From nobody Thu Feb 12 22:42:37 2026 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 6DD4915A842 for ; Wed, 5 Feb 2025 15:34:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738769672; cv=none; b=EwFNZSsmloETpMmY6j+fL9wFvIS0Kmx3wOxnO7kEXFRLUWMbP1cxDeniIgO9KvNWKdLBybkk5eobeWqQo/1MJ7sHp6D/QwGSl3bMn+3lVcJYy3fUUnIMBJV73kQ7/DBLhF3UVHjeVRhLBZzFkqviSGz+owW0+tlUDqmiCsFPJCY= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738769672; c=relaxed/simple; bh=NkwVJuFwbmro6D09UcQWrrhpAKhpU7MvCrQQ5WiccZs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rwPgg03s43B5usw0MS6NmaZ80yY/GxMbi7b0jfbgtBsrOeBAVEob6gPfB/9zXf8j0iSyDAzIJslAeMGKLNdcQzRPkLZPC72iQNNhZfDXQjnPhuACJ8lv/dc9hInjuvO079ZfnkGili7Xi6on7awI/ad9WveeYb3lozD91l9ytCE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=HE2iPqpB; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="HE2iPqpB" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1738769669; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=xqTAo0pAonNELM7F6v+5zbpfquf/T3IQ8Tjo6CWKfSs=; b=HE2iPqpBmGLfbDdW+qnzSiNvD8AEWo7X5Th07KVKTQzVqstT9AX16GhhIpZ+iuAePn3WPy ShDu3KFm8R4ozbS6QeXhlJPjeudr9RtDEPky+AmQjkSPgz51IcjVXaq1DLBmBzths0vUzv GnIZQOwP1Vohkd01nqUhn7MKiNvuKD8= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-435-HSPirgIcOv-MKHOB_Gj_eg-1; Wed, 05 Feb 2025 10:34:26 -0500 X-MC-Unique: HSPirgIcOv-MKHOB_Gj_eg-1 X-Mimecast-MFC-AGG-ID: HSPirgIcOv-MKHOB_Gj_eg Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 23BCD180087A; Wed, 5 Feb 2025 15:34:24 +0000 (UTC) Received: from dhcp-27-174.brq.redhat.com (unknown [10.45.224.10]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with SMTP id 4ED361800570; Wed, 5 Feb 2025 15:34:19 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 5 Feb 2025 16:33:57 +0100 (CET) Date: Wed, 5 Feb 2025 16:33:51 +0100 From: Oleg Nesterov To: Christian Brauner , Jeff Layton , Linus Torvalds Cc: David Howells , "Gautham R. Shenoy" , K Prateek Nayak , Mateusz Guzik , Neeraj Upadhyay , Oliver Sang , Swapnil Sapkal , WangYuli , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v2 2/2] pipe: don't update {a,c,m}time for anonymous pipes Message-ID: <20250205153351.GB2255@redhat.com> References: <20250205153302.GA2216@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20250205153302.GA2216@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" These numbers are visible in fstat() but hopefully nobody uses this information and file_accessed/file_update_time are not that cheap. Stupid test-case: #include #include #include #include #include #include static char buf[17 * 4096]; static struct timeval TW, TR; int wr(int fd, int size) { int c, r; struct timeval t0, t1; gettimeofday(&t0, NULL); for (c =3D 0; (r =3D write(fd, buf, size)) > 0; c +=3D r); gettimeofday(&t1, NULL); timeradd(&TW, &t1, &TW); timersub(&TW, &t0, &TW); return c; } int rd(int fd, int size) { int c, r; struct timeval t0, t1; gettimeofday(&t0, NULL); for (c =3D 0; (r =3D read(fd, buf, size)) > 0; c +=3D r); gettimeofday(&t1, NULL); timeradd(&TR, &t1, &TR); timersub(&TR, &t0, &TR); return c; } int main(int argc, const char *argv[]) { int fd[2], nb =3D 1, loop, size; assert(argc =3D=3D 3); loop =3D atoi(argv[1]); size =3D atoi(argv[2]); assert(pipe(fd) =3D=3D 0); assert(ioctl(fd[0], FIONBIO, &nb) =3D=3D 0); assert(ioctl(fd[1], FIONBIO, &nb) =3D=3D 0); assert(size <=3D sizeof(buf)); while (loop--) assert(wr(fd[1], size) =3D=3D rd(fd[0], size)); struct timeval tt; timeradd(&TW, &TR, &tt); printf("TW =3D %lu.%03lu TR =3D %lu.%03lu TT =3D %lu.%03lu\n", TW.tv_sec, TW.tv_usec/1000, TR.tv_sec, TR.tv_usec/1000, tt.tv_sec, tt.tv_usec/1000); return 0; } Before: # for i in 1 2 3; do /host/tmp/test 10000 100; done TW =3D 8.047 TR =3D 5.845 TT =3D 13.893 TW =3D 8.091 TR =3D 5.872 TT =3D 13.963 TW =3D 8.083 TR =3D 5.885 TT =3D 13.969 After: # for i in 1 2 3; do /host/tmp/test 10000 100; done TW =3D 4.752 TR =3D 4.664 TT =3D 9.416 TW =3D 4.684 TR =3D 4.608 TT =3D 9.293 TW =3D 4.736 TR =3D 4.652 TT =3D 9.388 Signed-off-by: Oleg Nesterov --- fs/pipe.c | 41 +++++++++++++++++++++++++++++------------ 1 file changed, 29 insertions(+), 12 deletions(-) diff --git a/fs/pipe.c b/fs/pipe.c index b05cded28d9b..e772637c622c 100644 --- a/fs/pipe.c +++ b/fs/pipe.c @@ -248,7 +248,7 @@ static inline unsigned int pipe_update_tail(struct pipe= _inode_info *pipe, } =20 static ssize_t -pipe_read(struct kiocb *iocb, struct iov_iter *to) +anon_pipe_read(struct kiocb *iocb, struct iov_iter *to) { size_t total_len =3D iov_iter_count(to); struct file *filp =3D iocb->ki_filp; @@ -404,8 +404,15 @@ pipe_read(struct kiocb *iocb, struct iov_iter *to) if (wake_next_reader) wake_up_interruptible_sync_poll(&pipe->rd_wait, EPOLLIN | EPOLLRDNORM); kill_fasync(&pipe->fasync_writers, SIGIO, POLL_OUT); + return ret; +} + +static ssize_t +fifo_pipe_read(struct kiocb *iocb, struct iov_iter *to) +{ + int ret =3D anon_pipe_read(iocb, to); if (ret > 0) - file_accessed(filp); + file_accessed(iocb->ki_filp); return ret; } =20 @@ -426,7 +433,7 @@ static inline bool pipe_writable(const struct pipe_inod= e_info *pipe) } =20 static ssize_t -pipe_write(struct kiocb *iocb, struct iov_iter *from) +anon_pipe_write(struct kiocb *iocb, struct iov_iter *from) { struct file *filp =3D iocb->ki_filp; struct pipe_inode_info *pipe =3D filp->private_data; @@ -604,11 +611,21 @@ pipe_write(struct kiocb *iocb, struct iov_iter *from) kill_fasync(&pipe->fasync_readers, SIGIO, POLL_IN); if (wake_next_writer) wake_up_interruptible_sync_poll(&pipe->wr_wait, EPOLLOUT | EPOLLWRNORM); - if (ret > 0 && sb_start_write_trylock(file_inode(filp)->i_sb)) { - int err =3D file_update_time(filp); - if (err) - ret =3D err; - sb_end_write(file_inode(filp)->i_sb); + return ret; +} + +static ssize_t +fifo_pipe_write(struct kiocb *iocb, struct iov_iter *from) +{ + int ret =3D anon_pipe_write(iocb, from); + if (ret > 0) { + struct file *filp =3D iocb->ki_filp; + if (sb_start_write_trylock(file_inode(filp)->i_sb)) { + int err =3D file_update_time(filp); + if (err) + ret =3D err; + sb_end_write(file_inode(filp)->i_sb); + } } return ret; } @@ -1232,8 +1249,8 @@ static int fifo_open(struct inode *inode, struct file= *filp) =20 const struct file_operations pipefifo_fops =3D { .open =3D fifo_open, - .read_iter =3D pipe_read, - .write_iter =3D pipe_write, + .read_iter =3D fifo_pipe_read, + .write_iter =3D fifo_pipe_write, .poll =3D pipe_poll, .unlocked_ioctl =3D pipe_ioctl, .release =3D pipe_release, @@ -1243,8 +1260,8 @@ const struct file_operations pipefifo_fops =3D { =20 const struct file_operations pipeanon_fops =3D { .open =3D fifo_open, - .read_iter =3D pipe_read, - .write_iter =3D pipe_write, + .read_iter =3D anon_pipe_read, + .write_iter =3D anon_pipe_write, .poll =3D pipe_poll, .unlocked_ioctl =3D pipe_ioctl, .release =3D pipe_release, --=20 2.25.1.362.g51ebf55