Date: Thu, 2 Jul 2009 04:56:11 +0000 (UTC) From: Kip Macy <kmacy@FreeBSD.org> To: src-committers@freebsd.org, svn-src-user@freebsd.org Subject: svn commit: r195279 - user/kmacy/releng_7_2_fcs/sys/amd64/amd64 Message-ID: <200907020456.n624uBHt033925@svn.freebsd.org>
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Author: kmacy Date: Thu Jul 2 04:56:11 2009 New Revision: 195279 URL: http://svn.freebsd.org/changeset/base/195279 Log: avoid deadlock between pmap_collect and pageout Modified: user/kmacy/releng_7_2_fcs/sys/amd64/amd64/pmap.c Modified: user/kmacy/releng_7_2_fcs/sys/amd64/amd64/pmap.c ============================================================================== --- user/kmacy/releng_7_2_fcs/sys/amd64/amd64/pmap.c Thu Jul 2 00:50:19 2009 (r195278) +++ user/kmacy/releng_7_2_fcs/sys/amd64/amd64/pmap.c Thu Jul 2 04:56:11 2009 (r195279) @@ -1953,7 +1953,17 @@ pmap_collect(pmap_t locked_pmap, struct vm_offset_t va; vm_page_t m, free = NULL; - vm_page_lock_queues(); + /* + * This isn't really a solid fix as we need to assure the caller + * that pmap state hasn't changed - but the way pageout works + * we typically need to call pmap functions with the page queue lock + * held + */ + if (vm_page_trylock_queues() == 0) { + PMAP_UNLOCK(locked_pmap); + vm_page_lock_queues(); + PMAP_LOCK(locked_pmap); + } TAILQ_FOREACH(m, &vpq->pl, pageq) { if (m->hold_count || m->busy || vm_page_trylock(m) == 0) continue;
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