/* $NetBSD: uvm_pager.c,v 1.48 2001/06/23 20:47:44 chs 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 */ #include "opt_uvmhist.h" /* * uvm_pager.c: generic functions used to assist the pagers. */ #include #include #include #include #include #include #define UVM_PAGER #include struct pool *uvm_aiobuf_pool; /* * list of uvm pagers in the system */ extern struct uvm_pagerops uvm_deviceops; extern struct uvm_pagerops uvm_vnodeops; extern struct uvm_pagerops ubc_pager; struct uvm_pagerops *uvmpagerops[] = { &aobj_pager, &uvm_deviceops, &uvm_vnodeops, &ubc_pager, }; /* * the pager map: provides KVA for I/O */ struct vm_map *pager_map; /* XXX */ struct simplelock pager_map_wanted_lock; boolean_t pager_map_wanted; /* locked by pager map */ static vaddr_t emergva; static boolean_t emerginuse; /* * 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; emergva = uvm_km_valloc(kernel_map, MAXBSIZE); emerginuse = 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, flags) struct vm_page **pps; int npages; int flags; { vsize_t size; vaddr_t kva; 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)", pps, npages,0,0); /* * 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: size = npages << PAGE_SHIFT; kva = 0; /* let system choose VA */ if (uvm_map(pager_map, &kva, size, NULL, UVM_UNKNOWN_OFFSET, 0, UVM_FLAG_NOMERGE) != 0) { if (curproc == uvm.pagedaemon_proc) { simple_lock(&pager_map_wanted_lock); if (emerginuse) { UVM_UNLOCK_AND_WAIT(&emergva, &pager_map_wanted_lock, FALSE, "emergva", 0); goto ReStart; } emerginuse = TRUE; simple_unlock(&pager_map_wanted_lock); kva = emergva; KASSERT(npages <= MAXBSIZE >> PAGE_SHIFT); goto enter; } if ((flags & UVMPAGER_MAPIN_WAITOK) == 0) { 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; } enter: /* got it */ for (cva = kva ; size != 0 ; size -= PAGE_SIZE, cva += PAGE_SIZE) { pp = *pps++; KASSERT(pp); KASSERT(pp->flags & PG_BUSY); pmap_enter(vm_map_pmap(pager_map), cva, VM_PAGE_TO_PHYS(pp), prot, PMAP_WIRED | ((pp->flags & PG_FAKE) ? prot : VM_PROT_READ)); } pmap_update(); 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; struct vm_map_entry *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. */ if (kva == emergva) { simple_lock(&pager_map_wanted_lock); emerginuse = FALSE; wakeup(&emergva); simple_unlock(&pager_map_wanted_lock); entries = NULL; goto remove; } vm_map_lock(pager_map); 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); remove: pmap_remove(pmap_kernel(), kva, kva + (npages << PAGE_SHIFT)); if (entries) uvm_unmap_detach(entries, 0); pmap_update(); 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, incr; 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! */ 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]. */ for (forward = 0 ; forward <= 1 ; forward++) { incr = forward ? PAGE_SIZE : -PAGE_SIZE; curoff = center->offset + incr; for ( ;(forward == 0 && curoff >= lo) || (forward && curoff < hi); curoff += incr) { pclust = uvm_pagelookup(uobj, curoff); /* lookup page */ if (pclust == NULL) { break; /* no page */ } if ((flags & PGO_DOACTCLUST) == 0) { /* dont want mapped pages at all */ break; } /* * get an up-to-date view of the "clean" bit. * note this isn't 100% accurate, but it doesn't * have to be. if it's not quite right, the * worst that happens is we don't cluster as * aggressively. we'll sync-it-for-sure before * we free the page, and clean it if necessary. */ 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)++; } } /* * 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: wait for i/o to complete * 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 error 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 == 0 AND async. 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 * an error, 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; boolean_t async = (flags & PGO_SYNCIO) == 0; struct vm_page **ppsp = *ppsp_ptr; UVMHIST_FUNC("uvm_pager_put"); UVMHIST_CALLED(ubchist); /* * 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); UVMHIST_LOG(ubchist, "put -> %d", result, 0,0,0); /* object is now unlocked */ } else { /* nothing locked */ result = uvm_swap_put(swblk, ppsp, *npages, flags); /* 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 == 0) { if (flags & PGO_PDFREECLUST && !async) { /* * drop cluster and relock object for sync i/o. */ 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 #3 */ } return (result); } /* * a pager error occured. * 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 hard failures on swap-backed pageouts with a "pg" * we need to clear pg's swslot since uvm_pager_dropcluster() * didn't do it and we aren't going to retry. */ if (uobj == NULL && pg != NULL && result != EAGAIN) { if (pg->pqflags & PQ_ANON) { simple_lock(&pg->uanon->an_lock); pg->uanon->an_swslot = 0; simple_unlock(&pg->uanon->an_lock); } else { simple_lock(&pg->uobject->vmobjlock); uao_set_swslot(pg->uobject, pg->offset >> PAGE_SHIFT, 0); simple_unlock(&pg->uobject->vmobjlock); } } if (result == EAGAIN) { /* * 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 occured (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++) { /* skip "pg" or empty slot */ if (ppsp[lcv] == pg || ppsp[lcv] == NULL) 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 */ saved_uobj = ppsp[lcv]->uobject; obj_is_alive = saved_uobj->pgops->pgo_releasepg(ppsp[lcv], NULL); /* for normal objects, "pg" is still PG_BUSY by us, * so obj can't die */ KASSERT(!uobj || obj_is_alive); /* 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|PG_FAKE); 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); } } } /* * interrupt-context iodone handler for nested i/o bufs. * * => must be at splbio(). */ void uvm_aio_biodone1(bp) struct buf *bp; { struct buf *mbp = bp->b_private; KASSERT(mbp != bp); if (bp->b_flags & B_ERROR) { mbp->b_flags |= B_ERROR; mbp->b_error = bp->b_error; } mbp->b_resid -= bp->b_bcount; pool_put(&bufpool, bp); if (mbp->b_resid == 0) { biodone(mbp); } } /* * interrupt-context iodone handler for single-buf i/os * or the top-level buf of a nested-buf i/o. * * => must be at splbio(). */ void uvm_aio_biodone(bp) struct buf *bp; { /* reset b_iodone for when this is a single-buf i/o. */ bp->b_iodone = uvm_aio_aiodone; simple_lock(&uvm.aiodoned_lock); /* locks uvm.aio_done */ TAILQ_INSERT_TAIL(&uvm.aio_done, bp, b_freelist); wakeup(&uvm.aiodoned); simple_unlock(&uvm.aiodoned_lock); } /* * uvm_aio_aiodone: do iodone processing for async i/os. * this should be called in thread context, not interrupt context. */ void uvm_aio_aiodone(bp) struct buf *bp; { int npages = bp->b_bufsize >> PAGE_SHIFT; struct vm_page *pg, *pgs[npages]; struct uvm_object *uobj; int s, i, error; boolean_t write, swap; UVMHIST_FUNC("uvm_aio_aiodone"); UVMHIST_CALLED(ubchist); UVMHIST_LOG(ubchist, "bp %p", bp, 0,0,0); error = (bp->b_flags & B_ERROR) ? (bp->b_error ? bp->b_error : EIO) : 0; write = (bp->b_flags & B_READ) == 0; /* XXXUBC B_NOCACHE is for swap pager, should be done differently */ if (write && !(bp->b_flags & B_NOCACHE) && bioops.io_pageiodone) { (*bioops.io_pageiodone)(bp); } uobj = NULL; for (i = 0; i < npages; i++) { pgs[i] = uvm_pageratop((vaddr_t)bp->b_data + (i << PAGE_SHIFT)); UVMHIST_LOG(ubchist, "pgs[%d] = %p", i, pgs[i],0,0); } uvm_pagermapout((vaddr_t)bp->b_data, npages); for (i = 0; i < npages; i++) { pg = pgs[i]; if (i == 0) { swap = (pg->pqflags & PQ_SWAPBACKED) != 0; if (!swap) { uobj = pg->uobject; simple_lock(&uobj->vmobjlock); } } KASSERT(swap || pg->uobject == uobj); if (swap) { if (pg->pqflags & PQ_ANON) { simple_lock(&pg->uanon->an_lock); } else { simple_lock(&pg->uobject->vmobjlock); } } /* * if this is a read and we got an error, mark the pages * PG_RELEASED so that uvm_page_unbusy() will free them. */ if (!write && error) { pg->flags |= PG_RELEASED; continue; } KASSERT(!write || (pgs[i]->flags & PG_FAKE) == 0); /* * if this is a read and the page is PG_FAKE, * or this was a successful write, * mark the page PG_CLEAN and not PG_FAKE. */ if ((pgs[i]->flags & PG_FAKE) || (write && error != ENOMEM)) { pmap_clear_reference(pgs[i]); pmap_clear_modify(pgs[i]); pgs[i]->flags |= PG_CLEAN; pgs[i]->flags &= ~PG_FAKE; } uvm_pageactivate(pg); if (swap) { if (pg->pqflags & PQ_ANON) { simple_unlock(&pg->uanon->an_lock); } else { simple_unlock(&pg->uobject->vmobjlock); } } } uvm_page_unbusy(pgs, npages); if (!swap) { simple_unlock(&uobj->vmobjlock); } s = splbio(); if (write && (bp->b_flags & B_AGE) != 0) { vwakeup(bp); } pool_put(&bufpool, bp); splx(s); }