Date: Sat, 28 Apr 2012 18:03:58 +0000 (UTC) From: Alan Cox <alc@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-9@freebsd.org Subject: svn commit: r234765 - in stable/9/sys: amd64/amd64 i386/conf kern Message-ID: <201204281803.q3SI3wXa073799@svn.freebsd.org>
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Author: alc Date: Sat Apr 28 18:03:57 2012 New Revision: 234765 URL: http://svn.freebsd.org/changeset/base/234765 Log: MFC r233097 With the changes over the past year to how accesses to the page's dirty field are synchronized, there is no need for pmap_protect() to acquire the page queues lock unless it is going to access the pv lists. Modified: stable/9/sys/amd64/amd64/pmap.c Directory Properties: stable/9/sys/ (props changed) stable/9/sys/amd64/include/xen/ (props changed) stable/9/sys/boot/ (props changed) stable/9/sys/boot/i386/efi/ (props changed) stable/9/sys/boot/ia64/efi/ (props changed) stable/9/sys/boot/ia64/ski/ (props changed) stable/9/sys/boot/powerpc/boot1.chrp/ (props changed) stable/9/sys/boot/powerpc/ofw/ (props changed) stable/9/sys/cddl/contrib/opensolaris/ (props changed) stable/9/sys/conf/ (props changed) stable/9/sys/contrib/dev/acpica/ (props changed) stable/9/sys/contrib/octeon-sdk/ (props changed) stable/9/sys/contrib/pf/ (props changed) stable/9/sys/contrib/x86emu/ (props changed) stable/9/sys/fs/ (props changed) stable/9/sys/fs/ntfs/ (props changed) stable/9/sys/i386/conf/XENHVM (props changed) stable/9/sys/kern/subr_witness.c (props changed) Modified: stable/9/sys/amd64/amd64/pmap.c ============================================================================== --- stable/9/sys/amd64/amd64/pmap.c Sat Apr 28 17:54:54 2012 (r234764) +++ stable/9/sys/amd64/amd64/pmap.c Sat Apr 28 18:03:57 2012 (r234765) @@ -2893,6 +2893,7 @@ pmap_protect(pmap_t pmap, vm_offset_t sv pd_entry_t ptpaddr, *pde; pt_entry_t *pte; int anychanged; + boolean_t pv_lists_locked; if ((prot & VM_PROT_READ) == VM_PROT_NONE) { pmap_remove(pmap, sva, eva); @@ -2903,9 +2904,10 @@ pmap_protect(pmap_t pmap, vm_offset_t sv (VM_PROT_WRITE|VM_PROT_EXECUTE)) return; + pv_lists_locked = FALSE; +resume: anychanged = 0; - vm_page_lock_queues(); PMAP_LOCK(pmap); for (; sva < eva; sva = va_next) { @@ -2954,9 +2956,25 @@ pmap_protect(pmap_t pmap, vm_offset_t sv if (pmap_protect_pde(pmap, pde, sva, prot)) anychanged = 1; continue; - } else if (!pmap_demote_pde(pmap, pde, sva)) { - /* The large page mapping was destroyed. */ - continue; + } else { + if (!pv_lists_locked) { + pv_lists_locked = TRUE; + if (!mtx_trylock(&vm_page_queue_mtx)) { + if (anychanged) + pmap_invalidate_all( + pmap); + PMAP_UNLOCK(pmap); + vm_page_lock_queues(); + goto resume; + } + } + if (!pmap_demote_pde(pmap, pde, sva)) { + /* + * The large page mapping was + * destroyed. + */ + continue; + } } } @@ -2996,7 +3014,8 @@ retry: } if (anychanged) pmap_invalidate_all(pmap); - vm_page_unlock_queues(); + if (pv_lists_locked) + vm_page_unlock_queues(); PMAP_UNLOCK(pmap); }
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