pipe: only enable the extra wake_up(rd_wait) when epoll is actually used

[PATCH 0/1] pipe: only enable the extra wake_up(rd_wait) when epoll is actually used

Oleg Nesterov posted 1 patch 14 hours ago

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fs/pipe.c                 | 23 +++++++++++++++++++----
include/linux/pipe_fs_i.h |  6 ++++--
2 files changed, 23 insertions(+), 6 deletions(-)

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[PATCH 0/1] pipe: only enable the extra wake_up(rd_wait) when epoll is actually used

Posted by Oleg Nesterov 14 hours ago

Breno, Christian, Mateusz,

To be honest, I am not sure this change makes a lot of sense.
But somehow the extra wakeup in anon_pipe_write() looks annoying to me.

Can you take a look?

Plus I'd like to know what sashiko.dev thinks.

I have no idea how to test it wrt performance...

Oleg.
---

 fs/pipe.c                 | 23 +++++++++++++++++++----
 include/linux/pipe_fs_i.h |  6 ++++--
 2 files changed, 23 insertions(+), 6 deletions(-)

Re: [PATCH 0/1] pipe: only enable the extra wake_up(rd_wait) when epoll is actually used

Posted by Oleg Nesterov 13 hours ago

OK, sashiko has some concerns

	https://sashiko.dev/#/patchset/amIqmbbZx3NlzUsX%40redhat.com

As for READ_ONCE(), I agree, I just forgot to add them.

But so far I don't understand the note about io_uring...
I'll try to check later.

Anyway, I'd like to know your opinion.

On 07/23, Oleg Nesterov wrote:
>
> Breno, Christian, Mateusz,
>
> To be honest, I am not sure this change makes a lot of sense.
> But somehow the extra wakeup in anon_pipe_write() looks annoying to me.
>
> Can you take a look?
>
> Plus I'd like to know what sashiko.dev thinks.
>
> I have no idea how to test it wrt performance...
>
> Oleg.
> ---
>
>  fs/pipe.c                 | 23 +++++++++++++++++++----
>  include/linux/pipe_fs_i.h |  6 ++++--
>  2 files changed, 23 insertions(+), 6 deletions(-)