linux-kernel - Re: [RFC net-next 4/5] eventpoll: Trigger napi_busy_loop, if prefer_busy

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Message-ID: <ZroL54bAzdR-Vr4d@infradead.org>
Date: Mon, 12 Aug 2024 06:19:35 -0700
From: Christoph Hellwig <hch@...radead.org>
To: Joe Damato <jdamato@...tly.com>
Cc: netdev@...r.kernel.org, mkarsten@...terloo.ca,
	amritha.nambiar@...el.com, sridhar.samudrala@...el.com,
	sdf@...ichev.me, Alexander Viro <viro@...iv.linux.org.uk>,
	Christian Brauner <brauner@...nel.org>, Jan Kara <jack@...e.cz>,
	"open list:FILESYSTEMS (VFS and infrastructure)" <linux-fsdevel@...r.kernel.org>,
	open list <linux-kernel@...r.kernel.org>
Subject: Re: [RFC net-next 4/5] eventpoll: Trigger napi_busy_loop, if
 prefer_busy_poll is set

On Mon, Aug 12, 2024 at 12:57:07PM +0000, Joe Damato wrote:
> From: Martin Karsten <mkarsten@...terloo.ca>
> 
> Setting prefer_busy_poll now leads to an effectively nonblocking
> iteration though napi_busy_loop, even when busy_poll_usecs is 0.

Hardcoding calls to the networking code from VFS code seems like
a bad idea.   Not that I disagree with the concept of disabling
interrupts during busy polling, but this needs a proper abstraction
through file_operations.