netdev - Re: [PATCH net-next v6 3/4] eventpoll: Add per-epoll prefer busy poll option

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Message-ID: <20240207110437.292f7eaf@kernel.org>
Date: Wed, 7 Feb 2024 11:04:37 -0800
From: Jakub Kicinski <kuba@...nel.org>
To: Joe Damato <jdamato@...tly.com>
Cc: linux-kernel@...r.kernel.org, netdev@...r.kernel.org,
 chuck.lever@...cle.com, jlayton@...nel.org, linux-api@...r.kernel.org,
 brauner@...nel.org, edumazet@...gle.com, davem@...emloft.net,
 alexander.duyck@...il.com, sridhar.samudrala@...el.com,
 willemdebruijn.kernel@...il.com, weiwan@...gle.com,
 David.Laight@...LAB.COM, arnd@...db.de, sdf@...gle.com,
 amritha.nambiar@...el.com, Alexander Viro <viro@...iv.linux.org.uk>, Jan
 Kara <jack@...e.cz>, linux-fsdevel@...r.kernel.org (open list:FILESYSTEMS
 (VFS and infrastructure))
Subject: Re: [PATCH net-next v6 3/4] eventpoll: Add per-epoll prefer busy
 poll option

On Mon,  5 Feb 2024 21:04:48 +0000 Joe Damato wrote:
> When using epoll-based busy poll, the prefer_busy_poll option is hardcoded
> to false. Users may want to enable prefer_busy_poll to be used in
> conjunction with gro_flush_timeout and defer_hard_irqs_count to keep device
> IRQs masked.
> 
> Other busy poll methods allow enabling or disabling prefer busy poll via
> SO_PREFER_BUSY_POLL, but epoll-based busy polling uses a hardcoded value.
> 
> Fix this edge case by adding support for a per-epoll context
> prefer_busy_poll option. The default is false, as it was hardcoded before
> this change.

Reviewed-by: Jakub Kicinski <kuba@...nel.org>