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>,
Android Kernel Team <email@example.com>
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: <firstname.lastname@example.org> (raw)
On 7/30/21 7:23 PM, Linus Torvalds wrote:
> On Fri, Jul 30, 2021 at 12:11 PM Sandeep Patil <email@example.com> wrote:
>> Yes, your patch fixes all apps on Android I can test that include this
> 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)
> 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).
> Thanks for testing,
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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