Commit Graph

155 Commits

Author SHA1 Message Date
Dave Chinner
f250eedcf7 xfs: make for_each_perag... a first class citizen
for_each_perag_tag() is defined in xfs_icache.c for local use.
Promote this to xfs_ag.h and define equivalent iteration functions
so that we can use them to iterate AGs instead to replace open coded
perag walks and perag lookups.

We also convert as many of the straight forward open coded AG walks
to use these iterators as possible. Anything that is not a direct
conversion to an iterator is ignored and will be updated in future
commits.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-06-02 10:48:24 +10:00
Dave Chinner
9bbafc7191 xfs: move xfs_perag_get/put to xfs_ag.[ch]
They are AG functions, not superblock functions, so move them to the
appropriate location.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
2021-06-02 10:48:24 +10:00
Darrick J. Wong
2b156ff8c8 xfs: move the xfs_can_free_eofblocks call under the IOLOCK
In xfs_inode_free_eofblocks, move the xfs_can_free_eofblocks call
further down in the function to the point where we have taken the
IOLOCK.  This is preparation for the next patch, where we will need that
lock (or equivalent) so that we can check if there are any post-eof
blocks to clean out.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-04-07 14:38:16 -07:00
Christoph Hellwig
3e09ab8fdc xfs: move the di_flags2 field to struct xfs_inode
In preparation of removing the historic icinode struct, move the flags2
field into the containing xfs_inode structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07 14:37:05 -07:00
Christoph Hellwig
7821ea302d xfs: move the di_forkoff field to struct xfs_inode
In preparation of removing the historic icinode struct, move the
forkoff field into the containing xfs_inode structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07 14:37:05 -07:00
Christoph Hellwig
965e0a1ad2 xfs: move the di_flushiter field to struct xfs_inode
In preparation of removing the historic icinode struct, move the
flushiter field into the containing xfs_inode structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07 14:37:04 -07:00
Christoph Hellwig
6e73a545f9 xfs: move the di_nblocks field to struct xfs_inode
In preparation of removing the historic icinode struct, move the nblocks
field into the containing xfs_inode structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07 14:37:03 -07:00
Christoph Hellwig
ceaf603c70 xfs: move the di_projid field to struct xfs_inode
In preparation of removing the historic icinode struct, move the projid
field into the containing xfs_inode structure.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07 14:37:03 -07:00
Christoph Hellwig
7e2a8af528 xfs: don't clear the "dinode core" in xfs_inode_alloc
The xfs_icdinode structure just contains a random mix of inode field,
which are all read from the on-disk inode and mostly not looked at
before reading the inode or initializing a new inode cluster.  The
only exceptions are the forkoff and blocks field, which are used
in sanity checks for freshly allocated inodes.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07 14:37:03 -07:00
Christoph Hellwig
4cb6f2e8c2 xfs: consistently initialize di_flags2
Make sure di_flags2 is always initialized.  We currently get this implicitly
by clearing the dinode core on allocating the in-core inode, but that is
about to go away.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07 14:37:02 -07:00
Christoph Hellwig
af9dcddef6 xfs: split xfs_imap_to_bp
Split looking up the dinode from xfs_imap_to_bp, which can be
significantly simplified as a result.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07 14:37:02 -07:00
Darrick J. Wong
3fef46fc43 xfs: rename the blockgc workqueue
Since we're about to start using the blockgc workqueue to dispose of
inactivated inodes, strip the "block" prefix from the name; now it's
merely the general garbage collection (gc) workqueue.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-03-25 16:47:50 -07:00
Darrick J. Wong
0fa4a10a2f xfs: don't bounce the iolock between free_{eof,cow}blocks
Since xfs_inode_free_eofblocks and xfs_inode_free_cowblocks are now
internal static functions, we can save ourselves a cycling of the iolock
by passing the lock state out to xfs_blockgc_scan_inode and letting it
do all the unlocking.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:50 -08:00
Darrick J. Wong
894ecacf0f xfs: parallelize block preallocation garbage collection
Split the block preallocation garbage collection work into per-AG work
items so that we can take advantage of parallelization.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:50 -08:00
Darrick J. Wong
c9a6526fe7 xfs: rename block gc start and stop functions
Shorten the names of the two functions that start and stop block
preallocation garbage collection and move them up to the other blockgc
functions.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:50 -08:00
Darrick J. Wong
419567534e xfs: only walk the incore inode tree once per blockgc scan
Perform background block preallocation gc scans more efficiently by
walking the incore inode tree once.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
9669f51de5 xfs: consolidate the eofblocks and cowblocks workers
Remove the separate cowblocks work items and knob so that we can control
and run everything from a single blockgc work queue.  Note that the
speculative_prealloc_lifetime sysfs knob retains its historical name
even though the functions move to prefix xfs_blockgc_*.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
ce2d3bbe06 xfs: consolidate incore inode radix tree posteof/cowblocks tags
The clearing of posteof blocks and cowblocks serve the same purpose:
removing speculative block preallocations from inactive files.  We don't
need to burn two radix tree tags on this, so combine them into one.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
865ac8e253 xfs: remove trivial eof/cowblocks functions
Get rid of these trivial helpers.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
b943c0cd56 xfs: hide xfs_icache_free_cowblocks
Change the one remaining caller of xfs_icache_free_cowblocks to use our
new combined blockgc scan function instead, since we will soon be
combining the two scans.  This introduces a slight behavior change,
since a readonly remount now clears out post-EOF preallocations and not
just CoW staging extents.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
0461a320e3 xfs: hide xfs_icache_free_eofblocks
Change the one remaining caller of xfs_icache_free_eofblocks to use our
new combined blockgc scan function instead, since we will soon be
combining the two scans.  This introduces a slight behavior change,
since the XFS_IOC_FREE_EOFBLOCKS now clears out speculative CoW
reservations in addition to post-eof blocks.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
f929656983 xfs: relocate the eofb/cowb workqueue functions
Move the xfs_{eof,cow}blocks_worker and xfs_queue_{eof,cow}blocks
functions further down in the file so that the cleanups in the next
patches won't have to pre-declare static functions.  No functional
changes.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
85c5b27075 xfs: refactor xfs_icache_free_{eof,cow}blocks call sites
In anticipation of more restructuring of the eof/cowblocks gc code,
refactor calling of those two functions into a single internal helper
function, then present a new standard interface to purge speculative
block preallocations and start shifting higher level code to use that.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
c237dd7c70 xfs: flush eof/cowblocks if we can't reserve quota for inode creation
If an inode creation is unable to reserve enough quota to handle the
modification, try clearing whatever space the filesystem might have been
hanging onto in the hopes of speeding up the filesystem.  The flushing
behavior will become particularly important when we add deferred inode
inactivation because that will increase the amount of space that isn't
actively tied to user data.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
111068f80e xfs: pass flags and return gc errors from xfs_blockgc_free_quota
Change the signature of xfs_blockgc_free_quota in preparation for the
next few patches.  Callers can now pass EOF_FLAGS into the function to
control scan parameters; and the function will now pass back any
corruption errors seen while scanning, though for our retry loops we'll
just try again unconditionally.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
3d4feec006 xfs: move and rename xfs_inode_free_quota_blocks to avoid conflicts
Move this function further down in the file so that later cleanups won't
have to declare static functions.  Change the name because we're about
to rework all the code that performs garbage collection of speculatively
allocated file blocks.  No functional changes.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
9a537de3b0 xfs: xfs_inode_free_quota_blocks should scan project quota
Buffered writers who have run out of quota reservation call
xfs_inode_free_quota_blocks to try to free any space reservations that
might reduce the quota usage.  Unfortunately, the buffered write path
treats "out of project quota" the same as "out of overall space" so this
function has never supported scanning for space that might ease an "out
of project quota" condition.

We're about to start using this function for cases where we actually
/can/ tell if we're out of project quota, so add in this functionality.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
f41a0716f4 xfs: don't stall cowblocks scan if we can't take locks
Don't stall the cowblocks scan on a locked inode if we possibly can.
We'd much rather the background scanner keep moving.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2021-02-03 09:18:49 -08:00
Darrick J. Wong
a636b1d1cf xfs: trigger all block gc scans when low on quota space
The functions to run an eof/cowblocks scan to try to reduce quota usage
are kind of a mess -- the logic repeatedly initializes an eofb structure
and there are logic bugs in the code that result in the cowblocks scan
never actually happening.

Replace all three functions with a single function that fills out an
eofb and runs both eof and cowblocks scans.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2021-02-03 09:18:49 -08:00
Zheng Bin
0f4ec0f157 xfs: Remove unneeded semicolon
Fixes coccicheck warning:

fs/xfs/xfs_icache.c:1214:2-3: Unneeded semicolon

Signed-off-by: Zheng Bin <zhengbin13@huawei.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-15 20:52:42 -07:00
Dave Chinner
718ecc5035 xfs: xfs_iflock is no longer a completion
With the recent rework of the inode cluster flushing, we no longer
ever wait on the the inode flush "lock". It was never a lock in the
first place, just a completion to allow callers to wait for inode IO
to complete. We now never wait for flush completion as all inode
flushing is non-blocking. Hence we can get rid of all the iflock
infrastructure and instead just set and check a state flag.

Rename the XFS_IFLOCK flag to XFS_IFLUSHING, convert all the
xfs_iflock_nowait() test-and-set operations on that flag, and
replace all the xfs_ifunlock() calls to clear operations.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-06 18:05:51 -07:00
Carlos Maiolino
3050bd0bfe xfs: Remove kmem_zone_alloc() usage
Use kmem_cache_alloc() directly.

All kmem_zone_alloc() users pass 0 as flags, which are translated into:
GFP_KERNEL | __GFP_NOWARN, and kmem_zone_alloc() loops forever until the
allocation succeeds.

We can use __GFP_NOFAIL to tell the allocator to loop forever rather
than doing it ourself, and because the allocation will never fail, we do
not need to use __GFP_NOWARN anymore. Hence, all callers can be
converted to use GFP_KERNEL | __GFP_NOFAIL

Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
[darrick: add a comment back in about nofail]
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2020-07-28 20:24:14 -07:00
Darrick J. Wong
8cd4901da5 xfs: rename XFS_DQ_{USER,GROUP,PROJ} to XFS_DQTYPE_*
We're going to split up the incore dquot state flags from the ondisk
dquot flags (eventually renaming this "type") so start by renaming the
three flags and the bitmask that are going to participate in this.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-07-28 20:24:14 -07:00
Dave Chinner
48d55e2ae3 xfs: attach inodes to the cluster buffer when dirtied
Rather than attach inodes to the cluster buffer just when we are
doing IO, attach the inodes to the cluster buffer when they are
dirtied. The means the buffer always carries a list of dirty inodes
that reference it, and we can use that list to make more fundamental
changes to inode writeback that aren't otherwise possible.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-07 07:15:08 -07:00
Dave Chinner
02511a5a6a xfs: clean up inode reclaim comments
Inode reclaim is quite different now to the way described in various
comments, so update all the comments explaining what it does and how
it works.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-07 07:15:08 -07:00
Dave Chinner
4d0bab3a44 xfs: remove SYNC_WAIT from xfs_reclaim_inodes()
Clean up xfs_reclaim_inodes() callers. Most callers want blocking
behaviour, so just make the existing SYNC_WAIT behaviour the
default.

For the xfs_reclaim_worker(), just call xfs_reclaim_inodes_ag()
directly because we just want optimistic clean inode reclaim to be
done in the background.

For xfs_quiesce_attr() we can just remove the inode reclaim calls as
they are a historic relic that was required to flush dirty inodes
that contained unlogged changes. We now log all changes to the
inodes, so the sync AIL push from xfs_log_quiesce() called by
xfs_quiesce_attr() will do all the required inode writeback for
freeze.

Seeing as we now want to loop until all reclaimable inodes have been
reclaimed, make xfs_reclaim_inodes() loop on the XFS_ICI_RECLAIM_TAG
tag rather than having xfs_reclaim_inodes_ag() tell it that inodes
were skipped. This is much more reliable and will always loop until
all reclaimable inodes are reclaimed.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-07 07:15:08 -07:00
Dave Chinner
50718b8d73 xfs: remove SYNC_TRYLOCK from inode reclaim
All background reclaim is SYNC_TRYLOCK already, and even blocking
reclaim (SYNC_WAIT) can use trylock mechanisms as
xfs_reclaim_inodes_ag() will keep cycling until there are no more
reclaimable inodes. Hence we can kill SYNC_TRYLOCK from inode
reclaim and make everything unconditionally non-blocking.

We remove all the optimistic "avoid blocking on locks" checks done
in xfs_reclaim_inode_grab() as nothing blocks on locks anymore.
Further, checking XFS_IFLOCK optimistically can result in detecting
inodes in the process of being cleaned (i.e. between being removed
from the AIL and having the flush lock dropped), so for
xfs_reclaim_inodes() to reliably reclaim all inodes we need to drop
these checks anyway.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-07 07:15:08 -07:00
Dave Chinner
9552e14d3e xfs: don't block inode reclaim on the ILOCK
When we attempt to reclaim an inode, the first thing we do is take
the inode lock. This is blocking right now, so if the inode being
accessed by something else (e.g. being flushed to the cluster
buffer) we will block here.

Change this to a trylock so that we do not block inode reclaim
unnecessarily here.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-07 07:15:08 -07:00
Dave Chinner
0e8e2c6343 xfs: allow multiple reclaimers per AG
Inode reclaim will still throttle direct reclaim on the per-ag
reclaim locks. This is no longer necessary as reclaim can run
non-blocking now. Hence we can remove these locks so that we don't
arbitrarily block reclaimers just because there are more direct
reclaimers than there are AGs.

This can result in multiple reclaimers working on the same range of
an AG, but this doesn't cause any apparent issues. Optimising the
spread of concurrent reclaimers for best efficiency can be done in a
future patchset.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-07 07:15:07 -07:00
Dave Chinner
617825fe34 xfs: remove IO submission from xfs_reclaim_inode()
We no longer need to issue IO from shrinker based inode reclaim to
prevent spurious OOM killer invocation. This leaves only the global
filesystem management operations such as unmount needing to
writeback dirty inodes and reclaim them.

Instead of using the reclaim pass to write dirty inodes before
reclaiming them, use the AIL to push all the dirty inodes before we
try to reclaim them. This allows us to remove all the conditional
SYNC_WAIT locking and the writeback code from xfs_reclaim_inode()
and greatly simplify the checks we need to do to reclaim an inode.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-07 07:15:07 -07:00
Dave Chinner
993f951f50 xfs: make inode reclaim almost non-blocking
Now that dirty inode writeback doesn't cause read-modify-write
cycles on the inode cluster buffer under memory pressure, the need
to throttle memory reclaim to the rate at which we can clean dirty
inodes goes away. That is due to the fact that we no longer thrash
inode cluster buffers under memory pressure to clean dirty inodes.

This means inode writeback no longer stalls on memory allocation
or read IO, and hence can be done asynchronously without generating
memory pressure. As a result, blocking inode writeback in reclaim is
no longer necessary to prevent reclaim priority windup as cleaning
dirty inodes is no longer dependent on having memory reserves
available for the filesystem to make progress reclaiming inodes.

Hence we can convert inode reclaim to be non-blocking for shrinker
callouts, both for direct reclaim and kswapd.

On a vanilla kernel, running a 16-way fsmark create workload on a
4 node/16p/16GB RAM machine, I can reliably pin 14.75GB of RAM via
userspace mlock(). The OOM killer gets invoked at 15GB of
pinned RAM.

Without the inode cluster pinning, this non-blocking reclaim patch
triggers premature OOM killer invocation with the same memory
pinning, sometimes with as much as 45% of RAM being free.  It's
trivially easy to trigger the OOM killer when reclaim does not
block.

With pinning inode clusters in RAM and then adding this patch, I can
reliably pin 14.5GB of RAM and still have the fsmark workload run to
completion. The OOM killer gets invoked 14.75GB of pinned RAM, which
is only a small amount of memory less than the vanilla kernel. It is
much more reliable than just with async reclaim alone.

simoops shows that allocation stalls go away when async reclaim is
used. Vanilla kernel:

Run time: 1924 seconds
Read latency (p50: 3,305,472) (p95: 3,723,264) (p99: 4,001,792)
Write latency (p50: 184,064) (p95: 553,984) (p99: 807,936)
Allocation latency (p50: 2,641,920) (p95: 3,911,680) (p99: 4,464,640)
work rate = 13.45/sec (avg 13.44/sec) (p50: 13.46) (p95: 13.58) (p99: 13.70)
alloc stall rate = 3.80/sec (avg: 2.59) (p50: 2.54) (p95: 2.96) (p99: 3.02)

With inode cluster pinning and async reclaim:

Run time: 1924 seconds
Read latency (p50: 3,305,472) (p95: 3,715,072) (p99: 3,977,216)
Write latency (p50: 187,648) (p95: 553,984) (p99: 789,504)
Allocation latency (p50: 2,748,416) (p95: 3,919,872) (p99: 4,448,256)
work rate = 13.28/sec (avg 13.32/sec) (p50: 13.26) (p95: 13.34) (p99: 13.34)
alloc stall rate = 0.02/sec (avg: 0.02) (p50: 0.01) (p95: 0.03) (p99: 0.03)

Latencies don't really change much, nor does the work rate. However,
allocation almost never stalls with these changes, whilst the
vanilla kernel is sometimes reporting 20 stalls/s over a 60s sample
period. This difference is due to inode reclaim being largely
non-blocking now.

IOWs, once we have pinned inode cluster buffers, we can make inode
reclaim non-blocking without a major risk of premature and/or
spurious OOM killer invocation, and without any changes to memory
reclaim infrastructure.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Amir Goldstein <amir73il@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-07 07:15:07 -07:00
Dave Chinner
96355d5a1f xfs: Don't allow logging of XFS_ISTALE inodes
In tracking down a problem in this patchset, I discovered we are
reclaiming dirty stale inodes. This wasn't discovered until inodes
were always attached to the cluster buffer and then the rcu callback
that freed inodes was assert failing because the inode still had an
active pointer to the cluster buffer after it had been reclaimed.

Debugging the issue indicated that this was a pre-existing issue
resulting from the way the inodes are handled in xfs_inactive_ifree.
When we free a cluster buffer from xfs_ifree_cluster, all the inodes
in cache are marked XFS_ISTALE. Those that are clean have nothing
else done to them and so eventually get cleaned up by background
reclaim. i.e. it is assumed we'll never dirty/relog an inode marked
XFS_ISTALE.

On journal commit dirty stale inodes as are handled by both
buffer and inode log items to run though xfs_istale_done() and
removed from the AIL (buffer log item commit) or the log item will
simply unpin it because the buffer log item will clean it. What happens
to any specific inode is entirely dependent on which log item wins
the commit race, but the result is the same - stale inodes are
clean, not attached to the cluster buffer, and not in the AIL. Hence
inode reclaim can just free these inodes without further care.

However, if the stale inode is relogged, it gets dirtied again and
relogged into the CIL. Most of the time this isn't an issue, because
relogging simply changes the inode's location in the current
checkpoint. Problems arise, however, when the CIL checkpoints
between two transactions in the xfs_inactive_ifree() deferops
processing. This results in the XFS_ISTALE inode being redirtied
and inserted into the CIL without any of the other stale cluster
buffer infrastructure being in place.

Hence on journal commit, it simply gets unpinned, so it remains
dirty in memory. Everything in inode writeback avoids XFS_ISTALE
inodes so it can't be written back, and it is not tracked in the AIL
so there's not even a trigger to attempt to clean the inode. Hence
the inode just sits dirty in memory until inode reclaim comes along,
sees that it is XFS_ISTALE, and goes to reclaim it. This reclaiming
of a dirty inode caused use after free, list corruptions and other
nasty issues later in this patchset.

Hence this patch addresses a violation of the "never log XFS_ISTALE
inodes" caused by the deferops processing rolling a transaction
and relogging a stale inode in xfs_inactive_free. It also adds a
bunch of asserts to catch this problem in debug kernels so that
we don't reintroduce this problem in future.

Reproducer for this issue was generic/558 on a v4 filesystem.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-07-06 10:46:58 -07:00
Linus Torvalds
8eeae5bae1 (More) new code for 5.8:
- Introduce DONTCACHE flags for dentries and inodes.  This hint will
   cause the VFS to drop the associated objects immediately after the
   last put, so that we can change the file access mode (DAX or page
   cache) on the fly.
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Merge tag 'vfs-5.8-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull DAX updates part two from Darrick Wong:
 "This time around, we're hoisting the DONTCACHE flag from XFS into the
  VFS so that we can make the incore DAX mode changes become effective
  sooner.

  We can't change the file data access mode on a live inode because we
  don't have a safe way to change the file ops pointers. The incore
  state change becomes effective at inode loading time, which can happen
  if the inode is evicted. Therefore, we're making it so that
  filesystems can ask the VFS to evict the inode as soon as the last
  holder drops.

  The per-fs changes to make this call this will be in subsequent pull
  requests from Ted and myself.

  Summary:

   - Introduce DONTCACHE flags for dentries and inodes. This hint will
     cause the VFS to drop the associated objects immediately after the
     last put, so that we can change the file access mode (DAX or page
     cache) on the fly"

* tag 'vfs-5.8-merge-2' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  fs: Introduce DCACHE_DONTCACHE
  fs: Lift XFS_IDONTCACHE to the VFS layer
2020-06-02 19:48:41 -07:00
Darrick J. Wong
964176bd32 xfs: rearrange xfs_inode_walk_ag parameters
The perag structure already has a pointer to the xfs_mount, so we don't
need to pass that separately and can drop it.  Having done that, move
iter_flags so that the argument order is the same between xfs_inode_walk
and xfs_inode_walk_ag.  The latter will make things less confusing for a
future patch that enables background scanning work to be done in
parallel.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-05-27 08:49:28 -07:00
Darrick J. Wong
042f65f4a7 xfs: straighten out all the naming around incore inode tree walks
We're not very consistent about function names for the incore inode
iteration function.  Turn them all into xfs_inode_walk* variants.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-27 08:49:27 -07:00
Darrick J. Wong
5662d38ccd xfs: move xfs_inode_ag_iterator to be closer to the perag walking code
Move the xfs_inode_ag_iterator function to be nearer xfs_inode_ag_walk
so that we don't have to scroll back and forth to figure out how the
incore inode walking function works.  No functional changes.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-05-27 08:49:27 -07:00
Darrick J. Wong
7e88d31423 xfs: use bool for done in xfs_inode_ag_walk
This is a boolean variable, so use the bool type.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-05-27 08:49:27 -07:00
Darrick J. Wong
39b1cfd75b xfs: fix inode ag walk predicate function return values
There are a number of predicate functions that help the incore inode
walking code decide if we really want to apply the iteration function to
the inode.  These are boolean decisions, so change the return types to
boolean to match.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-05-27 08:49:27 -07:00
Darrick J. Wong
a91bf9928e xfs: refactor eofb matching into a single helper
Refactor the two eofb-matching logics into a single helper so that we
don't repeat ourselves.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2020-05-27 08:49:27 -07:00
Darrick J. Wong
8921a0fda5 xfs: remove __xfs_icache_free_eofblocks
This is now a pointless wrapper, so kill it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2020-05-27 08:49:27 -07:00