/* * Copyright (c) 1991 Regents of the University of California. * All rights reserved. * Copyright (c) 1994 John S. Dyson * All rights reserved. * Copyright (c) 1994 David Greenman * 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_pageout.c 7.4 (Berkeley) 5/7/91 * * * 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. * * $Id: vm_pageout.c,v 1.58 1995/10/23 05:35:48 dyson Exp $ */ /* * The proverbial page-out daemon. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * System initialization */ /* the kernel process "vm_pageout"*/ static void vm_pageout __P((void)); struct proc *pageproc; static struct kproc_desc page_kp = { "pagedaemon", vm_pageout, &pageproc }; SYSINIT_KT(pagedaemon, SI_SUB_KTHREAD_PAGE, SI_ORDER_FIRST, kproc_start, &page_kp) /* the kernel process "vm_daemon"*/ static void vm_daemon __P((void)); struct proc *vmproc; static struct kproc_desc vm_kp = { "vmdaemon", vm_daemon, &vmproc }; SYSINIT_KT(vmdaemon, SI_SUB_KTHREAD_VM, SI_ORDER_FIRST, kproc_start, &vm_kp) int vm_pages_needed; /* Event on which pageout daemon sleeps */ int vm_pageout_pages_needed; /* flag saying that the pageout daemon needs pages */ extern int npendingio; int vm_pageout_req_swapout; /* XXX */ int vm_daemon_needed; extern int nswiodone; extern int vm_swap_size; extern int vfs_update_wakeup; #define MAXSCAN 1024 /* maximum number of pages to scan in queues */ #define MAXLAUNDER (cnt.v_page_count > 1800 ? 32 : 16) #define VM_PAGEOUT_PAGE_COUNT 8 int vm_pageout_page_count = VM_PAGEOUT_PAGE_COUNT; int vm_page_max_wired; /* XXX max # of wired pages system-wide */ typedef int freeer_fcn_t __P((vm_map_t, vm_object_t, int, int)); static void vm_pageout_map_deactivate_pages __P((vm_map_t, vm_map_entry_t, int *, freeer_fcn_t *)); static freeer_fcn_t vm_pageout_object_deactivate_pages; static void vm_req_vmdaemon __P((void)); /* * vm_pageout_clean: * * Clean the page and remove it from the laundry. * * We set the busy bit to cause potential page faults on this page to * block. * * And we set pageout-in-progress to keep the object from disappearing * during pageout. This guarantees that the page won't move from the * inactive queue. (However, any other page on the inactive queue may * move!) */ int vm_pageout_clean(m, sync) vm_page_t m; int sync; { register vm_object_t object; int pageout_status[VM_PAGEOUT_PAGE_COUNT]; vm_page_t mc[2*VM_PAGEOUT_PAGE_COUNT]; int pageout_count; int i, forward_okay, backward_okay, page_base; vm_offset_t offset = m->offset; object = m->object; /* * If not OBJT_SWAP, additional memory may be needed to do the pageout. * Try to avoid the deadlock. */ if ((sync != VM_PAGEOUT_FORCE) && (object->type != OBJT_SWAP) && ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_pageout_free_min)) return 0; /* * Don't mess with the page if it's busy. */ if ((!sync && m->hold_count != 0) || ((m->busy != 0) || (m->flags & PG_BUSY))) return 0; /* * Try collapsing before it's too late. */ if (!sync && object->backing_object) { vm_object_collapse(object); } mc[VM_PAGEOUT_PAGE_COUNT] = m; pageout_count = 1; page_base = VM_PAGEOUT_PAGE_COUNT; forward_okay = TRUE; if (offset != 0) backward_okay = TRUE; else backward_okay = FALSE; /* * Scan object for clusterable pages. * * We can cluster ONLY if: ->> the page is NOT * clean, wired, busy, held, or mapped into a * buffer, and one of the following: * 1) The page is inactive, or a seldom used * active page. * -or- * 2) we force the issue. */ for (i = 1; (i < vm_pageout_page_count) && (forward_okay || backward_okay); i++) { vm_page_t p; /* * See if forward page is clusterable. */ if (forward_okay) { /* * Stop forward scan at end of object. */ if ((offset + i * PAGE_SIZE) > object->size) { forward_okay = FALSE; goto do_backward; } p = vm_page_lookup(object, offset + i * PAGE_SIZE); if (p) { if ((p->flags & (PG_BUSY|PG_CACHE)) || p->busy) { forward_okay = FALSE; goto do_backward; } vm_page_test_dirty(p); if ((p->dirty & p->valid) != 0 && ((p->flags & PG_INACTIVE) || (sync == VM_PAGEOUT_FORCE)) && (p->wire_count == 0) && (p->hold_count == 0)) { mc[VM_PAGEOUT_PAGE_COUNT + i] = p; pageout_count++; if (pageout_count == vm_pageout_page_count) break; } else { forward_okay = FALSE; } } else { forward_okay = FALSE; } } do_backward: /* * See if backward page is clusterable. */ if (backward_okay) { /* * Stop backward scan at beginning of object. */ if ((offset - i * PAGE_SIZE) == 0) { backward_okay = FALSE; } p = vm_page_lookup(object, offset - i * PAGE_SIZE); if (p) { if ((p->flags & (PG_BUSY|PG_CACHE)) || p->busy) { backward_okay = FALSE; continue; } vm_page_test_dirty(p); if ((p->dirty & p->valid) != 0 && ((p->flags & PG_INACTIVE) || (sync == VM_PAGEOUT_FORCE)) && (p->wire_count == 0) && (p->hold_count == 0)) { mc[VM_PAGEOUT_PAGE_COUNT - i] = p; pageout_count++; page_base--; if (pageout_count == vm_pageout_page_count) break; } else { backward_okay = FALSE; } } else { backward_okay = FALSE; } } } /* * we allow reads during pageouts... */ for (i = page_base; i < (page_base + pageout_count); i++) { mc[i]->flags |= PG_BUSY; vm_page_protect(mc[i], VM_PROT_READ); } return vm_pageout_flush(&mc[page_base], pageout_count, sync); } int vm_pageout_flush(mc, count, sync) vm_page_t *mc; int count; int sync; { register vm_object_t object; int pageout_status[count]; int anyok = 0; int i; object = mc[0]->object; object->paging_in_progress += count; vm_pager_put_pages(object, mc, count, ((sync || (object == kernel_object)) ? TRUE : FALSE), pageout_status); for (i = 0; i < count; i++) { vm_page_t mt = mc[i]; switch (pageout_status[i]) { case VM_PAGER_OK: ++anyok; break; case VM_PAGER_PEND: ++anyok; break; case VM_PAGER_BAD: /* * Page outside of range of object. Right now we * essentially lose the changes by pretending it * worked. */ pmap_clear_modify(VM_PAGE_TO_PHYS(mt)); mt->dirty = 0; break; case VM_PAGER_ERROR: case VM_PAGER_FAIL: /* * If page couldn't be paged out, then reactivate the * page so it doesn't clog the inactive list. (We * will try paging out it again later). */ if (mt->flags & PG_INACTIVE) vm_page_activate(mt); break; case VM_PAGER_AGAIN: break; } /* * If the operation is still going, leave the page busy to * block all other accesses. Also, leave the paging in * progress indicator set so that we don't attempt an object * collapse. */ if (pageout_status[i] != VM_PAGER_PEND) { vm_object_pip_wakeup(object); if ((mt->flags & (PG_REFERENCED|PG_WANTED)) || pmap_is_referenced(VM_PAGE_TO_PHYS(mt))) { pmap_clear_reference(VM_PAGE_TO_PHYS(mt)); mt->flags &= ~PG_REFERENCED; if (mt->flags & PG_INACTIVE) vm_page_activate(mt); } PAGE_WAKEUP(mt); } } return anyok; } /* * vm_pageout_object_deactivate_pages * * deactivate enough pages to satisfy the inactive target * requirements or if vm_page_proc_limit is set, then * deactivate all of the pages in the object and its * backing_objects. * * The object and map must be locked. */ static int vm_pageout_object_deactivate_pages(map, object, count, map_remove_only) vm_map_t map; vm_object_t object; int count; int map_remove_only; { register vm_page_t p, next; int rcount; int dcount; dcount = 0; if (count == 0) count = 1; if (object->type == OBJT_DEVICE) return 0; if (object->backing_object) { if (object->backing_object->ref_count == 1) dcount += vm_pageout_object_deactivate_pages(map, object->backing_object, count / 2 + 1, map_remove_only); else vm_pageout_object_deactivate_pages(map, object->backing_object, count, 1); } if (object->paging_in_progress) return dcount; /* * scan the objects entire memory queue */ rcount = object->resident_page_count; p = object->memq.tqh_first; while (p && (rcount-- > 0)) { next = p->listq.tqe_next; cnt.v_pdpages++; if (p->wire_count != 0 || p->hold_count != 0 || p->busy != 0 || !pmap_page_exists(vm_map_pmap(map), VM_PAGE_TO_PHYS(p))) { p = next; continue; } /* * if a page is active, not wired and is in the processes * pmap, then deactivate the page. */ if ((p->flags & (PG_ACTIVE | PG_BUSY)) == PG_ACTIVE) { if (!pmap_is_referenced(VM_PAGE_TO_PHYS(p)) && (p->flags & (PG_REFERENCED|PG_WANTED)) == 0) { p->act_count -= min(p->act_count, ACT_DECLINE); /* * if the page act_count is zero -- then we * deactivate */ if (!p->act_count) { if (!map_remove_only) vm_page_deactivate(p); vm_page_protect(p, VM_PROT_NONE); /* * else if on the next go-around we * will deactivate the page we need to * place the page on the end of the * queue to age the other pages in * memory. */ } else { TAILQ_REMOVE(&vm_page_queue_active, p, pageq); TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq); } /* * see if we are done yet */ if (p->flags & PG_INACTIVE) { --count; ++dcount; if (count <= 0 && cnt.v_inactive_count > cnt.v_inactive_target) { return dcount; } } } else { /* * Move the page to the bottom of the queue. */ pmap_clear_reference(VM_PAGE_TO_PHYS(p)); p->flags &= ~PG_REFERENCED; if (p->act_count < ACT_MAX) p->act_count += ACT_ADVANCE; TAILQ_REMOVE(&vm_page_queue_active, p, pageq); TAILQ_INSERT_TAIL(&vm_page_queue_active, p, pageq); } } else if ((p->flags & (PG_INACTIVE | PG_BUSY)) == PG_INACTIVE) { vm_page_protect(p, VM_PROT_NONE); } p = next; } return dcount; } /* * deactivate some number of pages in a map, try to do it fairly, but * that is really hard to do. */ static void vm_pageout_map_deactivate_pages(map, entry, count, freeer) vm_map_t map; vm_map_entry_t entry; int *count; freeer_fcn_t *freeer; { vm_map_t tmpm; vm_map_entry_t tmpe; vm_object_t obj; if (*count <= 0) return; vm_map_reference(map); if (!lock_try_read(&map->lock)) { vm_map_deallocate(map); return; } if (entry == 0) { tmpe = map->header.next; while (tmpe != &map->header && *count > 0) { vm_pageout_map_deactivate_pages(map, tmpe, count, freeer); tmpe = tmpe->next; }; } else if (entry->is_sub_map || entry->is_a_map) { tmpm = entry->object.share_map; tmpe = tmpm->header.next; while (tmpe != &tmpm->header && *count > 0) { vm_pageout_map_deactivate_pages(tmpm, tmpe, count, freeer); tmpe = tmpe->next; }; } else if ((obj = entry->object.vm_object) != 0) { *count -= (*freeer) (map, obj, *count, TRUE); } lock_read_done(&map->lock); vm_map_deallocate(map); return; } static void vm_req_vmdaemon() { static int lastrun = 0; if ((ticks > (lastrun + hz / 10)) || (ticks < lastrun)) { wakeup(&vm_daemon_needed); lastrun = ticks; } } /* * vm_pageout_scan does the dirty work for the pageout daemon. */ int vm_pageout_scan() { vm_page_t m; int page_shortage, maxscan, maxlaunder, pcount; int pages_freed; vm_page_t next; struct proc *p, *bigproc; vm_offset_t size, bigsize; vm_object_t object; int force_wakeup = 0; int vnodes_skipped = 0; pages_freed = 0; /* * Start scanning the inactive queue for pages we can free. We keep * scanning until we have enough free pages or we have scanned through * the entire queue. If we encounter dirty pages, we start cleaning * them. */ maxlaunder = (cnt.v_inactive_target > MAXLAUNDER) ? MAXLAUNDER : cnt.v_inactive_target; rescan1: maxscan = cnt.v_inactive_count; m = vm_page_queue_inactive.tqh_first; while ((m != NULL) && (maxscan-- > 0) && ((cnt.v_cache_count + cnt.v_free_count) < (cnt.v_cache_min + cnt.v_free_target))) { vm_page_t next; cnt.v_pdpages++; next = m->pageq.tqe_next; #if defined(VM_DIAGNOSE) if ((m->flags & PG_INACTIVE) == 0) { printf("vm_pageout_scan: page not inactive?\n"); break; } #endif /* * dont mess with busy pages */ if (m->hold_count || m->busy || (m->flags & PG_BUSY)) { TAILQ_REMOVE(&vm_page_queue_inactive, m, pageq); TAILQ_INSERT_TAIL(&vm_page_queue_inactive, m, pageq); m = next; continue; } if (((m->flags & PG_REFERENCED) == 0) && pmap_is_referenced(VM_PAGE_TO_PHYS(m))) { m->flags |= PG_REFERENCED; } if (m->object->ref_count == 0) { m->flags &= ~PG_REFERENCED; pmap_clear_reference(VM_PAGE_TO_PHYS(m)); } if ((m->flags & (PG_REFERENCED|PG_WANTED)) != 0) { m->flags &= ~PG_REFERENCED; pmap_clear_reference(VM_PAGE_TO_PHYS(m)); vm_page_activate(m); if (m->act_count < ACT_MAX) m->act_count += ACT_ADVANCE; m = next; continue; } vm_page_test_dirty(m); if (m->dirty == 0) { if (m->bmapped == 0) { if (m->valid == 0) { pmap_page_protect(VM_PAGE_TO_PHYS(m), VM_PROT_NONE); vm_page_free(m); cnt.v_dfree++; } else { vm_page_cache(m); } ++pages_freed; } else { m = next; continue; } } else if (maxlaunder > 0) { int written; struct vnode *vp = NULL; object = m->object; if (object->flags & OBJ_DEAD) { m = next; continue; } if (object->type == OBJT_VNODE) { vp = object->handle; if (VOP_ISLOCKED(vp) || vget(vp, 1)) { if (object->flags & OBJ_MIGHTBEDIRTY) ++vnodes_skipped; m = next; continue; } } /* * If a page is dirty, then it is either being washed * (but not yet cleaned) or it is still in the * laundry. If it is still in the laundry, then we * start the cleaning operation. */ written = vm_pageout_clean(m, 0); if (vp) vput(vp); if (!next) { break; } maxlaunder -= written; /* * if the next page has been re-activated, start * scanning again */ if ((next->flags & PG_INACTIVE) == 0) { goto rescan1; } } m = next; } /* * Compute the page shortage. If we are still very low on memory be * sure that we will move a minimal amount of pages from active to * inactive. */ page_shortage = cnt.v_inactive_target - (cnt.v_free_count + cnt.v_inactive_count + cnt.v_cache_count); if (page_shortage <= 0) { if (pages_freed == 0) { page_shortage = cnt.v_free_min - cnt.v_free_count; } else { page_shortage = 1; } } maxscan = MAXSCAN; pcount = cnt.v_active_count; m = vm_page_queue_active.tqh_first; while ((m != NULL) && (maxscan > 0) && (pcount-- > 0) && (page_shortage > 0)) { cnt.v_pdpages++; next = m->pageq.tqe_next; /* * Don't deactivate pages that are busy. */ if ((m->busy != 0) || (m->flags & PG_BUSY) || (m->hold_count != 0)) { TAILQ_REMOVE(&vm_page_queue_active, m, pageq); TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); m = next; continue; } if (m->object->ref_count && ((m->flags & (PG_REFERENCED|PG_WANTED)) || pmap_is_referenced(VM_PAGE_TO_PHYS(m)))) { int s; pmap_clear_reference(VM_PAGE_TO_PHYS(m)); m->flags &= ~PG_REFERENCED; if (m->act_count < ACT_MAX) { m->act_count += ACT_ADVANCE; } TAILQ_REMOVE(&vm_page_queue_active, m, pageq); TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); } else { m->flags &= ~PG_REFERENCED; pmap_clear_reference(VM_PAGE_TO_PHYS(m)); m->act_count -= min(m->act_count, ACT_DECLINE); /* * if the page act_count is zero -- then we deactivate */ if (!m->act_count && (page_shortage > 0)) { if (m->object->ref_count == 0) { --page_shortage; vm_page_test_dirty(m); if ((m->bmapped == 0) && (m->dirty == 0) ) { m->act_count = 0; vm_page_cache(m); } else { vm_page_deactivate(m); } } else { vm_page_deactivate(m); --page_shortage; } } else if (m->act_count) { TAILQ_REMOVE(&vm_page_queue_active, m, pageq); TAILQ_INSERT_TAIL(&vm_page_queue_active, m, pageq); } } maxscan--; m = next; } /* * We try to maintain some *really* free pages, this allows interrupt * code to be guaranteed space. */ while (cnt.v_free_count < cnt.v_free_reserved) { m = vm_page_queue_cache.tqh_first; if (!m) break; vm_page_free(m); cnt.v_dfree++; } /* * If we didn't get enough free pages, and we have skipped a vnode * in a writeable object, wakeup the sync daemon. And kick swapout * if we did not get enough free pages. */ if ((cnt.v_cache_count + cnt.v_free_count) < cnt.v_free_target) { if (vnodes_skipped && (cnt.v_cache_count + cnt.v_free_count) < cnt.v_free_min) { if (!vfs_update_wakeup) { vfs_update_wakeup = 1; wakeup(&vfs_update_wakeup); } } /* * now swap processes out if we are in low memory conditions */ if (!swap_pager_full && vm_swap_size && vm_pageout_req_swapout == 0) { vm_pageout_req_swapout = 1; vm_req_vmdaemon(); } } if ((cnt.v_inactive_count + cnt.v_free_count + cnt.v_cache_count) < (cnt.v_inactive_target + cnt.v_free_min)) { vm_req_vmdaemon(); } /* * make sure that we have swap space -- if we are low on memory and * swap -- then kill the biggest process. */ if ((vm_swap_size == 0 || swap_pager_full) && ((cnt.v_free_count + cnt.v_cache_count) < cnt.v_free_min)) { bigproc = NULL; bigsize = 0; for (p = (struct proc *) allproc; p != NULL; p = p->p_next) { /* * if this is a system process, skip it */ if ((p->p_flag & P_SYSTEM) || (p->p_pid == 1) || ((p->p_pid < 48) && (vm_swap_size != 0))) { continue; } /* * if the process is in a non-running type state, * don't touch it. */ if (p->p_stat != SRUN && p->p_stat != SSLEEP) { continue; } /* * get the process size */ size = p->p_vmspace->vm_pmap.pm_stats.resident_count; /* * if the this process is bigger than the biggest one * remember it. */ if (size > bigsize) { bigproc = p; bigsize = size; } } if (bigproc != NULL) { printf("Process %lu killed by vm_pageout -- out of swap\n", (u_long) bigproc->p_pid); psignal(bigproc, SIGKILL); bigproc->p_estcpu = 0; bigproc->p_nice = PRIO_MIN; resetpriority(bigproc); wakeup(&cnt.v_free_count); } } return force_wakeup; } /* * vm_pageout is the high level pageout daemon. */ static void vm_pageout() { (void) spl0(); /* * Initialize some paging parameters. */ cnt.v_interrupt_free_min = 2; if (cnt.v_page_count > 1024) cnt.v_free_min = 4 + (cnt.v_page_count - 1024) / 200; else cnt.v_free_min = 4; /* * free_reserved needs to include enough for the largest swap pager * structures plus enough for any pv_entry structs when paging. */ cnt.v_pageout_free_min = 6 + cnt.v_page_count / 1024 + cnt.v_interrupt_free_min; cnt.v_free_reserved = cnt.v_pageout_free_min + 6; cnt.v_free_target = 3 * cnt.v_free_min + cnt.v_free_reserved; cnt.v_free_min += cnt.v_free_reserved; if (cnt.v_page_count > 1024) { cnt.v_cache_max = (cnt.v_free_count - 1024) / 2; cnt.v_cache_min = (cnt.v_free_count - 1024) / 8; cnt.v_inactive_target = 2*cnt.v_cache_min + 192; } else { cnt.v_cache_min = 0; cnt.v_cache_max = 0; cnt.v_inactive_target = cnt.v_free_count / 4; } /* XXX does not really belong here */ if (vm_page_max_wired == 0) vm_page_max_wired = cnt.v_free_count / 3; swap_pager_swap_init(); /* * The pageout daemon is never done, so loop forever. */ while (TRUE) { int s = splhigh(); if (!vm_pages_needed || ((cnt.v_free_count >= cnt.v_free_reserved) && (cnt.v_free_count + cnt.v_cache_count >= cnt.v_free_min))) { vm_pages_needed = 0; tsleep(&vm_pages_needed, PVM, "psleep", 0); } vm_pages_needed = 0; splx(s); cnt.v_pdwakeups++; vm_pager_sync(); vm_pageout_scan(); vm_pager_sync(); wakeup(&cnt.v_free_count); wakeup(kmem_map); } } static void vm_daemon() { vm_object_t object; struct proc *p; while (TRUE) { tsleep(&vm_daemon_needed, PUSER, "psleep", 0); if (vm_pageout_req_swapout) { swapout_procs(); vm_pageout_req_swapout = 0; } /* * scan the processes for exceeding their rlimits or if * process is swapped out -- deactivate pages */ for (p = (struct proc *) allproc; p != NULL; p = p->p_next) { int overage; quad_t limit; vm_offset_t size; /* * if this is a system process or if we have already * looked at this process, skip it. */ if (p->p_flag & (P_SYSTEM | P_WEXIT)) { continue; } /* * if the process is in a non-running type state, * don't touch it. */ if (p->p_stat != SRUN && p->p_stat != SSLEEP) { continue; } /* * get a limit */ limit = qmin(p->p_rlimit[RLIMIT_RSS].rlim_cur, p->p_rlimit[RLIMIT_RSS].rlim_max); /* * let processes that are swapped out really be * swapped out set the limit to nothing (will force a * swap-out.) */ if ((p->p_flag & P_INMEM) == 0) limit = 0; /* XXX */ size = p->p_vmspace->vm_pmap.pm_stats.resident_count * PAGE_SIZE; if (limit >= 0 && size >= limit) { overage = (size - limit) >> PAGE_SHIFT; vm_pageout_map_deactivate_pages(&p->p_vmspace->vm_map, (vm_map_entry_t) 0, &overage, vm_pageout_object_deactivate_pages); } } /* * we remove cached objects that have no RSS... */ restart: object = vm_object_cached_list.tqh_first; while (object) { /* * if there are no resident pages -- get rid of the object */ if (object->resident_page_count == 0) { vm_object_reference(object); pager_cache(object, FALSE); goto restart; } object = object->cached_list.tqe_next; } } }