From owner-cvs-all@FreeBSD.ORG Tue Sep 25 06:25:08 2007 Return-Path: Delivered-To: cvs-all@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 5B01D16A417; Tue, 25 Sep 2007 06:25:08 +0000 (UTC) (envelope-from alc@FreeBSD.org) Received: from repoman.freebsd.org (repoman.freebsd.org [IPv6:2001:4f8:fff6::29]) by mx1.freebsd.org (Postfix) with ESMTP id 39F6813C43E; Tue, 25 Sep 2007 06:25:08 +0000 (UTC) (envelope-from alc@FreeBSD.org) Received: from repoman.freebsd.org (localhost [127.0.0.1]) by repoman.freebsd.org (8.14.1/8.14.1) with ESMTP id l8P6P8i0082234; Tue, 25 Sep 2007 06:25:08 GMT (envelope-from alc@repoman.freebsd.org) Received: (from alc@localhost) by repoman.freebsd.org (8.14.1/8.14.1/Submit) id l8P6P7w7082233; Tue, 25 Sep 2007 06:25:07 GMT (envelope-from alc) Message-Id: <200709250625.l8P6P7w7082233@repoman.freebsd.org> From: Alan Cox Date: Tue, 25 Sep 2007 06:25:07 +0000 (UTC) To: src-committers@FreeBSD.org, cvs-src@FreeBSD.org, cvs-all@FreeBSD.org X-FreeBSD-CVS-Branch: HEAD Cc: Subject: cvs commit: src/sys/amd64/include vmparam.h src/sys/arm/include vmparam.h src/sys/i386/include vmparam.h src/sys/ia64/include vmparam.h src/sys/kern kern_exec.c vfs_bio.c src/sys/powerpc/include vmparam.h src/sys/sparc64/include ... X-BeenThere: cvs-all@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: CVS commit messages for the entire tree List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 25 Sep 2007 06:25:08 -0000 alc 2007-09-25 06:25:07 UTC FreeBSD src repository Modified files: sys/amd64/include vmparam.h sys/arm/include vmparam.h sys/i386/include vmparam.h sys/ia64/include vmparam.h sys/kern kern_exec.c vfs_bio.c sys/powerpc/include vmparam.h sys/sparc64/include vmparam.h sys/sun4v/include vmparam.h sys/sys vmmeter.h sys/vm vm_contig.c vm_fault.c vm_map.c vm_object.c vm_object.h vm_page.c vm_page.h vm_pageout.c vm_pageq.c vm_phys.c vm_phys.h Log: Change the management of cached pages (PQ_CACHE) in two fundamental ways: (1) Cached pages are no longer kept in the object's resident page splay tree and memq. Instead, they are kept in a separate per-object splay tree of cached pages. However, access to this new per-object splay tree is synchronized by the _free_ page queues lock, not to be confused with the heavily contended page queues lock. Consequently, a cached page can be reclaimed by vm_page_alloc(9) without acquiring the object's lock or the page queues lock. This solves a problem independently reported by tegge@ and Isilon. Specifically, they observed the page daemon consuming a great deal of CPU time because of pages bouncing back and forth between the cache queue (PQ_CACHE) and the inactive queue (PQ_INACTIVE). The source of this problem turned out to be a deadlock avoidance strategy employed when selecting a cached page to reclaim in vm_page_select_cache(). However, the root cause was really that reclaiming a cached page required the acquisition of an object lock while the page queues lock was already held. Thus, this change addresses the problem at its root, by eliminating the need to acquire the object's lock. Moreover, keeping cached pages in the object's primary splay tree and memq was, in effect, optimizing for the uncommon case. Cached pages are reclaimed far, far more often than they are reactivated. Instead, this change makes reclamation cheaper, especially in terms of synchronization overhead, and reactivation more expensive, because reactivated pages will have to be reentered into the object's primary splay tree and memq. (2) Cached pages are now stored alongside free pages in the physical memory allocator's buddy queues, increasing the likelihood that large allocations of contiguous physical memory (i.e., superpages) will succeed. Finally, as a result of this change long-standing restrictions on when and where a cached page can be reclaimed and returned by vm_page_alloc(9) are eliminated. Specifically, calls to vm_page_alloc(9) specifying VM_ALLOC_INTERRUPT can now reclaim and return a formerly cached page. Consequently, a call to malloc(9) specifying M_NOWAIT is less likely to fail. Discussed with: many over the course of the summer, including jeff@, Justin Husted @ Isilon, peter@, tegge@ Tested by: an earlier version by kris@ Approved by: re (kensmith) Revision Changes Path 1.49 +3 -2 src/sys/amd64/include/vmparam.h 1.11 +3 -2 src/sys/arm/include/vmparam.h 1.45 +3 -2 src/sys/i386/include/vmparam.h 1.17 +3 -2 src/sys/ia64/include/vmparam.h 1.308 +1 -1 src/sys/kern/kern_exec.c 1.527 +4 -10 src/sys/kern/vfs_bio.c 1.10 +3 -2 src/sys/powerpc/include/vmparam.h 1.18 +3 -2 src/sys/sparc64/include/vmparam.h 1.5 +3 -2 src/sys/sun4v/include/vmparam.h 1.34 +2 -2 src/sys/sys/vmmeter.h 1.63 +2 -11 src/sys/vm/vm_contig.c 1.236 +8 -21 src/sys/vm/vm_fault.c 1.388 +7 -11 src/sys/vm/vm_map.c 1.383 +30 -14 src/sys/vm/vm_object.c 1.114 +1 -0 src/sys/vm/vm_object.h 1.354 +271 -86 src/sys/vm/vm_page.c 1.151 +11 -15 src/sys/vm/vm_page.h 1.292 +2 -35 src/sys/vm/vm_pageout.c 1.35 +0 -27 src/sys/vm/vm_pageq.c 1.4 +115 -33 src/sys/vm/vm_phys.c 1.3 +3 -0 src/sys/vm/vm_phys.h