/* $OpenBSD: uvm_pager.c,v 1.16 2001/09/20 17:02:32 mpech Exp $ */ /* $NetBSD: uvm_pager.c,v 1.30 2000/05/20 03:36:06 thorpej Exp $ */ /* * * Copyright (c) 1997 Charles D. Cranor and Washington University. * All rights reserved. * * 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 Charles D. Cranor and * Washington University. * 4. The name of the author may not be used to endorse or promote products * derived from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``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 AUTHOR 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: Id: uvm_pager.c,v 1.1.2.23 1998/02/02 20:38:06 chuck Exp */ /* * uvm_pager.c: generic functions used to assist the pagers. */ #include #include #include #include #include #include #define UVM_PAGER #include /* * list of uvm pagers in the system */ extern struct uvm_pagerops uvm_deviceops; extern struct uvm_pagerops uvm_vnodeops; struct uvm_pagerops *uvmpagerops[] = { &aobj_pager, &uvm_deviceops, &uvm_vnodeops, }; /* * the pager map: provides KVA for I/O */ #define PAGER_MAP_SIZE (4 * 1024 * 1024) vm_map_t pager_map; /* XXX */ simple_lock_data_t pager_map_wanted_lock; boolean_t pager_map_wanted; /* locked by pager map */ /* * uvm_pager_init: init pagers (at boot time) */ void uvm_pager_init() { int lcv; /* * init pager map */ pager_map = uvm_km_suballoc(kernel_map, &uvm.pager_sva, &uvm.pager_eva, PAGER_MAP_SIZE, 0, FALSE, NULL); simple_lock_init(&pager_map_wanted_lock); pager_map_wanted = FALSE; /* * init ASYNC I/O queue */ TAILQ_INIT(&uvm.aio_done); /* * call pager init functions */ for (lcv = 0 ; lcv < sizeof(uvmpagerops)/sizeof(struct uvm_pagerops *); lcv++) { if (uvmpagerops[lcv]->pgo_init) uvmpagerops[lcv]->pgo_init(); } } /* * uvm_pagermapin: map pages into KVA (pager_map) for I/O that needs mappings * * we basically just map in a blank map entry to reserve the space in the * map and then use pmap_enter() to put the mappings in by hand. */ vaddr_t uvm_pagermapin(pps, npages, aiop, flags) struct vm_page **pps; int npages; struct uvm_aiodesc **aiop; /* OUT */ int flags; { vsize_t size; vaddr_t kva; struct uvm_aiodesc *aio; vaddr_t cva; struct vm_page *pp; vm_prot_t prot; UVMHIST_FUNC("uvm_pagermapin"); UVMHIST_CALLED(maphist); UVMHIST_LOG(maphist,"(pps=0x%x, npages=%d, aiop=0x%x, flags=0x%x)", pps, npages, aiop, flags); /* * compute protection. outgoing I/O only needs read * access to the page, whereas incoming needs read/write. */ prot = VM_PROT_READ; if (flags & UVMPAGER_MAPIN_READ) prot |= VM_PROT_WRITE; ReStart: if (aiop) { MALLOC(aio, struct uvm_aiodesc *, sizeof(*aio), M_TEMP, (flags & UVMPAGER_MAPIN_WAITOK)); if (aio == NULL) return(0); *aiop = aio; } else { aio = NULL; } size = npages << PAGE_SHIFT; kva = 0; /* let system choose VA */ if (uvm_map(pager_map, &kva, size, NULL, UVM_UNKNOWN_OFFSET, UVM_FLAG_NOMERGE) != KERN_SUCCESS) { if ((flags & UVMPAGER_MAPIN_WAITOK) == 0) { if (aio) FREE(aio, M_TEMP); UVMHIST_LOG(maphist,"<- NOWAIT failed", 0,0,0,0); return(0); } simple_lock(&pager_map_wanted_lock); pager_map_wanted = TRUE; UVMHIST_LOG(maphist, " SLEEPING on pager_map",0,0,0,0); UVM_UNLOCK_AND_WAIT(pager_map, &pager_map_wanted_lock, FALSE, "pager_map",0); goto ReStart; } /* got it */ for (cva = kva ; size != 0 ; size -= PAGE_SIZE, cva += PAGE_SIZE) { pp = *pps++; #ifdef DEBUG if ((pp->flags & PG_BUSY) == 0) panic("uvm_pagermapin: page not busy"); #endif pmap_enter(vm_map_pmap(pager_map), cva, VM_PAGE_TO_PHYS(pp), prot, PMAP_WIRED | prot); } UVMHIST_LOG(maphist, "<- done (KVA=0x%x)", kva,0,0,0); return(kva); } /* * uvm_pagermapout: remove pager_map mapping * * we remove our mappings by hand and then remove the mapping (waking * up anyone wanting space). */ void uvm_pagermapout(kva, npages) vaddr_t kva; int npages; { vsize_t size = npages << PAGE_SHIFT; vm_map_entry_t entries; UVMHIST_FUNC("uvm_pagermapout"); UVMHIST_CALLED(maphist); UVMHIST_LOG(maphist, " (kva=0x%x, npages=%d)", kva, npages,0,0); /* * duplicate uvm_unmap, but add in pager_map_wanted handling. */ vm_map_lock(pager_map); (void) uvm_unmap_remove(pager_map, kva, kva + size, &entries); simple_lock(&pager_map_wanted_lock); if (pager_map_wanted) { pager_map_wanted = FALSE; wakeup(pager_map); } simple_unlock(&pager_map_wanted_lock); vm_map_unlock(pager_map); if (entries) uvm_unmap_detach(entries, 0); UVMHIST_LOG(maphist,"<- done",0,0,0,0); } /* * uvm_mk_pcluster * * generic "make 'pager put' cluster" function. a pager can either * [1] set pgo_mk_pcluster to NULL (never cluster), [2] set it to this * generic function, or [3] set it to a pager specific function. * * => caller must lock object _and_ pagequeues (since we need to look * at active vs. inactive bits, etc.) * => caller must make center page busy and write-protect it * => we mark all cluster pages busy for the caller * => the caller must unbusy all pages (and check wanted/released * status if it drops the object lock) * => flags: * PGO_ALLPAGES: all pages in object are valid targets * !PGO_ALLPAGES: use "lo" and "hi" to limit range of cluster * PGO_DOACTCLUST: include active pages in cluster. * NOTE: the caller should clear PG_CLEANCHK bits if PGO_DOACTCLUST. * PG_CLEANCHK is only a hint, but clearing will help reduce * the number of calls we make to the pmap layer. */ struct vm_page ** uvm_mk_pcluster(uobj, pps, npages, center, flags, mlo, mhi) struct uvm_object *uobj; /* IN */ struct vm_page **pps, *center; /* IN/OUT, IN */ int *npages, flags; /* IN/OUT, IN */ voff_t mlo, mhi; /* IN (if !PGO_ALLPAGES) */ { struct vm_page **ppsp, *pclust; voff_t lo, hi, curoff; int center_idx, forward; UVMHIST_FUNC("uvm_mk_pcluster"); UVMHIST_CALLED(maphist); /* * center page should already be busy and write protected. XXX: * suppose page is wired? if we lock, then a process could * fault/block on it. if we don't lock, a process could write the * pages in the middle of an I/O. (consider an msync()). let's * lock it for now (better to delay than corrupt data?). */ /* * get cluster boundaries, check sanity, and apply our limits as well. */ uobj->pgops->pgo_cluster(uobj, center->offset, &lo, &hi); if ((flags & PGO_ALLPAGES) == 0) { if (lo < mlo) lo = mlo; if (hi > mhi) hi = mhi; } if ((hi - lo) >> PAGE_SHIFT > *npages) { /* pps too small, bail out! */ #ifdef DIAGNOSTIC printf("uvm_mk_pcluster: provided page array too small (fixed)\n"); #endif pps[0] = center; *npages = 1; return(pps); } /* * now determine the center and attempt to cluster around the * edges */ center_idx = (center->offset - lo) >> PAGE_SHIFT; pps[center_idx] = center; /* plug in the center page */ ppsp = &pps[center_idx]; *npages = 1; /* * attempt to cluster around the left [backward], and then * the right side [forward]. * * note that for inactive pages (pages that have been deactivated) * there are no valid mappings and PG_CLEAN should be up to date. * [i.e. there is no need to query the pmap with pmap_is_modified * since there are no mappings]. */ for (forward = 0 ; forward <= 1 ; forward++) { curoff = center->offset + (forward ? PAGE_SIZE : -PAGE_SIZE); for ( ;(forward == 0 && curoff >= lo) || (forward && curoff < hi); curoff += (forward ? 1 : -1) << PAGE_SHIFT) { pclust = uvm_pagelookup(uobj, curoff); /* lookup page */ if (pclust == NULL) break; /* no page */ /* handle active pages */ /* NOTE: inactive pages don't have pmap mappings */ if ((pclust->pqflags & PQ_INACTIVE) == 0) { if ((flags & PGO_DOACTCLUST) == 0) /* dont want mapped pages at all */ break; /* make sure "clean" bit is sync'd */ if ((pclust->flags & PG_CLEANCHK) == 0) { if ((pclust->flags & (PG_CLEAN|PG_BUSY)) == PG_CLEAN && pmap_is_modified(pclust)) pclust->flags &= ~PG_CLEAN; /* now checked */ pclust->flags |= PG_CLEANCHK; } } /* is page available for cleaning and does it need it */ if ((pclust->flags & (PG_CLEAN|PG_BUSY)) != 0) break; /* page is already clean or is busy */ /* yes! enroll the page in our array */ pclust->flags |= PG_BUSY; /* busy! */ UVM_PAGE_OWN(pclust, "uvm_mk_pcluster"); /* XXX: protect wired page? see above comment. */ pmap_page_protect(pclust, VM_PROT_READ); if (!forward) { ppsp--; /* back up one page */ *ppsp = pclust; } else { /* move forward one page */ ppsp[*npages] = pclust; } *npages = *npages + 1; } } /* * done! return the cluster array to the caller!!! */ UVMHIST_LOG(maphist, "<- done",0,0,0,0); return(ppsp); } /* * uvm_pager_put: high level pageout routine * * we want to pageout page "pg" to backing store, clustering if * possible. * * => page queues must be locked by caller * => if page is not swap-backed, then "uobj" points to the object * backing it. this object should be locked by the caller. * => if page is swap-backed, then "uobj" should be NULL. * => "pg" should be PG_BUSY (by caller), and !PG_CLEAN * for swap-backed memory, "pg" can be NULL if there is no page * of interest [sometimes the case for the pagedaemon] * => "ppsp_ptr" should point to an array of npages vm_page pointers * for possible cluster building * => flags (first two for non-swap-backed pages) * PGO_ALLPAGES: all pages in uobj are valid targets * PGO_DOACTCLUST: include "PQ_ACTIVE" pages as valid targets * PGO_SYNCIO: do SYNC I/O (no async) * PGO_PDFREECLUST: pagedaemon: drop cluster on successful I/O * => start/stop: if (uobj && !PGO_ALLPAGES) limit targets to this range * if (!uobj) start is the (daddr_t) of the starting swapblk * => return state: * 1. we return the VM_PAGER status code of the pageout * 2. we return with the page queues unlocked * 3. if (uobj != NULL) [!swap_backed] we return with * uobj locked _only_ if PGO_PDFREECLUST is set * AND result != VM_PAGER_PEND. in all other cases * we return with uobj unlocked. [this is a hack * that allows the pagedaemon to save one lock/unlock * pair in the !swap_backed case since we have to * lock the uobj to drop the cluster anyway] * 4. on errors we always drop the cluster. thus, if we return * !PEND, !OK, then the caller only has to worry about * un-busying the main page (not the cluster pages). * 5. on success, if !PGO_PDFREECLUST, we return the cluster * with all pages busy (caller must un-busy and check * wanted/released flags). */ int uvm_pager_put(uobj, pg, ppsp_ptr, npages, flags, start, stop) struct uvm_object *uobj; /* IN */ struct vm_page *pg, ***ppsp_ptr;/* IN, IN/OUT */ int *npages; /* IN/OUT */ int flags; /* IN */ voff_t start, stop; /* IN, IN */ { int result; daddr_t swblk; struct vm_page **ppsp = *ppsp_ptr; /* * note that uobj is null if we are doing a swap-backed pageout. * note that uobj is !null if we are doing normal object pageout. * note that the page queues must be locked to cluster. */ if (uobj) { /* if !swap-backed */ /* * attempt to build a cluster for pageout using its * make-put-cluster function (if it has one). */ if (uobj->pgops->pgo_mk_pcluster) { ppsp = uobj->pgops->pgo_mk_pcluster(uobj, ppsp, npages, pg, flags, start, stop); *ppsp_ptr = ppsp; /* update caller's pointer */ } else { ppsp[0] = pg; *npages = 1; } swblk = 0; /* XXX: keep gcc happy */ } else { /* * for swap-backed pageout, the caller (the pagedaemon) has * already built the cluster for us. the starting swap * block we are writing to has been passed in as "start." * "pg" could be NULL if there is no page we are especially * interested in (in which case the whole cluster gets dropped * in the event of an error or a sync "done"). */ swblk = (daddr_t) start; /* ppsp and npages should be ok */ } /* now that we've clustered we can unlock the page queues */ uvm_unlock_pageq(); /* * now attempt the I/O. if we have a failure and we are * clustered, we will drop the cluster and try again. */ ReTry: if (uobj) { /* object is locked */ result = uobj->pgops->pgo_put(uobj, ppsp, *npages, flags & PGO_SYNCIO); /* object is now unlocked */ } else { /* nothing locked */ result = uvm_swap_put(swblk, ppsp, *npages, flags & PGO_SYNCIO); /* nothing locked */ } /* * we have attempted the I/O. * * if the I/O was a success then: * if !PGO_PDFREECLUST, we return the cluster to the * caller (who must un-busy all pages) * else we un-busy cluster pages for the pagedaemon * * if I/O is pending (async i/o) then we return the pending code. * [in this case the async i/o done function must clean up when * i/o is done...] */ if (result == VM_PAGER_PEND || result == VM_PAGER_OK) { if (result == VM_PAGER_OK && (flags & PGO_PDFREECLUST)) { /* * drop cluster and relock object (only if I/O is * not pending) */ if (uobj) /* required for dropcluster */ simple_lock(&uobj->vmobjlock); if (*npages > 1 || pg == NULL) uvm_pager_dropcluster(uobj, pg, ppsp, npages, PGO_PDFREECLUST); /* if (uobj): object still locked, as per * return-state item #3 */ } return (result); } /* * a pager error occurred. * for transient errors, drop to a cluster of 1 page ("pg") * and try again. for hard errors, don't bother retrying. */ if (*npages > 1 || pg == NULL) { if (uobj) { simple_lock(&uobj->vmobjlock); } uvm_pager_dropcluster(uobj, pg, ppsp, npages, PGO_REALLOCSWAP); /* * for failed swap-backed pageouts with a "pg", * we need to reset pg's swslot to either: * "swblk" (for transient errors, so we can retry), * or 0 (for hard errors). */ if (uobj == NULL && pg != NULL) { int nswblk = (result == VM_PAGER_AGAIN) ? swblk : 0; if (pg->pqflags & PQ_ANON) { simple_lock(&pg->uanon->an_lock); pg->uanon->an_swslot = nswblk; simple_unlock(&pg->uanon->an_lock); } else { simple_lock(&pg->uobject->vmobjlock); uao_set_swslot(pg->uobject, pg->offset >> PAGE_SHIFT, nswblk); simple_unlock(&pg->uobject->vmobjlock); } } if (result == VM_PAGER_AGAIN) { /* * for transient failures, free all the swslots that * we're not going to retry with. */ if (uobj == NULL) { if (pg) { uvm_swap_free(swblk + 1, *npages - 1); } else { uvm_swap_free(swblk, *npages); } } if (pg) { ppsp[0] = pg; *npages = 1; goto ReTry; } } else if (uobj == NULL) { /* * for hard errors on swap-backed pageouts, * mark the swslots as bad. note that we do not * free swslots that we mark bad. */ uvm_swap_markbad(swblk, *npages); } } /* * a pager error occurred (even after dropping the cluster, if there * was one). give up! the caller only has one page ("pg") * to worry about. */ if (uobj && (flags & PGO_PDFREECLUST) != 0) simple_lock(&uobj->vmobjlock); return(result); } /* * uvm_pager_dropcluster: drop a cluster we have built (because we * got an error, or, if PGO_PDFREECLUST we are un-busying the * cluster pages on behalf of the pagedaemon). * * => uobj, if non-null, is a non-swap-backed object that is * locked by the caller. we return with this object still * locked. * => page queues are not locked * => pg is our page of interest (the one we clustered around, can be null) * => ppsp/npages is our current cluster * => flags: PGO_PDFREECLUST: pageout was a success: un-busy cluster * pages on behalf of the pagedaemon. * PGO_REALLOCSWAP: drop previously allocated swap slots for * clustered swap-backed pages (except for "pg" if !NULL) * "swblk" is the start of swap alloc (e.g. for ppsp[0]) * [only meaningful if swap-backed (uobj == NULL)] */ void uvm_pager_dropcluster(uobj, pg, ppsp, npages, flags) struct uvm_object *uobj; /* IN */ struct vm_page *pg, **ppsp; /* IN, IN/OUT */ int *npages; /* IN/OUT */ int flags; { int lcv; boolean_t obj_is_alive; struct uvm_object *saved_uobj; /* * drop all pages but "pg" */ for (lcv = 0 ; lcv < *npages ; lcv++) { if (ppsp[lcv] == pg) /* skip "pg" */ continue; /* * if swap-backed, gain lock on object that owns page. note * that PQ_ANON bit can't change as long as we are holding * the PG_BUSY bit (so there is no need to lock the page * queues to test it). * * once we have the lock, dispose of the pointer to swap, if * requested */ if (!uobj) { if (ppsp[lcv]->pqflags & PQ_ANON) { simple_lock(&ppsp[lcv]->uanon->an_lock); if (flags & PGO_REALLOCSWAP) /* zap swap block */ ppsp[lcv]->uanon->an_swslot = 0; } else { simple_lock(&ppsp[lcv]->uobject->vmobjlock); if (flags & PGO_REALLOCSWAP) uao_set_swslot(ppsp[lcv]->uobject, ppsp[lcv]->offset >> PAGE_SHIFT, 0); } } /* did someone want the page while we had it busy-locked? */ if (ppsp[lcv]->flags & PG_WANTED) /* still holding obj lock */ wakeup(ppsp[lcv]); /* if page was released, release it. otherwise un-busy it */ if (ppsp[lcv]->flags & PG_RELEASED) { if (ppsp[lcv]->pqflags & PQ_ANON) { /* so that anfree will free */ ppsp[lcv]->flags &= ~(PG_BUSY); UVM_PAGE_OWN(ppsp[lcv], NULL); pmap_page_protect(ppsp[lcv], VM_PROT_NONE); simple_unlock(&ppsp[lcv]->uanon->an_lock); /* kills anon and frees pg */ uvm_anfree(ppsp[lcv]->uanon); continue; } /* * pgo_releasepg will dump the page for us */ #ifdef DIAGNOSTIC if (ppsp[lcv]->uobject->pgops->pgo_releasepg == NULL) panic("uvm_pager_dropcluster: no releasepg " "function"); #endif saved_uobj = ppsp[lcv]->uobject; obj_is_alive = saved_uobj->pgops->pgo_releasepg(ppsp[lcv], NULL); #ifdef DIAGNOSTIC /* for normal objects, "pg" is still PG_BUSY by us, * so obj can't die */ if (uobj && !obj_is_alive) panic("uvm_pager_dropcluster: object died " "with active page"); #endif /* only unlock the object if it is still alive... */ if (obj_is_alive && saved_uobj != uobj) simple_unlock(&saved_uobj->vmobjlock); /* * XXXCDC: suppose uobj died in the pgo_releasepg? * how pass that * info up to caller. we are currently ignoring it... */ continue; /* next page */ } else { ppsp[lcv]->flags &= ~(PG_BUSY|PG_WANTED); UVM_PAGE_OWN(ppsp[lcv], NULL); } /* * if we are operating on behalf of the pagedaemon and we * had a successful pageout update the page! */ if (flags & PGO_PDFREECLUST) { pmap_clear_reference(ppsp[lcv]); pmap_clear_modify(ppsp[lcv]); ppsp[lcv]->flags |= PG_CLEAN; } /* if anonymous cluster, unlock object and move on */ if (!uobj) { if (ppsp[lcv]->pqflags & PQ_ANON) simple_unlock(&ppsp[lcv]->uanon->an_lock); else simple_unlock(&ppsp[lcv]->uobject->vmobjlock); } } }