/* $OpenBSD: uvm_object.c,v 1.28 2025/12/10 08:38:18 mpi Exp $ */ /* * Copyright (c) 2006, 2010, 2019 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Mindaugas Rasiukevicius. * * 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 NETBSD FOUNDATION, INC. 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 FOUNDATION 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. */ /* * uvm_object.c: operate with memory objects * */ #include <sys/param.h> #include <sys/systm.h> #include <sys/mman.h> #include <sys/atomic.h> #include <sys/rwlock.h> #include <uvm/uvm.h> /* Dummy object used by some pmaps for sanity checks. */ const struct uvm_pagerops pmap_pager = { /* nothing */ }; /* Dummy object used by the buffer cache for sanity checks. */ const struct uvm_pagerops bufcache_pager = { /* nothing */ }; /* Page count to fetch per single step. */ #define FETCH_PAGECOUNT 16 /* * uvm_obj_init: initialize UVM memory object. */ void uvm_obj_init(struct uvm_object *uobj, const struct uvm_pagerops *pgops, int refs) { int alock; alock = ((pgops != NULL) && (pgops != &pmap_pager) && (pgops != &bufcache_pager) && (refs != UVM_OBJ_KERN)); if (alock) { /* Allocate and assign a lock. */ rw_obj_alloc(&uobj->vmobjlock, "uobjlk"); } else { /* The lock will need to be set via uvm_obj_setlock(). */ uobj->vmobjlock = NULL; } uobj->pgops = pgops; RBT_INIT(uvm_objtree, &uobj->memt); uobj->uo_npages = 0; uobj->uo_refs = refs; } /* * uvm_obj_destroy: destroy UVM memory object. */ void uvm_obj_destroy(struct uvm_object *uo) { KASSERT(RBT_EMPTY(uvm_objtree, &uo->memt)); rw_obj_free(uo->vmobjlock); } /* * uvm_obj_setlock: assign a vmobjlock to the UVM object. * * => Caller is responsible to ensure that UVM objects is not use. * => Only dynamic lock may be previously set. We drop the reference then. */ void uvm_obj_setlock(struct uvm_object *uo, struct rwlock *lockptr) { struct rwlock *olockptr = uo->vmobjlock; if (olockptr) { /* Drop the reference on the old lock. */ rw_obj_free(olockptr); } if (lockptr == NULL) { /* If new lock is not passed - allocate default one. */ rw_obj_alloc(&lockptr, "uobjlk"); } uo->vmobjlock = lockptr; } #ifndef SMALL_KERNEL /* * uvm_obj_wire: wire the pages of entire UVM object. * * => NOTE: this function should only be used for types of objects * where PG_RELEASED flag is never set (aobj objects) * => caller must pass page-aligned start and end values * => if the caller passes in a pageq pointer, we'll return a list of * wired pages. */ int uvm_obj_wire(struct uvm_object *uobj, voff_t start, voff_t end, struct pglist *pageq) { int i, npages, left, error; struct vm_page *pgs[FETCH_PAGECOUNT]; voff_t offset = start; left = (end - start) >> PAGE_SHIFT; rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK); while (left) { npages = MIN(FETCH_PAGECOUNT, left); /* Get the pages */ memset(pgs, 0, sizeof(pgs)); error = (*uobj->pgops->pgo_get)(uobj, offset, pgs, &npages, 0, PROT_READ | PROT_WRITE, MADV_SEQUENTIAL, PGO_ALLPAGES | PGO_SYNCIO); if (error) goto error; rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK); for (i = 0; i < npages; i++) { KASSERT(pgs[i] != NULL); KASSERT(!(pgs[i]->pg_flags & PG_RELEASED)); if (pgs[i]->pg_flags & PQ_AOBJ) { atomic_clearbits_int(&pgs[i]->pg_flags, PG_CLEAN); uao_dropswap(uobj, i); } } /* Wire the pages */ for (i = 0; i < npages; i++) { uvm_pagewire(pgs[i]); if (pageq != NULL) TAILQ_INSERT_TAIL(pageq, pgs[i], pageq); } /* Unbusy the pages */ uvm_page_unbusy(pgs, npages); left -= npages; offset += (voff_t)npages << PAGE_SHIFT; } rw_exit(uobj->vmobjlock); return 0; error: /* Unwire the pages which have been wired */ uvm_obj_unwire(uobj, start, offset); return error; } /* * uvm_obj_unwire: unwire the pages of entire UVM object. * * => caller must pass page-aligned start and end values */ void uvm_obj_unwire(struct uvm_object *uobj, voff_t start, voff_t end) { struct vm_page *pg; off_t offset; rw_enter(uobj->vmobjlock, RW_WRITE | RW_DUPOK); for (offset = start; offset < end; offset += PAGE_SIZE) { pg = uvm_pagelookup(uobj, offset); KASSERT(pg != NULL); KASSERT(!(pg->pg_flags & PG_RELEASED)); uvm_pageunwire(pg); } rw_exit(uobj->vmobjlock); } #endif /* !SMALL_KERNEL */ /* * uvm_obj_free: free all pages in a uvm object, used by the buffer * cache to free all pages attached to a buffer. */ void uvm_obj_free(struct uvm_object *uobj) { struct vm_page *pg; struct pglist pgl; KASSERT(UVM_OBJ_IS_BUFCACHE(uobj)); KERNEL_ASSERT_LOCKED(); TAILQ_INIT(&pgl); /* * Extract from rb tree in offset order. The phys addresses * usually increase in that order, which is better for * uvm_pglistfree(). */ RBT_FOREACH(pg, uvm_objtree, &uobj->memt) { /* * clear PG_TABLED and `uobject' so we don't do work to * remove this pg from the uobj we are throwing away. */ atomic_clearbits_int(&pg->pg_flags, PG_TABLED); pg->uobject = NULL; uvm_pageclean(pg); TAILQ_INSERT_TAIL(&pgl, pg, pageq); } uvm_pglistfree(&pgl); }
