/* * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the University of * California, Berkeley and its contributors. * 4. 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. * * $FreeBSD: src/sys/vm/vm_pager.c,v 1.54.2.2 2001/11/18 07:11:00 dillon Exp $ * $DragonFly: src/sys/vm/vm_pager.c,v 1.11 2004/07/14 03:10:17 hmp Exp $ */ /* * Paging space routine stubs. Emulates a matchmaker-like interface * for builtin pagers. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include MALLOC_DEFINE(M_VMPGDATA, "VM pgdata", "XXX: VM pager private data"); extern struct pagerops defaultpagerops; extern struct pagerops swappagerops; extern struct pagerops vnodepagerops; extern struct pagerops devicepagerops; extern struct pagerops physpagerops; int cluster_pbuf_freecnt = -1; /* unlimited to begin with */ static int dead_pager_getpages (vm_object_t, vm_page_t *, int, int); static vm_object_t dead_pager_alloc (void *, vm_ooffset_t, vm_prot_t, vm_ooffset_t); 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 int dead_pager_getpages(vm_object_t obj, vm_page_t *ma, int count, int req) { 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) { 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) *prev = 0; if (next) *next = 0; return FALSE; } static void dead_pager_dealloc(vm_object_t object) { return; } static struct pagerops deadpagerops = { NULL, dead_pager_alloc, dead_pager_dealloc, dead_pager_getpages, dead_pager_putpages, dead_pager_haspage, NULL }; struct pagerops *pagertab[] = { &defaultpagerops, /* OBJT_DEFAULT */ &swappagerops, /* OBJT_SWAP */ &vnodepagerops, /* OBJT_VNODE */ &devicepagerops, /* OBJT_DEVICE */ &physpagerops, /* OBJT_PHYS */ &deadpagerops /* OBJT_DEAD */ }; int npagers = sizeof(pagertab) / sizeof(pagertab[0]); /* * Kernel address space for mapping pages. * Used by pagers where KVAs are needed for IO. * * XXX needs to be large enough to support the number of pending async * cleaning requests (NPENDINGIO == 64) * the maximum swap cluster size * (MAXPHYS == 64k) if you want to get the most efficiency. */ #define PAGER_MAP_SIZE (8 * 1024 * 1024) int pager_map_size = PAGER_MAP_SIZE; vm_map_t pager_map; static int bswneeded; static vm_offset_t swapbkva; /* swap buffers kva */ void vm_pager_init(void) { struct pagerops **pgops; /* * Initialize known pagers */ for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) if (pgops && ((*pgops)->pgo_init != NULL)) (*(*pgops)->pgo_init) (); } void vm_pager_bufferinit(void) { struct buf *bp; int i; bp = swbuf; /* * Now set up swap and physical I/O buffer headers. */ for (i = 0; i < nswbuf; i++, bp++) { TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); BUF_LOCKINIT(bp); LIST_INIT(&bp->b_dep); bp->b_xflags = 0; } cluster_pbuf_freecnt = nswbuf / 2; swapbkva = kmem_alloc_pageable(pager_map, nswbuf * MAXPHYS); if (!swapbkva) panic("Not enough pager_map VM space for physical buffers"); } /* * 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 pagerops *ops; ops = pagertab[type]; if (ops) return ((*ops->pgo_alloc) (handle, size, prot, off)); return (NULL); } void vm_pager_deallocate(vm_object_t object) { (*pagertab[object->type]->pgo_dealloc) (object); } /* * vm_pager_strategy: * * called with no specific spl * Execute strategy routine directly to pager. */ void vm_pager_strategy(vm_object_t object, struct buf *bp) { if (pagertab[object->type]->pgo_strategy) { (*pagertab[object->type]->pgo_strategy)(object, bp); } else { bp->b_flags |= B_ERROR; bp->b_error = ENXIO; biodone(bp); } } /* * vm_pager_get_pages() - inline, see vm/vm_pager.h * vm_pager_put_pages() - inline, see vm/vm_pager.h * vm_pager_has_page() - inline, see vm/vm_pager.h * vm_pager_page_inserted() - inline, see vm/vm_pager.h * vm_pager_page_removed() - inline, see vm/vm_pager.h */ #if 0 /* * vm_pager_sync: * * Called by pageout daemon before going back to sleep. * Gives pagers a chance to clean up any completed async pageing * operations. */ void vm_pager_sync(void) { struct pagerops **pgops; for (pgops = pagertab; pgops < &pagertab[npagers]; pgops++) if (pgops && ((*pgops)->pgo_sync != NULL)) (*(*pgops)->pgo_sync) (); } #endif vm_object_t vm_pager_object_lookup(struct pagerlst *pg_list, void *handle) { vm_object_t object; for (object = TAILQ_FIRST(pg_list); object != NULL; object = TAILQ_NEXT(object,pager_object_list)) if (object->handle == handle) return (object); return (NULL); } /* * initialize a physical buffer */ static void initpbuf(struct buf *bp) { bp->b_qindex = QUEUE_NONE; bp->b_data = (caddr_t) (MAXPHYS * (bp - swbuf)) + swapbkva; bp->b_kvabase = bp->b_data; bp->b_kvasize = MAXPHYS; bp->b_xflags = 0; bp->b_flags = 0; bp->b_error = 0; xio_init(&bp->b_xio); BUF_LOCK(bp, LK_EXCLUSIVE); } /* * allocate a physical buffer * * There are a limited number (nswbuf) of physical buffers. We need * to make sure that no single subsystem is able to hog all of them, * so each subsystem implements a counter which is typically initialized * to 1/2 nswbuf. getpbuf() decrements this counter in allocation and * increments it on release, and blocks if the counter hits zero. A * subsystem may initialize the counter to -1 to disable the feature, * but it must still be sure to match up all uses of getpbuf() with * relpbuf() using the same variable. * * NOTE: pfreecnt can be NULL, but this 'feature' will be removed * relatively soon when the rest of the subsystems get smart about it. XXX */ struct buf * getpbuf(int *pfreecnt) { int s; struct buf *bp; s = splvm(); for (;;) { if (pfreecnt) { while (*pfreecnt == 0) { tsleep(pfreecnt, 0, "wswbuf0", 0); } } /* get a bp from the swap buffer header pool */ if ((bp = TAILQ_FIRST(&bswlist)) != NULL) break; bswneeded = 1; tsleep(&bswneeded, 0, "wswbuf1", 0); /* loop in case someone else grabbed one */ } TAILQ_REMOVE(&bswlist, bp, b_freelist); if (pfreecnt) --*pfreecnt; splx(s); initpbuf(bp); return bp; } /* * allocate a physical buffer, if one is available. * * Note that there is no NULL hack here - all subsystems using this * call understand how to use pfreecnt. */ struct buf * trypbuf(int *pfreecnt) { int s; struct buf *bp; s = splvm(); if (*pfreecnt == 0 || (bp = TAILQ_FIRST(&bswlist)) == NULL) { splx(s); return NULL; } TAILQ_REMOVE(&bswlist, bp, b_freelist); --*pfreecnt; splx(s); initpbuf(bp); return bp; } /* * release a physical buffer * * NOTE: pfreecnt can be NULL, but this 'feature' will be removed * relatively soon when the rest of the subsystems get smart about it. XXX */ void relpbuf(struct buf *bp, int *pfreecnt) { int s; s = splvm(); if (bp->b_vp) pbrelvp(bp); BUF_UNLOCK(bp); TAILQ_INSERT_HEAD(&bswlist, bp, b_freelist); if (bswneeded) { bswneeded = 0; wakeup(&bswneeded); } if (pfreecnt) { if (++*pfreecnt == 1) wakeup(pfreecnt); } splx(s); } /******************************************************** * CHAINING FUNCTIONS * ******************************************************** * * These functions support recursion of I/O operations * on bp's, typically by chaining one or more 'child' bp's * to the parent. Synchronous, asynchronous, and semi-synchronous * chaining is possible. */ /* * vm_pager_chain_iodone: * * io completion routine for child bp. Currently we fudge a bit * on dealing with b_resid. Since users of these routines may issue * multiple children simultaniously, sequencing of the error can be lost. */ static void vm_pager_chain_iodone(struct buf *nbp) { struct buf *bp; if ((bp = nbp->b_chain.parent) != NULL) { if (nbp->b_flags & B_ERROR) { bp->b_flags |= B_ERROR; bp->b_error = nbp->b_error; } else if (nbp->b_resid != 0) { bp->b_flags |= B_ERROR; bp->b_error = EINVAL; } else { bp->b_resid -= nbp->b_bcount; } nbp->b_chain.parent = NULL; --bp->b_chain.count; if (bp->b_flags & B_WANT) { bp->b_flags &= ~B_WANT; wakeup(bp); } if (!bp->b_chain.count && (bp->b_xflags & BX_AUTOCHAINDONE)) { bp->b_xflags &= ~BX_AUTOCHAINDONE; if (bp->b_resid != 0 && !(bp->b_flags & B_ERROR)) { bp->b_flags |= B_ERROR; bp->b_error = EINVAL; } biodone(bp); } } nbp->b_flags |= B_DONE; nbp->b_flags &= ~B_ASYNC; relpbuf(nbp, NULL); } /* * getchainbuf: * * Obtain a physical buffer and chain it to its parent buffer. When * I/O completes, the parent buffer will be B_SIGNAL'd. Errors are * automatically propogated to the parent * * Since these are brand new buffers, we do not have to clear B_INVAL * and B_ERROR because they are already clear. */ struct buf * getchainbuf(struct buf *bp, struct vnode *vp, int flags) { struct buf *nbp = getpbuf(NULL); nbp->b_chain.parent = bp; ++bp->b_chain.count; if (bp->b_chain.count > 4) waitchainbuf(bp, 4, 0); nbp->b_flags = B_CALL | (bp->b_flags & B_ORDERED) | flags; nbp->b_iodone = vm_pager_chain_iodone; if (vp) pbgetvp(vp, nbp); return(nbp); } void flushchainbuf(struct buf *nbp) { if (nbp->b_bcount) { nbp->b_bufsize = nbp->b_bcount; if ((nbp->b_flags & B_READ) == 0) nbp->b_dirtyend = nbp->b_bcount; BUF_KERNPROC(nbp); VOP_STRATEGY(nbp->b_vp, nbp); } else { biodone(nbp); } } void waitchainbuf(struct buf *bp, int count, int done) { int s; s = splbio(); while (bp->b_chain.count > count) { bp->b_flags |= B_WANT; tsleep(bp, 0, "bpchain", 0); } if (done) { if (bp->b_resid != 0 && !(bp->b_flags & B_ERROR)) { bp->b_flags |= B_ERROR; bp->b_error = EINVAL; } biodone(bp); } splx(s); } void autochaindone(struct buf *bp) { int s; s = splbio(); if (bp->b_chain.count == 0) biodone(bp); else bp->b_xflags |= BX_AUTOCHAINDONE; splx(s); }