From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756933Ab1COJgt (ORCPT ); Tue, 15 Mar 2011 05:36:49 -0400 Received: from mx1.redhat.com ([209.132.183.28]:2143 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755429Ab1COJeF (ORCPT ); Tue, 15 Mar 2011 05:34:05 -0400 From: Steven Whitehouse To: cluster-devel@redhat.com, linux-kernel@vger.kernel.org Cc: Steven Whitehouse Subject: [PATCH 04/15] GFS2: Improve cluster mmap scalability Date: Tue, 15 Mar 2011 09:11:34 +0000 Message-Id: <1300180305-5993-5-git-send-email-swhiteho@redhat.com> In-Reply-To: <1300180305-5993-1-git-send-email-swhiteho@redhat.com> References: <1300180305-5993-1-git-send-email-swhiteho@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The mmap system call grabs a glock when an update to atime maybe required. It does this in order to ensure that the flags on the inode are uptodate, but since it will only mark atime for a future update, an exclusive lock is not required here (one will be taken later when the actual update is performed). Also, the lock can be skipped when the mount is marked noatime in addition to the original check which only looked at the noatime flag for the inode itself. This should increase the scalability of the mmap call when multiple nodes are all mmaping the same file. Reported-by: Scooter Morris Signed-off-by: Steven Whitehouse diff --git a/fs/gfs2/file.c b/fs/gfs2/file.c index 7cfdcb9..216ad27 100644 --- a/fs/gfs2/file.c +++ b/fs/gfs2/file.c @@ -448,15 +448,20 @@ static int gfs2_mmap(struct file *file, struct vm_area_struct *vma) { struct gfs2_inode *ip = GFS2_I(file->f_mapping->host); - if (!(file->f_flags & O_NOATIME)) { + if (!(file->f_flags & O_NOATIME) && + !IS_NOATIME(&ip->i_inode)) { struct gfs2_holder i_gh; int error; - gfs2_holder_init(ip->i_gl, LM_ST_EXCLUSIVE, 0, &i_gh); + gfs2_holder_init(ip->i_gl, LM_ST_SHARED, LM_FLAG_ANY, &i_gh); error = gfs2_glock_nq(&i_gh); - file_accessed(file); - if (error == 0) - gfs2_glock_dq_uninit(&i_gh); + if (error == 0) { + file_accessed(file); + gfs2_glock_dq(&i_gh); + } + gfs2_holder_uninit(&i_gh); + if (error) + return error; } vma->vm_ops = &gfs2_vm_ops; vma->vm_flags |= VM_CAN_NONLINEAR; -- 1.7.4