From: Sandeep Patil <email@example.com> To: Linus Torvalds <firstname.lastname@example.org> Cc: linux-fsdevel <email@example.com>, Linux Kernel Mailing List <firstname.lastname@example.org>, David Howells <email@example.com>, Greg Kroah-Hartman <firstname.lastname@example.org>, stable <email@example.com>, Android Kernel Team <firstname.lastname@example.org> Subject: Re: [PATCH 1/1] fs: pipe: wakeup readers everytime new data written is to pipe Date: Fri, 30 Jul 2021 19:47:22 +0000 [thread overview] Message-ID: <email@example.com> (raw) In-Reply-To: <CAHk-=wjStQurUzSAPVajL6Rj=CaPuSSgwaMO=0FJzFvSD66ACw@mail.gmail.com> On 7/30/21 7:23 PM, Linus Torvalds wrote: > On Fri, Jul 30, 2021 at 12:11 PM Sandeep Patil <firstname.lastname@example.org> wrote: >> >> Yes, your patch fixes all apps on Android I can test that include this >> library. > > Ok, thanks for checking. > >> fwiw, the library seems to have been fixed. However, I am not sure >> how long it will be for all apps to take that update :(. > > I wonder if I could make the wakeup logic do this only for the epollet case. aren't we supposed to wakeup on each write in level-triggered (default) case though? > > I'll have to think about it, but maybe I'll just apply that simple > patch. I dislike the pointless wakeups, and as long as the only case I > knew of was only a test of broken behavior, it was fine. But now that > you've reported actual application breakage, this is in the "real > regression" category, and so I'll fix it one way or the other. > > And on the other hand I also have a slight preference towards your > patch simply because you did the work of finding this out, so you > should get the credit. Ha, I can't really claim credit here. This was also reported to us in Android that triggered the search. Plus, now that I see your thread with Michael Kerrisk, he was way ahead of us in finding this out. > > I'll mull it over a bit more, but whatever I'll do I'll do before rc4 > and mark it for stable. Thanks, I was actually going to suggest taking your patch cause it also makes changes in pipe_read(). I am not sure if there are apps that do EPOLLET | EPOLLOUT (can't think of a reason why). - ssp > > Thanks for testing, > > Linus >
next prev parent reply other threads:[~2021-07-30 19:48 UTC|newest] Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-07-29 22:26 [PATCH 0/1] Revert change in pipe reader wakeup behavior Sandeep Patil 2021-07-29 22:26 ` [PATCH 1/1] fs: pipe: wakeup readers everytime new data written is to pipe Sandeep Patil 2021-07-29 23:01 ` Linus Torvalds 2021-07-30 19:11 ` Sandeep Patil 2021-07-30 19:23 ` Linus Torvalds 2021-07-30 19:47 ` Sandeep Patil [this message] 2021-07-30 22:06 ` Linus Torvalds 2021-07-30 22:53 ` Linus Torvalds 2021-07-30 22:55 ` Linus Torvalds 2021-07-31 5:32 ` Greg Kroah-Hartman 2021-08-02 18:59 ` Sandeep Patil
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