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The root on the trans->root can be anything, and generally we're
committing from the transaction kthread so it's usually the tree_root.
Change this to just take an fs_info, and to maintain compatibility
simply put the ROOT_TREE_OBJECTID as the root objectid for the
tracepoint. This will allow use to remove trans->root.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently we do this awful thing where we get another ref on a trans
handle, async off that handle and commit the transaction from that work.
Because we do this we have to mess with current->journal_info and the
freeze counting stuff.
We already have an async thing to kick for the transaction commit, the
transaction kthread. Replace this work struct with a flag on the
fs_info to tell the kthread to go ahead and commit even if it's before
our timeout. Then we can drastically simplify the async transaction
commit path.
Note: this can be simplified and functionality based on the pending
operation COMMIT.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add note ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This is no longer used, the -o nobarrier is handled by
BTRFS_MOUNT_NOBARRIER. Remove the flag.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Reshuffle the code inside the first loop of tree_search_offset so that
one if() is eliminated and the becomes more linear.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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[BUG]
When debugging calc_bio_boundaries(), I found that even for RAID1
metadata, we're following stripe length to calculate stripe boundary.
# mkfs.btrfs -m raid1 -d raid1 /dev/test/scratch[12]
# mount /dev/test/scratch /mnt/btrfs
# xfs_io -f -c "pwrite 0 64K" /mnt/btrfs/file
# umount
Above very basic operations will make calc_bio_boundaries() to report
the following result:
submit_extent_page: r/i=1/1 file_offset=22036480 len_to_stripe_boundary=49152
submit_extent_page: r/i=1/1 file_offset=30474240 len_to_stripe_boundary=65536
...
submit_extent_page: r/i=1/1 file_offset=30523392 len_to_stripe_boundary=16384
submit_extent_page: r/i=1/1 file_offset=30457856 len_to_stripe_boundary=16384
submit_extent_page: r/i=5/257 file_offset=0 len_to_stripe_boundary=65536
submit_extent_page: r/i=5/257 file_offset=65536 len_to_stripe_boundary=65536
submit_extent_page: r/i=1/1 file_offset=30490624 len_to_stripe_boundary=49152
submit_extent_page: r/i=1/1 file_offset=30507008 len_to_stripe_boundary=32768
Where "r/i" is the rootid and inode, 1/1 means they metadata.
The remaining names match the member used in kernel.
Even all data/metadata are using RAID1, we're still following stripe
length.
[CAUSE]
This behavior is caused by a wrong condition in btrfs_get_io_geometry():
if (map->type & BTRFS_BLOCK_GROUP_PROFILE_MASK) {
/* Fill using stripe_len */
len = min_t(u64, em->len - offset, max_len);
} else {
len = em->len - offset;
}
This means, only for SINGLE we will not follow stripe_len.
However for profiles like RAID1*, DUP, they don't need to bother
stripe_len.
This can lead to unnecessary bio split for RAID1*/DUP profiles, and can
even be a blockage for future zoned RAID support.
[FIX]
Introduce one single-use macro, BTRFS_BLOCK_GROUP_STRIPE_MASK, and
change the condition to only calculate the length using stripe length
for stripe based profiles.
Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com>
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This is a small optimisation since the currently 'entry' is already
checked in the if () {} else if {} construct above the loop. In essence
the first iteration of the final while loop is redundant. To eliminate
this extra check simply get the next entry at the beginning of the loop.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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I noticed a few corner cases when looking at my bytes_index patch for
obvious bugs, so add a bunch of tests to validate proper behavior of the
bytes_index tree. A couple of basic tests to make sure it puts things
in the correct order, and then more complicated tests to make sure it
re-arranges bitmap entries properly and does the right thing when we try
to make allocations.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently we index free space on offset only, because usually we have a
hint from the allocator that we want to honor for locality reasons.
However if we fail to use this hint we have to go back to a brute force
search through the free space entries to find a large enough extent.
With sufficiently fragmented free space this becomes quite expensive, as
we have to linearly search all of the free space entries to find if we
have a part that's long enough.
To fix this add a cached rb tree to index based on free space entry
bytes. This will allow us to quickly look up the largest chunk in the
free space tree for this block group, and stop searching once we've
found an entry that is too small to satisfy our allocation. We simply
choose to use this tree if we're searching from the beginning of the
block group, as we know we do not care about locality at that point.
I wrote an allocator test that creates a 10TiB ram backed null block
device and then fallocates random files until the file system is full.
I think go through and delete all of the odd files. Then I spawn 8
threads that fallocate 64MiB files (1/2 our extent size cap) until the
file system is full again. I use bcc's funclatency to measure the
latency of find_free_extent. The baseline results are
nsecs : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 10356 |**** |
512 -> 1023 : 58242 |************************* |
1024 -> 2047 : 74418 |******************************** |
2048 -> 4095 : 90393 |****************************************|
4096 -> 8191 : 79119 |*********************************** |
8192 -> 16383 : 35614 |*************** |
16384 -> 32767 : 13418 |***** |
32768 -> 65535 : 12811 |***** |
65536 -> 131071 : 17090 |******* |
131072 -> 262143 : 26465 |*********** |
262144 -> 524287 : 40179 |***************** |
524288 -> 1048575 : 55469 |************************ |
1048576 -> 2097151 : 48807 |********************* |
2097152 -> 4194303 : 26744 |*********** |
4194304 -> 8388607 : 35351 |*************** |
8388608 -> 16777215 : 13918 |****** |
16777216 -> 33554431 : 21 | |
avg = 908079 nsecs, total: 580889071441 nsecs, count: 639690
And the patch results are
nsecs : count distribution
0 -> 1 : 0 | |
2 -> 3 : 0 | |
4 -> 7 : 0 | |
8 -> 15 : 0 | |
16 -> 31 : 0 | |
32 -> 63 : 0 | |
64 -> 127 : 0 | |
128 -> 255 : 0 | |
256 -> 511 : 6883 |** |
512 -> 1023 : 54346 |********************* |
1024 -> 2047 : 79170 |******************************** |
2048 -> 4095 : 98890 |****************************************|
4096 -> 8191 : 81911 |********************************* |
8192 -> 16383 : 27075 |********** |
16384 -> 32767 : 14668 |***** |
32768 -> 65535 : 13251 |***** |
65536 -> 131071 : 15340 |****** |
131072 -> 262143 : 26715 |********** |
262144 -> 524287 : 43274 |***************** |
524288 -> 1048575 : 53870 |********************* |
1048576 -> 2097151 : 55368 |********************** |
2097152 -> 4194303 : 41036 |**************** |
4194304 -> 8388607 : 24927 |********** |
8388608 -> 16777215 : 33 | |
16777216 -> 33554431 : 9 | |
avg = 623599 nsecs, total: 397259314759 nsecs, count: 637042
There's a little variation in the amount of calls done because of timing
of the threads with metadata requirements, but the avg, total, and
count's are relatively consistent between runs (usually within 2-5% of
each other). As you can see here we have around a 30% decrease in
average latency with a 30% decrease in overall time spent in
find_free_extent.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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While adding self tests for my space index change I was hitting a
problem where the space indexed tree wasn't returning the expected
->max_extent_size. This is because we will skip searching any entry
that doesn't have ->bytes >= the amount of bytes we want. However we'll
still set the max_extent_size based on that entry. The problem is if we
don't search the bitmap we won't have ->max_extent_size set properly, so
we can't really trust it.
This doesn't really result in a problem per-se, it can just result in us
not finding contiguous area that may exist. Fix the max_extent_size
helper to return ->bytes if ->max_extent_size isn't set, and add a big
comment explaining why we're doing this.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We use @nr_written to record how many pages have been started by
btrfs_run_delalloc_range().
Currently there are only two cases that would populate @nr_written:
- Inline extent creation
- Compressed write
But both cases will also set @page_started to one.
In fact, in writepage_delalloc() we have the following code, showing
that @nr_written is really only utilized for above two cases:
/* did the fill delalloc function already unlock and start
* the IO?
*/
if (page_started) {
/*
* we've unlocked the page, so we can't update
* the mapping's writeback index, just update
* nr_to_write.
*/
wbc->nr_to_write -= nr_written;
return 1;
}
But for such cases, writepage_delalloc() will return 1, and exit
__extent_writepage() without going through __extent_writepage_io().
Thus this means, inside __extent_writepage_io(), we always get
@nr_written as 0.
So this patch is going to remove the unnecessary parameter from the
following functions:
- writepage_delalloc()
As @nr_written passed in is always the initial value 0.
Although inside that function, we still need a local @nr_written
to update wbc->nr_to_write.
- __extent_writepage_io()
As explained above, @nr_written passed in can only be 0.
This also means we can remove one update_nr_written() call.
Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We used to need the root for btrfs_reserve_metadata_bytes to check the
orphan cleanup state, but we no longer need that, we simply need the
fs_info. Change btrfs_reserve_metadata_bytes() to use the fs_info, and
change both btrfs_block_rsv_refill() and btrfs_block_rsv_add() to do the
same as they simply call btrfs_reserve_metadata_bytes() and then
manipulate the block_rsv that is being used.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Now that we don't care about the stage of the orphan_cleanup_state,
simply replace it with a bit on ->state to make sure we don't call the
orphan cleanup every time we wander into this root.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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This is very old code before we were stealing from the global reserve
during evict. We have proper ways to steal from the global reserve
while we're evicting, so rip out this code as it's no longer necessary.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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I forgot to convert this over when I introduced the global reserve
stealing code to the space flushing code. Evict was simply trying to
make its reservation and then if it failed it would steal from the
global rsv, which is racey because it's outside of the normal ticketing
code.
Fix this by setting ticket->steal if we are BTRFS_RESERVE_FLUSH_EVICT,
and then make the priority flushing path do the steal for us.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We're going to use this helper in the priority flushing loop, move this
check into the helper to simplify the logic.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Since we're dropping locks before we enter the priority flushing loops
we could have had our ticket granted before we got the space_info->lock.
So add this check to avoid doing some extra flushing in the priority
flushing cases.
The case in priority_reclaim_metadata_space is an optimization. Think
we came in to reserve, we didn't have the space, we added our ticket to
the list. But at the same time somebody was waiting on the space_info
lock to add space and do btrfs_try_granting_ticket(), so we drop the
lock, get satisfied, come in to do our loop, and we have been
satisfied.
This is the priority reclaim path, so to_reclaim could be !0 still
because we may have only satisfied the priority tickets and still left
non priority tickets on the list. We would then have to_reclaim but
->bytes == 0.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
[ add note about the optimization ]
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently the error case for the priority tickets is handled where we
deal with all of the tickets, priority and non-priority. This is OK in
general, but it makes for some awkward locking. We take and drop the
space_info->lock back to back because of these different types of
tickets.
Rework the code to handle priority ticket failures in their respective
helpers. This allows us to be less wonky with our space_info->lock
usage, and means that the main handler simply has to check
ticket->error, as the ticket is guaranteed to be off any list and
completely handled by the time it exits one of the handlers.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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When mounting a device, we are reporting the zones twice: once for
checking the zone attributes in btrfs_get_dev_zone_info and once for
loading block groups' zone info in
btrfs_load_block_group_zone_info(). With a lot of block groups, that
leads to a lot of REPORT ZONE commands and slows down the mount
process.
This patch introduces a zone info cache in struct
btrfs_zoned_device_info. The cache is populated while in
btrfs_get_dev_zone_info() and used for
btrfs_load_block_group_zone_info() to reduce the number of REPORT ZONE
commands. The zone cache is then released after loading the block
groups, as it will not be much effective during the run time.
Benchmark: Mount an HDD with 57,007 block groups
Before patch: 171.368 seconds
After patch: 64.064 seconds
While it still takes a minute due to the slowness of loading all the
block groups, the patch reduces the mount time by 1/3.
Link: https://lore.kernel.org/linux-btrfs/CAHQ7scUiLtcTqZOMMY5kbWUBOhGRwKo6J6wYPT5WY+C=cD49nQ@mail.gmail.com/
Fixes: 5b316468983d ("btrfs: get zone information of zoned block devices")
CC: stable@vger.kernel.org
Signed-off-by: Naohiro Aota <naohiro.aota@wdc.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Since commit ba8a9d079543 ("Btrfs: delete the entire async bio submission
framework") removed submit workqueues, the parameter fs_devices is not used
anymore.
Remove it, no functional changes.
Reviewed-by: Anand Jain <anand.jain@oracle.com>
Signed-off-by: Su Yue <l@damenly.su>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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In the transaction commit path we are acquiring the tree log mutex too
early and we have a stale comment because:
1) It mentions a function named btrfs_commit_tree_roots(), which does not
exists anymore, it was the old name of commit_cowonly_roots(), renamed
a very long time ago by commit 5d4f98a28c7d33 ("Btrfs: Mixed back
reference (FORWARD ROLLING FORMAT CHANGE)"));
2) It mentions that we need to acquire the tree log mutex at that point
to ensure we have no running log writers. That is not correct anymore,
for many years at least, since we are guaranteed that we do not have
any log writers at that point simply because we have set the state of
the transaction to TRANS_STATE_COMMIT_DOING and have waited for all
writers to complete - meaning no one can log until we change the state
of the transaction to TRANS_STATE_UNBLOCKED. Any attempts to join the
transaction or start a new one will block until we do that state
transition;
3) The comment mentions a "trans mutex" which doesn't exists since 2011,
commit a4abeea41adf ("Btrfs: kill trans_mutex") removed it;
4) The current use of the tree log mutex is to ensure proper serialization
of super block writes - if someone started a new transaction and uses it
for logging, it will wait for the previous transaction to write its
super block before writing the super block when attempting to sync the
log.
So acquire the tree log mutex only when it's absolutely needed, before
setting the transaction state to TRANS_STATE_UNBLOCKED, fix and move the
stale comment, add some assertions and new comments where appropriate.
Also, this has no effect on concurrency or performance, since the new
start of the critical section is still when the transaction is in the
state TRANS_STATE_COMMIT_DOING.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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btrfs_prepare_sprout() splices seed devices into its own struct fs_devices,
so that its parent function btrfs_init_new_device() can add the new sprout
device to fs_info->fs_devices.
Both btrfs_prepare_sprout() and btrfs_init_new_device() need
device_list_mutex. But they are holding it separately, thus create a
small race window. Close it and hold device_list_mutex across both
functions btrfs_init_new_device() and btrfs_prepare_sprout().
Split btrfs_prepare_sprout() into btrfs_init_sprout() and
btrfs_setup_sprout(). This split is essential because device_list_mutex
must not be held for allocations in btrfs_init_sprout() but must be held
for btrfs_setup_sprout(). So now a common device_list_mutex can be used
between btrfs_init_new_device() and btrfs_setup_sprout().
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Declare int seeding_dev as a bool. Also, move its declaration a line
below to adjust packing.
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Again, I don't think this was ever used since iterate_dir_item() is only
used for xattrs. No functional change.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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As far as I can tell, this was never used. No functional change.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The name btrfs_item_end_nr() is a bit of a misnomer, as it's actually
the offset of the end of the data the item points to. In fact all of
the helpers that we use btrfs_item_end_nr() use data in their name, like
BTRFS_LEAF_DATA_SIZE() and leaf_data(). Rename to btrfs_item_data_end()
to make it clear what this helper is giving us.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We're only using btrfs_item_end() from btrfs_item_end_nr(), so this can
be collapsed.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Now that all call sites are using the slot number to modify item values,
rename the SETGET helpers to raw_item_*(), and then rework the _nr()
helpers to be the btrfs_item_*() btrfs_set_item_*() helpers, and then
rename all of the callers to the new helpers.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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The last remaining place where we have the pattern of
item = btrfs_item_nr(slot)
<do something with the item>
are the token helpers. Handle this by introducing token helpers that
will do the btrfs_item_nr() work inside of the helper itself, and then
convert all users of the btrfs_item token helpers to the new _nr()
variants.
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Instead of getting the btrfs_item for this, simply pass in the slot of
the item and then use the btrfs_item_size_nr() helper inside of
btrfs_file_extent_inline_item_len().
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We have the pattern of
item = btrfs_item_nr(slot);
btrfs_set_item_*(leaf, item);
in a bunch of places in our code. Fix this by adding
btrfs_set_item_*_nr() helpers which will do the appropriate work, and
replace those calls with
btrfs_set_item_*_nr(leaf, slot);
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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We have this pattern in a lot of places
item = btrfs_item_nr(slot);
btrfs_item_size(leaf, item);
when we could simply use
btrfs_item_size(leaf, slot);
Fix all callers of btrfs_item_size() and btrfs_item_offset() to use the
_nr variation of the helpers.
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Josef Bacik <josef@toxicpanda.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Now that we log only dir index keys when logging a directory, we no longer
need to deal with dir item keys in the log replay code for replaying
directory deletes. This is also true for the case when we replay a log
tree created by a kernel that still logs dir items.
So remove the remaining code of the replay of directory deletes algorithm
that deals with dir item keys.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
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Currently, when logging a directory, we copy both dir items and dir index
items from the fs/subvolume tree to the log tree. Both items have exactly
the same data (same struct btrfs_dir_item), the difference lies in the key
values, where a dir index key contains the index number of a directory
entry while the dir item key does not, as it's used for doing fast lookups
of an entry by name, while the former is used for sorting entries when
listing a directory.
We can exploit that and log only the dir index items, since they contain
all the information needed to correctly add, replace and delete directory
entries when replaying a log tree. Logging only the dir index items is
also backward and forward compatible: an unpatched kernel (without this
change) can correctly replay a log tree generated by a patched kernel
(with this patch), and a patched kernel can correctly replay a log tree
generated by an unpatched kernel.
The backward compatibility is ensured because:
1) For inserting a new dentry: a dentry is only inserted when we find a
new dir index key - we can only insert if we know the dir index offset,
which is encoded in the dir index key's offset;
2) For deleting dentries: during log replay, before adding or replacing
dentries, we first replay dentry deletions. Whenever we find a dir item
key or a dir index key in the subvolume/fs tree that is not logged in
a range for which the log tree is authoritative, we do the unlink of
the dentry, which removes both the existing dir item key and the dir
index key. Therefore logging just dir index keys is enough to ensure
dentry deletions are correctly replayed;
3) For dentry replacements: they work when we log only dir index keys
and this is mostly due to a combination of 1) and 2). If we replace a
dentry with name "foobar" to point from inode A to inode B, then we
know the dir index key for the new dentry is different from the old
one, as it has an index number (key offset) larger than the old one.
This results in replaying a deletion, through replay_dir_deletes(),
that causes the old dentry to be removed, both the dir item key and
the dir index key, as mentioned at 2). Then when processing the new
dir index key, we add the new dentry, adding both a new dir item key
and a new index key pointing to inode B, as stated in 1).
The forward compatibility, the ability for a patched kernel to replay a
log created by an older, unpatched kernel, comes from the changes required
for making sure we are able to replay a log that only contains dir index
keys - we simply ignore every dir item key we find.
So modify directory logging to log only dir index items, and modify the
log replay process to ignore dir item keys, from log trees created by an
unpatched kernel, and process only with dir index keys. This reduces the
amount of logged metadata by about half, and therefore the time spent
logging or fsyncing large directories (less CPU time and less IO).
The following test script was used to measure this change:
#!/bin/bash
DEV=/dev/nvme0n1
MNT=/mnt/nvme0n1
NUM_NEW_FILES=1000000
NUM_FILE_DELETES=10000
mkfs.btrfs -f $DEV
mount -o ssd $DEV $MNT
mkdir $MNT/testdir
for ((i = 1; i <= $NUM_NEW_FILES; i++)); do
echo -n > $MNT/testdir/file_$i
done
start=$(date +%s%N)
xfs_io -c "fsync" $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "dir fsync took $dur ms after adding $NUM_NEW_FILES files"
# sync to force transaction commit and wipeout the log.
sync
del_inc=$(( $NUM_NEW_FILES / $NUM_FILE_DELETES ))
for ((i = 1; i <= $NUM_NEW_FILES; i += $del_inc)); do
rm -f $MNT/testdir/file_$i
done
start=$(date +%s%N)
xfs_io -c "fsync" $MNT/testdir
end=$(date +%s%N)
dur=$(( (end - start) / 1000000 ))
echo "dir fsync took $dur ms after deleting $NUM_FILE_DELETES files"
echo
umount $MNT
The tests were run on a physical machine, with a non-debug kernel (Debian's
default kernel config), for different values of $NUM_NEW_FILES and
$NUM_FILE_DELETES, and the results were the following:
** Before patch, NUM_NEW_FILES = 1 000 000, NUM_DELETE_FILES = 10 000 **
dir fsync took 8412 ms after adding 1000000 files
dir fsync took 500 ms after deleting 10000 files
** After patch, NUM_NEW_FILES = 1 000 000, NUM_DELETE_FILES = 10 000 **
dir fsync took 4252 ms after adding 1000000 files (-49.5%)
dir fsync took 269 ms after deleting 10000 files (-46.2%)
** Before patch, NUM_NEW_FILES = 100 000, NUM_DELETE_FILES = 1 000 **
dir fsync took 745 ms after adding 100000 files
dir fsync took 59 ms after deleting 1000 files
** After patch, NUM_NEW_FILES = 100 000, NUM_DELETE_FILES = 1 000 **
dir fsync took 404 ms after adding 100000 files (-45.8%)
dir fsync took 31 ms after deleting 1000 files (-47.5%)
** Before patch, NUM_NEW_FILES = 10 000, NUM_DELETE_FILES = 1 000 **
dir fsync took 67 ms after adding 10000 files
dir fsync took 9 ms after deleting 1000 files
** After patch, NUM_NEW_FILES = 10 000, NUM_DELETE_FILES = 1 000 **
dir fsync took 36 ms after adding 10000 files (-46.3%)
dir fsync took 5 ms after deleting 1000 files (-44.4%)
** Before patch, NUM_NEW_FILES = 1 000, NUM_DELETE_FILES = 100 **
dir fsync took 9 ms after adding 1000 files
dir fsync took 4 ms after deleting 100 files
** After patch, NUM_NEW_FILES = 1 000, NUM_DELETE_FILES = 100 **
dir fsync took 7 ms after adding 1000 files (-22.2%)
dir fsync took 3 ms after deleting 100 files (-25.0%)
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
Since both unused block groups and reclaim bgs lists are protected by
unused_bgs_lock then free them in the same critical section without
doing an extra unlock/lock pair.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
When enabling quotas, we attempt to commit a transaction while holding the
mutex fs_info->qgroup_ioctl_lock. This can result on a deadlock with other
quota operations such as:
- qgroup creation and deletion, ioctl BTRFS_IOC_QGROUP_CREATE;
- adding and removing qgroup relations, ioctl BTRFS_IOC_QGROUP_ASSIGN.
This is because these operations join a transaction and after that they
attempt to lock the mutex fs_info->qgroup_ioctl_lock. Acquiring that mutex
after joining or starting a transaction is a pattern followed everywhere
in qgroups, so the quota enablement operation is the one at fault here,
and should not commit a transaction while holding that mutex.
Fix this by making the transaction commit while not holding the mutex.
We are safe from two concurrent tasks trying to enable quotas because
we are serialized by the rw semaphore fs_info->subvol_sem at
btrfs_ioctl_quota_ctl(), which is the only call site for enabling
quotas.
When this deadlock happens, it produces a trace like the following:
INFO: task syz-executor:25604 blocked for more than 143 seconds.
Not tainted 5.15.0-rc6 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:24800 pid:25604 ppid: 24873 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4940 [inline]
__schedule+0xcd9/0x2530 kernel/sched/core.c:6287
schedule+0xd3/0x270 kernel/sched/core.c:6366
btrfs_commit_transaction+0x994/0x2e90 fs/btrfs/transaction.c:2201
btrfs_quota_enable+0x95c/0x1790 fs/btrfs/qgroup.c:1120
btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:4229 [inline]
btrfs_ioctl+0x637e/0x7b70 fs/btrfs/ioctl.c:5010
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
RIP: 0033:0x7f86920b2c4d
RSP: 002b:00007f868f61ac58 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f86921d90a0 RCX: 00007f86920b2c4d
RDX: 0000000020005e40 RSI: 00000000c0109428 RDI: 0000000000000008
RBP: 00007f869212bd80 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f86921d90a0
R13: 00007fff6d233e4f R14: 00007fff6d233ff0 R15: 00007f868f61adc0
INFO: task syz-executor:25628 blocked for more than 143 seconds.
Not tainted 5.15.0-rc6 #4
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor state:D stack:29080 pid:25628 ppid: 24873 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:4940 [inline]
__schedule+0xcd9/0x2530 kernel/sched/core.c:6287
schedule+0xd3/0x270 kernel/sched/core.c:6366
schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6425
__mutex_lock_common kernel/locking/mutex.c:669 [inline]
__mutex_lock+0xc96/0x1680 kernel/locking/mutex.c:729
btrfs_remove_qgroup+0xb7/0x7d0 fs/btrfs/qgroup.c:1548
btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:4333 [inline]
btrfs_ioctl+0x683c/0x7b70 fs/btrfs/ioctl.c:5014
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:874 [inline]
__se_sys_ioctl fs/ioctl.c:860 [inline]
__x64_sys_ioctl+0x193/0x200 fs/ioctl.c:860
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x44/0xae
Reported-by: Hao Sun <sunhao.th@gmail.com>
Link: https://lore.kernel.org/linux-btrfs/CACkBjsZQF19bQ1C6=yetF3BvL10OSORpFUcWXTP6HErshDB4dQ@mail.gmail.com/
Fixes: 340f1aa27f36 ("btrfs: qgroups: Move transaction management inside btrfs_quota_enable/disable")
CC: stable@vger.kernel.org # 4.19
Reviewed-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
When doing a direct IO write against a file range that either has
preallocated extents in that range or has regular extents and the file
has the NOCOW attribute set, the write fails with -ENOSPC when all of
the following conditions are met:
1) There are no data blocks groups with enough free space matching
the size of the write;
2) There's not enough unallocated space for allocating a new data block
group;
3) The extents in the target file range are not shared, neither through
snapshots nor through reflinks.
This is wrong because a NOCOW write can be done in such case, and in fact
it's possible to do it using a buffered IO write, since when failing to
allocate data space, the buffered IO path checks if a NOCOW write is
possible.
The failure in direct IO write path comes from the fact that early on,
at btrfs_dio_iomap_begin(), we try to allocate data space for the write
and if it that fails we return the error and stop - we never check if we
can do NOCOW. But later, at btrfs_get_blocks_direct_write(), we check
if we can do a NOCOW write into the range, or a subset of the range, and
then release the previously reserved data space.
Fix this by doing the data reservation only if needed, when we must COW,
at btrfs_get_blocks_direct_write() instead of doing it at
btrfs_dio_iomap_begin(). This also simplifies a bit the logic and removes
the inneficiency of doing unnecessary data reservations.
The following example test script reproduces the problem:
$ cat dio-nocow-enospc.sh
#!/bin/bash
DEV=/dev/sdj
MNT=/mnt/sdj
# Use a small fixed size (1G) filesystem so that it's quick to fill
# it up.
# Make sure the mixed block groups feature is not enabled because we
# later want to not have more space available for allocating data
# extents but still have enough metadata space free for the file writes.
mkfs.btrfs -f -b $((1024 * 1024 * 1024)) -O ^mixed-bg $DEV
mount $DEV $MNT
# Create our test file with the NOCOW attribute set.
touch $MNT/foobar
chattr +C $MNT/foobar
# Now fill in all unallocated space with data for our test file.
# This will allocate a data block group that will be full and leave
# no (or a very small amount of) unallocated space in the device, so
# that it will not be possible to allocate a new block group later.
echo
echo "Creating test file with initial data..."
xfs_io -c "pwrite -S 0xab -b 1M 0 900M" $MNT/foobar
# Now try a direct IO write against file range [0, 10M[.
# This should succeed since this is a NOCOW file and an extent for the
# range was previously allocated.
echo
echo "Trying direct IO write over allocated space..."
xfs_io -d -c "pwrite -S 0xcd -b 10M 0 10M" $MNT/foobar
umount $MNT
When running the test:
$ ./dio-nocow-enospc.sh
(...)
Creating test file with initial data...
wrote 943718400/943718400 bytes at offset 0
900 MiB, 900 ops; 0:00:01.43 (625.526 MiB/sec and 625.5265 ops/sec)
Trying direct IO write over allocated space...
pwrite: No space left on device
A test case for fstests will follow, testing both this direct IO write
scenario as well as the buffered IO write scenario to make it less likely
to get future regressions on the buffered IO case.
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
|
|
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux
Pull perf tools fixes from Arnaldo Carvalho de Melo:
- Fix TUI exit screen refresh race condition in 'perf top'.
- Fix parsing of Intel PT VM time correlation arguments.
- Honour CPU filtering command line request of a script's switch events
in 'perf script'.
- Fix printing of switch events in Intel PT python script.
- Fix duplicate alias events list printing in 'perf list', noticed on
heterogeneous arm64 systems.
- Fix return value of ids__new(), users expect NULL for failure, not
ERR_PTR(-ENOMEM).
* tag 'perf-tools-fixes-for-v5.16-2022-01-02' of git://git.kernel.org/pub/scm/linux/kernel/git/acme/linux:
perf top: Fix TUI exit screen refresh race condition
perf pmu: Fix alias events list
perf scripts python: intel-pt-events.py: Fix printing of switch events
perf script: Fix CPU filtering of a script's switch events
perf intel-pt: Fix parsing of VM time correlation arguments
perf expr: Fix return value of ids__new()
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux
Pull i2c fixes from Wolfram Sang:
"Better input validation for compat ioctls and a documentation bugfix
for 5.16"
* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
Docs: Fixes link to I2C specification
i2c: validate user data in compat ioctl
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 fix from Borislav Petkov:
- Use the proper CONFIG symbol in a preprocessor check.
* tag 'x86_urgent_for_v5.16_rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
x86/build: Use the proper name CONFIG_FW_LOADER
|
|
When the following command is executed several times, a coredump file is
generated.
$ timeout -k 9 5 perf top -e task-clock
*******
*******
*******
0.01% [kernel] [k] __do_softirq
0.01% libpthread-2.28.so [.] __pthread_mutex_lock
0.01% [kernel] [k] __ll_sc_atomic64_sub_return
double free or corruption (!prev) perf top --sort comm,dso
timeout: the monitored command dumped core
When we terminate "perf top" using sending signal method,
SLsmg_reset_smg() called. SLsmg_reset_smg() resets the SLsmg screen
management routines by freeing all memory allocated while it was active.
However SLsmg_reinit_smg() maybe be called by another thread.
SLsmg_reinit_smg() will free the same memory accessed by
SLsmg_reset_smg(), thus it results in a double free.
SLsmg_reinit_smg() is called already protected by ui__lock, so we fix
the problem by adding pthread_mutex_trylock of ui__lock when calling
SLsmg_reset_smg().
Signed-off-by: Wenyu Liu <liuwenyu7@huawei.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: wuxu.wu@huawei.com
Link: http://lore.kernel.org/lkml/a91e3943-7ddc-f5c0-a7f5-360f073c20e6@huawei.com
Signed-off-by: Hewenliang <hewenliang4@huawei.com>
Signed-off-by: yaowenbin <yaowenbin1@huawei.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|
|
Commit 0e0ae8742207c3b4 ("perf list: Display hybrid PMU events with cpu
type") changes the event list for uncore PMUs or arm64 heterogeneous CPU
systems, such that duplicate aliases are incorrectly listed per PMU
(which they should not be), like:
# perf list
...
unc_cbo_cache_lookup.any_es
[Unit: uncore_cbox L3 Lookup any request that access cache and found
line in E or S-state]
unc_cbo_cache_lookup.any_es
[Unit: uncore_cbox L3 Lookup any request that access cache and found
line in E or S-state]
unc_cbo_cache_lookup.any_i
[Unit: uncore_cbox L3 Lookup any request that access cache and found
line in I-state]
unc_cbo_cache_lookup.any_i
[Unit: uncore_cbox L3 Lookup any request that access cache and found
line in I-state]
...
Notice how the events are listed twice.
The named commit changed how we remove duplicate events, in that events
for different PMUs are not treated as duplicates. I suppose this is to
handle how "Each hybrid pmu event has been assigned with a pmu name".
Fix PMU alias listing by restoring behaviour to remove duplicates for
non-hybrid PMUs.
Fixes: 0e0ae8742207c3b4 ("perf list: Display hybrid PMU events with cpu type")
Signed-off-by: John Garry <john.garry@huawei.com>
Tested-by: Zhengjun Xing <zhengjun.xing@linux.intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/1640103090-140490-1-git-send-email-john.garry@huawei.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input
Pull input fixes from Dmitry Torokhov:
"Two small fixups for spaceball joystick driver and appletouch touchpad
driver"
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
Input: spaceball - fix parsing of movement data packets
Input: appletouch - initialize work before device registration
|
|
Hugh Dickins reported the following
My tmpfs swapping load (tweaked to use huge pages more heavily
than in real life) is far from being a realistic load: but it was
notably slowed down by your throttling mods in 5.16-rc, and this
patch makes it well again - thanks.
But: it very quickly hit NULL pointer until I changed that last
line to
if (first_pgdat)
consider_reclaim_throttle(first_pgdat, sc);
The likely issue is that huge pages are a major component of the test
workload. When this is the case, first_pgdat may never get set if
compaction is ready to continue due to this check
if (IS_ENABLED(CONFIG_COMPACTION) &&
sc->order > PAGE_ALLOC_COSTLY_ORDER &&
compaction_ready(zone, sc)) {
sc->compaction_ready = true;
continue;
}
If this was true for every zone in the zonelist, first_pgdat would never
get set resulting in a NULL pointer exception.
Link: https://lkml.kernel.org/r/20211209095453.GM3366@techsingularity.net
Fixes: 1b4e3f26f9f75 ("mm: vmscan: Reduce throttling due to a failure to make progress")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Reported-by: Hugh Dickins <hughd@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Rik van Riel <riel@surriel.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Darrick J. Wong <djwong@kernel.org>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Mike Galbraith, Alexey Avramov and Darrick Wong all reported similar
problems due to reclaim throttling for excessive lengths of time. In
Alexey's case, a memory hog that should go OOM quickly stalls for
several minutes before stalling. In Mike and Darrick's cases, a small
memcg environment stalled excessively even though the system had enough
memory overall.
Commit 69392a403f49 ("mm/vmscan: throttle reclaim when no progress is
being made") introduced the problem although commit a19594ca4a8b
("mm/vmscan: increase the timeout if page reclaim is not making
progress") made it worse. Systems at or near an OOM state that cannot
be recovered must reach OOM quickly and memcg should kill tasks if a
memcg is near OOM.
To address this, only stall for the first zone in the zonelist, reduce
the timeout to 1 tick for VMSCAN_THROTTLE_NOPROGRESS and only stall if
the scan control nr_reclaimed is 0, kswapd is still active and there
were excessive pages pending for writeback. If kswapd has stopped
reclaiming due to excessive failures, do not stall at all so that OOM
triggers relatively quickly. Similarly, if an LRU is simply congested,
only lightly throttle similar to NOPROGRESS.
Alexey's original case was the most straight forward
for i in {1..3}; do tail /dev/zero; done
On vanilla 5.16-rc1, this test stalled heavily, after the patch the test
completes in a few seconds similar to 5.15.
Alexey's second test case added watching a youtube video while tail runs
10 times. On 5.15, playback only jitters slightly, 5.16-rc1 stalls a
lot with lots of frames missing and numerous audio glitches. With this
patch applies, the video plays similarly to 5.15.
[lkp@intel.com: Fix W=1 build warning]
Link: https://lore.kernel.org/r/99e779783d6c7fce96448a3402061b9dc1b3b602.camel@gmx.de
Link: https://lore.kernel.org/r/20211124011954.7cab9bb4@mail.inbox.lv
Link: https://lore.kernel.org/r/20211022144651.19914-1-mgorman@techsingularity.net
Link: https://lore.kernel.org/r/20211202150614.22440-1-mgorman@techsingularity.net
Link: https://linux-regtracking.leemhuis.info/regzbot/regression/20211124011954.7cab9bb4@mail.inbox.lv/
Reported-and-tested-by: Alexey Avramov <hakavlad@inbox.lv>
Reported-and-tested-by: Mike Galbraith <efault@gmx.de>
Reported-and-tested-by: Darrick J. Wong <djwong@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Acked-by: Hugh Dickins <hughd@google.com>
Tracked-by: Thorsten Leemhuis <regressions@leemhuis.info>
Fixes: 69392a403f49 ("mm/vmscan: throttle reclaim when no progress is being made")
Signed-off-by: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
|
|
Merge misc mm fixes from Andrew Morton:
"2 patches.
Subsystems affected by this patch series: mm (userfaultfd and damon)"
* akpm:
mm/damon/dbgfs: fix 'struct pid' leaks in 'dbgfs_target_ids_write()'
userfaultfd/selftests: fix hugetlb area allocations
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi
Pull SCSI fixes from James Bottomley:
"Three fixes, all in drivers. The lpfc one doesn't look exploitable,
but nasty things could happen in string operations if mybuf ends up
with an on stack unterminated string"
* tag 'scsi-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/jejb/scsi:
scsi: vmw_pvscsi: Set residual data length conditionally
scsi: libiscsi: Fix UAF in iscsi_conn_get_param()/iscsi_conn_teardown()
scsi: lpfc: Terminate string in lpfc_debugfs_nvmeio_trc_write()
|
|
DAMON debugfs interface increases the reference counts of 'struct pid's
for targets from the 'target_ids' file write callback
('dbgfs_target_ids_write()'), but decreases the counts only in DAMON
monitoring termination callback ('dbgfs_before_terminate()').
Therefore, when 'target_ids' file is repeatedly written without DAMON
monitoring start/termination, the reference count is not decreased and
therefore memory for the 'struct pid' cannot be freed. This commit
fixes this issue by decreasing the reference counts when 'target_ids' is
written.
Link: https://lkml.kernel.org/r/20211229124029.23348-1-sj@kernel.org
Fixes: 4bc05954d007 ("mm/damon: implement a debugfs-based user space interface")
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: <stable@vger.kernel.org> [5.15+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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Currently, userfaultfd selftest for hugetlb as run from run_vmtests.sh
or any environment where there are 'just enough' hugetlb pages will
always fail with:
testing events (fork, remap, remove):
ERROR: UFFDIO_COPY error: -12 (errno=12, line=616)
The ENOMEM error code implies there are not enough hugetlb pages.
However, there are free hugetlb pages but they are all reserved. There
is a basic problem with the way the test allocates hugetlb pages which
has existed since the test was originally written.
Due to the way 'cleanup' was done between different phases of the test,
this issue was masked until recently. The issue was uncovered by commit
8ba6e8640844 ("userfaultfd/selftests: reinitialize test context in each
test").
For the hugetlb test, src and dst areas are allocated as PRIVATE
mappings of a hugetlb file. This means that at mmap time, pages are
reserved for the src and dst areas. At the start of event testing (and
other tests) the src area is populated which results in allocation of
huge pages to fill the area and consumption of reserves associated with
the area. Then, a child is forked to fault in the dst area. Note that
the dst area was allocated in the parent and hence the parent owns the
reserves associated with the mapping. The child has normal access to
the dst area, but can not use the reserves created/owned by the parent.
Thus, if there are no other huge pages available allocation of a page
for the dst by the child will fail.
Fix by not creating reserves for the dst area. In this way the child
can use free (non-reserved) pages.
Also, MAP_PRIVATE of a file only makes sense if you are interested in
the contents of the file before making a COW copy. The test does not do
this. So, just use MAP_ANONYMOUS | MAP_HUGETLB to create an anonymous
hugetlb mapping. There is no need to create a hugetlb file in the
non-shared case.
Link: https://lkml.kernel.org/r/20211217172919.7861-1-mike.kravetz@oracle.com
Signed-off-by: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Axel Rasmussen <axelrasmussen@google.com>
Cc: Peter Xu <peterx@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Mina Almasry <almasrymina@google.com>
Cc: Shuah Khan <shuah@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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The link to the I2C specification is broken. Although
"https://www.nxp.com" hosts Rev 7 (2021) of this specification, it is
behind a login-wall. Thus, an additional link has been added (which
doesn't require a login) and the NXP official docs link has been
updated.
Signed-off-by: Deep Majumder <deep@fastmail.in>
[wsa: minor updates to text and commit message]
Signed-off-by: Wolfram Sang <wsa@kernel.org>
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