From: Sandeep Patil <sspatil@android.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
David Howells <dhowells@redhat.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable <stable@vger.kernel.org>,
Android Kernel Team <kernel-team@android.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: <fc0e2c8a-96cc-7787-6866-3802a1d5c50e@android.com> (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
> <torvalds@linux-foundation.org> 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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