From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id ACEA021D49196 for ; Wed, 15 May 2019 12:27:34 -0700 (PDT) From: Vivek Goyal Subject: [PATCH v2 28/30] fuse: Reschedule dax free work if too many EAGAIN attempts Date: Wed, 15 May 2019 15:27:13 -0400 Message-Id: <20190515192715.18000-29-vgoyal@redhat.com> In-Reply-To: <20190515192715.18000-1-vgoyal@redhat.com> References: <20190515192715.18000-1-vgoyal@redhat.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-nvdimm@lists.01.org Cc: swhiteho@redhat.com, dgilbert@redhat.com, stefanha@redhat.com, miklos@szeredi.hu List-ID: 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 b0293a308b5e..9b82d9b4ebc3 100644 --- a/fs/fuse/file.c +++ b/fs/fuse/file.c @@ -4047,7 +4047,7 @@ 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; @@ -4056,6 +4056,12 @@ 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); @@ -4093,8 +4099,10 @@ 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; -- 2.20.1 _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm