Re: [PATCH 6.6.y 1/2] jbd2: check need_resched() when skipping busy checkpoint buffers

[sashiko-bot@kernel.org]

> From: Max Kellermann <max.kellermann@ionos.com>
> 
> [ Upstream commit f213e12ff5c9590b1034ae8da0e6d09665c772d0 ]
> 
> journal_shrink_one_cp_list() skips busy checkpoint buffers when called
> with JBD2_SHRINK_BUSY_SKIP.  The continue statement on this path also
> skips the need_resched() check at the end of the loop body.
> 
> Consequently, when a checkpoint list contains mostly busy buffers, the
> shrinker can walk the entire list while holding journal->j_list_lock,
> even when a reschedule has been requested.  Large checkpoint lists under
> memory pressure can therefore cause long lock hold times and leave other
> CPUs spinning on j_list_lock, resulting in soft lockups or RCU stalls.
> 
> Route the busy-buffer path through the need_resched() check so that the
> [ ... ]
> Reviewed-by: Jan Kara <jack@suse.cz>
> Link: https://patch.msgid.link/20260713102229.1598812-2-max.kellermann@ionos.com
> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
> Assisted-by: LLM
> Signed-off-by: Artem Dinaburg <artem@trailofbits.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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Sashiko AI review · https://sashiko.dev/#/patchset/20261008192048.98833-1-artem@trailofbits.com?part=1