- 17 Feb, 2011 40 commits
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Amit Shah authored
commit 2770c5ea upstream. The outvq needs to be woken up on host notifications so that buffers consumed by the host can be reclaimed, outvq freed, and application writes may proceed again. The need for this is now finally noticed when I have qemu patches ready to use nonblocking IO and flow control. CC: Hans de Goede <hdegoede@redhat.com> Signed-off-by:
Amit Shah <amit.shah@redhat.com> Signed-off-by:
Rusty Russell <rusty@rustcorp.com.au> Acked-by:
Hans de Goede <hdegoede@redhat.com> Signed-off-by:
Greg Kroah-Hartman <gregkh@suse.de>
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Bruce Rogers authored
commit 3e9d08ec upstream. Under harsh testing conditions, including low memory, the guest would stop receiving packets. With this patch applied we no longer see any problems in the driver while performing these tests for extended periods of time. Make sure napi is scheduled subsequent to each napi_enable. Signed-off-by:
Bruce Rogers <brogers@novell.com> Signed-off-by:
Olaf Kirch <okir@suse.de> Signed-off-by:
David S. Miller <davem@davemloft.net> Signed-off-by:
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Mark Brown authored
commit 7f94de48 upstream. Due to the different routing for AIF1 and AIF2 we weren't using a single widget to represent the ADCDAT signal. For consistency add one. Signed-off-by:
Mark Brown <broonie@opensource.wolfsonmicro.com> Acked-by:
Liam Girdwood <lrg@slimlogic.co.uk> Signed-off-by:
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Qiao Zhou authored
commit 78b3fb46 upstream. fix wrong value in wm8994_set_tristate func. when updating reg bits, it should use "value", not "reg". Signed-off-by:
Qiao Zhou <zhouqiao@marvell.com> Acked-by:
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Mark Brown authored
commit 20a4e7fc upstream. The DC servo codes are actually signed numbers so need to be treated as such. Signed-off-by:
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Dmitry Eremin-Solenikov authored
commit a3adfa00 upstream. ASoC DAI link descriptions for Corgi, Poodle and Spitz platforms contained incorrect names for cpu_dai and codec, which effectievly disabled sound on theese platforms. Fix that errors. Signed-off-by:
Dmitry Eremin-Solenikov <dbaryshkov@gmail.com> Acked-by:
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Mark Brown authored
commit 7d8316df upstream. soc_unregister_ac97_dai_link() takes a CODEC as an argument, not a rtd like the registration function, so give it what it's looking for. Signed-off-by:
Mike Frysinger <vapier.adi@gmail.com> Acked-by:
Mike Frysinger <vapier@gentoo.org> Signed-off-by:
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Sudhakar Rajashekhara authored
commit dc5a460a upstream. The codec_name entry for da8xx evm in sound/soc/davinci/davinci-evm.c is not matching with the i2c ids in the board file. Without this fix the soundcard does not get detected on da850/omap-l138/am18x evm. Signed-off-by:
Sudhakar Rajashekhara <sudhakar.raj@ti.com> Tested-by:
Dan Sharon <dansharon@nanometrics.ca> Acked-by:
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Jean Delvare authored
commit 5219bf88 upstream. Remove real devices first and dummy devices last. This gives device driver which instantiated dummy devices themselves a chance to clean them up before we do. Signed-off-by:
Jean Delvare <khali@linux-fr.org> Tested-by:
Hans Verkuil <hverkuil@xs4all.nl> Signed-off-by:
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Christian Lamparter authored
commit 3b5c5827 upstream. P54_HDR_FLAG_DATA_OUT_SEQNR is meant to tell the firmware that "the frame's sequence number has already been set by the application." Whereas IEEE80211_TX_CTL_ASSIGN_SEQ is set for frames which lack a valid sequence number and either the driver or firmware has to assign one. Yup, it's the exact opposite! Signed-off-by:
Christian Lamparter <chunkeey@googlemail.com> Signed-off-by:
John W. Linville <linville@tuxdriver.com> Signed-off-by:
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Shaohua Li authored
commit ec30f343 upstream. Fix a shutdown regression caused by 2a2d31c8 ("intel_idle: open broadcast clock event"). The clockevent framework can automatically shutdown broadcast timers for hotremove CPUs. And we get a shutdown regression when we shutdown broadcast timer for hot remove CPU, so just delete some code. Also fix some section mismatch. Reported-by:
Ari Savolainen <ari.m.savolainen@gmail.com> Signed-off-by:
Shaohua Li <shaohua.li@intel.com> Tested-by:
Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by:
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Shaohua Li authored
commit 2a2d31c8 upstream. Intel_idle driver uses CLOCK_EVT_NOTIFY_BROADCAST_ENTER CLOCK_EVT_NOTIFY_BROADCAST_EXIT for broadcast clock events. The _ENTER/_EXIT doesn't really open broadcast clock events, please see processor_idle.c for an example. In some situation, this will cause boot hang, because some CPUs enters idle but local APIC timer stalls. Reported-and-tested-by:
Yan Zheng <zheng.z.yan@intel.com> Signed-off-by:
Len Brown <len.brown@intel.com> Signed-off-by:
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Rafael J. Wysocki authored
commit d8c216cf upstream. The following scenario is possible with the current cpuidle code and the ACPI cpuidle driver: (1) acpi_processor_cst_has_changed() is called, (2) cpuidle_disable_device() is called, (3) cpuidle_remove_state_sysfs() is called to remove the (presumably outdated) states info from sysfs, (3) acpi_processor_get_power_info() is called, the first entry in the pr->power.states[] table is filled with zeros, (4) acpi_processor_setup_cpuidle() is called and it doesn't fill the first entry in pr->power.states[], (5) cpuidle_enable_device() is called, (6) __cpuidle_register_device() is _not_ called, since the device has already been registered, (7) Consequently, poll_idle_init() is _not_ called either, (8) cpuidle_add_state_sysfs() is called to create the sysfs attributes for the new states and it uses the bogus first table entry from acpi_processor_get_power_info() for creating state0. This problem is avoided if cpuidle_enable_device() unconditionally calls poll_idle_init(). Reported-by:
Rafael J. Wysocki <rjw@sisk.pl> Signed-off-by:
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Hans-Christian Egtvedt authored
commit 664cb714 upstream. This patch removes the redundant syscalls prototypes in the architecture specific syscalls.h header file. These were identical with the ones in asm-generic/syscalls.h. Signed-off-by:
Hans-Christian Egtvedt <hans-christian.egtvedt@atmel.com> Reported-by:
Peter Huewe <PeterHuewe@gmx.de> Reported-by:
Sven Schnelle <svens@stackframe.org> Signed-off-by:
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Sven Neumann authored
commit 86af9503 upstream. A check against division by zero was modified in commit b0525b48. Since this change time_to_empty_now is always reported as zero while the battery is discharging and as a negative value while the battery is charging. This is because current is negative while the battery is discharging. Fix the check introduced by commit b0525b48 so that time_to_empty_now is reported correctly during discharge and as zero while charging. Signed-off-by:
Sven Neumann <s.neumann@raumfeld.com> Acked-by:
Daniel Mack <daniel@caiaq.de> Signed-off-by:
Anton Vorontsov <cbouatmailru@gmail.com> Signed-off-by:
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Lars-Peter Clausen authored
commit 8ec98fe0 upstream. We can not handle more then one ADC request at a time to the battery. The patch adds a mutex around the ADC read code to ensure this. Signed-off-by:
Lars-Peter Clausen <lars@metafoo.de> Signed-off-by:
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Milton Miller authored
commit 8b3bb3ec upstream. We sometimes need to map between the virtio device and the given pci device. One such use is OS installer that gets the boot pci device from BIOS and needs to find the relevant block device. Since it can't, installation fails. Instead of creating a top-level devices/virtio-pci directory, create each device under the corresponding pci device node. Symlinks to all virtio-pci devices can be found under the pci driver link in bus/pci/drivers/virtio-pci/devices, and all virtio devices under drivers/bus/virtio/devices. Signed-off-by:
Milton Miller <miltonm@bga.com> Signed-off-by:
Michael S. Tsirkin <mst@redhat.com> Tested-by:
Gleb Natapov <gleb@redhat.com> Tested-by:
"Daniel P. Berrange" <berrange@redhat.com> Signed-off-by:
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Tejun Heo authored
commit 99a0fadf upstream. pci-stub uses strsep() to separate list of ids and generates a warning message when it fails to parse an id. However, not specifying the parameter results in ids set to an empty string. strsep() happily returns the empty string as the first token and thus triggers the warning message spuriously. Make the tokner ignore zero length ids. Reported-by:
Chris Wright <chrisw@sous-sol.org> Reported-by:
Prasad Joshi <P.G.Joshi@student.reading.ac.uk> Signed-off-by:
Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by:
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Paul Mundt authored
commit efb3e34b upstream. When p3_ioremap() was converted to ioremap_prot() there was some breakage introduced where the 29-bit segmentation logic would trap the area range and return an identity mapping without having allowed the area specification to force mapping through page tables. This wires up a PCC mask for pgprot verification to work out whether to short-circuit the identity mapping on legacy parts, restoring the previous behaviour. Reported-by:
Nobuhiro Iwamatsu <iwamatsu@nigauri.org> Signed-off-by:
Paul Mundt <lethal@linux-sh.org> Signed-off-by:
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Eric Dumazet authored
[ Upstream commit 44b82883 ] commit 57dbb2d8 (sched: add head drop fifo queue) introduced pfifo_head_drop, and broke the invariant that sch->bstats.bytes and sch->bstats.packets are COUNTER (increasing counters only) This can break estimators because est_timer() handles unsigned deltas only. A decreasing counter can then give a huge unsigned delta. My mid term suggestion would be to change things so that sch->bstats.bytes and sch->bstats.packets are incremented in dequeue() only, not at enqueue() time. We also could add drop_bytes/drop_packets and provide estimations of drop rates. It would be more sensible anyway for very low speeds, and big bursts. Right now, if we drop packets, they still are accounted in byte/packets abolute counters and rate estimators. Before this mid term change, this patch makes pfifo_head_drop behavior similar to other qdiscs in case of drops : Dont decrement sch->bstats.bytes and sch->bstats.packets Signed-off-by:
Eric Dumazet <eric.dumazet@gmail.com> Acked-by:
Hagen Paul Pfeifer <hagen@jauu.net> Signed-off-by:
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Eric Dumazet authored
[ Upstream commit 6623e3b2 ] RFC3168 (The Addition of Explicit Congestion Notification to IP) states : 5.3. Fragmentation ECN-capable packets MAY have the DF (Don't Fragment) bit set. Reassembly of a fragmented packet MUST NOT lose indications of congestion. In other words, if any fragment of an IP packet to be reassembled has the CE codepoint set, then one of two actions MUST be taken: * Set the CE codepoint on the reassembled packet. However, this MUST NOT occur if any of the other fragments contributing to this reassembly carries the Not-ECT codepoint. * The packet is dropped, instead of being reassembled, for any other reason. This patch implements this requirement for IPv4, choosing the first action : If one fragment had NO-ECT codepoint reassembled frame has NO-ECT ElIf one fragment had CE codepoint reassembled frame has CE Signed-off-by:
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Eric Dumazet authored
[ Upstream commit 2c6607c6 ] Leonardo Chiquitto found poll() could block forever on tcp sockets and Urgent data was received, if the event flag only contains POLLPRI. He did a bisection and found commit 4938d7e0 (poll: avoid extra wakeups in select/poll) was the source of the problem. Problem is TCP sockets use standard sock_def_readable() function for their sk_data_ready() handler, and sock_def_readable() doesnt signal POLLPRI. Only TCP is affected by the problem. Adding POLLPRI to the list of flags might trigger unnecessary schedules, but URGENT handling is such a seldom used feature this seems a good compromise. Thanks a lot to Leonardo for providing the bisection result and a test program as well. Reference : http://www.spinics.net/lists/netdev/msg151793.htmlReported-and-bisected-by:
Leonardo Chiquitto <leonardo.lists@gmail.com> Signed-off-by:
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Alexey Kuznetsov authored
[ Upstream commit 72b43d08 ] Linux IPv6 forwards unicast packets, which are link layer multicasts... The hole was present since day one. I was 100% this check is there, but it is not. The problem shows itself, f.e. when Microsoft Network Load Balancer runs on a network. This software resolves IPv6 unicast addresses to multicast MAC addresses. Signed-off-by:
Alexey Kuznetsov <kuznet@ms2.inr.ac.ru> Signed-off-by:
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David S. Miller authored
[ Upstream commit 3610cda5 ] unix_release() can asynchornously set socket->sk to NULL, and it does so without holding the unix_state_lock() on "other" during stream connects. However, the reverse mapping, sk->sk_socket, is only transitioned to NULL under the unix_state_lock(). Therefore make the security hooks follow the reverse mapping instead of the forward mapping. Reported-by:
Jeremy Fitzhardinge <jeremy@goop.org> Reported-by:
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David S. Miller authored
[ Upstream commit 09798eb9 ] After commit 25edd694 ("sparc64: Get rid of indirect p1275 PROM call buffer.") we can't pass virtual addresses >4GB to PROM calls. Largely this is never necessary in drivers because we have a copy of the entire PROM device tree in the kernel and a set of of_*() interfaces to access it. Unfortunately there were some lingering prom calls in the atyfb driver, in particular prom_finddevice() was being called with an on-stack address which could be anywhere. This code is actually probing for information we already have, the PROM choosen console output device is stored in of_console_device so all of this nasty code consolidates into a one-line comparison. Next we have some prom_getintdefault() calls which are trivially transformed into the equivalent of_getintprop_default(). Special thanks to Fabio, who figured out exactly where the bootup was hanging. That made this bug trivial to fix. Reported-by:
Fabio M. Di NItto <fabbione@fabbione.net> Reported-by:
Sam Ravnborg <sam@ravnborg.org> Reported-by:
Frans van Berckel <fberckel@xs4all.nl> Signed-off-by:
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Thomas Taranowski authored
commit 12a4dc43 upstream. In fsl_rio_dbell_handler() the code currently simply acknowledges the QFI queue full interrupt, but does nothing to resolve the queue full condition. Instead, it jumps to the end of the isr. When a queue full condition occurs, the isr is then re-entered immediately and continually, forever. The fix is to just fall through and read out current doorbell entries. Signed-off-by:
Thomas Taranowski <tom@baringforge.com> Cc: Alexandre Bounine <alexandre.bounine@idt.com> Cc: Kumar Gala <galak@kernel.crashing.org> Cc: Matt Porter <mporter@kernel.crashing.org> Cc: Li Yang <leoli@freescale.com> Cc: Thomas Moll <thomas.moll@sysgo.com> Cc: Micha Nelissen <micha@neli.hopto.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Grant Likely <grant.likely@secretlab.ca> Signed-off-by:
Andrew Morton <akpm@linux-foundation.org> Signed-off-by:
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Eric Sandeen authored
commit 2892c15d upstream. In 2.6.37 I was running into oopses with repeated module loads & unloads. I tracked this down to: fb1813f4 ext4: use dedicated slab caches for group_info structures (this was in addition to the features advert unload problem) The kstrdup & subsequent kfree of the cache name was causing a double free. In slub, at least, if I read it right it allocates & frees the name itself, slab seems to do something different... so in slub I think we were leaking -our- cachep->name, and double freeing the one allocated by slub. After getting lost in slab/slub/slob a bit, I just looked at other sized-caches that get allocated. jbd2, biovec, sgpool all do it more or less the way jbd2 does. Below patch follows the jbd2 method of dynamically allocating a cache at mount time from a list of static names. (This might also possibly fix a race creating the caches with parallel mounts running). [Folded in a fix from Dan Carpenter which fixed an off-by-one error in the original patch] Signed-off-by:
Eric Sandeen <sandeen@redhat.com> Signed-off-by:
"Theodore Ts'o" <tytso@mit.edu> Signed-off-by:
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Curt Wohlgemuth authored
commit d50bdd5a upstream. This fixes a corruption problem with the multi-block writepages submittal change for ext4, from commit bd2d0210 ("ext4: use bio layer instead of buffer layer in mpage_da_submit_io"). (Note that this corruption is not present in 2.6.37 on ext4, because the corruption was detected after the feature was merged in 2.6.37-rc1, and so it was turned off by adding a non-default mount option, mblk_io_submit. With this commit, which hopefully fixes the last of the bugs with this feature, we'll be able to turn on this performance feature by default in 2.6.38, and remove the mblk_io_submit option.) The ext4 code path to bundle multiple pages for writeback in ext4_bio_write_page() had a bug: we should be clearing buffer head dirty flags *before* we submit the bio, not in the completion routine. The patch below was tested on 2.6.37 under KVM with the postgresql script which was submitted by Jon Nelson as documented in commit 1449032b. Without the patch, I'd hit the corruption problem about 50-70% of the time. With the patch, I executed the script > 100 times with no corruption seen. I also fixed a bug to make sure ext4_end_bio() doesn't dereference the bio after the bio_put() call. Reported-by:
Jon Nelson <jnelson@jamponi.net> Reported-by:
Matthias Bayer <jackdachef@gmail.com> Signed-off-by:
Curt Wohlgemuth <curtw@google.com> Signed-off-by:
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Lukas Czerner authored
commit 8f021222 upstream. Ext4 features interface was not properly unregistered which led to problems while unloading/reloading ext4 module. This commit fixes that by adding proper kobject unregistration code into ext4_exit_fs() as well as fail-path of ext4_init_fs() Reported-by:
Lukas Czerner <lczerner@redhat.com> Signed-off-by:
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Eric Sandeen authored
commit 8f1f7453 upstream. https://bugzilla.kernel.org/show_bug.cgi?id=27652 If the lazyinit thread is running, the teardown function ext4_destroy_lazyinit_thread() has problems: ext4_clear_request_list(); while (ext4_li_info->li_task) { wake_up(&ext4_li_info->li_wait_daemon); wait_event(ext4_li_info->li_wait_task, ext4_li_info->li_task == NULL); } Clearing the request list will cause the thread to exit and free ext4_li_info, so then we're waiting on something which is getting freed. Fix this up by making the thread respond to kthread_stop, and exit, without the need to wait for that exit in some other homegrown way. Reported-and-Tested-by:
Tao Ma <boyu.mt@taobao.com> Signed-off-by:
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Theodore Ts'o authored
commit 1c5b9e90 upstream. Commit 40389687 moved a call to ext4_forget() out of ext4_free_branches and let ext4_free_blocks() handle calling bforget(). But that change unfortunately did not replace the call to ext4_forget() with brelse(), which was needed to drop the in-use count of the indirect block's buffer head, which lead to a memory leak when deleting files that used indirect blocks. Fix this. Thanks to Hugh Dickins for pointing this out. Signed-off-by:
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Jan Kara authored
commit ca6e909f upstream. When ext4_trim_fs() is called to trim a part of a single group, the logic will wrongly set last block of the interval to 'len' instead of 'first_block + len'. Thus a shorter interval is possibly trimmed. Fix it. CC: Lukas Czerner <lczerner@redhat.com> Signed-off-by:
Jan Kara <jack@suse.cz> Signed-off-by:
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Andrew Morton authored
commit 6c5a6cb9 upstream. fs/ext4/super.c: In function 'ext4_register_li_request': fs/ext4/super.c:2936: warning: 'ret' may be used uninitialized in this function It looks buggy to me, too. Cc: Lukas Czerner <lczerner@redhat.com> Signed-off-by:
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Jan Kara authored
commit b9543dac upstream. When wb_writeback() is called in WB_SYNC_ALL mode, work->nr_to_write is usually set to LONG_MAX. The logic in wb_writeback() then calls __writeback_inodes_sb() with nr_to_write == MAX_WRITEBACK_PAGES and we easily end up with non-positive nr_to_write after the function returns, if the inode has more than MAX_WRITEBACK_PAGES dirty pages at the moment. When nr_to_write is <= 0 wb_writeback() decides we need another round of writeback but this is wrong in some cases! For example when a single large file is continuously dirtied, we would never finish syncing it because each pass would be able to write MAX_WRITEBACK_PAGES and inode dirty timestamp never gets updated (as inode is never completely clean). Thus __writeback_inodes_sb() would write the redirtied inode again and again. Fix the issue by setting nr_to_write to LONG_MAX in WB_SYNC_ALL mode. We do not need nr_to_write in WB_SYNC_ALL mode anyway since write_cache_pages() does livelock avoidance using page tagging in WB_SYNC_ALL mode. This makes wb_writeback() call __writeback_inodes_sb() only once on WB_SYNC_ALL. The latter function won't livelock because it works on - a finite set of files by doing queue_io() once at the beginning - a finite set of pages by PAGECACHE_TAG_TOWRITE page tagging After this patch, program from http://lkml.org/lkml/2010/10/24/154 is no longer able to stall sync forever. [fengguang.wu@intel.com: fix locking comment] Signed-off-by:
Wu Fengguang <fengguang.wu@intel.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Dave Chinner <david@fromorbit.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Jan Engelhardt <jengelh@medozas.de> Cc: Jens Axboe <axboe@kernel.dk> Signed-off-by:
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Jan Kara authored
commit aa373cf5 upstream. Background writeback is easily livelockable in a loop in wb_writeback() by a process continuously re-dirtying pages (or continuously appending to a file). This is in fact intended as the target of background writeback is to write dirty pages it can find as long as we are over dirty_background_threshold. But the above behavior gets inconvenient at times because no other work queued in the flusher thread's queue gets processed. In particular, since e.g. sync(1) relies on flusher thread to do all the IO for it, sync(1) can hang forever waiting for flusher thread to do the work. Generally, when a flusher thread has some work queued, someone submitted the work to achieve a goal more specific than what background writeback does. Moreover by working on the specific work, we also reduce amount of dirty pages which is exactly the target of background writeout. So it makes sense to give specific work a priority over a generic page cleaning. Thus we interrupt background writeback if there is some other work to do. We return to the background writeback after completing all the queued work. This may delay the writeback of expired inodes for a while, however the expired inodes will eventually be flushed to disk as long as the other works won't livelock. [fengguang.wu@intel.com: update comment] Signed-off-by:
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Jan Kara authored
commit 6585027a upstream. Check whether background writeback is needed after finishing each work. When bdi flusher thread finishes doing some work check whether any kind of background writeback needs to be done (either because dirty_background_ratio is exceeded or because we need to start flushing old inodes). If so, just do background write back. This way, bdi_start_background_writeback() just needs to wake up the flusher thread. It will do background writeback as soon as there is no other work. This is a preparatory patch for the next patch which stops background writeback as soon as there is other work to do. Signed-off-by:
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Thomas Gleixner authored
commit f1a06390 upstream. move_native_irq() masks and unmasks the interrupt line unconditionally, but the interrupt line might be masked due to a threaded oneshot handler in progress. Unmasking the line in that case can lead to interrupt storms. Observed on PREEMPT_RT. Originally-from: Ingo Molnar <mingo@elte.hu> Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
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Hugh Dickins authored
commit fd4a4663 upstream. 2.6.37 added an unmap_and_move_huge_page() for memory failure recovery, but its anon_vma handling was still based around the 2.6.35 conventions. Update it to use page_lock_anon_vma, get_anon_vma, page_unlock_anon_vma, drop_anon_vma in the same way as we're now changing unmap_and_move(). I don't particularly like to propose this for stable when I've not seen its problems in practice nor tested the solution: but it's clearly out of synch at present. Signed-off-by:
Hugh Dickins <hughd@google.com> Cc: Mel Gorman <mel@csn.ul.ie> Cc: Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by:
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Hugh Dickins authored
commit 1ce82b69 upstream. Increased usage of page migration in mmotm reveals that the anon_vma locking in unmap_and_move() has been deficient since 2.6.36 (or even earlier). Review at the time of f1819427 ("mm: fix hang on anon_vma->root->lock") missed the issue here: the anon_vma to which we get a reference may already have been freed back to its slab (it is in use when we check page_mapped, but that can change), and so its anon_vma->root may be switched at any moment by reuse in anon_vma_prepare. Perhaps we could fix that with a get_anon_vma_unless_zero(), but let's not: just rely on page_lock_anon_vma() to do all the hard thinking for us, then we don't need any rcu read locking over here. In removing the rcu_unlock label: since PageAnon is a bit in page->mapping, it's impossible for a !page->mapping page to be anon; but insert VM_BUG_ON in case the implementation ever changes. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by:
Mel Gorman <mel@csn.ul.ie> Reviewed-by:
Rik van Riel <riel@redhat.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Cc: "Jun'ichi Nomura" <j-nomura@ce.jp.nec.com> Cc: Andi Kleen <ak@linux.intel.com> Signed-off-by:
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Mel Gorman authored
mm: migration: use rcu_dereference_protected when dereferencing the radix tree slot during file page migration commit 29c1f677 upstream. migrate_pages() -> unmap_and_move() only calls rcu_read_lock() for anonymous pages, as introduced by git commit 989f89c5 ("fix rcu_read_lock() in page migraton"). The point of the RCU protection there is part of getting a stable reference to anon_vma and is only held for anon pages as file pages are locked which is sufficient protection against freeing. However, while a file page's mapping is being migrated, the radix tree is double checked to ensure it is the expected page. This uses radix_tree_deref_slot() -> rcu_dereference() without the RCU lock held triggering the following warning. [ 173.674290] =================================================== [ 173.676016] [ INFO: suspicious rcu_dereference_check() usage. ] [ 173.676016] --------------------------------------------------- [ 173.676016] include/linux/radix-tree.h:145 invoked rcu_dereference_check() without protection! [ 173.676016] [ 173.676016] other info that might help us debug this: [ 173.676016] [ 173.676016] [ 173.676016] rcu_scheduler_active = 1, debug_locks = 0 [ 173.676016] 1 lock held by hugeadm/2899: [ 173.676016] #0: (&(&inode->i_data.tree_lock)->rlock){..-.-.}, at: [<c10e3d2b>] migrate_page_move_mapping+0x40/0x1ab [ 173.676016] [ 173.676016] stack backtrace: [ 173.676016] Pid: 2899, comm: hugeadm Not tainted 2.6.37-rc5-autobuild [ 173.676016] Call Trace: [ 173.676016] [<c128cc01>] ? printk+0x14/0x1b [ 173.676016] [<c1063502>] lockdep_rcu_dereference+0x7d/0x86 [ 173.676016] [<c10e3db5>] migrate_page_move_mapping+0xca/0x1ab [ 173.676016] [<c10e41ad>] migrate_page+0x23/0x39 [ 173.676016] [<c10e491b>] buffer_migrate_page+0x22/0x107 [ 173.676016] [<c10e48f9>] ? buffer_migrate_page+0x0/0x107 [ 173.676016] [<c10e425d>] move_to_new_page+0x9a/0x1ae [ 173.676016] [<c10e47e6>] migrate_pages+0x1e7/0x2fa This patch introduces radix_tree_deref_slot_protected() which calls rcu_dereference_protected(). Users of it must pass in the mapping->tree_lock that is protecting this dereference. Holding the tree lock protects against parallel updaters of the radix tree meaning that rcu_dereference_protected is allowable. [akpm@linux-foundation.org: remove unneeded casts] Signed-off-by:
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