Re: [RFC PATCH] mm/damon/core: avoid overflow in damon_feed_loop_next_input()

[SeongJae Park <sj@kernel.org>]

Hi Guenter,

On Wed, 30 Oct 2024 21:18:51 -0700 Guenter Roeck <linux@roeck-us.net> wrote:

> On Thu, Sep 05, 2024 at 10:24:05AM -0700, SeongJae Park wrote:
> > damon_feed_loop_next_input() is fragile to overflows.  Rewrite code to
> > avoid overflows.  This is not yet well tested on 32bit archs.
> > 
> > Reported-by: Guenter Roeck <linux@roeck-us.net>
> > Closes: https://lore.kernel.org/944f3d5b-9177-48e7-8ec9-7f1331a3fea3@roeck-us.net
> > Fixes: 9294a037c015 ("mm/damon/core: implement goal-oriented feedback-driven quota auto-tuning")
> > Signed-off-by: SeongJae Park <sj@kernel.org>
> > ---
> > As mentioned on the commit message, this is not yet sufficiently tested
> > on 32bit machines.  That's why this is RFC.
> 
> Is that patch going anywhere ? I have been testing it on a lot of 32-bit architectures,
> and I do not see any failures.

Thank you for this nice reminder with the grateful test results, Guenter!

I was recently cleaning up the code and commit message, and testing on my own
with test setup.  I should confess that it took more than I expected in the
last RFC posting.  Sorry for the delay, and thank you for your patience.

I believe the patch is now in good form, but I was waiting just a couple of
more days before posting it, for a case that I find any mistake on it.  So
unless I find something wrong on the patch by Tomorrow morning (Pacific Time),
I will post it after dropping the RFC tag.

The current version of the patch to be posted is available at my patches
queue[1].  Please let me know if you find anything suspicious on it.

Thank you again for your patience and nice reminder!

[1] https://git.kernel.org/pub/scm/linux/kernel/git/sj/damon-hack.git/tree/patches/next/mm-damon-core-avoid-overflow-in-damon_feed_loop_next.patch?id=fb13d053bfdd5249bebdd1c253417f97cd41471e


Thanks,
SJ

> 
> Guenter