diff --git a/sys/vm/vm_pager.c b/sys/vm/vm_pager.c index ea5ce36f1963..cff8f5f9bdc3 100644 --- a/sys/vm/vm_pager.c +++ b/sys/vm/vm_pager.c @@ -1,613 +1,618 @@ /*- * SPDX-License-Identifier: (BSD-3-Clause AND MIT-CMU) * * Copyright (c) 1991, 1993 * The Regents of the University of California. All rights reserved. * * This code is derived from software contributed to Berkeley by * The Mach Operating System project at Carnegie-Mellon University. * * 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. * 3. Neither the name of the University nor the names of its contributors * may be used to endorse or promote products derived from this software * without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE REGENTS 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 REGENTS 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. * * from: @(#)vm_pager.c 8.6 (Berkeley) 1/12/94 * * * Copyright (c) 1987, 1990 Carnegie-Mellon University. * All rights reserved. * * Authors: Avadis Tevanian, Jr., Michael Wayne Young * * Permission to use, copy, modify and distribute this software and * its documentation is hereby granted, provided that both the copyright * notice and this permission notice appear in all copies of the * software, derivative works or modified versions, and any portions * thereof, and that both notices appear in supporting documentation. * * CARNEGIE MELLON ALLOWS FREE USE OF THIS SOFTWARE IN ITS "AS IS" * CONDITION. CARNEGIE MELLON DISCLAIMS ANY LIABILITY OF ANY KIND * FOR ANY DAMAGES WHATSOEVER RESULTING FROM THE USE OF THIS SOFTWARE. * * Carnegie Mellon requests users of this software to return to * * Software Distribution Coordinator or Software.Distribution@CS.CMU.EDU * School of Computer Science * Carnegie Mellon University * Pittsburgh PA 15213-3890 * * any improvements or extensions that they make and grant Carnegie the * rights to redistribute these changes. */ /* * Paging space routine stubs. Emulates a matchmaker-like interface * for builtin pagers. */ #include __FBSDID("$FreeBSD$"); #include "opt_param.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include uma_zone_t pbuf_zone; static int pbuf_init(void *, int, int); static int pbuf_ctor(void *, int, void *, int); static void pbuf_dtor(void *, int, void *); static int dead_pager_getpages(vm_object_t, vm_page_t *, int, int *, int *); static vm_object_t dead_pager_alloc(void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t, struct ucred *); static void dead_pager_putpages(vm_object_t, vm_page_t *, int, int, int *); static boolean_t dead_pager_haspage(vm_object_t, vm_pindex_t, int *, int *); static void dead_pager_dealloc(vm_object_t); static void dead_pager_getvp(vm_object_t, struct vnode **, bool *); static int dead_pager_getpages(vm_object_t obj, vm_page_t *ma, int count, int *rbehind, int *rahead) { return (VM_PAGER_FAIL); } static vm_object_t dead_pager_alloc(void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t off, struct ucred *cred) { return (NULL); } static void dead_pager_putpages(vm_object_t object, vm_page_t *m, int count, int flags, int *rtvals) { int i; for (i = 0; i < count; i++) rtvals[i] = VM_PAGER_AGAIN; } static int dead_pager_haspage(vm_object_t object, vm_pindex_t pindex, int *prev, int *next) { if (prev != NULL) *prev = 0; if (next != NULL) *next = 0; return (FALSE); } static void dead_pager_dealloc(vm_object_t object) { } static void dead_pager_getvp(vm_object_t object, struct vnode **vpp, bool *vp_heldp) { /* * For OBJT_DEAD objects, v_writecount was handled in * vnode_pager_dealloc(). */ } static const struct pagerops deadpagerops = { .pgo_kvme_type = KVME_TYPE_DEAD, .pgo_alloc = dead_pager_alloc, .pgo_dealloc = dead_pager_dealloc, .pgo_getpages = dead_pager_getpages, .pgo_putpages = dead_pager_putpages, .pgo_haspage = dead_pager_haspage, .pgo_getvp = dead_pager_getvp, }; const struct pagerops *pagertab[16] __read_mostly = { [OBJT_DEFAULT] = &defaultpagerops, [OBJT_SWAP] = &swappagerops, [OBJT_VNODE] = &vnodepagerops, [OBJT_DEVICE] = &devicepagerops, [OBJT_PHYS] = &physpagerops, [OBJT_DEAD] = &deadpagerops, [OBJT_SG] = &sgpagerops, [OBJT_MGTDEVICE] = &mgtdevicepagerops, }; static struct mtx pagertab_lock; void vm_pager_init(void) { const struct pagerops **pgops; int i; mtx_init(&pagertab_lock, "dynpag", NULL, MTX_DEF); /* * Initialize known pagers */ for (i = 0; i < OBJT_FIRST_DYN; i++) { pgops = &pagertab[i]; if ((*pgops)->pgo_init != NULL) (*(*pgops)->pgo_init)(); } } static int nswbuf_max; void vm_pager_bufferinit(void) { /* Main zone for paging bufs. */ pbuf_zone = uma_zcreate("pbuf", sizeof(struct buf) + PBUF_PAGES * sizeof(vm_page_t), pbuf_ctor, pbuf_dtor, pbuf_init, NULL, UMA_ALIGN_CACHE, UMA_ZONE_NOFREE); /* Few systems may still use this zone directly, so it needs a limit. */ nswbuf_max += uma_zone_set_max(pbuf_zone, NSWBUF_MIN); } uma_zone_t pbuf_zsecond_create(const char *name, int max) { uma_zone_t zone; zone = uma_zsecond_create(name, pbuf_ctor, pbuf_dtor, NULL, NULL, pbuf_zone); /* * uma_prealloc() rounds up to items per slab. If we would prealloc * immediately on every pbuf_zsecond_create(), we may accumulate too * much of difference between hard limit and prealloced items, which * means wasted memory. */ if (nswbuf_max > 0) nswbuf_max += uma_zone_set_max(zone, max); else uma_prealloc(pbuf_zone, uma_zone_set_max(zone, max)); return (zone); } static void pbuf_prealloc(void *arg __unused) { uma_prealloc(pbuf_zone, nswbuf_max); nswbuf_max = -1; } SYSINIT(pbuf, SI_SUB_KTHREAD_BUF, SI_ORDER_ANY, pbuf_prealloc, NULL); /* * Allocate an instance of a pager of the given type. * Size, protection and offset parameters are passed in for pagers that * need to perform page-level validation (e.g. the device pager). */ vm_object_t vm_pager_allocate(objtype_t type, void *handle, vm_ooffset_t size, vm_prot_t prot, vm_ooffset_t off, struct ucred *cred) { + vm_object_t object; + MPASS(type < nitems(pagertab)); - return ((*pagertab[type]->pgo_alloc)(handle, size, prot, off, cred)); + object = (*pagertab[type]->pgo_alloc)(handle, size, prot, off, cred); + if (object != NULL) + object->type = type; + return (object); } /* * The object must be locked. */ void vm_pager_deallocate(vm_object_t object) { VM_OBJECT_ASSERT_WLOCKED(object); MPASS(object->type < nitems(pagertab)); (*pagertab[object->type]->pgo_dealloc) (object); } static void vm_pager_assert_in(vm_object_t object, vm_page_t *m, int count) { #ifdef INVARIANTS /* * All pages must be consecutive, busied, not mapped, not fully valid, * not dirty and belong to the proper object. Some pages may be the * bogus page, but the first and last pages must be a real ones. */ VM_OBJECT_ASSERT_UNLOCKED(object); VM_OBJECT_ASSERT_PAGING(object); KASSERT(count > 0, ("%s: 0 count", __func__)); for (int i = 0 ; i < count; i++) { if (m[i] == bogus_page) { KASSERT(i != 0 && i != count - 1, ("%s: page %d is the bogus page", __func__, i)); continue; } vm_page_assert_xbusied(m[i]); KASSERT(!pmap_page_is_mapped(m[i]), ("%s: page %p is mapped", __func__, m[i])); KASSERT(m[i]->valid != VM_PAGE_BITS_ALL, ("%s: request for a valid page %p", __func__, m[i])); KASSERT(m[i]->dirty == 0, ("%s: page %p is dirty", __func__, m[i])); KASSERT(m[i]->object == object, ("%s: wrong object %p/%p", __func__, object, m[i]->object)); KASSERT(m[i]->pindex == m[0]->pindex + i, ("%s: page %p isn't consecutive", __func__, m[i])); } #endif } /* * Page in the pages for the object using its associated pager. * The requested page must be fully valid on successful return. */ int vm_pager_get_pages(vm_object_t object, vm_page_t *m, int count, int *rbehind, int *rahead) { #ifdef INVARIANTS vm_pindex_t pindex = m[0]->pindex; #endif int r; MPASS(object->type < nitems(pagertab)); vm_pager_assert_in(object, m, count); r = (*pagertab[object->type]->pgo_getpages)(object, m, count, rbehind, rahead); if (r != VM_PAGER_OK) return (r); for (int i = 0; i < count; i++) { /* * If pager has replaced a page, assert that it had * updated the array. */ #ifdef INVARIANTS KASSERT(m[i] == vm_page_relookup(object, pindex++), ("%s: mismatch page %p pindex %ju", __func__, m[i], (uintmax_t )pindex - 1)); #endif /* * Zero out partially filled data. */ if (m[i]->valid != VM_PAGE_BITS_ALL) vm_page_zero_invalid(m[i], TRUE); } return (VM_PAGER_OK); } int vm_pager_get_pages_async(vm_object_t object, vm_page_t *m, int count, int *rbehind, int *rahead, pgo_getpages_iodone_t iodone, void *arg) { MPASS(object->type < nitems(pagertab)); vm_pager_assert_in(object, m, count); return ((*pagertab[object->type]->pgo_getpages_async)(object, m, count, rbehind, rahead, iodone, arg)); } /* * vm_pager_put_pages() - inline, see vm/vm_pager.h * vm_pager_has_page() - inline, see vm/vm_pager.h */ /* * Search the specified pager object list for an object with the * specified handle. If an object with the specified handle is found, * increase its reference count and return it. Otherwise, return NULL. * * The pager object list must be locked. */ vm_object_t vm_pager_object_lookup(struct pagerlst *pg_list, void *handle) { vm_object_t object; TAILQ_FOREACH(object, pg_list, pager_object_list) { if (object->handle == handle) { VM_OBJECT_WLOCK(object); if ((object->flags & OBJ_DEAD) == 0) { vm_object_reference_locked(object); VM_OBJECT_WUNLOCK(object); break; } VM_OBJECT_WUNLOCK(object); } } return (object); } int vm_pager_alloc_dyn_type(struct pagerops *ops, int base_type) { int res; mtx_lock(&pagertab_lock); MPASS(base_type == -1 || (base_type >= OBJT_DEFAULT && base_type < nitems(pagertab))); for (res = OBJT_FIRST_DYN; res < nitems(pagertab); res++) { if (pagertab[res] == NULL) break; } if (res == nitems(pagertab)) { mtx_unlock(&pagertab_lock); return (-1); } if (base_type != -1) { MPASS(pagertab[base_type] != NULL); #define FIX(n) \ if (ops->pgo_##n == NULL) \ ops->pgo_##n = pagertab[base_type]->pgo_##n FIX(init); FIX(alloc); FIX(dealloc); FIX(getpages); FIX(getpages_async); FIX(putpages); FIX(haspage); FIX(populate); FIX(pageunswapped); FIX(update_writecount); FIX(release_writecount); FIX(set_writeable_dirty); FIX(mightbedirty); FIX(getvp); FIX(freespace); FIX(page_inserted); FIX(page_removed); FIX(can_alloc_page); #undef FIX } pagertab[res] = ops; /* XXXKIB should be rel, but acq is too much */ mtx_unlock(&pagertab_lock); return (res); } void vm_pager_free_dyn_type(objtype_t type) { MPASS(type >= OBJT_FIRST_DYN && type < nitems(pagertab)); mtx_lock(&pagertab_lock); MPASS(pagertab[type] != NULL); pagertab[type] = NULL; mtx_unlock(&pagertab_lock); } static int pbuf_ctor(void *mem, int size, void *arg, int flags) { struct buf *bp = mem; bp->b_vp = NULL; bp->b_bufobj = NULL; /* copied from initpbuf() */ bp->b_rcred = NOCRED; bp->b_wcred = NOCRED; bp->b_qindex = 0; /* On no queue (QUEUE_NONE) */ bp->b_data = bp->b_kvabase; bp->b_xflags = 0; bp->b_flags = B_MAXPHYS; bp->b_ioflags = 0; bp->b_iodone = NULL; bp->b_error = 0; BUF_LOCK(bp, LK_EXCLUSIVE, NULL); return (0); } static void pbuf_dtor(void *mem, int size, void *arg) { struct buf *bp = mem; if (bp->b_rcred != NOCRED) { crfree(bp->b_rcred); bp->b_rcred = NOCRED; } if (bp->b_wcred != NOCRED) { crfree(bp->b_wcred); bp->b_wcred = NOCRED; } BUF_UNLOCK(bp); } static const char pbuf_wmesg[] = "pbufwait"; static int pbuf_init(void *mem, int size, int flags) { struct buf *bp = mem; bp->b_kvabase = (void *)kva_alloc(ptoa(PBUF_PAGES)); if (bp->b_kvabase == NULL) return (ENOMEM); bp->b_kvasize = ptoa(PBUF_PAGES); BUF_LOCKINIT(bp, pbuf_wmesg); LIST_INIT(&bp->b_dep); bp->b_rcred = bp->b_wcred = NOCRED; bp->b_xflags = 0; return (0); } /* * Associate a p-buffer with a vnode. * * Also sets B_PAGING flag to indicate that vnode is not fully associated * with the buffer. i.e. the bp has not been linked into the vnode or * ref-counted. */ void pbgetvp(struct vnode *vp, struct buf *bp) { KASSERT(bp->b_vp == NULL, ("pbgetvp: not free")); KASSERT(bp->b_bufobj == NULL, ("pbgetvp: not free (bufobj)")); bp->b_vp = vp; bp->b_flags |= B_PAGING; bp->b_bufobj = &vp->v_bufobj; } /* * Associate a p-buffer with a vnode. * * Also sets B_PAGING flag to indicate that vnode is not fully associated * with the buffer. i.e. the bp has not been linked into the vnode or * ref-counted. */ void pbgetbo(struct bufobj *bo, struct buf *bp) { KASSERT(bp->b_vp == NULL, ("pbgetbo: not free (vnode)")); KASSERT(bp->b_bufobj == NULL, ("pbgetbo: not free (bufobj)")); bp->b_flags |= B_PAGING; bp->b_bufobj = bo; } /* * Disassociate a p-buffer from a vnode. */ void pbrelvp(struct buf *bp) { KASSERT(bp->b_vp != NULL, ("pbrelvp: NULL")); KASSERT(bp->b_bufobj != NULL, ("pbrelvp: NULL bufobj")); KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, ("pbrelvp: pager buf on vnode list.")); bp->b_vp = NULL; bp->b_bufobj = NULL; bp->b_flags &= ~B_PAGING; } /* * Disassociate a p-buffer from a bufobj. */ void pbrelbo(struct buf *bp) { KASSERT(bp->b_vp == NULL, ("pbrelbo: vnode")); KASSERT(bp->b_bufobj != NULL, ("pbrelbo: NULL bufobj")); KASSERT((bp->b_xflags & (BX_VNDIRTY | BX_VNCLEAN)) == 0, ("pbrelbo: pager buf on vnode list.")); bp->b_bufobj = NULL; bp->b_flags &= ~B_PAGING; } void vm_object_set_writeable_dirty(vm_object_t object) { pgo_set_writeable_dirty_t *method; MPASS(object->type < nitems(pagertab)); method = pagertab[object->type]->pgo_set_writeable_dirty; if (method != NULL) method(object); } bool vm_object_mightbedirty(vm_object_t object) { pgo_mightbedirty_t *method; MPASS(object->type < nitems(pagertab)); method = pagertab[object->type]->pgo_mightbedirty; if (method == NULL) return (false); return (method(object)); } /* * Return the kvme type of the given object. * If vpp is not NULL, set it to the object's vm_object_vnode() or NULL. */ int vm_object_kvme_type(vm_object_t object, struct vnode **vpp) { VM_OBJECT_ASSERT_LOCKED(object); MPASS(object->type < nitems(pagertab)); if (vpp != NULL) *vpp = vm_object_vnode(object); return (pagertab[object->type]->pgo_kvme_type); }