From patchwork Mon Dec 10 17:13:07 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Goyal X-Patchwork-Id: 10721831 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id AB39F14E2 for ; Mon, 10 Dec 2018 17:15:49 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 910402AF37 for ; Mon, 10 Dec 2018 17:15:49 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8537C2AF3F; Mon, 10 Dec 2018 17:15:49 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3754F2AF37 for ; Mon, 10 Dec 2018 17:15:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728809AbeLJRPh (ORCPT ); Mon, 10 Dec 2018 12:15:37 -0500 Received: from mx1.redhat.com ([209.132.183.28]:55354 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728471AbeLJRNi (ORCPT ); Mon, 10 Dec 2018 12:13:38 -0500 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 64BE6804E3; Mon, 10 Dec 2018 17:13:38 +0000 (UTC) Received: from horse.redhat.com (unknown [10.18.25.234]) by smtp.corp.redhat.com (Postfix) with ESMTP id 18420101962A; Mon, 10 Dec 2018 17:13:35 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id A6FB7224275; Mon, 10 Dec 2018 12:13:30 -0500 (EST) From: Vivek Goyal To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: vgoyal@redhat.com, miklos@szeredi.hu, stefanha@redhat.com, dgilbert@redhat.com, sweil@redhat.com, swhiteho@redhat.com Subject: [PATCH 41/52] fuse: Reschedule dax free work if too many EAGAIN attempts Date: Mon, 10 Dec 2018 12:13:07 -0500 Message-Id: <20181210171318.16998-42-vgoyal@redhat.com> In-Reply-To: <20181210171318.16998-1-vgoyal@redhat.com> References: <20181210171318.16998-1-vgoyal@redhat.com> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Mon, 10 Dec 2018 17:13:38 +0000 (UTC) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP fuse_dax_free_memory() can be very cpu intensive in corner cases. For example, if one inode has consumed all the memory and a setupmapping request is pending, that means inode lock is held by request and worker thread will not get lock for a while. And given there is only one inode consuming all the dax ranges, all the attempts to acquire lock will fail. So if there are too many inode lock failures (-EAGAIN), reschedule the worker with a 10ms delay. Signed-off-by: Vivek Goyal --- fs/fuse/file.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/fs/fuse/file.c b/fs/fuse/file.c index dbe3410a94d7..709747458335 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -3909,7 +3909,7 @@ int fuse_dax_free_one_mapping(struct fuse_conn *fc, struct inode *inode, int fuse_dax_free_memory(struct fuse_conn *fc, unsigned long nr_to_free) { struct fuse_dax_mapping *dmap, *pos, *temp; - int ret, nr_freed = 0; + int ret, nr_freed = 0, nr_eagain = 0; u64 dmap_start = 0, window_offset = 0; struct inode *inode = NULL; @@ -3918,6 +3918,12 @@ int fuse_dax_free_memory(struct fuse_conn *fc, unsigned long nr_to_free) if (nr_freed >= nr_to_free) break; + if (nr_eagain > 20) { + queue_delayed_work(system_long_wq, &fc->dax_free_work, + msecs_to_jiffies(10)); + return 0; + } + dmap = NULL; spin_lock(&fc->lock); @@ -3955,8 +3961,10 @@ int fuse_dax_free_memory(struct fuse_conn *fc, unsigned long nr_to_free) } /* Could not get inode lock. Try next element */ - if (ret == -EAGAIN) + if (ret == -EAGAIN) { + nr_eagain++; continue; + } nr_freed++; } return 0;