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 2771E1C728E for ; Thu, 24 Oct 2024 15:34:40 +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=1729784081; cv=none; b=jevX2jrBiJPAu7tww2BXDva4yBzUD/2Mc+LI0+rLUDWfwLIodS1RMVeg5As1a1xKPj08/bxjPRZFL3YcKPtDHK1O4qWKh+ExepqThJ0hAarID08ar0TBtUF9GXq5inA4eY0myc/SVIcWeevx6L3zbNfJXxcxp+DwADQkN9drokI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729784081; c=relaxed/simple; bh=EEJVnXxV4VQl5yPKBdp4U+4InSl6Grsgo42KdpMbZUQ=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=gwIV+Th+ZgIYGmTd27VhobC6upA8MJ6qDyFskOFHhBh00InAZXbpthM5VtzTemcOP65293lIvnBJSaxMETaxzbgpsA4KVZsCfyM/oCAqV6OStc2Km9FjAXsK9tPfAqRI6pz/PpYAM7s0w1yU6gIbuBwg5KmBUF/UPLsVmTLfkOU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=P4GyaQ23; 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="P4GyaQ23" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 85748C4CEC7; Thu, 24 Oct 2024 15:34:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729784080; bh=EEJVnXxV4VQl5yPKBdp4U+4InSl6Grsgo42KdpMbZUQ=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=P4GyaQ23t0cZGGRH2GqxiT3sjEv2buInBGybhSBv+s6BE/bZSU/tG1V32IcNaJ2vM AnPv5rXqEzouRB3KGWdEhUcflCArpK6Nc7NNv6gOXM5pD0VcGwKF8V247holZZgq/A 7WTXazhWcw9pHn9ZUHXwXN/fsmD0vZLvE4PBmPTa1mQ/HixbYZJ2f4ywARjF5VzbSu AtOcI4fJ38x3dccsX66v9E2kr88NrRnQ6tWwwkFmsBHLComOTZc7O+ktY0mTyvUk3L 2a/uv9RI64Qg6ulhXpVyYHCLBNkL34gWY3XdPMuOIhbgqYIJMJzA3YZUswbdKTi+3Q CeBp45CNCfJOg== Message-ID: <30f62ce7f3a6aa0d02f07bfd1be71b3f82f83961.camel@kernel.org> Subject: Re: [PATCH v2] nfsd: Don't fail OP_SETCLIENTID when there are too many clients. From: Jeff Layton To: NeilBrown , Chuck Lever Cc: linux-nfs@vger.kernel.org, okorniev@redhat.com, Dai Ngo , Tom Talpey Date: Thu, 24 Oct 2024 11:34:37 -0400 In-Reply-To: <172972144286.81717.3023946721770566532@noble.neil.brown.name> References: <172972144286.81717.3023946721770566532@noble.neil.brown.name> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw n8jdFUQMCR/GlpozMFlSFiZXiObE7sef9rTtM68ukUyZM4pJ9l0KjQNgDJ6Fr342Htkjxu/kFV1Wv egyjnSsFt7EGoDjdKqr1TS9syJYFjagYtvWk/UfHlW09X+jOh4vYtfX7iYSx/NfqV3W1D7EDi0PqV T2h6v8i8YqsATFPwO4nuiTmL6I40ZofxVd+9wdRI4Db8yUNA4ZSP2nqLcLtFjClYRBoJvRWvsv4lm 0OX6MYPtv76hka8lW4mnRmZqqx3UtfHX/hF/zH24Gj7A6sYKYLCU3YrI2Ogiu7/ksKcl7goQjpvtV YrOOI5VGLHge0awt7bhMCTM9KAfPc+xL/ZxAMVWd3NCk5SamL2cE99UWgtvNOIYU8m6EjTLhsj8sn VluJH0/RcxEeFbnSaswVChNSGa7mXJrTR22lRL6ZPjdMgS2Km90haWPRc8Wolcz07Y2se0xpGVLEQ cDEsvv5IMmeMe1/qLZ6NaVkNuL3WOXvxaVT9USW1+/SGipO2IpKJjeDZfehlB/kpfF24+RrK+seQf 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Yy9YbXtWctUz8uvDR7shsQxAhX3qO7DilMtuGo1v97I/Kx4gXQ52syh/w6EBny71CZrOgD6kJwPVV AaM1LRC28muq91WCFhs/nzHozpbzcheyGtMUI2Ao4K6mnY+3zIuXPygZMFr9KXE6fF7HzKxKuZMJO aEZCiDOq0anx6FmOzs5E6Jqdpo/mtI8beK+BE7Va6ni7YrQlnT0i3vaTVMTiCThbqsB20VrbMjlhp f8lfK1XVNbRq/R7GZ9zHESlsa35ha60yd/j3pu5hT2xyy8krV8vGhHvnJ1XRMJBAB/UYb6FyC7S+m QZIQXVeAA+smfTT0tDrisj1U5x6ZB9b3nBg65kc= Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.52.4 (3.52.4-1.fc40) Precedence: bulk X-Mailing-List: linux-nfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Thu, 2024-10-24 at 09:10 +1100, NeilBrown wrote: > Failing OP_SETCLIENTID or OP_EXCHANGE_ID should only happen if there is > memory allocation failure. Putting a hard limit on the number of > clients is really helpful as it will either happen too early and prevent "unhelpful" ? > clients that the server can easily handle, or too late and allow clients > when the server is swamped. >=20 > The calculated limit is still useful for expiring courtesy clients where > there are "too many" clients, but it shouldn't prevent the creation of > active clients. >=20 > Testing of lots of clients against small-mem servers reports repeated > NFS4ERR_DELAY responses which doesn't seem helpful. There may have been > reports of similar problems in production use. >=20 > Also remove an outdated comment - we do use a slab cache. >=20 > Signed-off-by: NeilBrown > --- > fs/nfsd/nfs4state.c | 11 +++-------- > 1 file changed, 3 insertions(+), 8 deletions(-) >=20 > diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c > index d585c267731b..0791a43b19e6 100644 > --- a/fs/nfsd/nfs4state.c > +++ b/fs/nfsd/nfs4state.c > @@ -2218,21 +2218,16 @@ STALE_CLIENTID(clientid_t *clid, struct nfsd_net = *nn) > return 1; > } > =20 > -/*=20 > - * XXX Should we use a slab cache ? > - * This type of memory management is somewhat inefficient, but we use it > - * anyway since SETCLIENTID is not a common operation. > - */ > static struct nfs4_client *alloc_client(struct xdr_netobj name, > struct nfsd_net *nn) > { > struct nfs4_client *clp; > int i; > =20 > - if (atomic_read(&nn->nfs4_client_count) >=3D nn->nfs4_max_clients) { > + if (atomic_read(&nn->nfs4_client_count) >=3D nn->nfs4_max_clients && > + atomic_read(&nn->nfsd_courtesy_clients) > 0) > mod_delayed_work(laundry_wq, &nn->laundromat_work, 0); > - return NULL; > - } > + > clp =3D kmem_cache_zalloc(client_slab, GFP_KERNEL); > if (clp =3D=3D NULL) > return NULL; Do we even need to check nn->nfs4_max_clients at all? Maybe we should just kick the laundromat whenever=20 nfsd_courtesy_clients > 0. I would suggest just removing nfs4_max_clients altogether, but it looks like nfs4_get_client_reaplist() uses it and it's not clear to me what would better replace it. --=20 Jeff Layton