From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 57AA321773D; Tue, 6 Jan 2026 21:53:48 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767736428; cv=none; b=t2QRxXAP8bRrAkWAy07zS6QqCWiTX/3e8dKTWCbKa44mSsuIkakWpXeuE4FO7++UuVS/iJvt6vYQd4wQQxjVjSB2ppyjN+1tR0htMtjmxhB05t6G6wlMJMblvT8yshv2KS/y3iA162P0FW5PWHksJGIDXwCiuCZVwxkI70Ux6ks= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1767736428; c=relaxed/simple; bh=Gs6oceE6SQpMrH3WNfLOUodJTBTYa55MhuBBLW86Axo=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=eKIXZWFgeIdR9Wg6mKHHnFvgbUvGlSZoGGYXS+VUOmRcoVbJrCIOejdJ3px4iPdP9/IV+N9MOELZ/RqnvFMHY5xoxmloaC5QFglpBLT1lXN1GNg5ySIjT85NyC3+qdRToCmWjcH67NoWq/+T/02hOmuthuf79/WYJJVZ7ZqIdRc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BX/4y93p; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BX/4y93p" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 02ACBC116C6; Tue, 6 Jan 2026 21:53:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1767736427; bh=Gs6oceE6SQpMrH3WNfLOUodJTBTYa55MhuBBLW86Axo=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=BX/4y93poQ1Jro0F85zL9Tq+YKuhifaq1q1rV4IyDitTT1rX8LLQS3qFXXLF2gn3M ehDqgUoZMqmR69SkJu0wzKE18EFSDPGMhYUEF2B9u+W06PSfgLgvlVLlnhdLne5BgK teFX0T6lTbSD8eDXMZgzMoDPXj2xxXQBVN4O4lUcM15KdU4UANOzKSasvG43LhL8Vz SBvmnEO7y2ddKDlQjonphRMETBFv7/kTbpQySv4AzFOdNbQxIQ4DE+9UjslterBub7 XKm+4l8ISaOOC87ASNIsrSpFz96NZOTpyYMZH7O61U8muYylQHy6W8tQsgALqDR19q OuIblJoze/nAg== Message-ID: <9409276a27b852abb276616ff38638d7abf8de82.camel@kernel.org> Subject: Re: [PATCH v2 0/8] nfsd, sunrpc: allow for a dynamically-sized threadpool From: Jeff Layton To: Chuck Lever , Chuck Lever , NeilBrown , Olga Kornievskaia , Dai Ngo , Tom Talpey , Trond Myklebust , Anna Schumaker Cc: linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Date: Tue, 06 Jan 2026 16:53:45 -0500 In-Reply-To: <5081c9a2-2a2a-469d-9df8-eef6be2d05ac@app.fastmail.com> References: <20260106-nfsd-dynathread-v2-0-416e5f27b2b6@kernel.org> <5081c9a2-2a2a-469d-9df8-eef6be2d05ac@app.fastmail.com> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv 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linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Tue, 2026-01-06 at 16:26 -0500, Chuck Lever wrote: >=20 > On Tue, Jan 6, 2026, at 1:59 PM, Jeff Layton wrote: > > This version of the patchset fixes a number of warts in the first, and > > hopefully gets this closer to something mergeable. > >=20 > > This patchset allows nfsd to dynamically size its threadpool as needed. > > The main user-visible change is the addition of new controls that allow > > the admin to set a minimum number of threads. > >=20 > > When the minimum is set to a non-zero value, the traditional "threads" > > setting is interpreted as a maximum number of threads instead of a > > static count. The server will start the minimum number of threads, and > > then ramp up the thread count as needed. When the server is idle, it > > will gradually ramp down the thread count. > >=20 > > This control scheme should allow us to sanely switch between kernels > > that do and do not support dynamic threading. In the case where dynamic > > threading is not supported, the user will just get the static maximum > > number of threads, just like they do today. > >=20 > > So far this is only lightly tested, but it seems to work well. I > > still need to do some benchmarking to see whether this affects > > performance, so I'm posting this as an RFC for now. > >=20 > > Does this approach look sane to everyone? > >=20 > > Signed-off-by: Jeff Layton > > --- > > Changes in v2: > > - svc_recv() now takes a timeout parameter. This should mean that > > non-dynamic RPC services are unaffected by these changes. > > - if min_threads is larger than the max, then clamp it to the max > > - simplify SP_TASK_STARTING usage. Have same task set and clear it. > > - rework thread starting logic (EBUSY handling) > > - reorder arguments to svc_set_num_threads() and svc_set_pool_threads() > > - break up larger patches > > - Link to v1:=20 > > https://lore.kernel.org/r/20251213-nfsd-dynathread-v1-0-de755e59cbc4@ke= rnel.org > >=20 > > --- > > Jeff Layton (8): > > sunrpc: split svc_set_num_threads() into two functions > > sunrpc: remove special handling of NULL pool from=20 > > svc_start/stop_kthreads() > > sunrpc: track the max number of requested threads in a pool > > sunrpc: introduce the concept of a minimum number of threads per= =20 > > pool > > sunrpc: split new thread creation into a separate function > > sunrpc: allow svc_recv() to return -ETIMEDOUT and -EBUSY > > nfsd: adjust number of running nfsd threads based on activity > > nfsd: add controls to set the minimum number of threads per pool > >=20 > > Documentation/netlink/specs/nfsd.yaml | 5 + > > fs/lockd/svc.c | 6 +- > > fs/nfs/callback.c | 10 +- > > fs/nfsd/netlink.c | 5 +- > > fs/nfsd/netns.h | 6 + > > fs/nfsd/nfsctl.c | 50 ++++++++ > > fs/nfsd/nfssvc.c | 63 +++++++--- > > fs/nfsd/trace.h | 54 +++++++++ > > include/linux/sunrpc/svc.h | 13 ++- > > include/linux/sunrpc/svcsock.h | 2 +- > > include/uapi/linux/nfsd_netlink.h | 1 + > > net/sunrpc/svc.c | 210 ++++++++++++++++++++------= -------- > > net/sunrpc/svc_xprt.c | 44 +++++-- > > 13 files changed, 349 insertions(+), 120 deletions(-) > > --- > > base-commit: 83f633515af9382e7201e205112e18b995a80f70 > > change-id: 20251212-nfsd-dynathread-9f7a31172005 > >=20 > > Best regards, > > --=20 > > Jeff Layton >=20 > I'm comfortable with this series. Let me know when you are > ready for me to apply it. >=20 I think it'd be great to put this in nfsd-testing soon so we can start playing with it. I'll plan to post the nfs-utils patches for this in the near future too (they need a bit more work). Thanks, --=20 Jeff Layton