lockdep_is_cpus_held() and lockdep_is_cpus_write_held() are undefined when
!CONFIG_HOTPLUG_CPU. This is ok because their few callers protect the calls
with a "if (IS_ENABLED(CONFIG_HOTPLUG_CPU) ..." check.
It is error prone to require callers to protect lockdep_is_cpus_held()
and lockdep_is_cpus_write_held() with an IS_ENABLED(CONFIG_HOTPLUG_CPU)
check while the custom for equivalent functions, for example the more
prevalent lockdep_is_held(), is to not require similar protection.
It is also inconsistent with CPU hotplug lockdep code self since related
call lockdep_assert_cpus_held() does not require protection.
Create stubs for lockdep_is_cpus_held() and lockdep_is_cpus_write_held()
that returns 1 (LOCK_STATE_UNKNOWN/LOCK_STATE_HELD) when !CONFIG_HOTPLUG_CPU.
This makes the CPU hotplug lockdep checks consistent while following
existing lockdep custom. Drop the "extern" from the function declaration
as part of the move to match kernel coding style.
Keep the IS_ENABLED(CONFIG_HOTPLUG_CPU) checks in existing users since
removing them would change the logic of these expressions.
Reported-by: Sashiko <sashiko-bot@kernel.org>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/7484f0b58fd86153d445819cc4e172adba16cff9.1780543665.git.reinette.chatre@intel.com
Closes: https://sashiko.dev/#/patchset/cover.1780456704.git.reinette.chatre%40intel.com?part=1
A bug was reported where the parsing of multi-character short options,
be it a short option with an argument specified without space (e.g.
"-p100") or multiple short options in one argument (e.g. -un), ignores
options specific to individual tools.
Furthermore, if the rest of the option is supposed to be an argument, it
gets reinterpreted as a string of options. For example, -p100 gets
interpreted as -100, which is due to hackish implementation read as
--no-thread --no-irq --no-irq with timerlat hist, causing rtla to error
out:
$ rtla timerlat hist -p100
no-irq and no-thread set, there is nothing to do here
This behavior is caused by getopt_long() being called twice on each
argument, once in common_parse_options(), once in [tool]_parse_args():
- common_parse_options() calls getopt_long() with an array of options
common for all rtla tools, while suppressing errors (opterr = 0).
- If the option fails to parse, common_parse_options() returns 0.
- If 0 is returned from common_parse_options(), [tool]_parse_args()
calls getopt_long() again, with its own set of options.
* [tool] means one of {osnoise,timerlat}_{top,hist}
At least in glibc, getopt_long() increments its internal nextchar
variable even if the option is not recognized. That means that in the
case of "-p100", common_parse_options() sets nextchar pointing to '1',
and timerlat_hist_parse_args() sees '1', not 'p'; the same then repeats
for the first and second '0'.
As there is no way to restore the correct internal state of
getopt_long() reliably, fix the issue by merging the common options back
to the longopt array and option string of the [tool]_parse_args()
functions using a macro; only the switch part is left in the original
function, which is renamed to set_common_option().
Fixes: 850cd24cb6 ("tools/rtla: Add common_parse_options()")
Reported-by: John Kacur <jkacur@redhat.com>
Tested-by: John Kacur <jkacur@redhat.com>
Link: https://lore.kernel.org/r/20260602125506.3325345-1-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
In geneve_post_decap_hint the length used for adjusting the UDP checksum
should be 'skb->len - gro_hint->nested_tp_offset' (UDP length) instead
of 'skb->len - gro_hint->nested_nh_offset' (IP length).
Fixes: fd0dd79657 ("geneve: use GRO hint option in the RX path")
Cc: Paolo Abeni <pabeni@redhat.com>
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://sashiko.dev/#/patchset/20260521131436.748832-1-jhs%40mojatatu.com
Signed-off-by: Antoine Tenart <atenart@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://patch.msgid.link/20260529144713.780938-1-atenart@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Matthew Wilcox (Oracle) <willy@infradead.org> says:
There are four benefits to this patchset. First, it removes an
indirect function call from the completion path. Instead of setting
bio->bi_end_io to end_bio_bh_io_sync() which then calls bh->b_end_io(),
we set bio->bi_end_io to the appropriate completion handler, replacing
two indirect function calls with one.
Second, there is a slight security advantage to this. It is one fewer
function pointer in the middle of a writable data structure that can
be corrupted. Third, it shrinks struct buffer_head from 104 bytes to 96
bytes, allowing for appropriximately 7% reduction in the amount of memory
used by buffer_heads (or, alternatively, allows 7% more buffer_heads to
be cached in the same amount of memory). Fourth, it removes some
atomic operations as the buffer refcount is no longer incremented before
calling the end_io handler.
I've run ext4 through its paces, and everything seems OK. I've only
compiled ocfs2/gfs2/nilfs/md-bitmap. Hopefully the maintainers can give
this series a try. I'm sending the entire series to linux-fsdevel
and cc'ing the fs-specific mailing lists for the fs-specific patches.
* patches from https://patch.msgid.link/20260528173150.1093780-1-willy@infradead.org: (34 commits)
buffer: Remove end_buffer_write_sync()
buffer: Change calling convention for end_buffer_read_sync()
buffer: Remove b_end_io
buffer: Remove submit_bh()
md-bitmap: Convert read_file_page and write_file_page to bh_submit()
nilfs2: Convert nilfs_mdt_submit_block to bh_submit()
nilfs2: Convert nilfs_gccache_submit_read_data to bh_submit()
nilfs2: Convert nilfs_btnode_submit_block to bh_submit()
buffer: Remove mark_buffer_async_write()
gfs2: Convert gfs2_aspace_write_folio to bh_submit()
gfs2: Remove use of b_end_io in gfs2_meta_read_endio()
gfs2: Convert gfs2_dir_readahead to bh_submit()
gfs2: Convert gfs2_metapath_ra to bh_submit()
ocfs2: Convert ocfs2_write_super_or_backup to bh_submit()
ocfs2: Convert ocfs2_read_blocks to bh_submit()
ocfs2: Convert ocfs2_read_block to bh_submit()
ocfs2: Convert ocfs2_write_block to bh_submit()
jbd2: Convert jbd2_write_superblock() to bh_submit()
jbd2: Convert journal commit to bh_submit()
ext4: Convert ext4_commit_super() to bh_submit()
...
Link: https://patch.msgid.link/20260528173150.1093780-1-willy@infradead.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
It has no callers left, so delete it. Inline __end_buffer_write_sync()
into bh_end_write().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-35-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Unify end_buffer_read_sync() and __end_buffer_read_notouch()
by requiring the caller put the refcount on the buffer. The only caller
is in the gfs2_meta_read() path, and there we can put the refcount
after locking the buffer.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-34-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
This shrinks buffer_head by 8 bytes, letting us pack more buffer heads
per slab. With a Debian config, it shrinks from 104 bytes to 96 bytes
which is 42 objects per 4KiB page rather than 39, a 7% reduction in the
amount of memory used.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-33-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
No users are left; remove this API. Also remove/fix comments mentioning
it, and end_bio_bh_io_sync() as it's now unused.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-32-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-30-willy@infradead.org
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-nilfs@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-29-willy@infradead.org
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-nilfs@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-28-willy@infradead.org
Acked-by: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Reviewed-by: Viacheslav Dubeyko <slava@dubeyko.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-nilfs@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
There are no more callers of this function, so delete it.
end_buffer_async_write() then has only one caller left, so
inline it into bh_end_async_write().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-27-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
All buffer heads submitted by gfs2_submit_bhs() use
end_buffer_read_sync() so we can call it directly.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-25-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: gfs2@lists.linux.dev
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call by using bh_submit() instead of
submit_bh(). Also simplify the control flow now that the buffer
refcount is not put by bh_end_read().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-24-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: gfs2@lists.linux.dev
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call by using bh_submit() instead
of submit_bh(). Also simplify the control flow now that the buffer
refcount is not put by bh_end_read().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-23-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: gfs2@lists.linux.dev
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-22-willy@infradead.org
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: ocfs2-devel@lists.linux.dev
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-21-willy@infradead.org
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: ocfs2-devel@lists.linux.dev
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-20-willy@infradead.org
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: ocfs2-devel@lists.linux.dev
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer
refcount by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-19-willy@infradead.org
Reviewed-by: Joseph Qi <joseph.qi@linux.alibaba.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: ocfs2-devel@lists.linux.dev
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-18-willy@infradead.org
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call by using bh_submit()
instead of submit_bh() in journal_submit_commit_record()
and jbd2_journal_commit_transaction(). These both use
journal_end_buffer_io_sync(), so it's more straightforward to do them
both at once.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-17-willy@infradead.org
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-16-willy@infradead.org
Acked-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-15-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call by converting
ext4_end_buffer_io_sync() from bh_end_io_t to bio_end_io_t and
calling bh_submit().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-14-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by converting ext4_end_bitmap_read() from bh_end_io_t to bio_end_io_t
and calling bh_submit().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-13-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Cc: linux-ext4@vger.kernel.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call by using __bh_submit() instead
of submit_bh_wbc(). Since there is only one caller of submit_bh_wbc()
left, inline it into submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-12-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call by using bh_submit() instead of
submit_bh(). Since mark_buffer_async_read() would collapse to a single
function call, inline it into block_read_full_folio() along with its
extensive comment. Convert end_buffer_async_read_io() to
bh_end_async_read().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-11-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-10-willy@infradead.org
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-9-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-8-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-7-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Avoid an extra indirect function call and changing the buffer refcount
by using bh_submit() instead of submit_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-6-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
These are the bio_end_io_t versions of end_buffer_read_sync(),
end_buffer_write_sync() and end_buffer_async_write(). They do not
contain a put_bh() call as it is no longer necessary.
Also add the helper function bio_endio_bh().
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-5-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
All callers of mark_buffer_async_write_endio() pass
end_buffer_async_write, so we can inline mark_buffer_async_write_endio()
into mark_buffer_async_write() and just call that instead.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-4-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
bh_submit() takes a bio_end_io allowing users to avoid the indirect
function call through bh->b_end_io, and eventually allowing us to remove
bh->b_end_io.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-3-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Rearrange functions to avoid this forward declaration.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Link: https://patch.msgid.link/20260528173150.1093780-2-willy@infradead.org
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Nam Cao <namcao@linutronix.de> says:
While staring at epoll, I noticed ep_events_available() looks wrong. I
wrote a small program to confirm, and yes it is definitely wrong.
This series adds a reproducer to kselftest, and fix the bug.
* patches from https://patch.msgid.link/cover.1780422137.git.namcao@linutronix.de:
eventpoll: Fix epoll_wait() report false negative
selftests/eventpoll: Add test for multiple waiters
Link: https://patch.msgid.link/cover.1780422137.git.namcao@linutronix.de
Signed-off-by: Christian Brauner <brauner@kernel.org>
ep_events_available() checks for available events by looking at
ep->rdllist and ep_is_scanning(). However, this is done without a lock
and can report false negative if ep_start_scan() or ep_done_scan() are
executed by another task concurrently. For example:
_________________________________________________________________________
|ep_start_scan()
| list_splice_init(&ep->rdllist, ...)
ep_events_available() |
!list_empty_careful(&ep->rdllist)|
|| ep_is_scanning(ep) |
| ep_enter_scan(ep)
___________________________________|_____________________________________
Another example:
_________________________________________________________________________
ep_events_available() |
|ep_start_scan()
| list_splice_init(&ep->rdllist, ...)
| ep_enter_scan(ep)
!list_empty_careful(&ep->rdllist)|
|ep_done_scan()
| ep_exit_scan(ep)
| list_splice(..., &ep->rdllist)
|| ep_is_scanning(ep) |
___________________________________|_____________________________________
In the above examples, ep_events_available() sees no event despite
events being available. In case epoll_wait() is called with timeout=0,
epoll_wait() will wrongly return "no event" to user.
Introduce a sequence lock to resolve this issue.
Measuring the time consumption of 10 million loop iterations doing
epoll_wait(), the following performance drop is observed:
timeout #event before after diff
0ms 0 3727ms 3974ms +6.6%
0ms 1 8099ms 9134ms +13%
1ms 1 13525ms 13586ms +0.45%
Considering the use case of epoll_wait() (wait for events, do something
with the events, repeat), it should only contribute to a small portion of
user's CPU consumption. Therefore this performance drop is not alarming.
Fixes: c5a282e963 ("fs/epoll: reduce the scope of wq lock in epoll_wait()")
Suggested-by: Mateusz Guzik <mjguzik@gmail.com>
Signed-off-by: Nam Cao <namcao@linutronix.de>
Link: https://patch.msgid.link/4363cd8e34a21d4f0d257be1b33e84dc25030fdf.1780422138.git.namcao@linutronix.de
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Add a test whichs creates 64 threads who all epoll_wait() on the same
eventpoll. The source eventfd is written but never read, therefore all the
threads should always see an EPOLLIN event.
This test fails because of a kernel bug, which will be fixed by a follow-up
commit.
Signed-off-by: Nam Cao <namcao@linutronix.de>
Link: https://patch.msgid.link/b11947013563875c046c0b0959c29fd95eeebd34.1780422138.git.namcao@linutronix.de
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
The OSS sequencer write and out-of-band paths may receive a temporary
snd_use_lock_t reference from snd_seq_oss_process_event(). This was added
to keep MIDI device data alive until events with embedded SysEx data are
dispatched.
Use a scoped cleanup helper for that temporary reference. This keeps the
lifetime rule local to the variable declaration and avoids future missing
snd_use_lock_free() paths if these event handling paths gain more exits.
No functional change is intended.
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260604-alsa-scoped-cleanups-v1-3-10c43152a728@gmail.com
Several ALSA paths acquire temporary card references with snd_card_ref()
and release them manually with snd_card_unref(). control_led.c already
defines a local cleanup helper for this pattern, while other core paths
still open-code the release.
Move the helper to the common ALSA core header and use it in control-layer
card-reference paths. This makes the ownership rule explicit and avoids
future missing-unref mistakes when adding early exits.
No functional change is intended.
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260604-alsa-scoped-cleanups-v1-2-10c43152a728@gmail.com
User-defined control TLV data and enum names are copied from user space
with vmemdup_user() before being installed in the user_element. Until
ownership is transferred, these temporary buffers have to be released on
every validation exit.
Use __free(kvfree) for the temporary buffers and no_free_ptr() when
ownership is transferred to the user_element. This removes the manual
kvfree() calls from the unchanged-TLV and enum-name validation paths,
makes the ownership hand-off explicit, and keeps the existing allocation
accounting and ABI unchanged.
No functional change is intended.
Signed-off-by: Cássio Gabriel <cassiogabrielcontato@gmail.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Link: https://patch.msgid.link/20260604-alsa-scoped-cleanups-v1-1-10c43152a728@gmail.com
When NVMe-TCP controller setup and teardown are repeated with lockdep
enabled, lockdep reports false positives WARN for the following locks:
1) &q->elevator_lock : IO scheduler change context
2) &q->q_usage_counter(io) : SCSI disk probe context
3) fs_reclaim : CPU hotplug bring-up context
4) cpu_hotplug_lock : socket establishment context
5) sk_lock-AF_INET-NVME : MQ sched dispatch context for the socket
6) set->srcu : NVMe controller delete context
The lockdep WARN was observed by running blktests test case nvme/005 for
tcp transport on v7.1-rc1 kernel with a patch. Refer to the Link tag for
the details of the WARN.
This is a false positive because lockdep confuses lock 4) (socket
establishment) with lock 5) (socket in use) for different socket
instances. The locks belong to different sockets, but lockdep treats
them as the same due to shared static lockdep keys.
Fix this by using dynamically allocated lockdep keys per socket instance
instead of static keys nvme_tcp_sk_key[] and nvme_tcp_slock_key[]. Add
nvme_tcp_sk_key and nvme_tcp_slock_key fields to struct nvme_tcp_queue
and pass them to sock_lock_init_class_and_name() for proper lockdep
tracking. Change the argument of nvme_tcp_reclassify_socket() from
'struct socket *' to 'struct nvme_tcp_queue *' to pass both the socket
and the keys. Add CONFIG_DEBUG_LOCK_ALLOC guards to nvme_tcp_alloc_queue()
and nvme_tcp_free_queue() to register and unregister the dynamic keys.
Additionally, move nvme_tcp_reclassify_socket() inside these guards since
it's only needed when lockdep is enabled.
Link: https://lore.kernel.org/linux-nvme/afB5syZbUrppgsDQ@shinmob/
Suggested-by: Nilay Shroff <nilay@linux.ibm.com>
Reviewed-by: Nilay Shroff <nilay@linux.ibm.com>
Signed-off-by: Shin'ichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Signed-off-by: Keith Busch <kbusch@kernel.org>
Jeff Layton <jlayton@kernel.org> says:
This patch series is intended to improve write performance with
RWF_DONTCACHE. This version fixes additional stat accounting issues
found during review: integer promotion on 32-bit, cgroup writeback
domain migration, folio split flag preservation, and a UAF that could
occur in filemap_dontcache_kick_writeback().
* patches from https://patch.msgid.link/20260511-dontcache-v7-0-2848ddce8090@kernel.org:
mm: kick writeback flusher for IOCB_DONTCACHE with targeted dirty tracking
mm: track DONTCACHE dirty pages per bdi_writeback
mm: preserve PG_dropbehind flag during folio split
Link: https://patch.msgid.link/20260511-dontcache-v7-0-2848ddce8090@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
The internal microphone on ASUS VivoBook X509DAP (subsystem ID
0x1043:0x197e) is not detected without a quirk entry. Add
ALC256_FIXUP_ASUS_MIC_NO_PRESENCE to fix the issue.
Signed-off-by: Andrei Faleichyk <andrei.faleichyk@noogadev.com>
Link: https://patch.msgid.link/20260603213313.6298-1-andrei.faleichyk@noogadev.com
Signed-off-by: Takashi Iwai <tiwai@suse.de>
The IOCB_DONTCACHE writeback path in generic_write_sync() calls
filemap_flush_range() on every write, submitting writeback inline in
the writer's context. Perf lock contention profiling shows the
performance problem is not lock contention but the writeback submission
work itself — walking the page tree and submitting I/O blocks the writer
for milliseconds, inflating p99.9 latency from 23ms (buffered) to 93ms
(dontcache).
Replace the inline filemap_flush_range() call with a flusher kick that
drains dirty pages in the background. This moves writeback submission
completely off the writer's hot path.
To avoid flushing unrelated buffered dirty data, add a dedicated
WB_start_dontcache bit and wb_check_start_dontcache() handler that uses
the per-wb WB_DONTCACHE_DIRTY counter to determine how many pages to
write back. The flusher writes back that many pages from the oldest dirty
inodes (not restricted to dontcache-specific inodes). This helps
preserve I/O batching while limiting the scope of expedited writeback.
Like WB_start_all, the WB_start_dontcache bit coalesces multiple
DONTCACHE writes into a single flusher wakeup without per-write
allocations. Use test_and_clear_bit to atomically consume the kick
request before reading the dirty counter and starting writeback, so that
concurrent DONTCACHE writes during writeback can re-set the bit and
schedule a follow-up flusher run.
Read the dirty counter with wb_stat_sum() (aggregating per-CPU batches)
rather than wb_stat() (which reads only the global counter) to ensure
small writes below the percpu batch threshold are visible to the flusher.
In filemap_dontcache_kick_writeback(), set the WB_start_dontcache bit
inside the unlocked_inode_to_wb_begin/end section for correct cgroup
writeback domain targeting, but defer the wb_wakeup() call until after
the section ends, since wb_wakeup() uses spin_unlock_irq() which would
unconditionally re-enable interrupts while the i_pages xa_lock may still
be held under irqsave during a cgroup writeback switch. Pin the wb with
wb_get() inside the RCU critical section before calling wb_wakeup()
outside it, since cgroup bdi_writeback structures are RCU-freed and the
wb pointer could become invalid after unlocked_inode_to_wb_end() drops
the RCU read lock.
Also add WB_REASON_DONTCACHE as a new writeback reason for tracing
visibility.
dontcache-bench results (same host, T6F_SKL_1920GBF, 251 GiB RAM,
xfs on NVMe, fio io_uring):
Buffered and direct I/O paths are unaffected by this patchset. All
improvements are confined to the dontcache path:
Single-stream throughput (MB/s):
Before After Change
seq-write/dontcache 298 897 +201%
rand-write/dontcache 131 236 +80%
Tail latency improvements (seq-write/dontcache):
p99: 135,266 us -> 23,986 us (-82%)
p99.9: 8,925,479 us -> 28,443 us (-99.7%)
Multi-writer (4 jobs, sequential write):
Before After Change
dontcache aggregate (MB/s) 2,529 4,532 +79%
dontcache p99 (us) 8,553 1,002 -88%
dontcache p99.9 (us) 109,314 1,057 -99%
Dontcache multi-writer throughput now matches buffered (4,532 vs
4,616 MB/s).
32-file write (Axboe test):
Before After Change
dontcache aggregate (MB/s) 1,548 3,499 +126%
dontcache p99 (us) 10,170 602 -94%
Peak dirty pages (MB) 1,837 213 -88%
Dontcache now reaches 81% of buffered throughput (was 35%).
Competing writers (dontcache vs buffered, separate files):
Before After
buffered writer 868 433 MB/s
dontcache writer 415 433 MB/s
Aggregate 1,284 866 MB/s
Previously the buffered writer starved the dontcache writer 2:1.
With per-bdi_writeback tracking, both writers now receive equal
bandwidth. The aggregate matches the buffered-vs-buffered baseline
(863 MB/s), indicating fair sharing regardless of I/O mode.
The dontcache writer's p99.9 latency collapsed from 119 ms to
33 ms (-73%), eliminating the severe periodic stalls seen in the
baseline. Both writers now share identical latency profiles,
matching the buffered-vs-buffered pattern.
The per-bdi_writeback dirty tracking dramatically reduces peak dirty
pages in dontcache workloads, with the 32-file test dropping from
1.8 GB to 213 MB. Dontcache sequential write throughput triples and
multi-writer throughput reaches parity with buffered I/O, with tail
latencies collapsing by 1-2 orders of magnitude.
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260511-dontcache-v7-3-2848ddce8090@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
Add a per-wb WB_DONTCACHE_DIRTY counter that tracks the number of dirty
pages with the dropbehind flag set (i.e., pages dirtied via RWF_DONTCACHE
writes).
Increment the counter alongside WB_RECLAIMABLE in folio_account_dirtied()
when the folio has the dropbehind flag set, and decrement it in
folio_clear_dirty_for_io() and folio_account_cleaned(). Also decrement it
when a non-DONTCACHE lookup atomically clears the dropbehind flag on a
dirty folio in __filemap_get_folio_mpol(), using folio_test_clear_dropbehind()
to prevent concurrent lookups from double-decrementing the counter, and
guarding the decrement with mapping_can_writeback() to match the increment
path.
Transfer the counter alongside WB_RECLAIMABLE in inode_do_switch_wbs() so
that the stat is properly migrated when an inode switches cgroup writeback
domains.
The counter will be used by the writeback flusher to determine how many
pages to write back when expediting writeback for IOCB_DONTCACHE writes,
without flushing the entire BDI's dirty pages.
Suggested-by: Jan Kara <jack@suse.cz>
Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Jeff Layton <jlayton@kernel.org>
Link: https://patch.msgid.link/20260511-dontcache-v7-2-2848ddce8090@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>
