27 Aug, 2019
1 commit
-
Since no caller is using KM_NOSLEEP and no callee branches on KM_SLEEP,
we can remove KM_NOSLEEP and replace KM_SLEEP with 0.Signed-off-by: Tetsuo Handa
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
04 Jul, 2019
1 commit
-
Add a new xfs_bulk_ireq flag to constrain the iteration to a single AG.
If the passed-in startino value is zero then we start with the first
inode in the AG that the user passes in; otherwise, we iterate only
within the same AG as the passed-in inode.Signed-off-by: Darrick J. Wong
Reviewed-by: Allison Collins
Reviewed-by: Brian Foster
03 Jul, 2019
3 commits
-
Create a pwork destroy function that uses polling instead of
uninterruptible sleep to wait for work items to finish so that we can
touch the softlockup watchdog. IOWs, gross hack.Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster -
Create a parallel iwalk implementation and switch quotacheck to use it.
Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster -
Convert quotacheck to use the new iwalk iterator to dig through the
inodes.Signed-off-by: Darrick J. Wong
Reviewed-by: Dave Chinner
Reviewed-by: Brian Foster
29 Jun, 2019
1 commit
-
There are many, many xfs header files which are included but
unneeded (or included twice) in the xfs code, so remove them.nb: xfs_linux.h includes about 9 headers for everyone, so those
explicit includes get removed by this. I'm not sure what the
preference is, but if we wanted explicit includes everywhere,
a followup patch could remove those xfs_*.h includes from
xfs_linux.h and move them into the files that need them.
Or it could be left as-is.Signed-off-by: Eric Sandeen
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
23 Apr, 2019
1 commit
-
Widen the incore inode's i_delayed_blks counter to be a 64-bit integer.
This is necessary to fix an integer overflow problem that can be
reproduced easily now that we use the counter to track blocks that are
assigned to the inode in memory but not on disk. This includes actual
delalloc reservations as well as real extents in the COW fork that
are waiting to be remapped into the data fork.These 'delayed mapping' blocks can easily exceed 2^32 blocks if one
creates a very large sparse file of size approximately 2^33 bytes with
one byte written every 2^23 bytes, sets a very large COW extent size
hint of 2^23 blocks, reflinks the first file into a second file, and
then writes a single byte every 2^23 blocks in the original file.When this happens, we'll try to create approximately 1024 2^23 extent
reservations in the COW fork, which will overflow the counter and cause
problems.Note that on x64 we end up filling a 4-byte gap in the structure so this
doesn't increase the incore size.Signed-off-by: Darrick J. Wong
Reviewed-by: Allison Collins
Reviewed-by: Dave Chinner
Reviewed-by: Christoph Hellwig
27 Jul, 2018
1 commit
-
Replace the IRELE macro with a proper function so that we can do proper
typechecking and so that we can stop open-coding iput in scrub, which
means that we'll be able to ftrace inode lifetimes going through scrub
correctly.Signed-off-by: Darrick J. Wong
Reviewed-by: Carlos Maiolino
Reviewed-by: Brian Foster
07 Jun, 2018
1 commit
-
Remove the verbose license text from XFS files and replace them
with SPDX tags. This does not change the license of any of the code,
merely refers to the common, up-to-date license files in LICENSES/This change was mostly scripted. fs/xfs/Makefile and
fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected
and modified by the following command:for f in `git grep -l "GNU General" fs/xfs/` ; do
echo $f
cat $f | awk -f hdr.awk > $f.new
mv -f $f.new $f
doneAnd the hdr.awk script that did the modification (including
detecting the difference between GPL-2.0 and GPL-2.0+ licenses)
is as follows:$ cat hdr.awk
BEGIN {
hdr = 1.0
tag = "GPL-2.0"
str = ""
}/^ \* This program is free software/ {
hdr = 2.0;
next
}/any later version./ {
tag = "GPL-2.0+"
next
}/^ \*\// {
if (hdr > 0.0) {
print "// SPDX-License-Identifier: " tag
print str
print $0
str=""
hdr = 0.0
next
}
print $0
next
}/^ \* / {
if (hdr > 1.0)
next
if (hdr > 0.0) {
if (str != "")
str = str "\n"
str = str $0
next
}
print $0
next
}/^ \*/ {
if (hdr > 0.0)
next
print $0
next
}// {
if (hdr > 0.0) {
if (str != "")
str = str "\n"
str = str $0
next
}
print $0
}END { }
$Signed-off-by: Dave Chinner
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
16 May, 2018
1 commit
-
Replace all the if (!error) weirdness with helper functions that follow
our regular coding practices, and factor out the ternary expression soup.Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster
Reviewed-by: Dave Chinner
10 May, 2018
12 commits
-
The function 'xfs_qm_dqiterate' doesn't iterate dquots at all, it
iterates all dquot blocks of a quota inode and clears the counters.
Therefore, change the name to something more descriptive so that we can
introduce a real dquot iterator later.Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster
Reviewed-by: Christoph Hellwig -
DQALLOC is only ever used with xfs_qm_dqget*, and the only flag that the
_dqget family of functions cares about is DQALLOC. Therefore, change
it to a boolean 'can alloc?' flag for the dqget interfaces where that
makes sense.Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster -
The quota initialization code needs an "uncached" variant of _dqget to
read in default quota limits and timers before the dquot cache is fully
set up. We've already split up _dqget into its component pieces so
create a fourth variant to address this need, and make dqread internal
to xfs_dquot.c again.Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster
Reviewed-by: Christoph Hellwig -
Quotacheck only runs during mount, which means that there are no other
processes in the system that could be doing chown or chproj. Therefore
there's no potential for racing to attach dquots to the inode so we can
drop all the ILOCK and race detection bits from quotacheck.Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster
Reviewed-by: Christoph Hellwig -
There are two uses of dqget here -- one is to return the dquot for a
given type and id, and the other is to return the dquot for a given type
and inode. Those are two separate things, so split them into two
smaller functions.Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster
Reviewed-by: Christoph Hellwig -
The flags argument is always zero, get rid of it.
Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster
Reviewed-by: Christoph Hellwig -
When dquot flush or purge fail there's no need to spam the logs, we've
already logged the IO error or fs shutdown that caused the flush
failures.Signed-off-by: Darrick J. Wong
Reviewed-by: Brian Foster -
The log item flags contain a field that is protected by the AIL
lock - the XFS_LI_IN_AIL flag. We use non-atomic RMW operations to
set and clear these flags, but most of the updates and checks are
not done with the AIL lock held and so are susceptible to update
races.Fix this by changing the log item flags to use atomic bitops rather
than be reliant on the AIL lock for update serialisation.Signed-Off-By: Dave Chinner
Reviewed-by: Christoph Hellwig
Reviewed-by: Brian Foster
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong -
Add an xfs_dqblk verifier so that it can check the uuid on V5 filesystems;
it calls the existing xfs_dquot_verify verifier to validate the
xfs_disk_dquot_t contained inside it. This lets us move the uuid
verification out of the crc verifier, which makes little sense.Signed-off-by: Eric Sandeen
Reviewed-by: Christoph Hellwig
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong -
It's a bit dicey to pass in the smaller xfs_disk_dquot and then cast it to
something larger; pass in the full xfs_dqblk so we know the caller has sent
us the right thing. Rename the function to xfs_dqblk_repair for
clarity.Signed-off-by: Eric Sandeen
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong -
Long ago the flags argument was used to determine whether to issue warnings
about corruptions, but that's done elsewhere now and the flag is unused
here, so remove it.Signed-off-by: Eric Sandeen
Reviewed-by: Christoph Hellwig
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong -
Move xfs_buf_incore out of line and make it the only way to look up
a buffer in the buffer cache from outside the buffer cache. Convert
the external users of _xfs_buf_find() to xfs_buf_incore() and make
_xfs_buf_find() static.Signed-Off-By: Dave Chinner
Reviewed-by: Christoph Hellwig
Reviewed-by: Carlos Maiolino
Reviewed-by: Darrick J. Wong
[darrick: actually rename xfs_incore -> xfs_buf_incore]
Signed-off-by: Darrick J. Wong
03 Apr, 2018
1 commit
-
xfs_dir_ialloc() rolls the current transaction when allocation of a new
inode required the space manager to perform an allocation and replinish
the Inode btree.None of the callers of xfs_dir_ialloc() need to know if the
transaction was committed. Hence this commit removes the "committed"
argument of xfs_dir_ialloc.Signed-off-by: Chandan Rajendra
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
13 Jan, 2018
1 commit
-
Starting with commit 57e734423ad ("vsprintf: refactor %pK code out of
pointer"), the behavior of the raw '%p' printk format specifier was
changed to print a 32-bit hash of the pointer value to avoid leaking
kernel pointers into dmesg. For most situations that's good.This is /undesirable/ behavior when we're trying to debug XFS, however,
so define a PTR_FMT that prints the actual pointer when we're in debug
mode.Note that %p for tracepoints still prints the raw pointer, so in the
long run we could consider rewriting some of these messages as
tracepoints.Signed-off-by: Darrick J. Wong
Reviewed-by: Dave Chinner
09 Jan, 2018
2 commits
-
Rename xfs_dqcheck to xfs_dquot_verify and make it return an
xfs_failaddr_t like every other structure verifier function.
This enables us to check on-disk quotas in the same way that we check
everything else. Callers are now responsible for logging errors, as
XFS_QMOPT_DOWARN goes away.Signed-off-by: Darrick J. Wong
Reviewed-by: Dave Chinner -
Move the dquot repair code into a separate function and remove
XFS_QMOPT_DQREPAIR in favor of calling the helper directly. Remove
other dead code because quotacheck is the only caller of DQREPAIR.Signed-off-by: Darrick J. Wong
Reviewed-by: Dave Chinner
03 Jan, 2018
2 commits
-
xfs_qm_init_quotainfo() does not check result of register_shrinker()
which was tagged as __must_check recently, reported by sparse.Signed-off-by: Aliaksei Karaliou
[darrick: move xfs_qm_destroy_quotainos nearer xfs_qm_init_quotainos]
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong -
xfs_qm_destroy_quotainfo() does not destroy quotainfo->qi_tree_lock
while destroys quotainfo->qi_quotaofflock.Signed-off-by: Aliaksei Karaliou
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
09 Dec, 2017
1 commit
-
If we create a new file we will need an inode, and usually some metadata
in the parent direction. Aiming for everything to go well despite the
lack of a reservation leads to dirty transactions cancelled under a heavy
create/delete load. This patch removes those nospace transactions, which
will lead to slightly earlier ENOSPC on some workloads, but instead
prevent file system shutdowns due to cancelling dirty transactions for
others.A customer could observe assertations failures and shutdowns due to
cancelation of dirty transactions during heavy NFS workloads as shown
below:2017-05-30 21:17:06 kernel: WARNING: [ 2670.728125] XFS: Assertion failed: error != -ENOSPC, file: fs/xfs/xfs_inode.c, line: 1262
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728222] Call Trace:
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728246] [] dump_stack+0x63/0x81
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728262] [] warn_slowpath_common+0x8a/0xc0
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728264] [] warn_slowpath_null+0x1a/0x20
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728285] [] asswarn+0x33/0x40 [xfs]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728308] [] xfs_create+0x7be/0x7d0 [xfs]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728329] [] xfs_generic_create+0x1fb/0x2e0 [xfs]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728348] [] xfs_vn_mknod+0x14/0x20 [xfs]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728366] [] xfs_vn_create+0x13/0x20 [xfs]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728380] [] vfs_create+0xd5/0x140
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728390] [] do_nfsd_create+0x499/0x610 [nfsd]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728396] [] nfsd3_proc_create+0x135/0x210 [nfsd]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728401] [] nfsd_dispatch+0xc3/0x210 [nfsd]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728416] [] svc_process_common+0x453/0x6f0 [sunrpc]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728423] [] svc_process+0x113/0x1f0 [sunrpc]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728427] [] nfsd+0x10f/0x180 [nfsd]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728432] [] ? nfsd_destroy+0x80/0x80 [nfsd]
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728438] [] kthread+0xd8/0xf0
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728441] [] ? kthread_create_on_node+0x1b0/0x1b0
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728451] [] ret_from_fork+0x42/0x70
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728453] [] ? kthread_create_on_node+0x1b0/0x1b0
2017-05-30 21:17:06 kernel: WARNING: [ 2670.728454] ---[ end trace f9822c842fec81d4 ]---2017-05-30 21:17:06 kernel: ALERT: [ 2670.728477] XFS (sdb): Internal error xfs_trans_cancel at line 983 of file fs/xfs/xfs_trans.c. Caller xfs_create+0x4ee/0x7d0 [xfs]
2017-05-30 21:17:06 kernel: ALERT: [ 2670.728684] XFS (sdb): Corruption of in-memory data detected. Shutting down filesystem
2017-05-30 21:17:06 kernel: ALERT: [ 2670.728685] XFS (sdb): Please umount the filesystem and rectify the problem(s)Signed-off-by: Christoph Hellwig
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
02 Sep, 2017
1 commit
-
Use the existing functionality instead of directly poking into the extent
list.Signed-off-by: Christoph Hellwig
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
24 Jul, 2017
1 commit
-
If a dquot has an id of U32_MAX, the next lookup index increment
overflows the uint32_t back to 0. This starts the lookup sequence
over from the beginning, repeats indefinitely and results in a
livelock.Update xfs_qm_dquot_walk() to explicitly check for the lookup
overflow and exit the loop.Signed-off-by: Brian Foster
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
19 Jun, 2017
1 commit
-
Reclaim during quotacheck can lead to deadlocks on the dquot flush
lock:- Quotacheck populates a local delwri queue with the physical dquot
buffers.
- Quotacheck performs the xfs_qm_dqusage_adjust() bulkstat and
dirties all of the dquots.
- Reclaim kicks in and attempts to flush a dquot whose buffer is
already queud on the quotacheck queue. The flush succeeds but
queueing to the reclaim delwri queue fails as the backing buffer is
already queued. The flush unlock is now deferred to I/O completion
of the buffer from the quotacheck queue.
- The dqadjust bulkstat continues and dirties the recently flushed
dquot once again.
- Quotacheck proceeds to the xfs_qm_flush_one() walk which requires
the flush lock to update the backing buffers with the in-core
recalculated values. It deadlocks on the redirtied dquot as the
flush lock was already acquired by reclaim, but the buffer resides
on the local delwri queue which isn't submitted until the end of
quotacheck.This is reproduced by running quotacheck on a filesystem with a
couple million inodes in low memory (512MB-1GB) situations. This is
a regression as of commit 43ff2122e6 ("xfs: on-stack delayed write
buffer lists"), which removed a trylock and buffer I/O submission
from the quotacheck dquot flush sequence.Quotacheck first resets and collects the physical dquot buffers in a
delwri queue. Then, it traverses the filesystem inodes via bulkstat,
updates the in-core dquots, flushes the corrected dquots to the
backing buffers and finally submits the delwri queue for I/O. Since
the backing buffers are queued across the entire quotacheck
operation, dquot reclaim cannot possibly complete a dquot flush
before quotacheck completes.Therefore, quotacheck must submit the buffer for I/O in order to
cycle the flush lock and flush the dirty in-core dquot to the
buffer. Add a delwri queue buffer push mechanism to submit an
individual buffer for I/O without losing the delwri queue status and
use it from quotacheck to avoid the deadlock. This restores
quotacheck behavior to as before the regression was introduced.Reported-by: Martin Svec
Signed-off-by: Brian Foster
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
26 Apr, 2017
2 commits
-
The quotacheck error handling of the delwri buffer list assumes the
resident buffers are locked and doesn't clear the _XBF_DELWRI_Q flag
on the buffers that are dequeued. This can lead to assert failures
on buffer release and possibly other locking problems.Move this code to a delwri queue cancel helper function to
encapsulate the logic required to properly release buffers from a
delwri queue. Update the helper to clear the delwri queue flag and
call it from quotacheck.Signed-off-by: Brian Foster
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong -
The kbuild test robot caught this; in debug code we have another
caller of do_div with a 32-bit dividend (j) which is caught now
that we are using the kernel-supplied do_div.None of the values used here are 64-bit; just use simple division.
Signed-off-by: Eric Sandeen
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
28 Jan, 2017
1 commit
-
Quotacheck runs at mount time in situations where quota accounting must
be recalculated. In doing so, it uses bulkstat to visit every inode in
the filesystem. Historically, every inode processed during quotacheck
was released and immediately tagged for reclaim because quotacheck runs
before the superblock is marked active by the VFS. In other words,
the final iput() lead to an immediate ->destroy_inode() call, which
allowed the XFS background reclaim worker to start reclaiming inodes.Commit 17c12bcd3 ("xfs: when replaying bmap operations, don't let
unlinked inodes get reaped") marks the XFS superblock active sooner as
part of the mount process to support caching inodes processed during log
recovery. This occurs before quotacheck and thus means all inodes
processed by quotacheck are inserted to the LRU on release. The
s_umount lock is held until the mount has completed and thus prevents
the shrinkers from operating on the sb. This means that quotacheck can
excessively populate the inode LRU and lead to OOM conditions on systems
without sufficient RAM.Update the quotacheck bulkstat handler to set XFS_IGET_DONTCACHE on
inodes processed by quotacheck. This causes ->drop_inode() to return 1
and in turn causes iput_final() to evict the inode. This preserves the
original quotacheck behavior and prevents it from overloading the LRU
and running out of memory.CC: stable@vger.kernel.org # v4.9
Reported-by: Martin Svec
Signed-off-by: Brian Foster
Reviewed-by: Eric Sandeen
Reviewed-by: Darrick J. Wong
Signed-off-by: Darrick J. Wong
08 Nov, 2016
1 commit
-
The open-coded pattern:
ifp->if_bytes / (uint)sizeof(xfs_bmbt_rec_t)
is all over the xfs code; provide a new helper
xfs_iext_count(ifp) to count the number of inline extents
in an inode fork.[dchinner: pick up several missed conversions]
Signed-off-by: Eric Sandeen
Reviewed-by: Brian Foster
Signed-off-by: Dave Chinner
06 Apr, 2016
1 commit
-
Merge xfs_trans_reserve and xfs_trans_alloc into a single function call
that returns a transaction with all the required log and block reservations,
and which allows passing transaction flags directly to avoid the cumbersome
_xfs_trans_alloc interface.While we're at it we also get rid of the transaction type argument that has
been superflous since we stopped supporting the non-CIL logging mode. The
guts of it will be removed in another patch.[dchinner: fixed transaction leak in error path in xfs_setattr_nonsize]
Signed-off-by: Christoph Hellwig
Reviewed-by: Dave Chinner
Signed-off-by: Dave Chinner
08 Feb, 2016
1 commit
-
Default quotas are globally set due historical reasons. IRIX only
supported user and project quotas, and default quota was only
applied to user quotas.In Linux, when a default quota is set, all different quota types
inherits the same default value.An user with a quota limit larger than the default quota value, will
still be limited to the default value because the group quotas also
inherits the default quotas. Unless the group which the user belongs
to have a custom quota limit set.This patch aims to split the default quota value by quota type.
Allowing each quota type having different default values.Default time limits are still set globally. XFS does not set a
per-user/group timer, but a single global timer. For changing this
behavior, some changes should be made in user-space tools another
bugs being fixed.Signed-off-by: Carlos Maiolino
Reviewed-by: Eric Sandeen
Signed-off-by: Dave Chinner
12 Nov, 2015
1 commit
-
Pull xfs updates from Dave Chinner:
"There is nothing really major here - the only significant addition is
the per-mount operation statistics infrastructure. Otherwises there's
various ACL, xattr, DAX, AIO and logging fixes, and a smattering of
small cleanups and fixes elsewhere.Summary:
- per-mount operational statistics in sysfs
- fixes for concurrent aio append write submission
- various logging fixes
- detection of zeroed logs and invalid log sequence numbers on v5 filesystems
- memory allocation failure message improvements
- a bunch of xattr/ACL fixes
- fdatasync optimisation
- miscellaneous other fixes and cleanups"* tag 'xfs-for-linus-4.4' of git://git.kernel.org/pub/scm/linux/kernel/git/dgc/linux-xfs: (39 commits)
xfs: give all workqueues rescuer threads
xfs: fix log recovery op header validation assert
xfs: Fix error path in xfs_get_acl
xfs: optimise away log forces on timestamp updates for fdatasync
xfs: don't leak uuid table on rmmod
xfs: invalidate cached acl if set via ioctl
xfs: Plug memory leak in xfs_attrmulti_attr_set
xfs: Validate the length of on-disk ACLs
xfs: invalidate cached acl if set directly via xattr
xfs: xfs_filemap_pmd_fault treats read faults as write faults
xfs: add ->pfn_mkwrite support for DAX
xfs: DAX does not use IO completion callbacks
xfs: Don't use unwritten extents for DAX
xfs: introduce BMAPI_ZERO for allocating zeroed extents
xfs: fix inode size update overflow in xfs_map_direct()
xfs: clear PF_NOFREEZE for xfsaild kthread
xfs: fix an error code in xfs_fs_fill_super()
xfs: stats are no longer dependent on CONFIG_PROC_FS
xfs: simplify /proc teardown & error handling
xfs: per-filesystem stats counter implementation
...
07 Nov, 2015
1 commit
-
…d avoiding waking kswapd
__GFP_WAIT has been used to identify atomic context in callers that hold
spinlocks or are in interrupts. They are expected to be high priority and
have access one of two watermarks lower than "min" which can be referred
to as the "atomic reserve". __GFP_HIGH users get access to the first
lower watermark and can be called the "high priority reserve".Over time, callers had a requirement to not block when fallback options
were available. Some have abused __GFP_WAIT leading to a situation where
an optimisitic allocation with a fallback option can access atomic
reserves.This patch uses __GFP_ATOMIC to identify callers that are truely atomic,
cannot sleep and have no alternative. High priority users continue to use
__GFP_HIGH. __GFP_DIRECT_RECLAIM identifies callers that can sleep and
are willing to enter direct reclaim. __GFP_KSWAPD_RECLAIM to identify
callers that want to wake kswapd for background reclaim. __GFP_WAIT is
redefined as a caller that is willing to enter direct reclaim and wake
kswapd for background reclaim.This patch then converts a number of sites
o __GFP_ATOMIC is used by callers that are high priority and have memory
pools for those requests. GFP_ATOMIC uses this flag.o Callers that have a limited mempool to guarantee forward progress clear
__GFP_DIRECT_RECLAIM but keep __GFP_KSWAPD_RECLAIM. bio allocations fall
into this category where kswapd will still be woken but atomic reserves
are not used as there is a one-entry mempool to guarantee progress.o Callers that are checking if they are non-blocking should use the
helper gfpflags_allow_blocking() where possible. This is because
checking for __GFP_WAIT as was done historically now can trigger false
positives. Some exceptions like dm-crypt.c exist where the code intent
is clearer if __GFP_DIRECT_RECLAIM is used instead of the helper due to
flag manipulations.o Callers that built their own GFP flags instead of starting with GFP_KERNEL
and friends now also need to specify __GFP_KSWAPD_RECLAIM.The first key hazard to watch out for is callers that removed __GFP_WAIT
and was depending on access to atomic reserves for inconspicuous reasons.
In some cases it may be appropriate for them to use __GFP_HIGH.The second key hazard is callers that assembled their own combination of
GFP flags instead of starting with something like GFP_KERNEL. They may
now wish to specify __GFP_KSWAPD_RECLAIM. It's almost certainly harmless
if it's missed in most cases as other activity will wake kswapd.Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Vitaly Wool <vitalywool@gmail.com>
Cc: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
