Re: [PATCH v2] mm/damon/vaddr: remove redundant RCU lock

[SJ Park <sj@kernel.org>]

Hello Igor,


Thank you for this patch.

From next time, please give enough time for others to comment before posting a
new revision of the patch.

Also, please post a new revision as a new thread with a changelog [1] including
links to previous revisions, rather than a reply to the previous revision.

On Tue, 30 Jun 2026 16:02:53 +0300 Igor Putko <igorpetindev@gmail.com> wrote:

> __damon_va_three_regions() is called only by damon_va_three_regions(),
> which already holds mmap_read_lock(). Since mmap_read_lock() is held,
> the maple tree and VMA list are protected from concurrent changes.
> Remove the unnecessary rcu_read_lock() and rcu_read_unlock() calls.

This is not explaining the test part change.  Could you please update for that?

Also, have you had a chance to theoretically or experiemently confirm the
problem [2] that motivated to add the rcu_read_lock() at that place is not
reintroduced by this change?  If so, could you please add that to the commit
log, too?


Thanks,
SJ

[1] https://docs.kernel.org/process/submitting-patches.html#commentary
[2] https://lore.kernel.org/b83651a0-5b24-4206-b860-cb54ffdf209b@roeck-us.net

[...]