From patchwork Wed Feb 5 18:18:12 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Oleg Nesterov X-Patchwork-Id: 13961654 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 C5AA91779AE for ; Wed, 5 Feb 2025 18:18:51 +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=1738779533; cv=none; b=X6faxzWnXJH4YME7yMTw+5Q2IhlMXsLpFfbrsld2sxd1u3fP8xrcKhcZOSV6Qoad57mhF66/wGTO1RxpVVsSVDNRHCGr7vwpC/3PaHCwvIIE/n9Y9yeSaTvZRA3AkkydZDnWq7p+8fVVvdXLQUu19is1TWlyNYpZpKtXspXpuhk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1738779533; c=relaxed/simple; bh=McltsGuhrdjKSLzYSZ2RB5cGI/ob/Aq3P+nHQ5SQmI8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=TdVMUCJMxqgF4mfs2U4ROY8Zepy3DgwPF2zweBCpEdFRWJfTeQFDXU6nLC6c4FJhjfloCvo9hvc9azGyGShRe5ORbgWZqlUizB8kf49pJUObJJzp7/116Y686DZLcGp5xCZw1VSKEJICbDHGImtCRm0giZsVheHLAZI5OLKjy+A= 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=J/LHoV1t; 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="J/LHoV1t" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1738779530; 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=YAZPH6LoBdfmC4eKY2rMSg24boi4M+z/rfTpR2/KoTE=; b=J/LHoV1tJWcupIYoFq6a3uY4t1fCOdMdMUzl8W3DYo1rg09DV9s+CJpDysTKdHd+0o62YN qsOoZnjgpHelrtEePM6dk2R2Z0zOeef/hVYQpm1mO8r3Lq9HF5a22y74LAcAZ7o69OOdYH 13/FjDurol8x748Z/pMvcp+E5euvNsA= 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-531-eyRvOxkLMm-K86gnIv0iOQ-1; Wed, 05 Feb 2025 13:18:47 -0500 X-MC-Unique: eyRvOxkLMm-K86gnIv0iOQ-1 X-Mimecast-MFC-AGG-ID: eyRvOxkLMm-K86gnIv0iOQ 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 7D59A180087B; Wed, 5 Feb 2025 18:18:45 +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 8DD721800265; Wed, 5 Feb 2025 18:18:40 +0000 (UTC) Received: by dhcp-27-174.brq.redhat.com (nbSMTP-1.00) for uid 1000 oleg@redhat.com; Wed, 5 Feb 2025 19:18:18 +0100 (CET) Date: Wed, 5 Feb 2025 19:18:12 +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 v3 2/2] pipe: don't update {a,c,m}time for anonymous pipes Message-ID: <20250205181812.GC13817@redhat.com> References: <20250205181716.GA13817@redhat.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <20250205181716.GA13817@redhat.com> User-Agent: Mutt/1.5.24 (2015-08-30) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 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 = 0; (r = write(fd, buf, size)) > 0; c += 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 = 0; (r = read(fd, buf, size)) > 0; c += 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 = 1, loop, size; assert(argc == 3); loop = atoi(argv[1]); size = atoi(argv[2]); assert(pipe(fd) == 0); assert(ioctl(fd[0], FIONBIO, &nb) == 0); assert(ioctl(fd[1], FIONBIO, &nb) == 0); assert(size <= sizeof(buf)); while (loop--) assert(wr(fd[1], size) == rd(fd[0], size)); struct timeval tt; timeradd(&TW, &TR, &tt); printf("TW = %lu.%03lu TR = %lu.%03lu TT = %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 = 8.047 TR = 5.845 TT = 13.893 TW = 8.091 TR = 5.872 TT = 13.963 TW = 8.083 TR = 5.885 TT = 13.969 After: # for i in 1 2 3; do /host/tmp/test 10000 100; done TW = 4.752 TR = 4.664 TT = 9.416 TW = 4.684 TR = 4.608 TT = 9.293 TW = 4.736 TR = 4.652 TT = 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 2eacfde61e74..2ae75adfba64 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, } 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 = iov_iter_count(to); struct file *filp = 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 = anon_pipe_read(iocb, to); if (ret > 0) - file_accessed(filp); + file_accessed(iocb->ki_filp); return ret; } @@ -426,7 +433,7 @@ static inline bool pipe_writable(const struct pipe_inode_info *pipe) } 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 = iocb->ki_filp; struct pipe_inode_info *pipe = 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 = file_update_time(filp); - if (err) - ret = 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 = anon_pipe_write(iocb, from); + if (ret > 0) { + struct file *filp = iocb->ki_filp; + if (sb_start_write_trylock(file_inode(filp)->i_sb)) { + int err = file_update_time(filp); + if (err) + ret = err; + sb_end_write(file_inode(filp)->i_sb); + } } return ret; } @@ -1234,8 +1251,8 @@ static int fifo_open(struct inode *inode, struct file *filp) const struct file_operations pipefifo_fops = { .open = fifo_open, - .read_iter = pipe_read, - .write_iter = pipe_write, + .read_iter = fifo_pipe_read, + .write_iter = fifo_pipe_write, .poll = pipe_poll, .unlocked_ioctl = pipe_ioctl, .release = pipe_release, @@ -1245,8 +1262,8 @@ const struct file_operations pipefifo_fops = { static const struct file_operations pipeanon_fops = { .open = fifo_open, - .read_iter = pipe_read, - .write_iter = pipe_write, + .read_iter = anon_pipe_read, + .write_iter = anon_pipe_write, .poll = pipe_poll, .unlocked_ioctl = pipe_ioctl, .release = pipe_release,