/*- * SPDX-License-Identifier: BSD-2-Clause * * Copyright (c) 2002-2006 Rice University * Copyright (c) 2007-2011 Alan L. Cox * 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 * * Any external functions defined by this module are only to be used by the * virtual memory system. */ #include __FBSDID("$FreeBSD$"); #include "opt_vm.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * 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 #ifndef VM_LEVEL_0_ORDER_MAX #define VM_LEVEL_0_ORDER_MAX VM_LEVEL_0_ORDER #endif /* * The number of small pages that are contained in a level 0 reservation */ #define VM_LEVEL_0_NPAGES (1 << VM_LEVEL_0_ORDER) #define VM_LEVEL_0_NPAGES_MAX (1 << VM_LEVEL_0_ORDER_MAX) /* * 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)) /* * Number of elapsed ticks before we update the LRU queue position. Used * to reduce contention and churn on the list. */ #define PARTPOPSLOP 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. * * c - constant after boot * d - vm_reserv_domain_lock * o - vm_reserv_object_lock * r - vm_reserv_lock * s - vm_reserv_domain_scan_lock */ struct vm_reserv { struct mtx lock; /* reservation lock. */ TAILQ_ENTRY(vm_reserv) partpopq; /* (d, r) per-domain queue. */ LIST_ENTRY(vm_reserv) objq; /* (o, r) object queue */ vm_object_t object; /* (o, r) containing object */ vm_pindex_t pindex; /* (o, r) offset in object */ vm_page_t pages; /* (c) first page */ uint16_t popcnt; /* (r) # of pages in use */ uint8_t domain; /* (c) NUMA domain. */ char inpartpopq; /* (d, r) */ int lasttick; /* (r) last pop update tick. */ bitstr_t bit_decl(popmap, VM_LEVEL_0_NPAGES_MAX); /* (r) bit vector, used pages */ }; TAILQ_HEAD(vm_reserv_queue, vm_reserv); #define vm_reserv_lockptr(rv) (&(rv)->lock) #define vm_reserv_assert_locked(rv) \ mtx_assert(vm_reserv_lockptr(rv), MA_OWNED) #define vm_reserv_lock(rv) mtx_lock(vm_reserv_lockptr(rv)) #define vm_reserv_trylock(rv) mtx_trylock(vm_reserv_lockptr(rv)) #define vm_reserv_unlock(rv) mtx_unlock(vm_reserv_lockptr(rv)) /* * 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 per-domain partially populated reservation queues * * These queues enable the fast recovery of an unused free small page from a * partially populated reservation. The reservation at the head of a queue * is the least recently changed, partially populated reservation. * * Access to this queue is synchronized by the per-domain reservation lock. * Threads reclaiming free pages from the queue must hold the per-domain scan * lock. */ struct vm_reserv_domain { struct mtx lock; struct vm_reserv_queue partpop; /* (d) */ struct vm_reserv marker; /* (d, s) scan marker/lock */ } __aligned(CACHE_LINE_SIZE); static struct vm_reserv_domain vm_rvd[MAXMEMDOM]; #define vm_reserv_domain_lockptr(d) (&vm_rvd[(d)].lock) #define vm_reserv_domain_assert_locked(d) \ mtx_assert(vm_reserv_domain_lockptr(d), MA_OWNED) #define vm_reserv_domain_lock(d) mtx_lock(vm_reserv_domain_lockptr(d)) #define vm_reserv_domain_unlock(d) mtx_unlock(vm_reserv_domain_lockptr(d)) #define vm_reserv_domain_scan_lock(d) mtx_lock(&vm_rvd[(d)].marker.lock) #define vm_reserv_domain_scan_unlock(d) mtx_unlock(&vm_rvd[(d)].marker.lock) static SYSCTL_NODE(_vm, OID_AUTO, reserv, CTLFLAG_RD | CTLFLAG_MPSAFE, 0, "Reservation Info"); static COUNTER_U64_DEFINE_EARLY(vm_reserv_broken); SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, broken, CTLFLAG_RD, &vm_reserv_broken, "Cumulative number of broken reservations"); static COUNTER_U64_DEFINE_EARLY(vm_reserv_freed); SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, freed, CTLFLAG_RD, &vm_reserv_freed, "Cumulative number of freed reservations"); static int sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS); SYSCTL_PROC(_vm_reserv, OID_AUTO, fullpop, CTLTYPE_INT | CTLFLAG_MPSAFE | CTLFLAG_RD, NULL, 0, sysctl_vm_reserv_fullpop, "I", "Current number of full reservations"); static int sysctl_vm_reserv_partpopq(SYSCTL_HANDLER_ARGS); SYSCTL_OID(_vm_reserv, OID_AUTO, partpopq, CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0, sysctl_vm_reserv_partpopq, "A", "Partially populated reservation queues"); static COUNTER_U64_DEFINE_EARLY(vm_reserv_reclaimed); SYSCTL_COUNTER_U64(_vm_reserv, OID_AUTO, reclaimed, CTLFLAG_RD, &vm_reserv_reclaimed, "Cumulative number of reclaimed reservations"); /* * The object lock pool is used to synchronize the rvq. We can not use a * pool mutex because it is required before malloc works. * * The "hash" function could be made faster without divide and modulo. */ #define VM_RESERV_OBJ_LOCK_COUNT MAXCPU struct mtx_padalign vm_reserv_object_mtx[VM_RESERV_OBJ_LOCK_COUNT]; #define vm_reserv_object_lock_idx(object) \ (((uintptr_t)object / sizeof(*object)) % VM_RESERV_OBJ_LOCK_COUNT) #define vm_reserv_object_lock_ptr(object) \ &vm_reserv_object_mtx[vm_reserv_object_lock_idx((object))] #define vm_reserv_object_lock(object) \ mtx_lock(vm_reserv_object_lock_ptr((object))) #define vm_reserv_object_unlock(object) \ mtx_unlock(vm_reserv_object_lock_ptr((object))) static void vm_reserv_break(vm_reserv_t rv); static void vm_reserv_depopulate(vm_reserv_t rv, int index); 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, int index); static void vm_reserv_reclaim(vm_reserv_t rv); /* * Returns the current number of full reservations. * * Since the number of full reservations is computed without acquiring any * locks, the returned value is inexact. */ static int sysctl_vm_reserv_fullpop(SYSCTL_HANDLER_ARGS) { vm_paddr_t paddr; struct vm_phys_seg *seg; vm_reserv_t rv; int fullpop, segind; fullpop = 0; for (segind = 0; segind < vm_phys_nsegs; segind++) { seg = &vm_phys_segs[segind]; paddr = roundup2(seg->start, VM_LEVEL_0_SIZE); #ifdef VM_PHYSSEG_SPARSE rv = seg->first_reserv + (paddr >> VM_LEVEL_0_SHIFT) - (seg->start >> VM_LEVEL_0_SHIFT); #else rv = &vm_reserv_array[paddr >> VM_LEVEL_0_SHIFT]; #endif while (paddr + VM_LEVEL_0_SIZE > paddr && paddr + VM_LEVEL_0_SIZE <= seg->end) { fullpop += rv->popcnt == VM_LEVEL_0_NPAGES; paddr += VM_LEVEL_0_SIZE; rv++; } } return (sysctl_handle_int(oidp, &fullpop, 0, req)); } /* * 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, domain, 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, "\nDOMAIN LEVEL SIZE NUMBER\n\n"); for (domain = 0; domain < vm_ndomains; domain++) { for (level = -1; level <= VM_NRESERVLEVEL - 2; level++) { counter = 0; unused_pages = 0; vm_reserv_domain_lock(domain); TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) { if (rv == &vm_rvd[domain].marker) continue; counter++; unused_pages += VM_LEVEL_0_NPAGES - rv->popcnt; } vm_reserv_domain_unlock(domain); sbuf_printf(&sbuf, "%6d, %7d, %6dK, %6d\n", domain, level, unused_pages * ((int)PAGE_SIZE / 1024), counter); } } error = sbuf_finish(&sbuf); sbuf_delete(&sbuf); return (error); } /* * Remove a reservation from the object's objq. */ static void vm_reserv_remove(vm_reserv_t rv) { vm_object_t object; vm_reserv_assert_locked(rv); CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d", __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq); KASSERT(rv->object != NULL, ("vm_reserv_remove: reserv %p is free", rv)); KASSERT(!rv->inpartpopq, ("vm_reserv_remove: reserv %p's inpartpopq is TRUE", rv)); object = rv->object; vm_reserv_object_lock(object); LIST_REMOVE(rv, objq); rv->object = NULL; vm_reserv_object_unlock(object); } /* * Insert a new reservation into the object's objq. */ static void vm_reserv_insert(vm_reserv_t rv, vm_object_t object, vm_pindex_t pindex) { vm_reserv_assert_locked(rv); CTR6(KTR_VM, "%s: rv %p(%p) object %p new %p popcnt %d", __FUNCTION__, rv, rv->pages, rv->object, object, rv->popcnt); KASSERT(rv->object == NULL, ("vm_reserv_insert: reserv %p isn't free", rv)); KASSERT(rv->popcnt == 0, ("vm_reserv_insert: reserv %p's popcnt is corrupted", rv)); KASSERT(!rv->inpartpopq, ("vm_reserv_insert: reserv %p's inpartpopq is TRUE", rv)); KASSERT(bit_ntest(rv->popmap, 0, VM_LEVEL_0_NPAGES - 1, 0), ("vm_reserv_insert: reserv %p's popmap is corrupted", rv)); vm_reserv_object_lock(object); rv->pindex = pindex; rv->object = object; rv->lasttick = ticks; LIST_INSERT_HEAD(&object->rvq, rv, objq); vm_reserv_object_unlock(object); } /* * 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 reservation queue if the * population count is non-zero. */ static void vm_reserv_depopulate(vm_reserv_t rv, int index) { struct vm_domain *vmd; vm_reserv_assert_locked(rv); CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d", __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq); KASSERT(rv->object != NULL, ("vm_reserv_depopulate: reserv %p is free", rv)); KASSERT(bit_test(rv->popmap, index), ("vm_reserv_depopulate: reserv %p's popmap[%d] is clear", rv, index)); KASSERT(rv->popcnt > 0, ("vm_reserv_depopulate: reserv %p's popcnt is corrupted", rv)); KASSERT(rv->domain < vm_ndomains, ("vm_reserv_depopulate: reserv %p's domain is corrupted %d", rv, rv->domain)); if (rv->popcnt == VM_LEVEL_0_NPAGES) { KASSERT(rv->pages->psind == 1, ("vm_reserv_depopulate: reserv %p is already demoted", rv)); rv->pages->psind = 0; } bit_clear(rv->popmap, index); rv->popcnt--; if ((unsigned)(ticks - rv->lasttick) >= PARTPOPSLOP || rv->popcnt == 0) { vm_reserv_domain_lock(rv->domain); if (rv->inpartpopq) { TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq); rv->inpartpopq = FALSE; } if (rv->popcnt != 0) { rv->inpartpopq = TRUE; TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv, partpopq); } vm_reserv_domain_unlock(rv->domain); rv->lasttick = ticks; } vmd = VM_DOMAIN(rv->domain); if (rv->popcnt == 0) { vm_reserv_remove(rv); vm_domain_free_lock(vmd); vm_phys_free_pages(rv->pages, VM_LEVEL_0_ORDER); vm_domain_free_unlock(vmd); counter_u64_add(vm_reserv_freed, 1); } vm_domain_freecnt_inc(vmd, 1); } /* * Returns the reservation to which the given page might belong. */ static __inline vm_reserv_t vm_reserv_from_page(vm_page_t m) { #ifdef VM_PHYSSEG_SPARSE struct vm_phys_seg *seg; seg = &vm_phys_segs[m->segind]; return (seg->first_reserv + (VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT) - (seg->start >> VM_LEVEL_0_SHIFT)); #else return (&vm_reserv_array[VM_PAGE_TO_PHYS(m) >> VM_LEVEL_0_SHIFT]); #endif } /* * Returns an existing reservation or NULL and initialized successor pointer. */ static vm_reserv_t vm_reserv_from_object(vm_object_t object, vm_pindex_t pindex, vm_page_t mpred, vm_page_t *msuccp) { vm_reserv_t rv; vm_page_t msucc; msucc = NULL; if (mpred != NULL) { KASSERT(mpred->object == object, ("vm_reserv_from_object: object doesn't contain mpred")); KASSERT(mpred->pindex < pindex, ("vm_reserv_from_object: mpred doesn't precede pindex")); rv = vm_reserv_from_page(mpred); if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) goto found; msucc = TAILQ_NEXT(mpred, listq); } else msucc = TAILQ_FIRST(&object->memq); if (msucc != NULL) { KASSERT(msucc->pindex > pindex, ("vm_reserv_from_object: msucc doesn't succeed pindex")); rv = vm_reserv_from_page(msucc); if (rv->object == object && vm_reserv_has_pindex(rv, pindex)) goto found; } rv = NULL; found: *msuccp = msucc; return (rv); } /* * 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. */ static void vm_reserv_populate(vm_reserv_t rv, int index) { vm_reserv_assert_locked(rv); CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d", __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq); KASSERT(rv->object != NULL, ("vm_reserv_populate: reserv %p is free", rv)); KASSERT(!bit_test(rv->popmap, index), ("vm_reserv_populate: reserv %p's popmap[%d] is set", rv, index)); KASSERT(rv->popcnt < VM_LEVEL_0_NPAGES, ("vm_reserv_populate: reserv %p is already full", rv)); KASSERT(rv->pages->psind == 0, ("vm_reserv_populate: reserv %p is already promoted", rv)); KASSERT(rv->domain < vm_ndomains, ("vm_reserv_populate: reserv %p's domain is corrupted %d", rv, rv->domain)); bit_set(rv->popmap, index); rv->popcnt++; if ((unsigned)(ticks - rv->lasttick) < PARTPOPSLOP && rv->inpartpopq && rv->popcnt != VM_LEVEL_0_NPAGES) return; rv->lasttick = ticks; vm_reserv_domain_lock(rv->domain); if (rv->inpartpopq) { TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq); rv->inpartpopq = FALSE; } if (rv->popcnt < VM_LEVEL_0_NPAGES) { rv->inpartpopq = TRUE; TAILQ_INSERT_TAIL(&vm_rvd[rv->domain].partpop, rv, partpopq); } else { KASSERT(rv->pages->psind == 0, ("vm_reserv_populate: reserv %p is already promoted", rv)); rv->pages->psind = 1; } vm_reserv_domain_unlock(rv->domain); } /* * Allocates a contiguous set of physical pages of the given size "npages" * from existing or newly created reservations. All of the physical pages * must be at or above the given physical address "low" and below the given * physical address "high". The given value "alignment" determines the * alignment of the first physical page in the set. If the given value * "boundary" is non-zero, then the set of physical pages cannot cross any * physical address boundary that is a multiple of that value. Both * "alignment" and "boundary" must be a power of two. * * The page "mpred" must immediately precede the offset "pindex" within the * specified object. * * The object must be locked. */ vm_page_t vm_reserv_alloc_contig(vm_object_t object, vm_pindex_t pindex, int domain, int req, vm_page_t mpred, u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary) { struct vm_domain *vmd; vm_paddr_t pa, size; vm_page_t m, m_ret, msucc; vm_pindex_t first, leftcap, rightcap; vm_reserv_t rv; u_long allocpages, maxpages, minpages; int i, index, n; VM_OBJECT_ASSERT_WLOCKED(object); KASSERT(npages != 0, ("vm_reserv_alloc_contig: npages is 0")); /* * Is a reservation fundamentally impossible? */ if (pindex < VM_RESERV_INDEX(object, pindex) || pindex + npages > object->size) return (NULL); /* * All reservations of a particular size have the same alignment. * Assuming that the first page is allocated from a reservation, the * least significant bits of its physical address can be determined * from its offset from the beginning of the reservation and the size * of the reservation. * * Could the specified index within a reservation of the smallest * possible size satisfy the alignment and boundary requirements? */ pa = VM_RESERV_INDEX(object, pindex) << PAGE_SHIFT; size = npages << PAGE_SHIFT; if (!vm_addr_ok(pa, size, alignment, boundary)) return (NULL); /* * Look for an existing reservation. */ rv = vm_reserv_from_object(object, pindex, mpred, &msucc); if (rv != NULL) { KASSERT(object != kernel_object || rv->domain == domain, ("vm_reserv_alloc_contig: domain mismatch")); index = VM_RESERV_INDEX(object, pindex); /* Does the allocation fit within the reservation? */ if (index + npages > VM_LEVEL_0_NPAGES) return (NULL); domain = rv->domain; vmd = VM_DOMAIN(domain); vm_reserv_lock(rv); /* Handle reclaim race. */ if (rv->object != object) goto out; m = &rv->pages[index]; pa = VM_PAGE_TO_PHYS(m); if (pa < low || pa + size > high || !vm_addr_ok(pa, size, alignment, boundary)) goto out; /* Handle vm_page_rename(m, new_object, ...). */ if (!bit_ntest(rv->popmap, index, index + npages - 1, 0)) goto out; if (!vm_domain_allocate(vmd, req, npages)) goto out; for (i = 0; i < npages; i++) vm_reserv_populate(rv, index + i); vm_reserv_unlock(rv); return (m); out: vm_reserv_unlock(rv); return (NULL); } /* * Could at least one reservation fit between the first index to the * left that can be used ("leftcap") and the first index to the right * that cannot be used ("rightcap")? * * We must synchronize with the reserv object lock to protect the * pindex/object of the resulting reservations against rename while * we are inspecting. */ first = pindex - VM_RESERV_INDEX(object, pindex); minpages = VM_RESERV_INDEX(object, pindex) + npages; maxpages = roundup2(minpages, VM_LEVEL_0_NPAGES); allocpages = maxpages; vm_reserv_object_lock(object); if (mpred != NULL) { if ((rv = vm_reserv_from_page(mpred))->object != object) leftcap = mpred->pindex + 1; else leftcap = rv->pindex + VM_LEVEL_0_NPAGES; if (leftcap > first) { vm_reserv_object_unlock(object); return (NULL); } } if (msucc != NULL) { if ((rv = vm_reserv_from_page(msucc))->object != object) rightcap = msucc->pindex; else rightcap = rv->pindex; if (first + maxpages > rightcap) { if (maxpages == VM_LEVEL_0_NPAGES) { vm_reserv_object_unlock(object); return (NULL); } /* * At least one reservation will fit between "leftcap" * and "rightcap". However, a reservation for the * last of the requested pages will not fit. Reduce * the size of the upcoming allocation accordingly. */ allocpages = minpages; } } vm_reserv_object_unlock(object); /* * Would the last new reservation extend past the end of the object? * * If the object is unlikely to grow don't allocate a reservation for * the tail. */ if ((object->flags & OBJ_ANON) == 0 && first + maxpages > object->size) { if (maxpages == VM_LEVEL_0_NPAGES) return (NULL); allocpages = minpages; } /* * Allocate the physical pages. The alignment and boundary specified * for this allocation may be different from the alignment and * boundary specified for the requested pages. For instance, the * specified index may not be the first page within the first new * reservation. */ m = NULL; vmd = VM_DOMAIN(domain); if (vm_domain_allocate(vmd, req, npages)) { vm_domain_free_lock(vmd); m = vm_phys_alloc_contig(domain, allocpages, low, high, ulmax(alignment, VM_LEVEL_0_SIZE), boundary > VM_LEVEL_0_SIZE ? boundary : 0); vm_domain_free_unlock(vmd); if (m == NULL) { vm_domain_freecnt_inc(vmd, npages); return (NULL); } } else return (NULL); KASSERT(vm_page_domain(m) == domain, ("vm_reserv_alloc_contig: Page domain does not match requested.")); /* * The allocated physical pages always begin at a reservation * boundary, but they do not always end at a reservation boundary. * Initialize every reservation that is completely covered by the * allocated physical pages. */ m_ret = NULL; index = VM_RESERV_INDEX(object, pindex); do { rv = vm_reserv_from_page(m); KASSERT(rv->pages == m, ("vm_reserv_alloc_contig: reserv %p's pages is corrupted", rv)); vm_reserv_lock(rv); vm_reserv_insert(rv, object, first); n = ulmin(VM_LEVEL_0_NPAGES - index, npages); for (i = 0; i < n; i++) vm_reserv_populate(rv, index + i); npages -= n; if (m_ret == NULL) { m_ret = &rv->pages[index]; index = 0; } vm_reserv_unlock(rv); m += VM_LEVEL_0_NPAGES; first += VM_LEVEL_0_NPAGES; allocpages -= VM_LEVEL_0_NPAGES; } while (allocpages >= VM_LEVEL_0_NPAGES); return (m_ret); } /* * Allocate a physical page from an existing or newly created reservation. * * The page "mpred" must immediately precede the offset "pindex" within the * specified object. * * The object must be locked. */ vm_page_t vm_reserv_alloc_page(vm_object_t object, vm_pindex_t pindex, int domain, int req, vm_page_t mpred) { struct vm_domain *vmd; vm_page_t m, msucc; vm_pindex_t first, leftcap, rightcap; vm_reserv_t rv; int index; VM_OBJECT_ASSERT_WLOCKED(object); /* * Is a reservation fundamentally impossible? */ if (pindex < VM_RESERV_INDEX(object, pindex) || pindex >= object->size) return (NULL); /* * Look for an existing reservation. */ rv = vm_reserv_from_object(object, pindex, mpred, &msucc); if (rv != NULL) { KASSERT(object != kernel_object || rv->domain == domain, ("vm_reserv_alloc_page: domain mismatch")); domain = rv->domain; vmd = VM_DOMAIN(domain); index = VM_RESERV_INDEX(object, pindex); m = &rv->pages[index]; vm_reserv_lock(rv); /* Handle reclaim race. */ if (rv->object != object || /* Handle vm_page_rename(m, new_object, ...). */ bit_test(rv->popmap, index)) { m = NULL; goto out; } if (vm_domain_allocate(vmd, req, 1) == 0) m = NULL; else vm_reserv_populate(rv, index); out: vm_reserv_unlock(rv); return (m); } /* * Could a reservation fit between the first index to the left that * can be used and the first index to the right that cannot be used? * * We must synchronize with the reserv object lock to protect the * pindex/object of the resulting reservations against rename while * we are inspecting. */ first = pindex - VM_RESERV_INDEX(object, pindex); vm_reserv_object_lock(object); if (mpred != NULL) { if ((rv = vm_reserv_from_page(mpred))->object != object) leftcap = mpred->pindex + 1; else leftcap = rv->pindex + VM_LEVEL_0_NPAGES; if (leftcap > first) { vm_reserv_object_unlock(object); return (NULL); } } if (msucc != NULL) { if ((rv = vm_reserv_from_page(msucc))->object != object) rightcap = msucc->pindex; else rightcap = rv->pindex; if (first + VM_LEVEL_0_NPAGES > rightcap) { vm_reserv_object_unlock(object); return (NULL); } } vm_reserv_object_unlock(object); /* * Would the last new reservation extend past the end of the object? * * If the object is unlikely to grow don't allocate a reservation for * the tail. */ if ((object->flags & OBJ_ANON) == 0 && first + VM_LEVEL_0_NPAGES > object->size) return (NULL); /* * Allocate and populate the new reservation. */ m = NULL; vmd = VM_DOMAIN(domain); if (vm_domain_allocate(vmd, req, 1)) { vm_domain_free_lock(vmd); m = vm_phys_alloc_pages(domain, VM_FREEPOOL_DEFAULT, VM_LEVEL_0_ORDER); vm_domain_free_unlock(vmd); if (m == NULL) { vm_domain_freecnt_inc(vmd, 1); return (NULL); } } else return (NULL); rv = vm_reserv_from_page(m); vm_reserv_lock(rv); KASSERT(rv->pages == m, ("vm_reserv_alloc_page: reserv %p's pages is corrupted", rv)); vm_reserv_insert(rv, object, first); index = VM_RESERV_INDEX(object, pindex); vm_reserv_populate(rv, index); vm_reserv_unlock(rv); return (&rv->pages[index]); } /* * Breaks the given reservation. All free pages in the reservation * are returned to the physical memory allocator. The reservation's * population count and map are reset to their initial state. * * The given reservation must not be in the partially populated reservation * queue. */ static void vm_reserv_break(vm_reserv_t rv) { int hi, lo, pos; vm_reserv_assert_locked(rv); CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d", __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq); vm_reserv_remove(rv); rv->pages->psind = 0; hi = lo = -1; pos = 0; for (;;) { bit_ff_at(rv->popmap, pos, VM_LEVEL_0_NPAGES, lo != hi, &pos); if (lo == hi) { if (pos == -1) break; lo = pos; continue; } if (pos == -1) pos = VM_LEVEL_0_NPAGES; hi = pos; vm_domain_free_lock(VM_DOMAIN(rv->domain)); vm_phys_enqueue_contig(&rv->pages[lo], hi - lo); vm_domain_free_unlock(VM_DOMAIN(rv->domain)); lo = hi; } bit_nclear(rv->popmap, 0, VM_LEVEL_0_NPAGES - 1); rv->popcnt = 0; counter_u64_add(vm_reserv_broken, 1); } /* * Breaks all reservations belonging to the given object. */ void vm_reserv_break_all(vm_object_t object) { vm_reserv_t rv; /* * This access of object->rvq is unsynchronized so that the * object rvq lock can nest after the domain_free lock. We * must check for races in the results. However, the object * lock prevents new additions, so we are guaranteed that when * it returns NULL the object is properly empty. */ while ((rv = LIST_FIRST(&object->rvq)) != NULL) { vm_reserv_lock(rv); /* Reclaim race. */ if (rv->object != object) { vm_reserv_unlock(rv); continue; } vm_reserv_domain_lock(rv->domain); if (rv->inpartpopq) { TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq); rv->inpartpopq = FALSE; } vm_reserv_domain_unlock(rv->domain); vm_reserv_break(rv); vm_reserv_unlock(rv); } } /* * Frees the given page if it belongs to a reservation. Returns TRUE if the * page is freed and FALSE otherwise. */ boolean_t vm_reserv_free_page(vm_page_t m) { vm_reserv_t rv; boolean_t ret; rv = vm_reserv_from_page(m); if (rv->object == NULL) return (FALSE); vm_reserv_lock(rv); /* Re-validate after lock. */ if (rv->object != NULL) { vm_reserv_depopulate(rv, m - rv->pages); ret = TRUE; } else ret = FALSE; vm_reserv_unlock(rv); return (ret); } /* * 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; struct vm_phys_seg *seg; struct vm_reserv *rv; struct vm_reserv_domain *rvd; #ifdef VM_PHYSSEG_SPARSE vm_pindex_t used; #endif int i, segind; /* * Initialize the reservation array. Specifically, initialize the * "pages" field for every element that has an underlying superpage. */ #ifdef VM_PHYSSEG_SPARSE used = 0; #endif for (segind = 0; segind < vm_phys_nsegs; segind++) { seg = &vm_phys_segs[segind]; #ifdef VM_PHYSSEG_SPARSE seg->first_reserv = &vm_reserv_array[used]; used += howmany(seg->end, VM_LEVEL_0_SIZE) - seg->start / VM_LEVEL_0_SIZE; #else seg->first_reserv = &vm_reserv_array[seg->start >> VM_LEVEL_0_SHIFT]; #endif paddr = roundup2(seg->start, VM_LEVEL_0_SIZE); rv = seg->first_reserv + (paddr >> VM_LEVEL_0_SHIFT) - (seg->start >> VM_LEVEL_0_SHIFT); while (paddr + VM_LEVEL_0_SIZE > paddr && paddr + VM_LEVEL_0_SIZE <= seg->end) { rv->pages = PHYS_TO_VM_PAGE(paddr); rv->domain = seg->domain; mtx_init(&rv->lock, "vm reserv", NULL, MTX_DEF); paddr += VM_LEVEL_0_SIZE; rv++; } } for (i = 0; i < MAXMEMDOM; i++) { rvd = &vm_rvd[i]; mtx_init(&rvd->lock, "vm reserv domain", NULL, MTX_DEF); TAILQ_INIT(&rvd->partpop); mtx_init(&rvd->marker.lock, "vm reserv marker", NULL, MTX_DEF); /* * Fully populated reservations should never be present in the * partially populated reservation queues. */ rvd->marker.popcnt = VM_LEVEL_0_NPAGES; bit_nset(rvd->marker.popmap, 0, VM_LEVEL_0_NPAGES - 1); } for (i = 0; i < VM_RESERV_OBJ_LOCK_COUNT; i++) mtx_init(&vm_reserv_object_mtx[i], "resv obj lock", NULL, MTX_DEF); } /* * Returns true if the given page belongs to a reservation and that page is * free. Otherwise, returns false. */ bool vm_reserv_is_page_free(vm_page_t m) { vm_reserv_t rv; rv = vm_reserv_from_page(m); if (rv->object == NULL) return (false); return (!bit_test(rv->popmap, m - rv->pages)); } /* * If the given page belongs to a reservation, returns the level of that * reservation. Otherwise, returns -1. */ int vm_reserv_level(vm_page_t m) { vm_reserv_t rv; rv = vm_reserv_from_page(m); return (rv->object != NULL ? 0 : -1); } /* * 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); } /* * Remove a partially populated reservation from the queue. */ static void vm_reserv_dequeue(vm_reserv_t rv) { vm_reserv_domain_assert_locked(rv->domain); vm_reserv_assert_locked(rv); CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d", __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq); KASSERT(rv->inpartpopq, ("vm_reserv_reclaim: reserv %p's inpartpopq is FALSE", rv)); TAILQ_REMOVE(&vm_rvd[rv->domain].partpop, rv, partpopq); rv->inpartpopq = FALSE; } /* * Breaks the given partially populated reservation, releasing its free pages * to the physical memory allocator. */ static void vm_reserv_reclaim(vm_reserv_t rv) { vm_reserv_assert_locked(rv); CTR5(KTR_VM, "%s: rv %p object %p popcnt %d inpartpop %d", __FUNCTION__, rv, rv->object, rv->popcnt, rv->inpartpopq); if (rv->inpartpopq) { vm_reserv_domain_lock(rv->domain); vm_reserv_dequeue(rv); vm_reserv_domain_unlock(rv->domain); } vm_reserv_break(rv); counter_u64_add(vm_reserv_reclaimed, 1); } /* * Breaks a reservation near the head of the partially populated reservation * queue, releasing its free pages to the physical memory allocator. Returns * TRUE if a reservation is broken and FALSE otherwise. */ bool vm_reserv_reclaim_inactive(int domain) { vm_reserv_t rv; vm_reserv_domain_lock(domain); TAILQ_FOREACH(rv, &vm_rvd[domain].partpop, partpopq) { /* * A locked reservation is likely being updated or reclaimed, * so just skip ahead. */ if (rv != &vm_rvd[domain].marker && vm_reserv_trylock(rv)) { vm_reserv_dequeue(rv); break; } } vm_reserv_domain_unlock(domain); if (rv != NULL) { vm_reserv_reclaim(rv); vm_reserv_unlock(rv); return (true); } return (false); } /* * Determine whether this reservation has free pages that satisfy the given * request for contiguous physical memory. Start searching from the lower * bound, defined by lo, and stop at the upper bound, hi. Return the index * of the first satisfactory free page, or -1 if none is found. */ static int vm_reserv_find_contig(vm_reserv_t rv, int npages, int lo, int hi, int ppn_align, int ppn_bound) { vm_reserv_assert_locked(rv); KASSERT(npages <= VM_LEVEL_0_NPAGES - 1, ("%s: Too many pages", __func__)); KASSERT(ppn_bound <= VM_LEVEL_0_NPAGES, ("%s: Too big a boundary for reservation size", __func__)); KASSERT(npages <= ppn_bound, ("%s: Too many pages for given boundary", __func__)); KASSERT(ppn_align != 0 && powerof2(ppn_align), ("ppn_align is not a positive power of 2")); KASSERT(ppn_bound != 0 && powerof2(ppn_bound), ("ppn_bound is not a positive power of 2")); while (bit_ffc_area_at(rv->popmap, lo, hi, npages, &lo), lo != -1) { if (lo < roundup2(lo, ppn_align)) { /* Skip to next aligned page. */ lo = roundup2(lo, ppn_align); } else if (roundup2(lo + 1, ppn_bound) >= lo + npages) return (lo); if (roundup2(lo + 1, ppn_bound) < lo + npages) { /* Skip to next boundary-matching page. */ lo = roundup2(lo + 1, ppn_bound); } } return (-1); } /* * Searches the partially populated reservation queue for the least recently * changed reservation with free pages 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. */ vm_page_t vm_reserv_reclaim_contig(int domain, u_long npages, vm_paddr_t low, vm_paddr_t high, u_long alignment, vm_paddr_t boundary) { struct vm_reserv_queue *queue; vm_paddr_t pa, size; vm_page_t m_ret; vm_reserv_t marker, rv, rvn; int hi, lo, posn, ppn_align, ppn_bound; KASSERT(npages > 0, ("npages is 0")); KASSERT(powerof2(alignment), ("alignment is not a power of 2")); KASSERT(powerof2(boundary), ("boundary is not a power of 2")); if (npages > VM_LEVEL_0_NPAGES - 1) return (false); size = npages << PAGE_SHIFT; /* * Ensure that a free range starting at a boundary-multiple * doesn't include a boundary-multiple within it. Otherwise, * no boundary-constrained allocation is possible. */ if (!vm_addr_bound_ok(0, size, boundary)) return (NULL); marker = &vm_rvd[domain].marker; queue = &vm_rvd[domain].partpop; /* * Compute shifted alignment, boundary values for page-based * calculations. Constrain to range [1, VM_LEVEL_0_NPAGES] to * avoid overflow. */ ppn_align = (int)(ulmin(ulmax(PAGE_SIZE, alignment), VM_LEVEL_0_SIZE) >> PAGE_SHIFT); ppn_bound = boundary == 0 ? VM_LEVEL_0_NPAGES : (int)(MIN(MAX(PAGE_SIZE, boundary), VM_LEVEL_0_SIZE) >> PAGE_SHIFT); vm_reserv_domain_scan_lock(domain); vm_reserv_domain_lock(domain); TAILQ_FOREACH_SAFE(rv, queue, partpopq, rvn) { pa = VM_PAGE_TO_PHYS(&rv->pages[0]); if (pa + VM_LEVEL_0_SIZE - size < low) { /* This entire reservation is too low; go to next. */ continue; } if (pa + size > high) { /* This entire reservation is too high; go to next. */ continue; } if (!vm_addr_align_ok(pa, alignment)) { /* This entire reservation is unaligned; go to next. */ continue; } if (vm_reserv_trylock(rv) == 0) { TAILQ_INSERT_AFTER(queue, rv, marker, partpopq); vm_reserv_domain_unlock(domain); vm_reserv_lock(rv); if (TAILQ_PREV(marker, vm_reserv_queue, partpopq) != rv) { vm_reserv_unlock(rv); vm_reserv_domain_lock(domain); rvn = TAILQ_NEXT(marker, partpopq); TAILQ_REMOVE(queue, marker, partpopq); continue; } vm_reserv_domain_lock(domain); TAILQ_REMOVE(queue, marker, partpopq); } vm_reserv_domain_unlock(domain); lo = (pa >= low) ? 0 : (int)((low + PAGE_MASK - pa) >> PAGE_SHIFT); hi = (pa + VM_LEVEL_0_SIZE <= high) ? VM_LEVEL_0_NPAGES : (int)((high - pa) >> PAGE_SHIFT); posn = vm_reserv_find_contig(rv, (int)npages, lo, hi, ppn_align, ppn_bound); if (posn >= 0) { vm_reserv_domain_scan_unlock(domain); /* Allocate requested space */ rv->popcnt += npages; bit_nset(rv->popmap, posn, posn + npages - 1); vm_reserv_reclaim(rv); vm_reserv_unlock(rv); m_ret = &rv->pages[posn]; pa = VM_PAGE_TO_PHYS(m_ret); KASSERT(vm_addr_ok(pa, size, alignment, boundary), ("%s: adjusted address not aligned/bounded to " "%lx/%jx", __func__, alignment, (uintmax_t)boundary)); return (m_ret); } vm_reserv_domain_lock(domain); rvn = TAILQ_NEXT(rv, partpopq); vm_reserv_unlock(rv); } vm_reserv_domain_unlock(domain); vm_reserv_domain_scan_unlock(domain); return (NULL); } /* * 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_ASSERT_WLOCKED(new_object); rv = vm_reserv_from_page(m); if (rv->object == old_object) { vm_reserv_lock(rv); CTR6(KTR_VM, "%s: rv %p object %p new %p popcnt %d inpartpop %d", __FUNCTION__, rv, rv->object, new_object, rv->popcnt, rv->inpartpopq); if (rv->object == old_object) { vm_reserv_object_lock(old_object); rv->object = NULL; LIST_REMOVE(rv, objq); vm_reserv_object_unlock(old_object); vm_reserv_object_lock(new_object); rv->object = new_object; rv->pindex -= old_object_offset; LIST_INSERT_HEAD(&new_object->rvq, rv, objq); vm_reserv_object_unlock(new_object); } vm_reserv_unlock(rv); } } /* * Returns the size (in bytes) of a reservation of the specified level. */ int vm_reserv_size(int level) { switch (level) { case 0: return (VM_LEVEL_0_SIZE); case -1: return (PAGE_SIZE); default: return (0); } } /* * 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 new_end; vm_pindex_t count; size_t size; int i; count = 0; for (i = 0; i < vm_phys_nsegs; i++) { #ifdef VM_PHYSSEG_SPARSE count += howmany(vm_phys_segs[i].end, VM_LEVEL_0_SIZE) - vm_phys_segs[i].start / VM_LEVEL_0_SIZE; #else count = MAX(count, howmany(vm_phys_segs[i].end, VM_LEVEL_0_SIZE)); #endif } for (i = 0; phys_avail[i + 1] != 0; i += 2) { #ifdef VM_PHYSSEG_SPARSE count += howmany(phys_avail[i + 1], VM_LEVEL_0_SIZE) - phys_avail[i] / VM_LEVEL_0_SIZE; #else count = MAX(count, howmany(phys_avail[i + 1], VM_LEVEL_0_SIZE)); #endif } /* * Calculate the size (in bytes) of the reservation array. Rounding up * for partial superpages at boundaries, as 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 = count * 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); } /* * Returns the superpage containing the given page. */ vm_page_t vm_reserv_to_superpage(vm_page_t m) { vm_reserv_t rv; VM_OBJECT_ASSERT_LOCKED(m->object); rv = vm_reserv_from_page(m); if (rv->object == m->object && rv->popcnt == VM_LEVEL_0_NPAGES) m = rv->pages; else m = NULL; return (m); } #endif /* VM_NRESERVLEVEL > 0 */