread->should_stop = 1 wake_up_process() wait_for_completion() === kswapd_try_to_sleep (sleeper) === kswapd_try_to_sleep() prepare_to_wait() . . schedule() . . finish_wait() The schedule() needs to be protected by a test of kthread->should_stop, which is wrapped by kthread_should_stop(). Reproducer: Do heavy file I/O in background. Do a memory offline/online in a tight loop Signed-off-by:
Aaditya Kumar <aaditya.kumar@ap.sony.com> Acked-by:
Minchan Kim <minchan@kernel.org> Acked-by:
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John Stultz authored
commit 6b1859db upstream. In commit 6b43ae8a, I introduced a bug that kept the STA_INS or STA_DEL bit from being cleared from time_status via adjtimex() without forcing STA_PLL first. Usually once the STA_INS is set, it isn't cleared until the leap second is applied, so its unlikely this affected anyone. However during testing I noticed it took some effort to cancel a leap second once STA_INS was set. Signed-off-by:
John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Richard Cochran <richardcochran@gmail.com> Cc: Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1342156917-25092-2-git-send-email-john.stultz@linaro.orgSigned-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Jeff Layton authored
commit cd60042c upstream. When we get back a FIND_FIRST/NEXT result, we have some info about the dentry that we use to instantiate a new inode. We were ignoring and discarding that info when we had an existing dentry in the cache. Fix this by updating the inode in place when we find an existing dentry and the uniqueid is the same. Reported-and-Tested-by:
Andrew Bartlett <abartlet@samba.org> Reported-by:
Bill Robertson <bill_robertson@debortoli.com.au> Reported-by:
Dion Edwards <dion_edwards@debortoli.com.au> Signed-off-by:
Jeff Layton <jlayton@redhat.com> Signed-off-by:
Steve French <smfrench@gmail.com> Signed-off-by:
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- 19 Jul, 2012 21 commits
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Greg Kroah-Hartman authored
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Thomas Gleixner authored
This is a backport of 3e997130 The leap second rework unearthed another issue of inconsistent data. On timekeeping_resume() the timekeeper data is updated, but nothing calls timekeeping_update(), so now the update code in the timer interrupt sees stale values. This has been the case before those changes, but then the timer interrupt was using stale data as well so this went unnoticed for quite some time. Add the missing update call, so all the data is consistent everywhere. Reported-by:
Andreas Schwab <schwab@linux-m68k.org> Reported-and-tested-by:
"Rafael J. Wysocki" <rjw@sisk.pl> Reported-and-tested-by:
Martin Steigerwald <Martin@lichtvoll.de> Cc: John Stultz <johnstul@us.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, Cc: Prarit Bhargava <prarit@redhat.com> Signed-off-by:
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John Stultz authored
This is a backport of 5baefd6d The update of the hrtimer base offsets on all cpus cannot be made atomically from the timekeeper.lock held and interrupt disabled region as smp function calls are not allowed there. clock_was_set(), which enforces the update on all cpus, is called either from preemptible process context in case of do_settimeofday() or from the softirq context when the offset modification happened in the timer interrupt itself due to a leap second. In both cases there is a race window for an hrtimer interrupt between dropping timekeeper lock, enabling interrupts and clock_was_set() issuing the updates. Any interrupt which arrives in that window will see the new time but operate on stale offsets. So we need to make sure that an hrtimer interrupt always sees a consistent state of time and offsets. ktime_get_update_offsets() allows us to get the current monotonic time and update the per cpu hrtimer base offsets from hrtimer_interrupt() to capture a consistent state of monotonic time and the offsets. The function replaces the existing ktime_get() calls in hrtimer_interrupt(). The overhead of the new function vs. ktime_get() is minimal as it just adds two store operations. This ensures that any changes to realtime or boottime offsets are noticed and stored into the per-cpu hrtimer base structures, prior to any hrtimer expiration and guarantees that timers are not expired early. Signed-off-by:
Ingo Molnar <mingo@kernel.org> Acked-by:
Peter Zijlstra <a.p.zijlstra@chello.nl> Acked-by:
Prarit Bhargava <prarit@redhat.com> Link: http://lkml.kernel.org/r/1341960205-56738-8-git-send-email-johnstul@us.ibm.comSigned-off-by:
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Thomas Gleixner authored
This is a backport of f6c06abf To finally fix the infamous leap second issue and other race windows caused by functions which change the offsets between the various time bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a function which atomically gets the current monotonic time and updates the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic overhead. The previous patch which provides ktime_t offsets allows us to make this function almost as cheap as ktime_get() which is going to be replaced in hrtimer_interrupt(). Signed-off-by:
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Thomas Gleixner authored
This is a backport of 196951e9 We need to update the base offsets from this code and we need to do that under base->lock. Move the lock held region around the ktime_get() calls. The ktime_get() calls are going to be replaced with a function which gets the time and the offsets atomically. Signed-off-by:
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Thomas Gleixner authored
This is a backport of 5b9fe759 We need to update the hrtimer clock offsets from the hrtimer interrupt context. To avoid conversions from timespec to ktime_t maintain a ktime_t based representation of those offsets in the timekeeper. This puts the conversion overhead into the code which updates the underlying offsets and provides fast accessible values in the hrtimer interrupt. Signed-off-by:
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John Stultz authored
This is a backport of 4873fa07 The timekeeping code misses an update of the hrtimer subsystem after a leap second happened. Due to that timers based on CLOCK_REALTIME are either expiring a second early or late depending on whether a leap second has been inserted or deleted until an operation is initiated which causes that update. Unless the update happens by some other means this discrepancy between the timekeeping and the hrtimer data stays forever and timers are expired either early or late. The reported immediate workaround - $ data -s "`date`" - is causing a call to clock_was_set() which updates the hrtimer data structures. See: http://www.sheeri.com/content/mysql-and-leap-second-high-cpu-and-fix Add the missing clock_was_set() call to update_wall_time() in case of a leap second event. The actual update is deferred to softirq context as the necessary smp function call cannot be invoked from hard interrupt context. Signed-off-by:
Jan Engelhardt <jengelh@inai.de> Reviewed-by:
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John Stultz authored
This is a backport of f55a6faa clock_was_set() cannot be called from hard interrupt context because it calls on_each_cpu(). For fixing the widely reported leap seconds issue it is necessary to call it from hard interrupt context, i.e. the timer tick code, which does the timekeeping updates. Provide a new function which denotes it in the hrtimer cpu base structure of the cpu on which it is called and raise the hrtimer softirq. We then execute the clock_was_set() notificiation from softirq context in run_hrtimer_softirq(). The hrtimer softirq is rarely used, so polling the flag there is not a performance issue. [ tglx: Made it depend on CONFIG_HIGH_RES_TIMERS. We really should get rid of all this ifdeffery ASAP ] Signed-off-by:
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Thomas Gleixner authored
This is a backport of cc06268c While not a bugfix itself, it allows following fixes to backport in a more straightforward manner. CC: Thomas Gleixner <tglx@linutronix.de> CC: Eric Dumazet <eric.dumazet@gmail.com> CC: Richard Cochran <richardcochran@gmail.com> Signed-off-by:
John Stultz <john.stultz@linaro.org> Signed-off-by:
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John Stultz authored
This is a backport of fad0c66c which resolves a bug the previous commit. Commit 6b43ae8a (ntp: Fix leap-second hrtimer livelock) broke the leapsecond update of CLOCK_MONOTONIC. The missing leapsecond update to wall_to_monotonic causes discontinuities in CLOCK_MONOTONIC. Adjust wall_to_monotonic when NTP inserted a leapsecond. Reported-by:
Richard Cochran <richardcochran@gmail.com> Signed-off-by:
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Richard Cochran authored
This is a backport of dd48d708 When repeating a UTC time value during a leap second (when the UTC time should be 23:59:60), the TAI timescale should not stop. The kernel NTP code increments the TAI offset one second too late. This patch fixes the issue by incrementing the offset during the leap second itself. Signed-off-by:
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John Stultz authored
This is a backport of 6b43ae8a This should have been backported when it was commited, but I mistook the problem as requiring the ntp_lock changes that landed in 3.4 in order for it to occur. Unfortunately the same issue can happen (with only one cpu) as follows: do_adjtimex() write_seqlock_irq(&xtime_lock); process_adjtimex_modes() process_adj_status() ntp_start_leap_timer() hrtimer_start() hrtimer_reprogram() tick_program_event() clockevents_program_event() ktime_get() seq = req_seqbegin(xtime_lock); [DEADLOCK] This deadlock will no always occur, as it requires the leap_timer to force a hrtimer_reprogram which only happens if its set and there's no sooner timer to expire. NOTE: This patch, being faithful to the original commit, introduces a bug (we don't update wall_to_monotonic), which will be resovled by backporting a following fix. Original commit message below: Since commit 7dffa3c6 the ntp subsystem has used an hrtimer for triggering the leapsecond adjustment. However, this can cause a potential livelock. Thomas diagnosed this as the following pattern: CPU 0 CPU 1 do_adjtimex() spin_lock_irq(&ntp_lock); process_adjtimex_modes(); timer_interrupt() process_adj_status(); do_timer() ntp_start_leap_timer(); write_lock(&xtime_lock); hrtimer_start(); update_wall_time(); hrtimer_reprogram(); ntp_tick_length() tick_program_event() spin_lock(&ntp_lock); clockevents_program_event() ktime_get() seq = req_seqbegin(xtime_lock); This patch tries to avoid the problem by reverting back to not using an hrtimer to inject leapseconds, and instead we handle the leapsecond processing in the second_overflow() function. The downside to this change is that on systems that support highres timers, the leap second processing will occur on a HZ tick boundary, (ie: ~1-10ms, depending on HZ) after the leap second instead of possibly sooner (~34us in my tests w/ x86_64 lapic). This patch applies on top of tip/timers/core. CC: Sasha Levin <levinsasha928@gmail.com> CC: Thomas Gleixner <tglx@linutronix.de> Reported-by:
Sasha Levin <levinsasha928@gmail.com> Diagnoised-by:
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Michal Kazior authored
commit f8cdddb8 upstream. Don't validate interface combinations on a stopped interface. Otherwise we might end up being able to create a new interface with a certain type, but won't be able to change an existing interface into that type. This also skips some other functions when interface is stopped and changing interface type. Signed-off-by:
Michal Kazior <michal.kazior@tieto.com> Signed-off-by:
Johannes Berg <johannes.berg@intel.com> [Fixes regression introduced by cherry pick of 463454b5] Signed-off-by:
Paul Gortmaker <paul.gortmaker@windriver.com>
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Eric Dumazet authored
commit fdf5af0d upstream. Denys Fedoryshchenko reported that SYN+FIN attacks were bringing his linux machines to their limits. Dont call conn_request() if the TCP flags includes SYN flag Reported-by:
Denys Fedoryshchenko <denys@visp.net.lb> Signed-off-by:
Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by:
David S. Miller <davem@davemloft.net> Cc: Ben Hutchings <ben@decadent.org.uk> Signed-off-by:
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Yuri Khan authored
commit e76b8ee2 upstream. I couldn't find the vendor ID in any of the online databases, but this mat has a Pump It Up logo on the top side of the controller compartment, and a disclaimer stating that Andamiro will not be liable on the bottom. Signed-off-by:
Yuri Khan <yurivkhan@gmail.com> Signed-off-by:
Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by:
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Tushar Dave authored
commit d0efa8f2 upstream. SYNCH bit and IV bit of RXCW register are sticky. Before examining these bits, RXCW should be read twice to filter out one-time false events and have correct values for these bits. Incorrect values of these bits in link check logic can cause weird link stability issues if auto-negotiation fails. Reported-by:
Dean Nelson <dnelson@redhat.com> Signed-off-by:
Tushar Dave <tushar.n.dave@intel.com> Reviewed-by:
Bruce Allan <bruce.w.allan@intel.com> Tested-by:
Jeff Pieper <jeffrey.e.pieper@intel.com> Signed-off-by:
Jeff Kirsher <jeffrey.t.kirsher@intel.com> Signed-off-by:
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Stanislaw Gruszka authored
commit efd82118 upstream. On rt2x00_dmastart() we increase index specified by Q_INDEX and on rt2x00_dmadone() we increase index specified by Q_INDEX_DONE. So entries between Q_INDEX_DONE and Q_INDEX are those we currently process in the hardware. Entries between Q_INDEX and Q_INDEX_DONE are those we can submit to the hardware. According to that fix rt2x00usb_kick_queue(), as we need to submit RX entries that are not processed by the hardware. It worked before only for empty queue, otherwise was broken. Note that for TX queues indexes ordering are ok. We need to kick entries that have filled skb, but was not submitted to the hardware, i.e. started from Q_INDEX_DONE and have ENTRY_DATA_PENDING bit set. From practical standpoint this fixes RX queue stall, usually reproducible in AP mode, like for example reported here: https://bugzilla.redhat.com/show_bug.cgi?id=828824Reported-and-tested-by:
Franco Miceli <fmiceli@plan.ceibal.edu.uy> Reported-and-tested-by:
Tom Horsley <horsley1953@gmail.com> Signed-off-by:
Stanislaw Gruszka <sgruszka@redhat.com> Signed-off-by:
John W. Linville <linville@tuxdriver.com> Signed-off-by:
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Anders Kaseorg authored
commit 05d290d6 upstream. If a parent and child process open the two ends of a fifo, and the child immediately exits, the parent may receive a SIGCHLD before its open() returns. In that case, we need to make sure that open() will return successfully after the SIGCHLD handler returns, instead of throwing EINTR or being restarted. Otherwise, the restarted open() would incorrectly wait for a second partner on the other end. The following test demonstrates the EINTR that was wrongly thrown from the parent’s open(). Change .sa_flags = 0 to .sa_flags = SA_RESTART to see a deadlock instead, in which the restarted open() waits for a second reader that will never come. (On my systems, this happens pretty reliably within about 5 to 500 iterations. Others report that it manages to loop ~forever sometimes; YMMV.) #include <sys/stat.h> #include <sys/types.h> #include <sys/wait.h> #include <fcntl.h> #include <signal.h> #include <stdio.h> #include <stdlib.h> #include <unistd.h> #define CHECK(x) do if ((x) == -1) {perror(#x); abort();} while(0) void handler(int signum) {} int main() { struct sigaction act = {.sa_handler = handler, .sa_flags = 0}; CHECK(sigaction(SIGCHLD, &act, NULL)); CHECK(mknod("fifo", S_IFIFO | S_IRWXU, 0)); for (;;) { int fd; pid_t pid; putc('.', stderr); CHECK(pid = fork()); if (pid == 0) { CHECK(fd = open("fifo", O_RDONLY)); _exit(0); } CHECK(fd = open("fifo", O_WRONLY)); CHECK(close(fd)); CHECK(waitpid(pid, NULL, 0)); } } This is what I suspect was causing the Git test suite to fail in t9010-svn-fe.sh: http://bugs.debian.org/678852Signed-off-by:
Anders Kaseorg <andersk@mit.edu> Reviewed-by:
Jonathan Nieder <jrnieder@gmail.com> Signed-off-by:
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Takashi Iwai authored
commit 88ca518b upstream. intel_ips driver spews the warning message "ME failed to update for more than 1s, likely hung" at each second endlessly on HP ProBook laptops with IronLake. As this has never worked, better to blacklist the driver for now. Signed-off-by:
Takashi Iwai <tiwai@suse.de> Signed-off-by:
Matthew Garrett <mjg@redhat.com> Signed-off-by:
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Todd Poynor authored
commit 8265981b upstream. Checking for adc->ts_pend already claimed should be done with the lock held. Signed-off-by:
Todd Poynor <toddpoynor@google.com> Acked-by:
Ben Dooks <ben-linux@fluff.org> Signed-off-by:
Kukjin Kim <kgene.kim@samsung.com> Signed-off-by:
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Herton Ronaldo Krzesinski authored
commit 596fd462 upstream. We don't need to open code the divide function, just use div_u64 that already exists and do the same job. While this is a straightforward clean up, there is more to that, the real motivation for this. While building on a cross compiling environment in armel, using gcc 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5), I was getting the following build error: ERROR: "__aeabi_uldivmod" [drivers/mtd/nand/nandsim.ko] undefined! After investigating with objdump and hand built assembly version generated with the compiler, I narrowed __aeabi_uldivmod as being generated from the divide function. When nandsim.c is built with -fno-inline-functions-called-once, that happens when CONFIG_DEBUG_SECTION_MISMATCH is enabled, the do_div optimization in arch/arm/include/asm/div64.h doesn't work as expected with the open coded divide function: even if the do_div we are using doesn't have a constant divisor, the compiler still includes the else parts of the optimized do_div macro, and translates the divisions there to use __aeabi_uldivmod, instead of only calling __do_div_asm -> __do_div64 and optimizing/removing everything else out. So to reproduce, gcc 4.6 plus CONFIG_DEBUG_SECTION_MISMATCH=y and CONFIG_MTD_NAND_NANDSIM=m should do it, building on armel. After this change, the compiler does the intended thing even with -fno-inline-functions-called-once, and optimizes out as expected the constant handling in the optimized do_div on arm. As this also avoids a build issue, I'm marking for Stable, as I think is applicable for this case. Signed-off-by:
Herton Ronaldo Krzesinski <herton.krzesinski@canonical.com> Acked-by:
Nicolas Pitre <nico@linaro.org> Signed-off-by:
David Woodhouse <David.Woodhouse@intel.com> Signed-off-by:
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