From: Christoph Hellwig <hch@lst.de>
To: Chuck Lever <cel@kernel.org>
Cc: Christoph Hellwig <hch@lst.de>, Mike Snitzer <snitzer@kernel.org>,
linux-nfs@vger.kernel.org, Chuck Lever <chuck.lever@oracle.com>,
linux-mm@kvack.org, linux-fsdevel@vger.kernel.org
Subject: Re: [RFC PATCH 1/2] NFSD: Add aggressive write throttling control
Date: Wed, 7 Jan 2026 15:42:43 +0100 [thread overview]
Message-ID: <20260107144243.GA15228@lst.de> (raw)
In-Reply-To: <cb269767-688d-46f1-8d82-1fd6dc32e94d@kernel.org>
On Wed, Jan 07, 2026 at 09:36:39AM -0500, Chuck Lever wrote:
> > What makes NFSD so special here vs say a userspace process with a bunch
> > of threads? Also what is the actual problem we're trying to solve?
>
> The problem, as I see it, is that the system is not providing enough
> backpressure to slow down noisy clients, allowing them to overwhelm
> the server's memory with UNSTABLE WRITE traffic.
>
> This is the same issue, IMO, that Mike's direct I/O is attempting to
> address. Our implementation of UNSTABLE WRITE is a denial-of-service
> vector.
But how is this different from Samba or a userspace NFS server?
next prev parent reply other threads:[~2026-01-07 14:42 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-19 14:11 [RFC PATCH 0/2] NFSD: Rate-limiting unstable WRITEs Chuck Lever
2025-12-19 14:11 ` [RFC PATCH 1/2] NFSD: Add aggressive write throttling control Chuck Lever
2026-01-07 7:55 ` Christoph Hellwig
2026-01-07 14:36 ` Chuck Lever
2026-01-07 14:42 ` Christoph Hellwig [this message]
2026-01-07 14:49 ` Chuck Lever
2025-12-19 14:11 ` [RFC PATCH 2/2] NFSD: Add asynchronous write throttling support Chuck Lever
2025-12-20 15:34 ` kernel test robot
2025-12-21 5:41 ` kernel test robot
2025-12-22 18:06 ` kernel test robot
2025-12-22 23:47 ` kernel test robot
2026-01-07 8:00 ` Christoph Hellwig
2026-01-07 14:42 ` Chuck Lever
2026-01-07 16:25 ` Christoph Hellwig
2026-01-07 19:40 ` Mike Snitzer
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