Current Path : /sys/vm/ |
FreeBSD hs32.drive.ne.jp 9.1-RELEASE FreeBSD 9.1-RELEASE #1: Wed Jan 14 12:18:08 JST 2015 root@hs32.drive.ne.jp:/sys/amd64/compile/hs32 amd64 |
Current File : //sys/vm/vm_reserv.c |
/*- * Copyright (c) 2002-2006 Rice University * Copyright (c) 2007-2008 Alan L. Cox <alc@cs.rice.edu> * All rights reserved. * * This software was developed for the FreeBSD Project by Alan L. Cox, * Olivier Crameri, Peter Druschel, Sitaram Iyer, and Juan Navarro. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY * WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE * POSSIBILITY OF SUCH DAMAGE. */ /* * Superpage reservation management module */ #include <sys/cdefs.h> __FBSDID("$FreeBSD: release/9.1.0/sys/vm/vm_reserv.c 234771 2012-04-28 20:34:14Z alc $"); #include "opt_vm.h" #include <sys/param.h> #include <sys/kernel.h> #include <sys/lock.h> #include <sys/malloc.h> #include <sys/mutex.h> #include <sys/queue.h> #include <sys/sbuf.h> #include <sys/sysctl.h> #include <sys/systm.h> #include <vm/vm.h> #include <vm/vm_param.h> #include <vm/vm_object.h> #include <vm/vm_page.h> #include <vm/vm_phys.h> #include <vm/vm_reserv.h> /* * The reservation system supports the speculative allocation of large physical * pages ("superpages"). Speculative allocation enables the fully-automatic * utilization of superpages by the virtual memory system. In other words, no * programmatic directives are required to use superpages. */ #if VM_NRESERVLEVEL > 0 /* * The number of small pages that are contained in a level 0 reservation */ #define VM_LEVEL_0_NPAGES (1 << VM_LEVEL_0_ORDER) /* * The number of bits by which a physical address is shifted to obtain the * reservation number */ #define VM_LEVEL_0_SHIFT (VM_LEVEL_0_ORDER + PAGE_SHIFT) /* * The size of a level 0 reservation in bytes */ #define VM_LEVEL_0_SIZE (1 << VM_LEVEL_0_SHIFT) /* * Computes the index of the small page underlying the given (object, pindex) * within the reservation's array of small pages. */ #define VM_RESERV_INDEX(object, pindex) \ (((object)->pg_color + (pindex)) & (VM_LEVEL_0_NPAGES - 1)) /* * The reservation structure * * A reservation structure is constructed whenever a large physical page is * speculatively allocated to an object. The reservation provides the small * physical pages for the range [pindex, pindex + VM_LEVEL_0_NPAGES) of offsets * within that object. The reservation's "popcnt" tracks the number of these * small physical pages that are in use at any given time. When and if the * reservation is not fully utilized, it appears in the queue of partially- * populated reservations. The reservation always appears on the containing * object's list of reservations. * * A partially-populated reservation can be broken and reclaimed at any time. */ struct vm_reserv { TAILQ_ENTRY(vm_reserv) partpopq; LIST_ENTRY(vm_reserv) objq; vm_object_t object; /* containing object */ vm_pindex_t pindex; /* offset within object */ vm_page_t pages; /* first page of a superpage */ int popcnt; /* # of pages in use */ char inpartpopq; }; /* * The reservation array * * This array is analoguous in function to vm_page_array. It differs in the * respect that it may contain a greater number of useful reservation * structures than there are (physical) superpages. These "invalid" * reservation structures exist to trade-off space for time in the * implementation of vm_reserv_from_page(). Invalid reservation structures are * distinguishable from "valid" reservation structures by inspecting the * reservation's "pages" field. Invalid reservation structures have a NULL * "pages" field. * * vm_reserv_from_page() maps a small (physical) page to an element of this * array by computing a physical reservation number from the page's physical * address. The physical reservation number is used as the array index. * * An "active" reservation is a valid reservation structure that has a non-NULL * "object" field and a non-zero "popcnt" field. In other words, every active * reservation belongs to a particular object. Moreover, every active * reservation has an entry in the containing object's list of reservations. */ static vm_reserv_t vm_reserv_array; /* * The partially-populated reservation queue * * This queue enables the fast recovery of an unused cached or free small page * from a partially-populated reservation. The reservation at the head of * this queue is the least-recently-changed, partially-populated reservation. * * Access to this queue is synchronized by the free page queue lock. */ static TAILQ_HEAD(, vm_reserv) vm_rvq_partpop = TAILQ_HEAD_INITIALIZER(vm_rvq_partpop); static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD, 0, "Reservation Info"); static long vm_reserv_broken; SYSCTL_LONG(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD, &vm_reserv_broken, 0, "Cumulative number of broken reservations"); static long vm_reserv_freed; SYSCTL_LONG(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD, &vm_reserv_freed, 0, "Cumulative number of freed reservations"); static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS); SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq, CTLTYPE_STRING | CTLFLAG_RD, NULL, 0, sysctl_vm_reserv_partpopq, "A", "Partially-populated reservation queues"); static long vm_reserv_reclaimed; SYSCTL_LONG(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD, &vm_reserv_reclaimed, 0, "Cumulative number of reclaimed reservations"); static void vm_reserv_depopulate(vm_reserv_t rv); static vm_reserv_t vm_reserv_from_page(vm_page_t m); static boolean_t vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex); static void vm_reserv_populate(vm_reserv_t rv); static void vm_reserv_reclaim(vm_reserv_t rv); /* * Describes the current state of the partially-populated reservation queue. */ static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS) { struct sbuf sbuf; vm_reserv_t rv; int counter, error, level, unused_pages; error = sysctl_wire_old_buffer(req, 0); if (error != 0) return (error); sbuf_new_for_sysctl(&sbuf, NULL, 128, req); sbuf_printf(&sbuf, "\nLEVEL SIZE NUMBER\n\n"); for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) { counter = 0; unused_pages = 0; mtx_lock(&vm_page_queue_free_mtx); TAILQ_FOREACH(rv, &vm_rvq_partpop/*[level]*/, partpopq) { counter++; unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt; } mtx_unlock(&vm_page_queue_free_mtx); sbuf_printf(&sbuf, "%5d: %6dK, %6d\n", level, unused_pages * ((int)PAGE_SIZE / 1024), counter); } error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); return (error); } /* * Reduces the given reservation's population count. If the population count * becomes zero, the reservation is destroyed. Additionally, moves the * reservation to the tail of the partially-populated reservations queue if the * population count is non-zero. * * The free page queue lock must be held. */ static void vm_reserv_depopulate(vm_reserv_t rv) { mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); KASSERT(rv->object != NULL, ("vm_reserv_depopulate: reserv %p is free", rv)); KASSERT(rv->popcnt > 0, ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv)); if (rv->inpartpopq) { TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); rv->inpartpopq = FALSE; } rv->popcnt--; if (rv->popcnt == 0) { LIST_REMOVE(rv, objq); rv->object = NULL; vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER); vm_reserv_freed++; } else { rv->inpartpopq = TRUE; TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq); } } /* * Returns the reservation to which the given page might belong. */ static __inline vm_reserv_t vm_reserv_from_page(vm_page_t m) { return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]); } /* * Returns TRUE if the given reservation contains the given page index and * FALSE otherwise. */ static __inline boolean_t vm_reserv_has_pindex(vm_reserv_t rv, vm_pindex_t pindex) { return (((pindex - rv->pindex) & ~(VM_LEVEL_0_NPAGES - 1)) == 0); } /* * Increases the given reservation's population count. Moves the reservation * to the tail of the partially-populated reservation queue. * * The free page queue must be locked. */ static void vm_reserv_populate(vm_reserv_t rv) { mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); KASSERT(rv->object != NULL, ("vm_reserv_populate: reserv %p is free", rv)); KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES, ("vm_reserv_populate: reserv %p is already full", rv)); if (rv->inpartpopq) { TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); rv->inpartpopq = FALSE; } rv->popcnt++; if (rv->popcnt < VM_LEVEL_0_NPAGES) { rv->inpartpopq = TRUE; TAILQ_INSERT_TAIL(&vm_rvq_partpop, rv, partpopq); } } /* * Allocates a page from an existing or newly-created reservation. * * 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_page_t m, mpred, msucc; vm_pindex_t first, leftcap, rightcap; vm_reserv_t rv; mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); /* * Is a reservation fundamentally not possible? */ VM_OBJECT_LOCK_ASSERT(object, MA_OWNED); if (pindex < VM_RESERV_INDEX(object, pindex) || pindex >= object->size) return (NULL); /* * Look for an existing reservation. */ msucc = NULL; mpred = object->root; while (mpred != NULL) { KASSERT(mpred->pindex != pindex, ("vm_reserv_alloc_page: pindex already allocated")); rv = vm_reserv_from_page(mpred); if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) { m = &rv->pages[VM_RESERV_INDEX(object, pindex)]; /* Handle vm_page_rename(m, new_object, ...). */ if ((m->flags & (PG_CACHED | PG_FREE)) == 0) return (NULL); vm_reserv_populate(rv); return (m); } else if (mpred->pindex < pindex) { if (msucc != NULL || (msucc = TAILQ_NEXT(mpred, listq)) == NULL) break; KASSERT(msucc->pindex != pindex, ("vm_reserv_alloc_page: pindex already allocated")); rv = vm_reserv_from_page(msucc); if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) { m = &rv->pages[VM_RESERV_INDEX(object, pindex)]; /* Handle vm_page_rename(m, new_object, ...). */ if ((m->flags & (PG_CACHED | PG_FREE)) == 0) return (NULL); vm_reserv_populate(rv); return (m); } else if (pindex < msucc->pindex) break; } else if (msucc == NULL) { msucc = mpred; mpred = TAILQ_PREV(msucc, pglist, listq); continue; } msucc = NULL; mpred = object->root = vm_page_splay(pindex, object->root); } /* * Determine the first index to the left that can be used. */ if (mpred == NULL) leftcap = 0; else if ((rv = vm_reserv_from_page(mpred))->object != object) leftcap = mpred->pindex + 1; else leftcap = rv->pindex + VM_LEVEL_0_NPAGES; /* * Determine the first index to the right that cannot be used. */ if (msucc == NULL) rightcap = pindex + VM_LEVEL_0_NPAGES; else if ((rv = vm_reserv_from_page(msucc))->object != object) rightcap = msucc->pindex; else rightcap = rv->pindex; /* * Determine if a reservation fits between the first index to * the left that can be used and the first index to the right * that cannot be used. */ first = pindex - VM_RESERV_INDEX(object, pindex); if (first < leftcap || first + VM_LEVEL_0_NPAGES > rightcap) return (NULL); /* * Would a new reservation extend past the end of the given object? */ if (object->size < first + VM_LEVEL_0_NPAGES) { /* * Don't allocate a new reservation if the object is a vnode or * backed by another object that is a vnode. */ if (object->type == OBJT_VNODE || (object->backing_object != NULL && object->backing_object->type == OBJT_VNODE)) return (NULL); /* Speculate that the object may grow. */ } /* * Allocate a new reservation. */ m = vm_phys_alloc_pages(VM_FREEPOOL_DEFAULT, VM_LEVEL_0_ORDER); if (m != NULL) { rv = vm_reserv_from_page(m); KASSERT(rv->pages == m, ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv)); KASSERT(rv->object == NULL, ("vm_reserv_alloc_page: reserv %p isn't free", rv)); LIST_INSERT_HEAD(&object->rvq, rv, objq); rv->object = object; rv->pindex = first; KASSERT(rv->popcnt == 0, ("vm_reserv_alloc_page: reserv %p's popcnt is corrupted", rv)); KASSERT(!rv->inpartpopq, ("vm_reserv_alloc_page: reserv %p's inpartpopq is TRUE", rv)); vm_reserv_populate(rv); m = &rv->pages[VM_RESERV_INDEX(object, pindex)]; } return (m); } /* * Breaks all reservations belonging to the given object. */ void vm_reserv_break_all(vm_object_t object) { vm_reserv_t rv; int i; mtx_lock(&vm_page_queue_free_mtx); while ((rv = LIST_FIRST(&object->rvq)) != NULL) { KASSERT(rv->object == object, ("vm_reserv_break_all: reserv %p is corrupted", rv)); if (rv->inpartpopq) { TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); rv->inpartpopq = FALSE; } LIST_REMOVE(rv, objq); rv->object = NULL; for (i = 0; i < VM_LEVEL_0_NPAGES; i++) { if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) vm_phys_free_pages(&rv->pages[i], 0); else rv->popcnt--; } KASSERT(rv->popcnt == 0, ("vm_reserv_break_all: reserv %p's popcnt is corrupted", rv)); vm_reserv_broken++; } mtx_unlock(&vm_page_queue_free_mtx); } /* * Frees the given page if it belongs to a reservation. Returns TRUE if the * page is freed and FALSE otherwise. * * The free page queue lock must be held. */ boolean_t vm_reserv_free_page(vm_page_t m) { vm_reserv_t rv; mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); rv = vm_reserv_from_page(m); if (rv->object == NULL) return (FALSE); if ((m->flags & PG_CACHED) != 0 && m->pool != VM_FREEPOOL_CACHE) vm_phys_set_pool(VM_FREEPOOL_CACHE, rv->pages, VM_LEVEL_0_ORDER); vm_reserv_depopulate(rv); return (TRUE); } /* * Initializes the reservation management system. Specifically, initializes * the reservation array. * * Requires that vm_page_array and first_page are initialized! */ void vm_reserv_init(void) { vm_paddr_t paddr; int i; /* * Initialize the reservation array. Specifically, initialize the * "pages" field for every element that has an underlying superpage. */ for (i = 0; phys_avail[i + 1] != 0; i += 2) { paddr = roundup2(phys_avail[i], VM_LEVEL_0_SIZE); while (paddr + VM_LEVEL_0_SIZE <= phys_avail[i + 1]) { vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT].pages = PHYS_TO_VM_PAGE(paddr); paddr += VM_LEVEL_0_SIZE; } } } /* * Returns a reservation level if the given page belongs to a fully-populated * reservation and -1 otherwise. */ int vm_reserv_level_iffullpop(vm_page_t m) { vm_reserv_t rv; rv = vm_reserv_from_page(m); return (rv->popcnt == VM_LEVEL_0_NPAGES ? 0 : -1); } /* * Prepare for the reactivation of a cached page. * * First, suppose that the given page "m" was allocated individually, i.e., not * as part of a reservation, and cached. Then, suppose a reservation * containing "m" is allocated by the same object. Although "m" and the * reservation belong to the same object, "m"'s pindex may not match the * reservation's. * * The free page queue must be locked. */ boolean_t vm_reserv_reactivate_page(vm_page_t m) { vm_reserv_t rv; int i, m_index; mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); rv = vm_reserv_from_page(m); if (rv->object == NULL) return (FALSE); KASSERT((m->flags & PG_CACHED) != 0, ("vm_reserv_uncache_page: page %p is not cached", m)); if (m->object == rv->object && m->pindex - rv->pindex == VM_RESERV_INDEX(m->object, m->pindex)) vm_reserv_populate(rv); else { KASSERT(rv->inpartpopq, ("vm_reserv_uncache_page: reserv %p's inpartpopq is FALSE", rv)); TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); rv->inpartpopq = FALSE; LIST_REMOVE(rv, objq); rv->object = NULL; /* Don't vm_phys_free_pages(m, 0). */ m_index = m - rv->pages; for (i = 0; i < m_index; i++) { if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) vm_phys_free_pages(&rv->pages[i], 0); else rv->popcnt--; } for (i++; i < VM_LEVEL_0_NPAGES; i++) { if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) vm_phys_free_pages(&rv->pages[i], 0); else rv->popcnt--; } KASSERT(rv->popcnt == 0, ("vm_reserv_uncache_page: reserv %p's popcnt is corrupted", rv)); vm_reserv_broken++; } return (TRUE); } /* * Breaks the given partially-populated reservation, releasing its cached and * free pages to the physical memory allocator. * * The free page queue lock must be held. */ static void vm_reserv_reclaim(vm_reserv_t rv) { int i; mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); KASSERT(rv->inpartpopq, ("vm_reserv_reclaim: reserv %p's inpartpopq is corrupted", rv)); TAILQ_REMOVE(&vm_rvq_partpop, rv, partpopq); rv->inpartpopq = FALSE; KASSERT(rv->object != NULL, ("vm_reserv_reclaim: reserv %p is free", rv)); LIST_REMOVE(rv, objq); rv->object = NULL; for (i = 0; i < VM_LEVEL_0_NPAGES; i++) { if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) vm_phys_free_pages(&rv->pages[i], 0); else rv->popcnt--; } KASSERT(rv->popcnt == 0, ("vm_reserv_reclaim: reserv %p's popcnt is corrupted", rv)); vm_reserv_reclaimed++; } /* * Breaks the reservation at the head of the partially-populated reservation * queue, releasing its cached and free pages to the physical memory * allocator. Returns TRUE if a reservation is broken and FALSE otherwise. * * The free page queue lock must be held. */ boolean_t vm_reserv_reclaim_inactive(void) { vm_reserv_t rv; mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); if ((rv = TAILQ_FIRST(&vm_rvq_partpop)) != NULL) { vm_reserv_reclaim(rv); return (TRUE); } return (FALSE); } /* * Searches the partially-populated reservation queue for the least recently * active reservation with unused pages, i.e., cached or free, that satisfy the * given request for contiguous physical memory. If a satisfactory reservation * is found, it is broken. Returns TRUE if a reservation is broken and FALSE * otherwise. * * The free page queue lock must be held. */ boolean_t vm_reserv_reclaim_contig(vm_paddr_t size, vm_paddr_t low, vm_paddr_t high, unsigned long alignment, unsigned long boundary) { vm_paddr_t pa, pa_length; vm_reserv_t rv; int i; mtx_assert(&vm_page_queue_free_mtx, MA_OWNED); if (size > VM_LEVEL_0_SIZE - PAGE_SIZE) return (FALSE); TAILQ_FOREACH(rv, &vm_rvq_partpop, partpopq) { pa = VM_PAGE_TO_PHYS(&rv->pages[VM_LEVEL_0_NPAGES - 1]); if (pa + PAGE_SIZE - size < low) { /* this entire reservation is too low; go to next */ continue; } pa_length = 0; for (i = 0; i < VM_LEVEL_0_NPAGES; i++) if ((rv->pages[i].flags & (PG_CACHED | PG_FREE)) != 0) { pa_length += PAGE_SIZE; if (pa_length == PAGE_SIZE) { pa = VM_PAGE_TO_PHYS(&rv->pages[i]); if (pa + size > high) { /* skip to next reservation */ break; } else if (pa < low || (pa & (alignment - 1)) != 0 || ((pa ^ (pa + size - 1)) & ~(boundary - 1)) != 0) pa_length = 0; } if (pa_length >= size) { vm_reserv_reclaim(rv); return (TRUE); } } else pa_length = 0; } return (FALSE); } /* * Transfers the reservation underlying the given page to a new object. * * The object must be locked. */ void vm_reserv_rename(vm_page_t m, vm_object_t new_object, vm_object_t old_object, vm_pindex_t old_object_offset) { vm_reserv_t rv; VM_OBJECT_LOCK_ASSERT(new_object, MA_OWNED); rv = vm_reserv_from_page(m); if (rv->object == old_object) { mtx_lock(&vm_page_queue_free_mtx); if (rv->object == old_object) { LIST_REMOVE(rv, objq); LIST_INSERT_HEAD(&new_object->rvq, rv, objq); rv->object = new_object; rv->pindex -= old_object_offset; } mtx_unlock(&vm_page_queue_free_mtx); } } /* * Allocates the virtual and physical memory required by the reservation * management system's data structures, in particular, the reservation array. */ vm_paddr_t vm_reserv_startup(vm_offset_t *vaddr, vm_paddr_t end, vm_paddr_t high_water) { vm_paddr_t new_end; size_t size; /* * Calculate the size (in bytes) of the reservation array. Round up * from "high_water" because every small page is mapped to an element * in the reservation array based on its physical address. Thus, the * number of elements in the reservation array can be greater than the * number of superpages. */ size = howmany(high_water, VM_LEVEL_0_SIZE) * sizeof(struct vm_reserv); /* * Allocate and map the physical memory for the reservation array. The * next available virtual address is returned by reference. */ new_end = end - round_page(size); vm_reserv_array = (void *)(uintptr_t)pmap_map(vaddr, new_end, end, VM_PROT_READ | VM_PROT_WRITE); bzero(vm_reserv_array, size); /* * Return the next available physical address. */ return (new_end); } #endif /* VM_NRESERVLEVEL > 0 */