Author: alc Date: Thu Dec 8 04:29:29 2016 New Revision: 309703 URL: https://svnweb.freebsd.org/changeset/base/309703
Log: Previously, vm_radix_remove() would panic if the radix trie didn't contain a vm_page_t at the specified index. However, with this change, vm_radix_remove() no longer panics. Instead, it returns NULL if there is no vm_page_t at the specified index. Otherwise, it returns the vm_page_t. The motivation for this change is that it simplifies the use of radix tries in the amd64, arm64, and i386 pmap implementations. Instead of performing a lookup before every remove, the pmap can simply perform the remove. Reviewed by: kib, markj Differential Revision: https://reviews.freebsd.org/D8708 Modified: head/sys/amd64/amd64/pmap.c head/sys/arm64/arm64/pmap.c head/sys/i386/i386/pmap.c head/sys/vm/vm_page.c head/sys/vm/vm_radix.c head/sys/vm/vm_radix.h Modified: head/sys/amd64/amd64/pmap.c ============================================================================== --- head/sys/amd64/amd64/pmap.c Thu Dec 8 01:07:00 2016 (r309702) +++ head/sys/amd64/amd64/pmap.c Thu Dec 8 04:29:29 2016 (r309703) @@ -614,7 +614,6 @@ static vm_page_t pmap_enter_quick_locked static void pmap_fill_ptp(pt_entry_t *firstpte, pt_entry_t newpte); static int pmap_insert_pt_page(pmap_t pmap, vm_page_t mpte); static void pmap_kenter_attr(vm_offset_t va, vm_paddr_t pa, int mode); -static vm_page_t pmap_lookup_pt_page(pmap_t pmap, vm_offset_t va); static void pmap_pde_attr(pd_entry_t *pde, int cache_bits, int mask); static void pmap_promote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va, struct rwlock **lockp); @@ -625,7 +624,7 @@ static int pmap_remove_pde(pmap_t pmap, struct spglist *free, struct rwlock **lockp); static int pmap_remove_pte(pmap_t pmap, pt_entry_t *ptq, vm_offset_t sva, pd_entry_t ptepde, struct spglist *free, struct rwlock **lockp); -static void pmap_remove_pt_page(pmap_t pmap, vm_page_t mpte); +static vm_page_t pmap_remove_pt_page(pmap_t pmap, vm_offset_t va); static void pmap_remove_page(pmap_t pmap, vm_offset_t va, pd_entry_t *pde, struct spglist *free); static boolean_t pmap_try_insert_pv_entry(pmap_t pmap, vm_offset_t va, @@ -2209,29 +2208,17 @@ pmap_insert_pt_page(pmap_t pmap, vm_page } /* - * Looks for a page table page mapping the specified virtual address in the - * specified pmap's collection of idle page table pages. Returns NULL if there - * is no page table page corresponding to the specified virtual address. + * Removes the page table page mapping the specified virtual address from the + * specified pmap's collection of idle page table pages, and returns it. + * Otherwise, returns NULL if there is no page table page corresponding to the + * specified virtual address. */ static __inline vm_page_t -pmap_lookup_pt_page(pmap_t pmap, vm_offset_t va) +pmap_remove_pt_page(pmap_t pmap, vm_offset_t va) { PMAP_LOCK_ASSERT(pmap, MA_OWNED); - return (vm_radix_lookup(&pmap->pm_root, pmap_pde_pindex(va))); -} - -/* - * Removes the specified page table page from the specified pmap's collection - * of idle page table pages. The specified page table page must be a member of - * the pmap's collection. - */ -static __inline void -pmap_remove_pt_page(pmap_t pmap, vm_page_t mpte) -{ - - PMAP_LOCK_ASSERT(pmap, MA_OWNED); - vm_radix_remove(&pmap->pm_root, mpte->pindex); + return (vm_radix_remove(&pmap->pm_root, pmap_pde_pindex(va))); } /* @@ -3450,10 +3437,8 @@ pmap_demote_pde_locked(pmap_t pmap, pd_e oldpde = *pde; KASSERT((oldpde & (PG_PS | PG_V)) == (PG_PS | PG_V), ("pmap_demote_pde: oldpde is missing PG_PS and/or PG_V")); - if ((oldpde & PG_A) != 0 && (mpte = pmap_lookup_pt_page(pmap, va)) != - NULL) - pmap_remove_pt_page(pmap, mpte); - else { + if ((oldpde & PG_A) == 0 || (mpte = pmap_remove_pt_page(pmap, va)) == + NULL) { KASSERT((oldpde & PG_W) == 0, ("pmap_demote_pde: page table page for a wired mapping" " is missing")); @@ -3567,11 +3552,10 @@ pmap_remove_kernel_pde(pmap_t pmap, pd_e KASSERT(pmap == kernel_pmap, ("pmap %p is not kernel_pmap", pmap)); PMAP_LOCK_ASSERT(pmap, MA_OWNED); - mpte = pmap_lookup_pt_page(pmap, va); + mpte = pmap_remove_pt_page(pmap, va); if (mpte == NULL) panic("pmap_remove_kernel_pde: Missing pt page."); - pmap_remove_pt_page(pmap, mpte); mptepa = VM_PAGE_TO_PHYS(mpte); newpde = mptepa | X86_PG_M | X86_PG_A | X86_PG_RW | X86_PG_V; @@ -3646,9 +3630,8 @@ pmap_remove_pde(pmap_t pmap, pd_entry_t if (pmap == kernel_pmap) { pmap_remove_kernel_pde(pmap, pdq, sva); } else { - mpte = pmap_lookup_pt_page(pmap, sva); + mpte = pmap_remove_pt_page(pmap, sva); if (mpte != NULL) { - pmap_remove_pt_page(pmap, mpte); pmap_resident_count_dec(pmap, 1); KASSERT(mpte->wire_count == NPTEPG, ("pmap_remove_pde: pte page wire count error")); @@ -5488,9 +5471,8 @@ pmap_remove_pages(pmap_t pmap) TAILQ_EMPTY(&mt->md.pv_list)) vm_page_aflag_clear(mt, PGA_WRITEABLE); } - mpte = pmap_lookup_pt_page(pmap, pv->pv_va); + mpte = pmap_remove_pt_page(pmap, pv->pv_va); if (mpte != NULL) { - pmap_remove_pt_page(pmap, mpte); pmap_resident_count_dec(pmap, 1); KASSERT(mpte->wire_count == NPTEPG, ("pmap_remove_pages: pte page wire count error")); Modified: head/sys/arm64/arm64/pmap.c ============================================================================== --- head/sys/arm64/arm64/pmap.c Thu Dec 8 01:07:00 2016 (r309702) +++ head/sys/arm64/arm64/pmap.c Thu Dec 8 04:29:29 2016 (r309703) @@ -2509,29 +2509,17 @@ pmap_insert_pt_page(pmap_t pmap, vm_page } /* - * Looks for a page table page mapping the specified virtual address in the - * specified pmap's collection of idle page table pages. Returns NULL if there - * is no page table page corresponding to the specified virtual address. + * Removes the page table page mapping the specified virtual address from the + * specified pmap's collection of idle page table pages, and returns it. + * Otherwise, returns NULL if there is no page table page corresponding to the + * specified virtual address. */ static __inline vm_page_t -pmap_lookup_pt_page(pmap_t pmap, vm_offset_t va) +pmap_remove_pt_page(pmap_t pmap, vm_offset_t va) { PMAP_LOCK_ASSERT(pmap, MA_OWNED); - return (vm_radix_lookup(&pmap->pm_root, pmap_l2_pindex(va))); -} - -/* - * Removes the specified page table page from the specified pmap's collection - * of idle page table pages. The specified page table page must be a member of - * the pmap's collection. - */ -static __inline void -pmap_remove_pt_page(pmap_t pmap, vm_page_t mpte) -{ - - PMAP_LOCK_ASSERT(pmap, MA_OWNED); - vm_radix_remove(&pmap->pm_root, mpte->pindex); + return (vm_radix_remove(&pmap->pm_root, pmap_l2_pindex(va))); } /* @@ -3586,10 +3574,9 @@ pmap_remove_pages(pmap_t pmap) TAILQ_EMPTY(&mt->md.pv_list)) vm_page_aflag_clear(mt, PGA_WRITEABLE); } - ml3 = pmap_lookup_pt_page(pmap, + ml3 = pmap_remove_pt_page(pmap, pv->pv_va); if (ml3 != NULL) { - pmap_remove_pt_page(pmap, ml3); pmap_resident_count_dec(pmap,1); KASSERT(ml3->wire_count == NL3PG, ("pmap_remove_pages: l3 page wire count error")); @@ -4374,9 +4361,7 @@ pmap_demote_l2_locked(pmap_t pmap, pt_en return (NULL); } - if ((ml3 = pmap_lookup_pt_page(pmap, va)) != NULL) { - pmap_remove_pt_page(pmap, ml3); - } else { + if ((ml3 = pmap_remove_pt_page(pmap, va)) == NULL) { ml3 = vm_page_alloc(NULL, pmap_l2_pindex(va), (VIRT_IN_DMAP(va) ? VM_ALLOC_INTERRUPT : VM_ALLOC_NORMAL) | VM_ALLOC_NOOBJ | VM_ALLOC_WIRED); Modified: head/sys/i386/i386/pmap.c ============================================================================== --- head/sys/i386/i386/pmap.c Thu Dec 8 01:07:00 2016 (r309702) +++ head/sys/i386/i386/pmap.c Thu Dec 8 04:29:29 2016 (r309703) @@ -318,7 +318,6 @@ static boolean_t pmap_is_modified_pvh(st static boolean_t pmap_is_referenced_pvh(struct md_page *pvh); static void pmap_kenter_attr(vm_offset_t va, vm_paddr_t pa, int mode); static void pmap_kenter_pde(vm_offset_t va, pd_entry_t newpde); -static vm_page_t pmap_lookup_pt_page(pmap_t pmap, vm_offset_t va); static void pmap_pde_attr(pd_entry_t *pde, int cache_bits); static void pmap_promote_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t va); static boolean_t pmap_protect_pde(pmap_t pmap, pd_entry_t *pde, vm_offset_t sva, @@ -328,7 +327,7 @@ static void pmap_remove_pde(pmap_t pmap, struct spglist *free); static int pmap_remove_pte(pmap_t pmap, pt_entry_t *ptq, vm_offset_t sva, struct spglist *free); -static void pmap_remove_pt_page(pmap_t pmap, vm_page_t mpte); +static vm_page_t pmap_remove_pt_page(pmap_t pmap, vm_offset_t va); static void pmap_remove_page(struct pmap *pmap, vm_offset_t va, struct spglist *free); static void pmap_remove_entry(struct pmap *pmap, vm_page_t m, @@ -1713,29 +1712,17 @@ pmap_insert_pt_page(pmap_t pmap, vm_page } /* - * Looks for a page table page mapping the specified virtual address in the - * specified pmap's collection of idle page table pages. Returns NULL if there - * is no page table page corresponding to the specified virtual address. + * Removes the page table page mapping the specified virtual address from the + * specified pmap's collection of idle page table pages, and returns it. + * Otherwise, returns NULL if there is no page table page corresponding to the + * specified virtual address. */ static __inline vm_page_t -pmap_lookup_pt_page(pmap_t pmap, vm_offset_t va) +pmap_remove_pt_page(pmap_t pmap, vm_offset_t va) { PMAP_LOCK_ASSERT(pmap, MA_OWNED); - return (vm_radix_lookup(&pmap->pm_root, va >> PDRSHIFT)); -} - -/* - * Removes the specified page table page from the specified pmap's collection - * of idle page table pages. The specified page table page must be a member of - * the pmap's collection. - */ -static __inline void -pmap_remove_pt_page(pmap_t pmap, vm_page_t mpte) -{ - - PMAP_LOCK_ASSERT(pmap, MA_OWNED); - vm_radix_remove(&pmap->pm_root, mpte->pindex); + return (vm_radix_remove(&pmap->pm_root, va >> PDRSHIFT)); } /* @@ -2630,10 +2617,8 @@ pmap_demote_pde(pmap_t pmap, pd_entry_t oldpde = *pde; KASSERT((oldpde & (PG_PS | PG_V)) == (PG_PS | PG_V), ("pmap_demote_pde: oldpde is missing PG_PS and/or PG_V")); - if ((oldpde & PG_A) != 0 && (mpte = pmap_lookup_pt_page(pmap, va)) != - NULL) - pmap_remove_pt_page(pmap, mpte); - else { + if ((oldpde & PG_A) == 0 || (mpte = pmap_remove_pt_page(pmap, va)) == + NULL) { KASSERT((oldpde & PG_W) == 0, ("pmap_demote_pde: page table page for a wired mapping" " is missing")); @@ -2770,11 +2755,10 @@ pmap_remove_kernel_pde(pmap_t pmap, pd_e vm_page_t mpte; PMAP_LOCK_ASSERT(pmap, MA_OWNED); - mpte = pmap_lookup_pt_page(pmap, va); + mpte = pmap_remove_pt_page(pmap, va); if (mpte == NULL) panic("pmap_remove_kernel_pde: Missing pt page."); - pmap_remove_pt_page(pmap, mpte); mptepa = VM_PAGE_TO_PHYS(mpte); newpde = mptepa | PG_M | PG_A | PG_RW | PG_V; @@ -2841,9 +2825,8 @@ pmap_remove_pde(pmap_t pmap, pd_entry_t if (pmap == kernel_pmap) { pmap_remove_kernel_pde(pmap, pdq, sva); } else { - mpte = pmap_lookup_pt_page(pmap, sva); + mpte = pmap_remove_pt_page(pmap, sva); if (mpte != NULL) { - pmap_remove_pt_page(pmap, mpte); pmap->pm_stats.resident_count--; KASSERT(mpte->wire_count == NPTEPG, ("pmap_remove_pde: pte page wire count error")); @@ -4542,9 +4525,8 @@ pmap_remove_pages(pmap_t pmap) if (TAILQ_EMPTY(&mt->md.pv_list)) vm_page_aflag_clear(mt, PGA_WRITEABLE); } - mpte = pmap_lookup_pt_page(pmap, pv->pv_va); + mpte = pmap_remove_pt_page(pmap, pv->pv_va); if (mpte != NULL) { - pmap_remove_pt_page(pmap, mpte); pmap->pm_stats.resident_count--; KASSERT(mpte->wire_count == NPTEPG, ("pmap_remove_pages: pte page wire count error")); Modified: head/sys/vm/vm_page.c ============================================================================== --- head/sys/vm/vm_page.c Thu Dec 8 01:07:00 2016 (r309702) +++ head/sys/vm/vm_page.c Thu Dec 8 04:29:29 2016 (r309703) @@ -1241,9 +1241,8 @@ vm_page_insert_radixdone(vm_page_t m, vm /* * vm_page_remove: * - * Removes the given mem entry from the object/offset-page - * table and the object page list, but do not invalidate/terminate - * the backing store. + * Removes the specified page from its containing object, but does not + * invalidate any backing storage. * * The object must be locked. The page must be locked if it is managed. */ @@ -1251,6 +1250,7 @@ void vm_page_remove(vm_page_t m) { vm_object_t object; + vm_page_t mrem; if ((m->oflags & VPO_UNMANAGED) == 0) vm_page_assert_locked(m); @@ -1259,11 +1259,12 @@ vm_page_remove(vm_page_t m) VM_OBJECT_ASSERT_WLOCKED(object); if (vm_page_xbusied(m)) vm_page_xunbusy_maybelocked(m); + mrem = vm_radix_remove(&object->rtree, m->pindex); + KASSERT(mrem == m, ("removed page %p, expected page %p", mrem, m)); /* * Now remove from the object's list of backed pages. */ - vm_radix_remove(&object->rtree, m->pindex); TAILQ_REMOVE(&object->memq, m, listq); /* Modified: head/sys/vm/vm_radix.c ============================================================================== --- head/sys/vm/vm_radix.c Thu Dec 8 01:07:00 2016 (r309702) +++ head/sys/vm/vm_radix.c Thu Dec 8 04:29:29 2016 (r309703) @@ -660,10 +660,10 @@ descend: } /* - * Remove the specified index from the tree. - * Panics if the key is not present. + * Remove the specified index from the trie, and return the value stored at + * that index. If the index is not present, return NULL. */ -void +vm_page_t vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index) { struct vm_radix_node *rnode, *parent; @@ -674,23 +674,23 @@ vm_radix_remove(struct vm_radix *rtree, if (vm_radix_isleaf(rnode)) { m = vm_radix_topage(rnode); if (m->pindex != index) - panic("%s: invalid key found", __func__); + return (NULL); vm_radix_setroot(rtree, NULL); - return; + return (m); } parent = NULL; for (;;) { if (rnode == NULL) - panic("vm_radix_remove: impossible to locate the key"); + return (NULL); slot = vm_radix_slot(index, rnode->rn_clev); if (vm_radix_isleaf(rnode->rn_child[slot])) { m = vm_radix_topage(rnode->rn_child[slot]); if (m->pindex != index) - panic("%s: invalid key found", __func__); + return (NULL); rnode->rn_child[slot] = NULL; rnode->rn_count--; if (rnode->rn_count > 1) - break; + return (m); for (i = 0; i < VM_RADIX_COUNT; i++) if (rnode->rn_child[i] != NULL) break; @@ -707,7 +707,7 @@ vm_radix_remove(struct vm_radix *rtree, rnode->rn_count--; rnode->rn_child[i] = NULL; vm_radix_node_put(rnode); - break; + return (m); } parent = rnode; rnode = rnode->rn_child[slot]; Modified: head/sys/vm/vm_radix.h ============================================================================== --- head/sys/vm/vm_radix.h Thu Dec 8 01:07:00 2016 (r309702) +++ head/sys/vm/vm_radix.h Thu Dec 8 04:29:29 2016 (r309703) @@ -42,7 +42,7 @@ vm_page_t vm_radix_lookup(struct vm_radi vm_page_t vm_radix_lookup_ge(struct vm_radix *rtree, vm_pindex_t index); vm_page_t vm_radix_lookup_le(struct vm_radix *rtree, vm_pindex_t index); void vm_radix_reclaim_allnodes(struct vm_radix *rtree); -void vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index); +vm_page_t vm_radix_remove(struct vm_radix *rtree, vm_pindex_t index); vm_page_t vm_radix_replace(struct vm_radix *rtree, vm_page_t newpage); #endif /* _KERNEL */ _______________________________________________ svn-src-head@freebsd.org mailing list https://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
