Re: Get rid of WALBufMappingLock

Hi, Michael!

On Wed, Feb 26, 2025 at 3:04 AM Michael Paquier <michael@paquier.xyz> wrote:
>
> On Tue, Feb 25, 2025 at 05:19:29PM +0200, Alexander Korotkov wrote:
> > It seems that I managed to reproduce the issue on my Raspberry PI 4.
> > After running our test suite in a loop for 2 days I found one timeout.
>
> Hmm.  It's surprising to not see a higher occurence.  My buildfarm
> host has caught that on its first run after the patch, for two
> different animals which are both on the same machine.
>
> > One way or another, we need protection against this situation any way.
> > The updated patch is attached.  Now, after acquiring ReservedPtr it
> > waits till OldPageRqstPtr gets initialized.  Additionally I've to
> > implement more accurate calculation of OldPageRqstPtr.  I run tests
> > with new patch on my Raspberry in a loop.  Let's see how it goes.
>
> Perhaps you'd prefer that I do more tests with your patch?  This is
> time-consuming for you.  This is not a review of the internals of the
> patch, and I cannot give you access to the host, but if my stuff is
> the only place where we have a good reproducibility of the issue, I'm
> OK to grab some time and run a couple of checks to avoid again a
> freeze of the buildfarm.

Thank you for offering the help.  Updated version of patch is attached
(I've added one memory barrier there just in case).  I would
appreciate if you could run it on batta, hachi or similar hardware.

------
Regards,
Alexander Korotkov
Supabase