Date: Sun, 12 May 2013 16:50:19 +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: r250577 - head/sys/vm Message-ID: <201305121650.r4CGoJL0087149@svn.freebsd.org>
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Author: alc Date: Sun May 12 16:50:18 2013 New Revision: 250577 URL: http://svnweb.freebsd.org/changeset/base/250577 Log: Refactor vm_page_alloc()'s interactions with vm_reserv_alloc_page() and vm_page_insert() so that (1) vm_radix_lookup_le() is never called while the free page queues lock is held and (2) vm_radix_lookup_le() is called at most once. This change reduces the average time that the free page queues lock is held by vm_page_alloc() as well as vm_page_alloc()'s average overall running time. Sponsored by: EMC / Isilon Storage Division Modified: head/sys/vm/vm_page.c head/sys/vm/vm_reserv.c head/sys/vm/vm_reserv.h Modified: head/sys/vm/vm_page.c ============================================================================== --- head/sys/vm/vm_page.c Sun May 12 16:43:26 2013 (r250576) +++ head/sys/vm/vm_page.c Sun May 12 16:50:18 2013 (r250577) @@ -161,6 +161,8 @@ static struct vnode *vm_page_alloc_init( static void vm_page_clear_dirty_mask(vm_page_t m, vm_page_bits_t pagebits); static void vm_page_enqueue(int queue, vm_page_t m); static void vm_page_init_fakepg(void *dummy); +static void vm_page_insert_after(vm_page_t m, vm_object_t object, + vm_pindex_t pindex, vm_page_t mpred); SYSINIT(vm_page, SI_SUB_VM, SI_ORDER_SECOND, vm_page_init_fakepg, NULL); @@ -809,11 +811,44 @@ vm_page_dirty_KBI(vm_page_t m) void vm_page_insert(vm_page_t m, vm_object_t object, vm_pindex_t pindex) { - vm_page_t neighbor; + vm_page_t mpred; VM_OBJECT_ASSERT_WLOCKED(object); - if (m->object != NULL) - panic("vm_page_insert: page already inserted"); + mpred = vm_radix_lookup_le(&object->rtree, pindex); + vm_page_insert_after(m, object, pindex, mpred); +} + +/* + * vm_page_insert_after: + * + * Inserts the page "m" into the specified object at offset "pindex". + * + * The page "mpred" must immediately precede the offset "pindex" within + * the specified object. + * + * The object must be locked. + */ +static void +vm_page_insert_after(vm_page_t m, vm_object_t object, vm_pindex_t pindex, + vm_page_t mpred) +{ + vm_page_t msucc; + + VM_OBJECT_ASSERT_WLOCKED(object); + KASSERT(m->object == NULL, + ("vm_page_insert_after: page already inserted")); + if (mpred != NULL) { + KASSERT(mpred->object == object || + (mpred->flags & PG_SLAB) != 0, + ("vm_page_insert_after: object doesn't contain mpred")); + KASSERT(mpred->pindex < pindex, + ("vm_page_insert_after: mpred doesn't precede pindex")); + msucc = TAILQ_NEXT(mpred, listq); + } else + msucc = TAILQ_FIRST(&object->memq); + if (msucc != NULL) + KASSERT(msucc->pindex > pindex, + ("vm_page_insert_after: msucc doesn't succeed pindex")); /* * Record the object/offset pair in this page @@ -824,18 +859,10 @@ vm_page_insert(vm_page_t m, vm_object_t /* * Now link into the object's ordered list of backed pages. */ - if (object->resident_page_count == 0) { - TAILQ_INSERT_TAIL(&object->memq, m, listq); - } else { - neighbor = vm_radix_lookup_le(&object->rtree, pindex); - if (neighbor != NULL) { - KASSERT(pindex > neighbor->pindex, - ("vm_page_insert: offset %ju less than %ju", - (uintmax_t)pindex, (uintmax_t)neighbor->pindex)); - TAILQ_INSERT_AFTER(&object->memq, neighbor, m, listq); - } else - TAILQ_INSERT_HEAD(&object->memq, m, listq); - } + if (mpred != NULL) + TAILQ_INSERT_AFTER(&object->memq, mpred, m, listq); + else + TAILQ_INSERT_HEAD(&object->memq, m, listq); vm_radix_insert(&object->rtree, m); /* @@ -1179,7 +1206,7 @@ vm_page_alloc(vm_object_t object, vm_pin { struct vnode *vp = NULL; vm_object_t m_object; - vm_page_t m; + vm_page_t m, mpred; int flags, req_class; KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0), @@ -1195,6 +1222,11 @@ vm_page_alloc(vm_object_t object, vm_pin if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT) req_class = VM_ALLOC_SYSTEM; + if (object != NULL) { + mpred = vm_radix_lookup_le(&object->rtree, pindex); + KASSERT(mpred == NULL || mpred->pindex != pindex, + ("vm_page_alloc: pindex already allocated")); + } mtx_lock(&vm_page_queue_free_mtx); if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved || (req_class == VM_ALLOC_SYSTEM && @@ -1225,8 +1257,8 @@ vm_page_alloc(vm_object_t object, vm_pin return (NULL); #if VM_NRESERVLEVEL > 0 } else if (object == NULL || (object->flags & (OBJ_COLORED | - OBJ_FICTITIOUS)) != OBJ_COLORED || - (m = vm_reserv_alloc_page(object, pindex)) == NULL) { + OBJ_FICTITIOUS)) != OBJ_COLORED || (m = + vm_reserv_alloc_page(object, pindex, mpred)) == NULL) { #else } else { #endif @@ -1320,7 +1352,7 @@ vm_page_alloc(vm_object_t object, vm_pin if (object->memattr != VM_MEMATTR_DEFAULT && (object->flags & OBJ_FICTITIOUS) == 0) pmap_page_set_memattr(m, object->memattr); - vm_page_insert(m, object, pindex); + vm_page_insert_after(m, object, pindex, mpred); } else m->pindex = pindex; Modified: head/sys/vm/vm_reserv.c ============================================================================== --- head/sys/vm/vm_reserv.c Sun May 12 16:43:26 2013 (r250576) +++ head/sys/vm/vm_reserv.c Sun May 12 16:50:18 2013 (r250577) @@ -476,12 +476,15 @@ found: /* * Allocates a page from an existing or newly-created reservation. * + * The page "mpred" must immediately precede the offset "pindex" within the + * specified object. + * * The object and free page queue must be locked. */ vm_page_t -vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex) +vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, vm_page_t mpred) { - vm_page_t m, mpred, msucc; + vm_page_t m, msucc; vm_pindex_t first, leftcap, rightcap; vm_reserv_t rv; @@ -498,10 +501,12 @@ vm_reserv_alloc_page(vm_object_t object, /* * Look for an existing reservation. */ - mpred = vm_radix_lookup_le(&object->rtree, pindex); if (mpred != NULL) { + KASSERT(mpred->object == object || + (mpred->flags & PG_SLAB) != 0, + ("vm_reserv_alloc_page: object doesn't contain mpred")); KASSERT(mpred->pindex < pindex, - ("vm_reserv_alloc_page: pindex already allocated")); + ("vm_reserv_alloc_page: mpred doesn't precede pindex")); rv = vm_reserv_from_page(mpred); if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) goto found; @@ -510,7 +515,7 @@ vm_reserv_alloc_page(vm_object_t object, msucc = TAILQ_FIRST(&object->memq); if (msucc != NULL) { KASSERT(msucc->pindex > pindex, - ("vm_reserv_alloc_page: pindex already allocated")); + ("vm_reserv_alloc_page: msucc doesn't succeed pindex")); rv = vm_reserv_from_page(msucc); if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) goto found; Modified: head/sys/vm/vm_reserv.h ============================================================================== --- head/sys/vm/vm_reserv.h Sun May 12 16:43:26 2013 (r250576) +++ head/sys/vm/vm_reserv.h Sun May 12 16:50:18 2013 (r250577) @@ -48,7 +48,8 @@ vm_page_t vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary); -vm_page_t vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex); +vm_page_t vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, + vm_page_t mpred); void vm_reserv_break_all(vm_object_t object); boolean_t vm_reserv_free_page(vm_page_t m); void vm_reserv_init(void); _______________________________________________ svn-src-all@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-all To unsubscribe, send any mail to "svn-src-all-unsubscribe@freebsd.org"
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