From owner-svn-src-user@FreeBSD.ORG Tue Dec 6 19:04:46 2011 Return-Path: Delivered-To: svn-src-user@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 15A5D106566C; Tue, 6 Dec 2011 19:04:46 +0000 (UTC) (envelope-from attilio@FreeBSD.org) Received: from svn.freebsd.org (svn.freebsd.org [IPv6:2001:4f8:fff6::2c]) by mx1.freebsd.org (Postfix) with ESMTP id E092F8FC0A; Tue, 6 Dec 2011 19:04:45 +0000 (UTC) Received: from svn.freebsd.org (localhost [127.0.0.1]) by svn.freebsd.org (8.14.4/8.14.4) with ESMTP id pB6J4j8K004326; Tue, 6 Dec 2011 19:04:45 GMT (envelope-from attilio@svn.freebsd.org) Received: (from attilio@localhost) by svn.freebsd.org (8.14.4/8.14.4/Submit) id pB6J4jTO004323; Tue, 6 Dec 2011 19:04:45 GMT (envelope-from attilio@svn.freebsd.org) Message-Id: <201112061904.pB6J4jTO004323@svn.freebsd.org> From: Attilio Rao Date: Tue, 6 Dec 2011 19:04:45 +0000 (UTC) To: src-committers@freebsd.org, svn-src-user@freebsd.org X-SVN-Group: user MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Cc: Subject: svn commit: r228312 - user/attilio/vmcontention/sys/vm X-BeenThere: svn-src-user@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: "SVN commit messages for the experimental " user" src tree" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 06 Dec 2011 19:04:46 -0000 Author: attilio Date: Tue Dec 6 19:04:45 2011 New Revision: 228312 URL: http://svn.freebsd.org/changeset/base/228312 Log: - Make rn_count 32-bits as it will naturally pad for 32-bit arches - Avoid to use atomic to manipulate it at level0 because it seems unneeded and introduces a bug on big-endian architectures where only the top half (2 bits) of the double-words are written (as sparc64, for example, doesn't support atomics at 16-bits) heading to a wrong handling of rn_count. Reported by: flo, andreast Found by: marius No answer by: jeff Modified: user/attilio/vmcontention/sys/vm/vm_radix.c user/attilio/vmcontention/sys/vm/vm_radix.h Modified: user/attilio/vmcontention/sys/vm/vm_radix.c ============================================================================== --- user/attilio/vmcontention/sys/vm/vm_radix.c Tue Dec 6 18:01:09 2011 (r228311) +++ user/attilio/vmcontention/sys/vm/vm_radix.c Tue Dec 6 19:04:45 2011 (r228312) @@ -344,7 +344,7 @@ vm_radix_insert(struct vm_radix *rtree, rnode->rn_child[slot], (u_long)index)); val = (void *)((uintptr_t)val | VM_RADIX_BLACK); rnode->rn_child[slot] = val; - atomic_add_int((volatile int *)&rnode->rn_count, 1); + rnode->rn_count++; CTR6(KTR_VM, "insert: tree %p, index %ju, level %d, slot %d, rnode %p, count %u", rtree, (uintmax_t)index, level, slot, rnode, rnode->rn_count); @@ -681,14 +681,7 @@ vm_radix_remove(struct vm_radix *rtree, (rnode != NULL) ? rnode->rn_child[slot] : NULL, (rnode != NULL) ? rnode->rn_count : 0); rnode->rn_child[slot] = NULL; - /* - * Use atomics for the last level since red and black - * will both adjust it. - */ - if (level == 0) - atomic_add_int((volatile int *)&rnode->rn_count, -1); - else - rnode->rn_count--; + rnode->rn_count--; /* * Only allow black removes to prune the tree. */ Modified: user/attilio/vmcontention/sys/vm/vm_radix.h ============================================================================== --- user/attilio/vmcontention/sys/vm/vm_radix.h Tue Dec 6 18:01:09 2011 (r228311) +++ user/attilio/vmcontention/sys/vm/vm_radix.h Tue Dec 6 19:04:45 2011 (r228312) @@ -61,8 +61,8 @@ struct vm_radix { CTASSERT(VM_RADIX_HEIGHT >= VM_RADIX_LIMIT); struct vm_radix_node { - void *rn_child[VM_RADIX_COUNT]; /* Child nodes. */ - volatile uint16_t rn_count; /* Valid children. */ + void *rn_child[VM_RADIX_COUNT]; /* Child nodes. */ + uint32_t rn_count; /* Valid children. */ }; void vm_radix_init(void);