From owner-svn-src-all@FreeBSD.ORG Tue May 6 03:42:05 2014 Return-Path: Delivered-To: svn-src-all@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 85FAA104; Tue, 6 May 2014 03:42:05 +0000 (UTC) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:1900:2254:2068::e6a:0]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 59C2DA46; Tue, 6 May 2014 03:42:05 +0000 (UTC) Received: from svn.freebsd.org ([127.0.1.70]) by svn.freebsd.org (8.14.8/8.14.8) with ESMTP id s463g5p4047448; Tue, 6 May 2014 03:42:05 GMT (envelope-from alc@svn.freebsd.org) Received: (from alc@localhost) by svn.freebsd.org (8.14.8/8.14.8/Submit) id s463g5Fx047447; Tue, 6 May 2014 03:42:05 GMT (envelope-from alc@svn.freebsd.org) Message-Id: <201405060342.s463g5Fx047447@svn.freebsd.org> From: Alan Cox Date: Tue, 6 May 2014 03:42:05 +0000 (UTC) To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r265418 - head/sys/vm X-SVN-Group: head MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.18 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 May 2014 03:42:05 -0000 Author: alc Date: Tue May 6 03:42:04 2014 New Revision: 265418 URL: http://svnweb.freebsd.org/changeset/base/265418 Log: Prior to r254304, a separate function, vm_pageout_page_stats(), was used to periodically update the reference status of the active pages. This function was called, instead of vm_pageout_scan(), when memory was not scarce. The objective was to provide up to date reference status for active pages in case memory did become scarce and active pages needed to be deactivated. The active page queue scan performed by vm_pageout_page_stats() was virtually identical to that performed by vm_pageout_scan(), and so r254304 eliminated vm_pageout_page_stats(). Instead, vm_pageout_scan() is called with the parameter "pass" set to zero. The intention was that when pass is zero, vm_pageout_scan() would only scan the active queue. However, the variable page_shortage can still be greater than zero when memory is not scarce and vm_pageout_scan() is called with pass equal to zero. Consequently, the inactive queue may be scanned and dirty pages laundered even though that was not intended by r254304. This revision fixes that. Reported by: avg MFC after: 1 week Sponsored by: EMC / Isilon Storage Division Modified: head/sys/vm/vm_pageout.c Modified: head/sys/vm/vm_pageout.c ============================================================================== --- head/sys/vm/vm_pageout.c Tue May 6 03:38:04 2014 (r265417) +++ head/sys/vm/vm_pageout.c Tue May 6 03:42:04 2014 (r265418) @@ -942,13 +942,15 @@ vm_pageout_scan(struct vm_domain *vmd, i */ addl_page_shortage = 0; - deficit = atomic_readandclear_int(&vm_pageout_deficit); - /* * Calculate the number of pages we want to either free or move * to the cache. */ - page_shortage = vm_paging_target() + deficit; + if (pass > 0) { + deficit = atomic_readandclear_int(&vm_pageout_deficit); + page_shortage = vm_paging_target() + deficit; + } else + page_shortage = deficit = 0; /* * maxlaunder limits the number of dirty pages we flush per scan.