Date: Sun, 9 Feb 2014 01:59:53 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: svn commit: r261647 - head/sys/vm Message-ID: <201402090159.s191xr5r020102@svn.freebsd.org>
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Author: alc Date: Sun Feb 9 01:59:52 2014 New Revision: 261647 URL: http://svnweb.freebsd.org/changeset/base/261647 Log: Don't call vm_fault_prefault() on zero-fill faults. It's a waste of time. Successful prefaults after a zero-fill fault are extremely rare. Modified: head/sys/vm/vm_fault.c Modified: head/sys/vm/vm_fault.c ============================================================================== --- head/sys/vm/vm_fault.c Sun Feb 9 01:21:30 2014 (r261646) +++ head/sys/vm/vm_fault.c Sun Feb 9 01:59:52 2014 (r261647) @@ -652,6 +652,8 @@ vnode_locked: } PCPU_INC(cnt.v_zfod); fs.m->valid = VM_PAGE_BITS_ALL; + /* Don't try to prefault neighboring pages. */ + faultcount = 1; break; /* break to PAGE HAS BEEN FOUND */ } else { KASSERT(fs.object != next_object, @@ -897,7 +899,8 @@ vnode_locked: * won't find it (yet). */ pmap_enter(fs.map->pmap, vaddr, fault_type, fs.m, prot, wired); - if ((fault_flags & VM_FAULT_CHANGE_WIRING) == 0 && wired == 0) + if (faultcount != 1 && (fault_flags & VM_FAULT_CHANGE_WIRING) == 0 && + wired == 0) vm_fault_prefault(&fs, vaddr, faultcount, reqpage); VM_OBJECT_WLOCK(fs.object); vm_page_lock(fs.m);
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