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 CE53E29C351; Thu, 3 Jul 2025 23:49:32 +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=1751586572; cv=none; b=Y2EHQYRtQl/voziKB+4FTk+tIDMf7IG2BJC8U9birA+KgcBrfqBaWd9Wc5QS3wODlRJvz3ckCZ4MzVIVk/INiEAvg/NS2MILDSsoHQuwAd/XNT5iYfzscu45lRaTJSeJjJjHSUsVNY0KFXK1pMAHIk8THc/pcE/j9OqUxxhOXJY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751586572; c=relaxed/simple; bh=jY7rDOkkyI5+s/NbXXiVAWe3wfl6Bmb0nOpR/yEGXx8=; h=Message-ID:Subject:From:To:Cc:Date:In-Reply-To:References: Content-Type:MIME-Version; b=qYq11gS2AadrELsH+m7V+vw/xBSierT+MFvnMT21LawejXb+lENPQBa0hikA81w5jVdYZBEnFI1CCJMObu/gbQSrCPhQh3v3hQZYQHHW6x3/Memt8NvC9pPfrfsROKoZ1kcqm/DROgc8RPHgtpJnedliih6Yvs3/d5w/Y4gxYcc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Qz4kowz9; 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="Qz4kowz9" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7A46FC4CEE3; Thu, 3 Jul 2025 23:49:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1751586572; bh=jY7rDOkkyI5+s/NbXXiVAWe3wfl6Bmb0nOpR/yEGXx8=; h=Subject:From:To:Cc:Date:In-Reply-To:References:From; b=Qz4kowz9/yCvxFhzhv9TpAeVjVlMciSqrvX/BuQ3JPjoFxiGS/0gkjRR05fL1IvKa HvjC2cU4x/1wmu0aU497Kg4tjLkHoRtAlSPG2+DDoDajEt0wEoVQ6f5Xzqlm1MliX8 EvHMwGq2xwASuo3TPzpGoXVaclws1DUWmebox7Xt8gQDR3Dn1fKow7nHZFUxnOsVse ZwTouQ2I78O9ow8o+dCwLgfFN70WGaBu7WvQFG64L+bB4vyMfYZAIo9p2laxKqzUSa Xc2drXxnxyQgHkG7zPkTqkLv79UlXHMk1qOpsPqx8kcAY//F14+Q7HfWzebk5dnDf3 +NfsF1sWPTg5A== Message-ID: <71a082fa1e74b51b49f3602d4f739fa5bacecf51.camel@kernel.org> Subject: Re: [PATCH RFC 2/2] nfsd: call generic_fadvise after v3 READ, stable WRITE or COMMIT From: Jeff Layton To: NeilBrown Cc: Trond Myklebust , Anna Schumaker , Chuck Lever , Olga Kornievskaia , Dai Ngo , Tom Talpey , Mike Snitzer , linux-nfs@vger.kernel.org, linux-kernel@vger.kernel.org Date: Thu, 03 Jul 2025 19:49:30 -0400 In-Reply-To: <175158625070.565058.13878074995107810351@noble.neil.brown.name> References: <20250703-nfsd-testing-v1-0-cece54f36556@kernel.org> , <20250703-nfsd-testing-v1-2-cece54f36556@kernel.org> <175158625070.565058.13878074995107810351@noble.neil.brown.name> Autocrypt: addr=jlayton@kernel.org; prefer-encrypt=mutual; keydata=mQINBE6V0TwBEADXhJg7s8wFDwBMEvn0qyhAnzFLTOCHooMZyx7XO7dAiIhDSi7G1NPxw 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Evolution 3.56.2 (3.56.2-1.fc42) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2025-07-04 at 09:44 +1000, NeilBrown wrote: > On Fri, 04 Jul 2025, Jeff Layton wrote: > > Recent testing has shown that keeping pagecache pages around for too > > long can be detrimental to performance with nfsd. Clients only rarely > > revisit the same data, so the pages tend to just hang around. > >=20 > > This patch changes the pc_release callbacks for NFSv3 READ, WRITE and > > COMMIT to call generic_fadvise(..., POSIX_FADV_DONTNEED) on the accesse= d > > range. > >=20 > > Signed-off-by: Jeff Layton > > --- > > fs/nfsd/debugfs.c | 2 ++ > > fs/nfsd/nfs3proc.c | 59 +++++++++++++++++++++++++++++++++++++++++++++-= -------- > > fs/nfsd/nfsd.h | 1 + > > fs/nfsd/nfsproc.c | 4 ++-- > > fs/nfsd/vfs.c | 21 ++++++++++++++----- > > fs/nfsd/vfs.h | 5 +++-- > > fs/nfsd/xdr3.h | 3 +++ > > 7 files changed, 77 insertions(+), 18 deletions(-) > >=20 > > diff --git a/fs/nfsd/debugfs.c b/fs/nfsd/debugfs.c > > index 84b0c8b559dc90bd5c2d9d5e15c8e0682c0d610c..b007718dd959bc081166ec8= 4e06f577a8fc2b46b 100644 > > --- a/fs/nfsd/debugfs.c > > +++ b/fs/nfsd/debugfs.c > > @@ -44,4 +44,6 @@ void nfsd_debugfs_init(void) > > =20 > > debugfs_create_file("disable-splice-read", S_IWUSR | S_IRUGO, > > nfsd_top_dir, NULL, &nfsd_dsr_fops); > > + debugfs_create_bool("enable-fadvise-dontneed", 0644, > > + nfsd_top_dir, &nfsd_enable_fadvise_dontneed); > > } > > diff --git a/fs/nfsd/nfs3proc.c b/fs/nfsd/nfs3proc.c > > index b6d03e1ef5f7a5e8dd111b0d56c061f1e91abff7..11261cf67ea817ec566626f= 08b733e09c9e121de 100644 > > --- a/fs/nfsd/nfs3proc.c > > +++ b/fs/nfsd/nfs3proc.c > > @@ -9,6 +9,7 @@ > > #include > > #include > > #include > > +#include > > =20 > > #include "cache.h" > > #include "xdr3.h" > > @@ -206,11 +207,25 @@ nfsd3_proc_read(struct svc_rqst *rqstp) > > =20 > > fh_copy(&resp->fh, &argp->fh); > > resp->status =3D nfsd_read(rqstp, &resp->fh, argp->offset, > > - &resp->count, &resp->eof); > > + &resp->count, &resp->eof, &resp->nf); > > resp->status =3D nfsd3_map_status(resp->status); > > return rpc_success; > > } > > =20 > > +static void > > +nfsd3_release_read(struct svc_rqst *rqstp) > > +{ > > + struct nfsd3_readargs *argp =3D rqstp->rq_argp; > > + struct nfsd3_readres *resp =3D rqstp->rq_resp; > > + > > + if (nfsd_enable_fadvise_dontneed && resp->status =3D=3D nfs_ok) > > + generic_fadvise(nfsd_file_file(resp->nf), argp->offset, resp->count, > > + POSIX_FADV_DONTNEED); > > + if (resp->nf) > > + nfsd_file_put(resp->nf); > > + fh_put(&resp->fh); >=20 > This looks wrong - testing resp->nf after assuming it was non-NULL. > I don't think it *is* wrong because ->state =3D=3D nfs_ok ensures > ->nf is valid. But still.... >=20 That was my thinking, but I agree that it's a bit fragile. > How about: >=20 > fh_put(resp->fh); > if (!resp->nf) > return; > if (nfsd_enable_fadvise_dontneed) > generic_fadvise(nfsd_file_file(resp->nf), argp->offset, resp->count, > POSIX_FADV_DONTNEED); > nfsd_file_put(resp->nf); >=20 > ?? > Note that we don't test ->status because that is identical to testing ->n= f. > Ditto for other release functions. >=20 That looks good. I'll plan to do that in the next respin. > Otherwise it makes sense for exploring how to optimise IO. >=20 > Reviewed-by: NeilBrown >=20 > NeilBrown Thanks for the reviews! --=20 Jeff Layton