From: Sandeep Patil <firstname.lastname@example.org> To: Linus Torvalds <email@example.com> Cc: linux-fsdevel <firstname.lastname@example.org>, Linux Kernel Mailing List <email@example.com>, David Howells <firstname.lastname@example.org>, Greg Kroah-Hartman <email@example.com>, stable <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: Mon, 2 Aug 2021 18:59:03 +0000 [thread overview] Message-ID: <firstname.lastname@example.org> (raw) In-Reply-To: <CAHk-=wjrfasYJUaZ-rJmYt9xa=DqmJ5-sVRG7cJ2X8nNcSXp9g@mail.gmail.com> On 7/30/21 10:53 PM, Linus Torvalds wrote: > On Fri, Jul 30, 2021 at 12:23 PM Linus Torvalds > <email@example.com> wrote: >> >> I'll mull it over a bit more, but whatever I'll do I'll do before rc4 >> and mark it for stable. > > Ok, I ended up committing the minimal possible change (and fixing up > the comment above it). > > It's very much *not* the original behavior either, but that original > behavior was truly insane ("wake up for each hunk written"), and I'm > trying to at least keep the kernel code from doing actively stupid > things. > > Since that old patch of mine worked for your test-case, then clearly > that realm-core library didn't rely on _that_ kind of insane internal > kernel implementation details exposed as semantics. So The minimal > patch basically says "each write() system call wil do at least one > wake-up, whether really necessary or not". > > I also intentionally kept the read side untouched, in that there > apparently still isn't a case that would need the confused semantics > for read events. > > End result: the commit message is a lot bigger than the patch, with > most of it being trying to explain the background. > > I've pushed it out as commit 3a34b13a88ca ("pipe: make pipe writes > always wake up readers"). Holler if you notice anything odd remaining. Since what you merged isn't different than what I tested, I don't expect any surprises but I will test it regardless. I will come back if I see anything unexpected. Thanks for the explanation about the default behavior earlier in the thread. - ssp
prev parent reply other threads:[~2021-08-02 18:59 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 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 [this message]
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