Hugh Dickins [Fri, 14 Jun 2013 20:54:30 +0000 (15:54 -0500)]
tmpfs: add support for read_iter and write_iter
Convert tmpfs do_shmem_file_read() to shmem_file_read_iter().
Make file_read_iter_actor() global so tmpfs can use it too: delete
file_read_actor(), which was made global in 2.4.4 for use by tmpfs.
Replace tmpfs generic_file_aio_write() by generic_file_write_iter().
Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com>
Dave Kleikamp [Fri, 14 Jun 2013 20:54:26 +0000 (15:54 -0500)]
xfs: add support for read_iter and write_iter
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Acked-by: Dave Chinner <dchinner@redhat.com> Cc: Ben Myers <bpm@sgi.com> Cc: Alex Elder <elder@kernel.org> Cc: xfs@oss.sgi.com
Dave Kleikamp [Fri, 14 Jun 2013 20:54:25 +0000 (15:54 -0500)]
btrfs: add support for read_iter and write_iter
btrfs can use generic_file_read_iter(). Base btrfs_file_write_iter()
on btrfs_file_aio_write(), then have the latter call the former.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Zach Brown <zab@zabbo.net> Cc: Chris Mason <chris.mason@fusionio.com> Cc: linux-btrfs@vger.kernel.org
Dave Kleikamp [Fri, 14 Jun 2013 20:54:24 +0000 (15:54 -0500)]
nfs: simplify swap
swap_writepage can now call nfs's write_iter f_op, eliminating the need to
implement for the special-case direct_IO a_op. There is no longer a need to
pass the uio flag through the direct write path.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Acked-by: Rik van Riel <riel@redhat.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: linux-nfs@vger.kernel.org
Dave Kleikamp [Fri, 14 Jun 2013 20:54:23 +0000 (15:54 -0500)]
nfs: add support for read_iter, write_iter
This patch implements the read_iter and write_iter file operations which
allow kernel code to initiate directIO. This allows the loop device to
read and write directly to the server, bypassing the page cache.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Zach Brown <zab@zabbo.net> Cc: Trond Myklebust <Trond.Myklebust@netapp.com> Cc: linux-nfs@vger.kernel.org
Dave Kleikamp [Fri, 14 Jun 2013 20:54:22 +0000 (15:54 -0500)]
ext4: add support for read_iter and write_iter
use the generic_file_read_iter(), create ext4_file_write_iter() based on
ext4_file_write(), and make ext4_file_write() a wrapper around
ext4_file_write_iter().
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Cc: Zach Brown <zab@zabbo.net> Cc: "Theodore Ts'o" <tytso@mit.edu> Cc: Andreas Dilger <adilger.kernel@dilger.ca> Cc: linux-ext4@vger.kernel.org
Dave Kleikamp [Fri, 14 Jun 2013 20:54:22 +0000 (15:54 -0500)]
ocfs2: add support for read_iter and write_iter
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Acked-by: Joel Becker <jlbec@evilplan.org> Cc: Zach Brown <zab@zabbo.net> Cc: Mark Fasheh <mfasheh@suse.com> Cc: ocfs2-devel@oss.oracle.com
Dave Kleikamp [Fri, 14 Jun 2013 20:54:21 +0000 (15:54 -0500)]
fs: add read_iter and write_iter to several file systems
These are the simple ones.
File systems that use generic_file_aio_read() and generic_file_aio_write()
can trivially support generic_file_read_iter() and generic_file_write_iter().
This patch adds those file_operations for 9p, adfs, affs, bfs, exofs, ext2,
ext3, fat, f2fs, hfs, hfsplus, hostfs, hpfs, jfs, jffs2, logfs, minix, nilfs2,
omfs, ramfs, reiserfs, romfs, sysv, and ufs.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Acked-by: Boaz Harrosh <bharrosh@panasas.com> Cc: Zach Brown <zab@zabbo.net>
Dave Kleikamp [Fri, 14 Jun 2013 20:54:21 +0000 (15:54 -0500)]
fs: use read_iter and write_iter rather than aio_read and aio_write
File systems implementing read_iter & write_iter should not be required
to keep aio_read and aio_write as well. The vfs should always call
read/write_iter if they exist. This will make it easier to remove the
aio_read/write operation in the future.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Zach Brown <zab@zabbo.net> Cc: Alexander Viro <viro@zeniv.linux.org.uk> Cc: linux-fsdevel@vger.kernel.org
Dave Kleikamp [Fri, 14 Jun 2013 20:54:20 +0000 (15:54 -0500)]
fs: create file_readable() and file_writable() functions
Create functions to simplify if file_ops contain either a read
or aio_read op, or likewise write or aio_write. We will be adding
read_iter and write_iter and don't need to be complicating the code
in multiple places.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Zach Brown [Fri, 14 Jun 2013 20:54:19 +0000 (15:54 -0500)]
loop: use aio to perform io on the underlying file
This uses the new kernel aio interface to process loopback IO by
submitting concurrent direct aio. Previously loop's IO was serialized
by synchronous processing in a thread.
The aio operations specify the memory for the IO with the bio_vec arrays
directly instead of mappings of the pages.
The use of aio operations is enabled when the backing file supports the
read_iter, write_iter and direct_IO methods.
Signed-off-by: Zach Brown <zab@zabbo.net> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Dave Kleikamp [Fri, 14 Jun 2013 20:54:18 +0000 (15:54 -0500)]
aio: add aio support for iov_iter arguments
This adds iocb cmds which specify that memory is held in iov_iter
structures. This lets kernel callers specify memory that can be
expressed in an iov_iter, which includes pages in bio_vec arrays.
Only kernel callers can provide an iov_iter so it doesn't make a lot of
sense to expose the IOCB_CMD values for this as part of the user space
ABI.
But kernel callers should also be able to perform the usual aio
operations which suggests using the the existing operation namespace and
support code.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Zach Brown <zab@zabbo.net>
Dave Kleikamp [Fri, 14 Jun 2013 20:54:17 +0000 (15:54 -0500)]
aio: add aio_kernel_() interface
This adds an interface that lets kernel callers submit aio iocbs without
going through the user space syscalls. This lets kernel callers avoid
the management limits and overhead of the context. It will also let us
integrate aio operations with other kernel apis that the user space
interface doesn't have access to.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Cc: Zach Brown <zab@zabbo.net>
Zach Brown [Fri, 14 Jun 2013 20:54:17 +0000 (15:54 -0500)]
fs: pull iov_iter use higher up the stack
Right now only callers of generic_perform_write() pack their iovec
arguments into an iov_iter structure. All the callers higher up in the
stack work on raw iovec arguments.
This patch introduces the use of the iov_iter abstraction higher up the
stack. Private generic path functions are changed to operation on
iov_iter instead of on raw iovecs. Exported interfaces that take iovecs
immediately pack their arguments into an iov_iter and call into the
shared functions.
File operation struct functions are added with iov_iter as an argument
so that callers to the generic file system functions can specify
abstract memory rather than iovec arrays only.
Almost all of this patch only transforms arguments and shouldn't change
functionality. The buffered read path is the exception. We add a
read_actor function which uses the iov_iter helper functions instead of
operating on each individual iovec element. This may improve
performance as the iov_iter helper can copy multiple iovec elements from
one mapped page cache page.
As always, the direct IO path is special. Sadly, it may still be
cleanest to have it work on the underlying memory structures directly
instead of working through the iov_iter abstraction.
Signed-off-by: Zach Brown <zab@zabbo.net> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Dave Kleikamp [Fri, 14 Jun 2013 20:54:16 +0000 (15:54 -0500)]
dio: add bio_vec support to __blockdev_direct_IO()
The trick here is to initialize the dio state so that do_direct_IO()
consumes the pages we provide and never tries to map user pages. This
is done by making sure that final_block_in_request covers the page that
we set in the dio. do_direct_IO() will return before running out of
pages.
The caller is responsible for dirtying these pages, if needed. We add
an option to the dio struct that makes sure we only dirty pages when
we're operating on iovecs of user addresses.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com> Cc: Zach Brown <zab@zabbo.net>
Dave Kleikamp [Fri, 14 Jun 2013 20:54:15 +0000 (15:54 -0500)]
dio: Convert direct_IO to use iov_iter
Change the direct_IO aop to take an iov_iter argument rather than an iovec.
This will get passed down through most filesystems so that only the
__blockdev_direct_IO helper need be aware of whether user or kernel memory
is being passed to the function.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Zach Brown [Fri, 14 Jun 2013 20:54:14 +0000 (15:54 -0500)]
iov_iter: let callers extract iovecs and bio_vecs
direct IO treats memory from user iovecs and memory from arrays of
kernel pages very differently. User memory is pinned and worked with in
batches while kernel pages are always pinned and don't require
additional processing.
Rather than try and provide an abstraction that includes these
different behaviours we let direct IO extract the memory structs and
hand them to the existing code.
Signed-off-by: Zach Brown <zab@zabbo.net> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Zach Brown [Fri, 14 Jun 2013 20:54:14 +0000 (15:54 -0500)]
iov_iter: add a shorten call
The generic direct write path wants to shorten its memory vector. It
does this when it finds that it has to perform a partial write due to
LIMIT_FSIZE. .direct_IO() always performs IO on all of the referenced
memory because it doesn't have an argument to specify the length of the
IO.
We add an iov_iter operation for this so that the generic path can ask
to shorten the memory vector without having to know what kind it is.
We're happy to shorten the kernel copy of the iovec array, but we refuse
to shorten the bio_vec array and return an error in this case.
Signed-off-by: Zach Brown <zab@zabbo.net> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Zach Brown [Fri, 14 Jun 2013 20:54:13 +0000 (15:54 -0500)]
iov_iter: add bvec support
This adds a set of iov_iter_ops calls which work with memory which is
specified by an array of bio_vec structs instead of an array of iovec
structs.
The big difference is that the pages referenced by the bio_vec elements
are pinned. They don't need to be faulted in and we can always use
kmap_atomic() to map them one at a time.
Signed-off-by: Zach Brown <zab@zabbo.net> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Zach Brown [Fri, 14 Jun 2013 20:54:12 +0000 (15:54 -0500)]
iov_iter: hide iovec details behind ops function pointers
This moves the current iov_iter functions behind an ops struct of
function pointers. The current iov_iter functions all work with memory
which is specified by iovec arrays of user space pointers.
This patch is part of a series that lets us specify memory with bio_vec
arrays of page pointers. By moving to an iov_iter operation struct we
can add that support in later patches in this series by adding another
set of function pointers.
I only came to this after having initialy tried to teach the current
iov_iter functions about bio_vecs by introducing conditional branches
that dealt with bio_vecs in all the functions. It wasn't pretty. This
approach seems to be the lesser evil.
Signed-off-by: Zach Brown <zab@zabbo.net> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Dave Kleikamp [Fri, 14 Jun 2013 20:54:11 +0000 (15:54 -0500)]
iov_iter: add __iovec_copy_to_user()
This patch adds __iovec_copy_to_user() which doesn't verify write access
to the user memory to be called from code where that verification has
already been done.
Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Zach Brown [Fri, 14 Jun 2013 20:54:09 +0000 (15:54 -0500)]
iov_iter: move into its own file
This moves the iov_iter functions in to their own file. We're going to
be working on them in upcoming patches. They become sufficiently large,
and remain self-contained, to justify seperating them from the rest of
the huge mm/filemap.c.
Signed-off-by: Zach Brown <zab@zabbo.net> Signed-off-by: Dave Kleikamp <dave.kleikamp@oracle.com> Acked-by: Jeff Moyer <jmoyer@redhat.com> Tested-by: Sedat Dilek <sedat.dilek@gmail.com>
Merge branch 'timers/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer code update from Thomas Gleixner:
- armada SoC clocksource overhaul with a trivial merge conflict
- Minor improvements to various SoC clocksource drivers
* 'timers/core' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clocksource: armada-370-xp: Add detailed clock requirements in devicetree binding
clocksource: armada-370-xp: Get reference fixed-clock by name
clocksource: armada-370-xp: Replace WARN_ON with BUG_ON
clocksource: armada-370-xp: Fix device-tree binding
clocksource: armada-370-xp: Introduce new compatibles
clocksource: armada-370-xp: Use CLOCKSOURCE_OF_DECLARE
clocksource: armada-370-xp: Simplify TIMER_CTRL register access
clocksource: armada-370-xp: Use BIT()
ARM: timer-sp: Set dynamic irq affinity
ARM: nomadik: add dynamic irq flag to the timer
clocksource: sh_cmt: 32-bit control register support
clocksource: em_sti: Convert to devm_* managed helpers
Merge branch 'for-next' of git://git.samba.org/sfrench/cifs-2.6
Pull CIFS fixes from Steve French:
"Two minor cifs fixes and a minor documentation cleanup for cifs.txt"
* 'for-next' of git://git.samba.org/sfrench/cifs-2.6:
cifs: update cifs.txt and remove some outdated infos
cifs: Avoid calling unlock_page() twice in cifs_readpage() when using fscache
cifs: Do not take a reference to the page in cifs_readpage_worker()
Merge branch 'for_linus' of git://cavan.codon.org.uk/platform-drivers-x86
Pull x86 platform updates from Matthew Garrett:
"Nothing amazing here, almost entirely cleanups and minor bugfixes and
one bit of hardware enablement in the amilo-rfkill driver"
* 'for_linus' of git://cavan.codon.org.uk/platform-drivers-x86:
platform/x86: panasonic-laptop: reuse module_acpi_driver
samsung-laptop: fix config build error
platform: x86: remove unnecessary platform_set_drvdata()
amilo-rfkill: Enable using amilo-rfkill with the FSC Amilo L1310.
wmi: parse_wdg() should return kernel error codes
hp_wmi: Fix unregister order in hp_wmi_rfkill_setup()
platform: replace strict_strto*() with kstrto*()
x86: irst: use module_acpi_driver to simplify the code
x86: smartconnect: use module_acpi_driver to simplify the code
platform samsung-q10: use ACPI instead of direct EC calls
thinkpad_acpi: add the ability setting TPACPI_LED_NONE by quirk
thinkpad_acpi: return -NODEV while operating uninitialized LEDs
Merge tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull misc SCSI driver updates from James Bottomley:
"This patch set is a set of driver updates (megaraid_sas, fnic, lpfc,
ufs, hpsa) we also have a couple of bug fixes (sd out of bounds and
ibmvfc error handling) and the first round of esas2r checker fixes and
finally the much anticipated big endian additions for megaraid_sas"
* tag 'scsi-misc' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi: (47 commits)
[SCSI] fnic: fnic Driver Tuneables Exposed through CLI
[SCSI] fnic: Kernel panic while running sh/nosh with max lun cfg
[SCSI] fnic: Hitting BUG_ON(io_req->abts_done) in fnic_rport_exch_reset
[SCSI] fnic: Remove QUEUE_FULL handling code
[SCSI] fnic: On system with >1.1TB RAM, VIC fails multipath after boot up
[SCSI] fnic: FC stat param seconds_since_last_reset not getting updated
[SCSI] sd: Fix potential out-of-bounds access
[SCSI] lpfc 8.3.42: Update lpfc version to driver version 8.3.42
[SCSI] lpfc 8.3.42: Fixed issue of task management commands having a fixed timeout
[SCSI] lpfc 8.3.42: Fixed inconsistent spin lock usage.
[SCSI] lpfc 8.3.42: Fix driver's abort loop functionality to skip IOs already getting aborted
[SCSI] lpfc 8.3.42: Fixed failure to allocate SCSI buffer on PPC64 platform for SLI4 devices
[SCSI] lpfc 8.3.42: Fix WARN_ON when driver unloads
[SCSI] lpfc 8.3.42: Avoided making pci bar ioremap call during dual-chute WQ/RQ pci bar selection
[SCSI] lpfc 8.3.42: Fixed driver iocbq structure's iocb_flag field running out of space
[SCSI] lpfc 8.3.42: Fix crash on driver load due to cpu affinity logic
[SCSI] lpfc 8.3.42: Fixed logging format of setting driver sysfs attributes hard to interpret
[SCSI] lpfc 8.3.42: Fixed back to back RSCNs discovery failure.
[SCSI] lpfc 8.3.42: Fixed race condition between BSG I/O dispatch and timeout handling
[SCSI] lpfc 8.3.42: Fixed function mode field defined too small for not recognizing dual-chute mode
...
Merge branch 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux
Pull SLAB update from Pekka Enberg:
"Nothing terribly exciting here apart from Christoph's kmalloc
unification patches that brings sl[aou]b implementations closer to
each other"
* 'slab/next' of git://git.kernel.org/pub/scm/linux/kernel/git/penberg/linux:
slab: Use correct GFP_DMA constant
slub: remove verify_mem_not_deleted()
mm/sl[aou]b: Move kmallocXXX functions to common code
mm, slab_common: add 'unlikely' to size check of kmalloc_slab()
mm/slub.c: beautify code for removing redundancy 'break' statement.
slub: Remove unnecessary page NULL check
slub: don't use cpu partial pages on UP
mm/slub: beautify code for 80 column limitation and tab alignment
mm/slub: remove 'per_cpu' which is useless variable
Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input update from Dmitry Torokhov:
"The only change is David Hermann's new EVIOCREVOKE evdev ioctl that
allows safely passing file descriptors to input devices to session
processes and later being able to stop delivery of events through
these fds so that inactive sessions will no longer receive user input
that does not belong to them"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: evdev - add EVIOCREVOKE ioctl
Matt found that commit 27a7c642174e ("partitions/efi: account for pmbr
size in lba") caused his GPT formatted eMMC device not to boot. The
reason is that this commit enforced Linux to always check the lesser of
the whole disk or 2Tib for the pMBR size in LBA. While most disk
partitioning tools out there create a pMBR with these characteristics,
Microsoft does not, as it always sets the entry to the maximum 32-bit
limitation - even though a drive may be smaller than that[1].
Loosen this check and only verify that the size is either the whole disk
or 0xFFFFFFFF. No tool in its right mind would set it to any value
other than these.
Merge tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux
Pull writeback fix from Wu Fengguang:
"A trivial writeback fix"
* tag 'writeback-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/wfg/linux:
writeback: Do not sort b_io list only because of block device inode
vfs: fix dentry LRU list handling and nr_dentry_unused accounting
The LRU list changes interacted badly with our nr_dentry_unused
accounting, and even worse with the new DCACHE_LRU_LIST bit logic.
This introduces helper functions to make sure everything follows the
proper dcache d_lru list rules: the dentry cache is complicated by the
fact that some of the hotpaths don't even want to look at the LRU list
at all, and the fact that we use the same list entry in the dentry for
both the LRU list and for our temporary shrinking lists when removing
things from the LRU.
The helper functions temporarily have some extra sanity checking for the
flag bits that have to match the current LRU state of the dentry. We'll
remove that before the final 3.12 release, but considering how easy it
is to get wrong, this first cleanup version has some very particular
sanity checking.
Acked-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
cifs: Avoid calling unlock_page() twice in cifs_readpage() when using fscache
When reading a single page with cifs_readpage(), we make a call to
fscache_read_or_alloc_page() which once done, asynchronously calls
the completion function cifs_readpage_from_fscache_complete(). This
completion function unlocks the page once it has been populated from
cache. The module then attempts to unlock the page a second time in
cifs_readpage() which leads to warning messages.
In case of a successful call to fscache_read_or_alloc_page() we should skip
the second unlock_page() since this will be called by the
cifs_readpage_from_fscache_complete() once the page has been populated by
fscache.
With the modifications to cifs_readpage_worker(), we will need to re-grab the
page lock in cifs_write_begin().
The problem was first noticed when testing new fscache patches for cifs.
https://bugzilla.redhat.com/show_bug.cgi?id=1005737
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
cifs: Do not take a reference to the page in cifs_readpage_worker()
We do not need to take a reference to the pagecache in
cifs_readpage_worker() since the calling function will have already
taken one before passing the pointer to the page as an argument to the
function.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com> Reviewed-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Steve French <smfrench@gmail.com>
Merge tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging
Pull hwmon fixes from Guenter Roeck:
"Some more low risk cleanup patches:
- Remove unnecessary pci_set_drvdata in k10temp driver from Jingoo Han
- Fix return values in several drivers from Sachin Kamat
- Remove redundant break in amc6821 driver from Sachin Kamat"
* tag 'hwmon-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/groeck/linux-staging:
hwmon: (k10temp) remove unnecessary pci_set_drvdata()
hwmon: (tmp421) Fix return value
hwmon: (amc6821) Remove redundant break
hwmon: (amc6821) Fix return value
hwmon: (ibmaem) Fix return value
hwmon: (emc2103) Fix return value
Pull aio changes from Ben LaHaise:
"First off, sorry for this pull request being late in the merge window.
Al had raised a couple of concerns about 2 items in the series below.
I addressed the first issue (the race introduced by Gu's use of
mm_populate()), but he has not provided any further details on how he
wants to rework the anon_inode.c changes (which were sent out months
ago but have yet to be commented on).
The bulk of the changes have been sitting in the -next tree for a few
months, with all the issues raised being addressed"
* git://git.kvack.org/~bcrl/aio-next: (22 commits)
aio: rcu_read_lock protection for new rcu_dereference calls
aio: fix race in ring buffer page lookup introduced by page migration support
aio: fix rcu sparse warnings introduced by ioctx table lookup patch
aio: remove unnecessary debugging from aio_free_ring()
aio: table lookup: verify ctx pointer
staging/lustre: kiocb->ki_left is removed
aio: fix error handling and rcu usage in "convert the ioctx list to table lookup v3"
aio: be defensive to ensure request batching is non-zero instead of BUG_ON()
aio: convert the ioctx list to table lookup v3
aio: double aio_max_nr in calculations
aio: Kill ki_dtor
aio: Kill ki_users
aio: Kill unneeded kiocb members
aio: Kill aio_rw_vect_retry()
aio: Don't use ctx->tail unnecessarily
aio: io_cancel() no longer returns the io_event
aio: percpu ioctx refcount
aio: percpu reqs_available
aio: reqs_active -> reqs_available
aio: fix build when migration is disabled
...
Merge branch 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild
Pull kconfig fix from Michal Marek:
"This is a fix for a regression caused by my previous pull request.
A sed command in scripts/config that used colons as separator was
accidentally changed to use slashes, which fails when you use slashes
in a value. Changing it back to colons is of course not a proper fix,
but at least it will be broken in the same way it had been for four
years. A proper fix is pending"
* 'kconfig' of git://git.kernel.org/pub/scm/linux/kernel/git/mmarek/kbuild:
scripts/config: fix variable substitution command
Merge tag 'blackfin-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/realmz6/blackfin-linux
Pull blackfin updates from Steven Miao.
* tag 'blackfin-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/realmz6/blackfin-linux:
blackfin: Ignore generated uImages
blackfin: Add STMMAC platform data to enable dwmac1000 driver on BF60x.
bf609: adv7343: add S-Video and Component output support
bf609: add adv7343 video encoder support
clock: add stmmac clock for ethernet driver
blackfin: scb: Add SCB1 to SCB9 config options and data.
blackfin: scb: Add system crossbar init code.
Pull crypto fixes from Herbert Xu:
"This fixes a 7+ year race condition in the crypto API that causes
sporadic crashes when multiple threads load the same algorithm.
It also fixes the crct10dif algorithm again to prevent boot failures
on systems where the initramfs tool ignores module softdeps"
* git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
crypto: crct10dif - Add fallback for broken initrds
crypto: api - Fix race condition in larval lookup
broke the build on MIPS since vpe_attrs should be an array
of 'struct device_attribute' pointers.
Fixes the following build problem:
arch/mips/kernel/vpe.c:1372:2: error: missing braces around initializer
[-Werror=missing-braces]
arch/mips/kernel/vpe.c:1372:2: error: (near initialization for 'vpe_attrs[0]')
[-Werror=missing-braces]
After the last architecture switched to generic hard irqs the config
options HAVE_GENERIC_HARDIRQS & GENERIC_HARDIRQS and the related code
for !CONFIG_GENERIC_HARDIRQS can be removed.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Leonid Yegoshin [Wed, 11 Sep 2013 19:17:47 +0000 (14:17 -0500)]
MIPS: Fix SMP core calculations when using MT support.
The TCBIND register is only available if the core has MT support. It
should not be read otherwise. Secondly, the number of TCs (siblings)
are calculated differently depending on if the kernel is configured
as SMVP or SMTC.
Signed-off-by: Leonid Yegoshin <Leonid.Yegoshin@imgtec.com> Signed-off-by: Steven J. Hill <Steven.Hill@imgtec.com> Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5822/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This change complements commit d0da7c002f7b2a93582187a9e3f73891a01d8ee4
and brings clear_ioasic_irq back, renaming it to clear_ioasic_dma_irq at
the same time, to make I/O ASIC DMA interrupts functional.
Unlike ordinary I/O ASIC interrupts DMA interrupts need to be deasserted
by software by writing 0 to the respective bit in I/O ASIC's System
Interrupt Register (SIR), similarly to how CP0.Cause.IP0 and CP0.Cause.IP1
bits are handled in the CPU (the difference is SIR DMA interrupt bits are
R/W0C so there's no need for an RMW cycle). Otherwise the handler is
reentered over and over again.
The only current user is the DEC LANCE Ethernet driver and its extremely
uncommon DMA memory error handler that does not care when exactly the
interrupt is cleared. Anticipating the use of DMA interrupts by the Zilog
SCC driver this change however exports clear_ioasic_dma_irq for device
drivers to choose the right application-specific sequence to clear the
request explicitly rather than calling it implicitly in the .irq_eoi
handler of `struct irq_chip'. Previously these interrupts were cleared in
the .end handler of the said structure, before it was removed.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5826/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Not all I/O ASIC versions have the free-running counter implemented, an
early revision used in the 5000/1xx models aka 3MIN and 4MIN did not have
it. Therefore we cannot unconditionally use it as a clock source.
Fortunately if not implemented its register slot has a fixed value so it
is enough if we check for the value at the end of the calibration period
being the same as at the beginning.
This also means we need to look for another high-precision clock source on
the systems affected. The 5000/1xx can have an R4000SC processor
installed where the CP0 Count register can be used as a clock source.
Unfortunately all the R4k DECstations suffer from the missed timer
interrupt on CP0 Count reads erratum, so we cannot use the CP0 timer as a
clock source and a clock event both at a time. However we never need an
R4k clock event device because all DECstations have a DS1287A RTC chip
whose periodic interrupt can be used as a clock source.
This gives us the following four configuration possibilities for I/O ASIC
DECstations:
1. No I/O ASIC counter and no CP0 timer, e.g. R3k 5000/1xx (3MIN).
2. No I/O ASIC counter but the CP0 timer, i.e. R4k 5000/150 (4MIN).
3. The I/O ASIC counter but no CP0 timer, e.g. R3k 5000/240 (3MAX+).
4. The I/O ASIC counter and the CP0 timer, e.g. R4k 5000/260 (4MAX+).
For #1 and #2 this change stops the I/O ASIC free-running counter from
being installed as a clock source of a 0Hz frequency. For #2 it also
arranges for the CP0 timer to be used as a clock source rather than a
clock event device, because having an accurate wall clock is more
important than a high-precision interval timer. For #3 there is no
change. For #4 the change makes the I/O ASIC free-running counter
installed as a clock source so that the CP0 timer can be used as a clock
event device.
Unfortunately the use of the CP0 timer as a clock event device relies on a
succesful completion of c0_compare_interrupt. That never happens, because
while waiting for a CP0 Compare interrupt to happen the function spins in
a loop reading the CP0 Count register. This makes the CP0 Count erratum
trigger reliably causing the interrupt waited for to be lost in all cases.
As a result #4 resorts to using the CP0 timer as a clock source as well,
just as #2. However we want to keep this separate arrangement in case
(hope) c0_compare_interrupt is eventually rewritten such that it avoids
the erratum.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org> Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/5825/ Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Merge branch 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus
Pull MIPS updates from Ralf Baechle:
"This has been sitting in -next for a while with no objections and all
MIPS defconfigs except one are building fine; that one platform got
broken by another patch in your tree and I'm going to submit a patch
separately.
- a handful of fixes that didn't make 3.11
- a few bits of Octeon 3 support with more to come for a later
release
- platform enhancements for Octeon, ath79, Lantiq, Netlogic and
Ralink SOCs
- a GPIO driver for the Octeon
- some dusting off of the DECstation code
- the usual dose of cleanups"
* 'upstream' of git://git.linux-mips.org/pub/scm/ralf/upstream-linus: (65 commits)
MIPS: DMA: Fix BUG due to smp_processor_id() in preemptible code
MIPS: kexec: Fix random crashes while loading crashkernel
MIPS: kdump: Skip walking indirection page for crashkernels
MIPS: DECstation HRT calibration bug fixes
MIPS: Export copy_from_user_page() (needed by lustre)
MIPS: Add driver for the built-in PCI controller of the RT3883 SoC
MIPS: DMA: For BMIPS5000 cores flush region just like non-coherent R10000
MIPS: ralink: Add support for reset-controller API
MIPS: ralink: mt7620: Add cpu-feature-override header
MIPS: ralink: mt7620: Add spi clock definition
MIPS: ralink: mt7620: Add wdt clock definition
MIPS: ralink: mt7620: Improve clock frequency detection
MIPS: ralink: mt7620: This SoC has EHCI and OHCI hosts
MIPS: ralink: mt7620: Add verbose ram info
MIPS: ralink: Probe clocksources from OF
MIPS: ralink: Add support for systick timer found on newer ralink SoC
MIPS: ralink: Add support for periodic timer irq
MIPS: Netlogic: Built-in DTB for XLP2xx SoC boards
MIPS: Netlogic: Add support for USB on XLP2xx
MIPS: Netlogic: XLP2xx update for I2C controller
...
Merge tag 'xfs-for-linus-v3.12-rc1-2' of git://oss.sgi.com/xfs/xfs
Pull xfs update #2 from Ben Myers:
"Here we have defrag support for v5 superblock, a number of bugfixes
and a cleanup or two.
- defrag support for CRC filesystems
- fix endian worning in xlog_recover_get_buf_lsn
- fixes for sparse warnings
- fix for assert in xfs_dir3_leaf_hdr_from_disk
- fix for log recovery of remote symlinks
- fix for log recovery of btree root splits
- fixes formemory allocation failures with ACLs
- fix for assert in xfs_buf_item_relse
- fix for assert in xfs_inode_buf_verify
- fix an assignment in an assert that should be a test in
xfs_bmbt_change_owner
- remove dead code in xlog_recover_inode_pass2"
* tag 'xfs-for-linus-v3.12-rc1-2' of git://oss.sgi.com/xfs/xfs:
xfs: remove dead code from xlog_recover_inode_pass2
xfs: = vs == typo in ASSERT()
xfs: don't assert fail on bad inode numbers
xfs: aborted buf items can be in the AIL.
xfs: factor all the kmalloc-or-vmalloc fallback allocations
xfs: fix memory allocation failures with ACLs
xfs: ensure we copy buffer type in da btree root splits
xfs: set remote symlink buffer type for recovery
xfs: recovery of swap extents operations for CRC filesystems
xfs: swap extents operations for CRC filesystems
xfs: check magic numbers in dir3 leaf verifier first
xfs: fix some minor sparse warnings
xfs: fix endian warning in xlog_recover_get_buf_lsn()
Merge branch 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending
Pull SCSI target updates from Nicholas Bellinger:
"Lots of activity again this round for I/O performance optimizations
(per-cpu IDA pre-allocation for vhost + iscsi/target), and the
addition of new fabric independent features to target-core
(COMPARE_AND_WRITE + EXTENDED_COPY).
The main highlights include:
- Support for iscsi-target login multiplexing across individual
network portals
- Generic Per-cpu IDA logic (kent + akpm + clameter)
- Conversion of vhost to use per-cpu IDA pre-allocation for
descriptors, SGLs and userspace page pointer list
- Conversion of iscsi-target + iser-target to use per-cpu IDA
pre-allocation for descriptors
- Add support for generic COMPARE_AND_WRITE (AtomicTestandSet)
emulation for virtual backend drivers
- Add support for generic EXTENDED_COPY (CopyOffload) emulation for
virtual backend drivers.
- Add support for fast memory registration mode to iser-target (Vu)
The patches to add COMPARE_AND_WRITE and EXTENDED_COPY support are of
particular significance, which make us the first and only open source
target to support the full set of VAAI primitives.
Currently Linux clients are lacking upstream support to actually
utilize these primitives. However, with server side support now in
place for folks like MKP + ZAB working on the client, this logic once
reserved for the highest end of storage arrays, can now be run in VMs
on their laptops"
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/nab/target-pending: (50 commits)
target/iscsi: Bump versions to v4.1.0
target: Update copyright ownership/year information to 2013
iscsi-target: Bump default TCP listen backlog to 256
target: Fix >= v3.9+ regression in PR APTPL + ALUA metadata write-out
iscsi-target; Bump default CmdSN Depth to 64
iscsi-target: Remove unnecessary wait_for_completion in iscsi_get_thread_set
iscsi-target: Add thread_set->ts_activate_sem + use common deallocate
iscsi-target: Fix race with thread_pre_handler flush_signals + ISCSI_THREAD_SET_DIE
target: remove unused including <linux/version.h>
iser-target: introduce fast memory registration mode (FRWR)
iser-target: generalize rdma memory registration and cleanup
iser-target: move rdma wr processing to a shared function
target: Enable global EXTENDED_COPY setup/release
target: Add Third Party Copy (3PC) bit in INQUIRY response
target: Enable EXTENDED_COPY setup in spc_parse_cdb
target: Add support for EXTENDED_COPY copy offload emulation
target: Avoid non-existent tg_pt_gp_mem in target_alua_state_check
target: Add global device list for EXTENDED_COPY
target: Make helpers non static for EXTENDED_COPY command setup
target: Make spc_parse_naa_6h_vendor_specific non static
...
Merge more patches from Andrew Morton:
"The rest of MM. Plus one misc cleanup"
* emailed patches from Andrew Morton <akpm@linux-foundation.org>: (35 commits)
mm/Kconfig: add MMU dependency for MIGRATION.
kernel: replace strict_strto*() with kstrto*()
mm, thp: count thp_fault_fallback anytime thp fault fails
thp: consolidate code between handle_mm_fault() and do_huge_pmd_anonymous_page()
thp: do_huge_pmd_anonymous_page() cleanup
thp: move maybe_pmd_mkwrite() out of mk_huge_pmd()
mm: cleanup add_to_page_cache_locked()
thp: account anon transparent huge pages into NR_ANON_PAGES
truncate: drop 'oldsize' truncate_pagecache() parameter
mm: make lru_add_drain_all() selective
memcg: document cgroup dirty/writeback memory statistics
memcg: add per cgroup writeback pages accounting
memcg: check for proper lock held in mem_cgroup_update_page_stat
memcg: remove MEMCG_NR_FILE_MAPPED
memcg: reduce function dereference
memcg: avoid overflow caused by PAGE_ALIGN
memcg: rename RESOURCE_MAX to RES_COUNTER_MAX
memcg: correct RESOURCE_MAX to ULLONG_MAX
mm: memcg: do not trap chargers with full callstack on OOM
mm: memcg: rework and document OOM waiting and wakeup
...
Chen Gang [Thu, 12 Sep 2013 22:14:08 +0000 (15:14 -0700)]
mm/Kconfig: add MMU dependency for MIGRATION.
MIGRATION must depend on MMU, or allmodconfig for the nommu sh
architecture fails to build:
CC mm/migrate.o
mm/migrate.c: In function 'remove_migration_pte':
mm/migrate.c:134:3: error: implicit declaration of function 'pmd_trans_huge' [-Werror=implicit-function-declaration]
if (pmd_trans_huge(*pmd))
^
mm/migrate.c:149:2: error: implicit declaration of function 'is_swap_pte' [-Werror=implicit-function-declaration]
if (!is_swap_pte(pte))
^
...
Also let CMA depend on MMU, or when NOMMU, if we select CMA, it will
select MIGRATION by force.
Signed-off-by: Chen Gang <gang.chen@asianux.com> Reviewed-by: Michal Hocko <mhocko@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
David Rientjes [Thu, 12 Sep 2013 22:14:06 +0000 (15:14 -0700)]
mm, thp: count thp_fault_fallback anytime thp fault fails
Currently, thp_fault_fallback in vmstat only gets incremented if a
hugepage allocation fails. If current's memcg hits its limit or the page
fault handler returns an error, it is incorrectly accounted as a
successful thp_fault_alloc.
Count thp_fault_fallback anytime the page fault handler falls back to
using regular pages and only count thp_fault_alloc when a hugepage has
actually been faulted.
Signed-off-by: David Rientjes <rientjes@google.com> Cc: Mel Gorman <mgorman@suse.de> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
- unindent most code of the function by inverting one condition;
- streamline code no-error path;
- move insert error path outside normal code path;
- call radix_tree_preload_end() earlier;
No functional changes.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Andi Kleen <ak@linux.intel.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hillf Danton <dhillf@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
thp: account anon transparent huge pages into NR_ANON_PAGES
We use NR_ANON_PAGES as base for reporting AnonPages to user. There's
not much sense in not accounting transparent huge pages there, but add
them on printing to user.
Let's account transparent huge pages in NR_ANON_PAGES in the first place.
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Dave Hansen <dave.hansen@linux.intel.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Hugh Dickins <hughd@google.com> Cc: Wu Fengguang <fengguang.wu@intel.com> Cc: Jan Kara <jack@suse.cz> Cc: Mel Gorman <mgorman@suse.de> Cc: Andi Kleen <ak@linux.intel.com> Cc: Matthew Wilcox <willy@linux.intel.com> Cc: Hillf Danton <dhillf@gmail.com> Cc: Ning Qu <quning@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Chris Metcalf [Thu, 12 Sep 2013 22:13:55 +0000 (15:13 -0700)]
mm: make lru_add_drain_all() selective
make lru_add_drain_all() only selectively interrupt the cpus that have
per-cpu free pages that can be drained.
This is important in nohz mode where calling mlockall(), for example,
otherwise will interrupt every core unnecessarily.
This is important on workloads where nohz cores are handling 10 Gb traffic
in userspace. Those CPUs do not enter the kernel and place pages into LRU
pagevecs and they really, really don't want to be interrupted, or they
drop packets on the floor.
Signed-off-by: Chris Metcalf <cmetcalf@tilera.com> Reviewed-by: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Add memcg routines to count writeback pages, later dirty pages will also
be accounted.
After Kame's commit 89c06bd52fb9 ("memcg: use new logic for page stat
accounting"), we can use 'struct page' flag to test page state instead
of per page_cgroup flag. But memcg has a feature to move a page from a
cgroup to another one and may have race between "move" and "page stat
accounting". So in order to avoid the race we have designed a new lock:
mem_cgroup_begin_update_page_stat()
modify page information -->(a)
mem_cgroup_update_page_stat() -->(b)
mem_cgroup_end_update_page_stat()
It requires both (a) and (b)(writeback pages accounting) to be pretected
in mem_cgroup_{begin/end}_update_page_stat(). It's full no-op for
!CONFIG_MEMCG, almost no-op if memcg is disabled (but compiled in), rcu
read lock in the most cases (no task is moving), and spin_lock_irqsave
on top in the slow path.
There're two writeback interfaces to modify: test_{clear/set}_page_writeback().
And the lock order is:
--> memcg->move_lock
--> mapping->tree_lock
memcg: check for proper lock held in mem_cgroup_update_page_stat
We should call mem_cgroup_begin_update_page_stat() before
mem_cgroup_update_page_stat() to get proper locks, however the latter
doesn't do any checking that we use proper locking, which would be hard.
Suggested by Michal Hock we could at least test for rcu_read_lock_held()
because RCU is held if !mem_cgroup_disabled().
While accounting memcg page stat, it's not worth to use
MEMCG_NR_FILE_MAPPED as an extra layer of indirection because of the
complexity and presumed performance overhead. We can use
MEM_CGROUP_STAT_FILE_MAPPED directly.
Since PAGE_ALIGN is aligning up(the next page boundary), so after
PAGE_ALIGN, the value might be overflow, such as write the MAX value to
*.limit_in_bytes.
Some user programs might depend on such behaviours(like libcg, we read
the value in snapshot, then use the value to reset cgroup later), and
that will cause confusion. So we need to fix it.
Signed-off-by: Sha Zhengju <handai.szj@taobao.com> Signed-off-by: Qiang Huang <h.huangqiang@huawei.com> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp> Cc: Jeff Liu <jeff.liu@oracle.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Current RESOURCE_MAX is ULONG_MAX, but the value we used to set resource
limit is unsigned long long, so we can set bigger value than that which is
strange. The XXX_MAX should be reasonable max value, bigger than that
should be overflow.
Notice that this change will affect user output of default *.limit_in_bytes:
before change:
Johannes Weiner [Thu, 12 Sep 2013 22:13:44 +0000 (15:13 -0700)]
mm: memcg: do not trap chargers with full callstack on OOM
The memcg OOM handling is incredibly fragile and can deadlock. When a
task fails to charge memory, it invokes the OOM killer and loops right
there in the charge code until it succeeds. Comparably, any other task
that enters the charge path at this point will go to a waitqueue right
then and there and sleep until the OOM situation is resolved. The problem
is that these tasks may hold filesystem locks and the mmap_sem; locks that
the selected OOM victim may need to exit.
For example, in one reported case, the task invoking the OOM killer was
about to charge a page cache page during a write(), which holds the
i_mutex. The OOM killer selected a task that was just entering truncate()
and trying to acquire the i_mutex:
The OOM handling task will retry the charge indefinitely while the OOM
killed task is not releasing any resources.
A similar scenario can happen when the kernel OOM killer for a memcg is
disabled and a userspace task is in charge of resolving OOM situations.
In this case, ALL tasks that enter the OOM path will be made to sleep on
the OOM waitqueue and wait for userspace to free resources or increase
the group's limit. But a userspace OOM handler is prone to deadlock
itself on the locks held by the waiting tasks. For example one of the
sleeping tasks may be stuck in a brk() call with the mmap_sem held for
writing but the userspace handler, in order to pick an optimal victim,
may need to read files from /proc/<pid>, which tries to acquire the same
mmap_sem for reading and deadlocks.
This patch changes the way tasks behave after detecting a memcg OOM and
makes sure nobody loops or sleeps with locks held:
1. When OOMing in a user fault, invoke the OOM killer and restart the
fault instead of looping on the charge attempt. This way, the OOM
victim can not get stuck on locks the looping task may hold.
2. When OOMing in a user fault but somebody else is handling it
(either the kernel OOM killer or a userspace handler), don't go to
sleep in the charge context. Instead, remember the OOMing memcg in
the task struct and then fully unwind the page fault stack with
-ENOMEM. pagefault_out_of_memory() will then call back into the
memcg code to check if the -ENOMEM came from the memcg, and then
either put the task to sleep on the memcg's OOM waitqueue or just
restart the fault. The OOM victim can no longer get stuck on any
lock a sleeping task may hold.
Debugged by Michal Hocko.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reported-by: azurIt <azurit@pobox.sk> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:43 +0000 (15:13 -0700)]
mm: memcg: rework and document OOM waiting and wakeup
The memcg OOM handler open-codes a sleeping lock for OOM serialization
(trylock, wait, repeat) because the required locking is so specific to
memcg hierarchies. However, it would be nice if this construct would be
clearly recognizable and not be as obfuscated as it is right now. Clean
up as follows:
1. Remove the return value of mem_cgroup_oom_unlock()
2. Rename mem_cgroup_oom_lock() to mem_cgroup_oom_trylock().
3. Pull the prepare_to_wait() out of the memcg_oom_lock scope. This
makes it more obvious that the task has to be on the waitqueue
before attempting to OOM-trylock the hierarchy, to not miss any
wakeups before going to sleep. It just didn't matter until now
because it was all lumped together into the global memcg_oom_lock
spinlock section.
4. Pull the mem_cgroup_oom_notify() out of the memcg_oom_lock scope.
It is proctected by the hierarchical OOM-lock.
5. The memcg_oom_lock spinlock is only required to propagate the OOM
lock in any given hierarchy atomically. Restrict its scope to
mem_cgroup_oom_(trylock|unlock).
6. Do not wake up the waitqueue unconditionally at the end of the
function. Only the lockholder has to wake up the next in line
after releasing the lock.
Note that the lockholder kicks off the OOM-killer, which in turn
leads to wakeups from the uncharges of the exiting task. But a
contender is not guaranteed to see them if it enters the OOM path
after the OOM kills but before the lockholder releases the lock.
Thus there has to be an explicit wakeup after releasing the lock.
7. Put the OOM task on the waitqueue before marking the hierarchy as
under OOM as that is the point where we start to receive wakeups.
No point in listening before being on the waitqueue.
8. Likewise, unmark the hierarchy before finishing the sleep, for
symmetry.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:40 +0000 (15:13 -0700)]
x86: finish user fault error path with fatal signal
The x86 fault handler bails in the middle of error handling when the
task has a fatal signal pending. For a subsequent patch this is a
problem in OOM situations because it relies on pagefault_out_of_memory()
being called even when the task has been killed, to perform proper
per-task OOM state unwinding.
Shortcutting the fault like this is a rather minor optimization that
saves a few instructions in rare cases. Just remove it for
user-triggered faults.
Use the opportunity to split the fault retry handling from actual fault
errors and add locking documentation that reads suprisingly similar to
ARM's.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:39 +0000 (15:13 -0700)]
arch: mm: pass userspace fault flag to generic fault handler
Unlike global OOM handling, memory cgroup code will invoke the OOM killer
in any OOM situation because it has no way of telling faults occuring in
kernel context - which could be handled more gracefully - from
user-triggered faults.
Pass a flag that identifies faults originating in user space from the
architecture-specific fault handlers to generic code so that memcg OOM
handling can be improved.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:38 +0000 (15:13 -0700)]
arch: mm: do not invoke OOM killer on kernel fault OOM
Kernel faults are expected to handle OOM conditions gracefully (gup,
uaccess etc.), so they should never invoke the OOM killer. Reserve this
for faults triggered in user context when it is the only option.
Most architectures already do this, fix up the remaining few.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Johannes Weiner [Thu, 12 Sep 2013 22:13:36 +0000 (15:13 -0700)]
arch: mm: remove obsolete init OOM protection
The memcg code can trap tasks in the context of the failing allocation
until an OOM situation is resolved. They can hold all kinds of locks
(fs, mm) at this point, which makes it prone to deadlocking.
This series converts memcg OOM handling into a two step process that is
started in the charge context, but any waiting is done after the fault
stack is fully unwound.
Patches 1-4 prepare architecture handlers to support the new memcg
requirements, but in doing so they also remove old cruft and unify
out-of-memory behavior across architectures.
Patch 5 disables the memcg OOM handling for syscalls, readahead, kernel
faults, because they can gracefully unwind the stack with -ENOMEM. OOM
handling is restricted to user triggered faults that have no other
option.
Patch 6 reworks memcg's hierarchical OOM locking to make it a little
more obvious wth is going on in there: reduce locked regions, rename
locking functions, reorder and document.
Patch 7 implements the two-part OOM handling such that tasks are never
trapped with the full charge stack in an OOM situation.
This patch:
Back before smart OOM killing, when faulting tasks were killed directly on
allocation failures, the arch-specific fault handlers needed special
protection for the init process.
Now that all fault handlers call into the generic OOM killer (see commit 609838cfed97: "mm: invoke oom-killer from remaining unconverted page
fault handlers"), which already provides init protection, the
arch-specific leftovers can be removed.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org> Reviewed-by: Michal Hocko <mhocko@suse.cz> Acked-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> Cc: David Rientjes <rientjes@google.com> Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: azurIt <azurit@pobox.sk> Acked-by: Vineet Gupta <vgupta@synopsys.com> [arch/arc bits] Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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