NetBSD/sys/uvm/uvm_pager.c

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/* $NetBSD: uvm_pager.c,v 1.15 1999/03/25 18:48:55 mrg 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.
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*
* from: Id: uvm_pager.c,v 1.1.2.23 1998/02/02 20:38:06 chuck Exp
*/
#include "opt_uvmhist.h"
#include "opt_pmap_new.h"
/*
* uvm_pager.c: generic functions used to assist the pagers.
*/
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/proc.h>
#include <sys/malloc.h>
#include <vm/vm.h>
#include <vm/vm_page.h>
#include <vm/vm_kern.h>
#define UVM_PAGER
#include <uvm/uvm.h>
/*
* list of uvm pagers in the system
*/
extern struct uvm_pagerops aobj_pager;
extern struct uvm_pagerops uvm_deviceops;
extern struct uvm_pagerops uvm_vnodeops;
struct uvm_pagerops *uvmpagerops[] = {
&aobj_pager,
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&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)
*/
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void
uvm_pager_init()
{
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int lcv;
/*
* init pager map
*/
pager_map = uvm_km_suballoc(kernel_map, &uvm.pager_sva, &uvm.pager_eva,
PAGER_MAP_SIZE, FALSE, 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
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uvm_pagermapin(pps, npages, aiop, waitf)
struct vm_page **pps;
int npages;
struct uvm_aiodesc **aiop; /* OUT */
int waitf;
{
vsize_t size;
vaddr_t kva;
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struct uvm_aiodesc *aio;
#if !defined(PMAP_NEW)
vaddr_t cva;
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struct vm_page *pp;
#endif
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UVMHIST_FUNC("uvm_pagermapin"); UVMHIST_CALLED(maphist);
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UVMHIST_LOG(maphist,"(pps=0x%x, npages=%d, aiop=0x%x, waitf=%d)",
pps, npages, aiop, waitf);
ReStart:
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if (aiop) {
MALLOC(aio, struct uvm_aiodesc *, sizeof(*aio), M_TEMP, waitf);
if (aio == NULL)
return(0);
*aiop = aio;
} else {
aio = NULL;
}
size = npages << PAGE_SHIFT;
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kva = NULL; /* let system choose VA */
if (uvm_map(pager_map, &kva, size, NULL,
UVM_UNKNOWN_OFFSET, UVM_FLAG_NOMERGE) != KERN_SUCCESS) {
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if (waitf == M_NOWAIT) {
if (aio)
FREE(aio, M_TEMP);
UVMHIST_LOG(maphist,"<- NOWAIT failed", 0,0,0,0);
return(NULL);
}
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;
}
#if defined(PMAP_NEW)
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/*
* XXX: (ab)using the pmap module to store state info for us.
* (pmap stores the PAs... we fetch them back later and convert back
* to pages with PHYS_TO_VM_PAGE).
*/
pmap_kenter_pgs(kva, pps, npages);
#else /* PMAP_NEW */
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/* got it */
for (cva = kva ; size != 0 ; size -= PAGE_SIZE, cva += PAGE_SIZE) {
pp = *pps++;
#ifdef DEBUG
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if ((pp->flags & PG_BUSY) == 0)
panic("uvm_pagermapin: page not busy");
#endif
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pmap_enter(vm_map_pmap(pager_map), cva, VM_PAGE_TO_PHYS(pp),
VM_PROT_DEFAULT, TRUE);
}
#endif /* PMAP_NEW */
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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).
*/
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void
uvm_pagermapout(kva, npages)
vaddr_t kva;
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int npages;
{
vsize_t size = npages << PAGE_SHIFT;
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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);
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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.
*/
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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 */
vaddr_t mlo, mhi; /* IN (if !PGO_ALLPAGES) */
{
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struct vm_page **ppsp, *pclust;
vaddr_t lo, hi, curoff;
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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
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printf("uvm_mk_pcluster: provided page array too small (fixed)\n");
#endif
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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;
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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);
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for ( ;(forward == 0 && curoff >= lo) ||
(forward && curoff < hi);
curoff += (forward ? 1 : -1) << PAGE_SHIFT) {
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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(PMAP_PGARG(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(PMAP_PGARG(pclust), VM_PROT_READ);
if (!forward) {
ppsp--; /* back up one page */
*ppsp = pclust;
} else {
/* move forward one page */
ppsp[*npages] = pclust;
}
*npages = *npages + 1;
}
}
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/*
* done! return the cluster array to the caller!!!
*/
UVMHIST_LOG(maphist, "<- done",0,0,0,0);
return(ppsp);
}
/*
* uvm_shareprot: generic share protect routine
*
* => caller must lock map entry's map
* => caller must lock object pointed to by map entry
*/
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void
uvm_shareprot(entry, prot)
vm_map_entry_t entry;
vm_prot_t prot;
{
struct uvm_object *uobj = entry->object.uvm_obj;
struct vm_page *pp;
vaddr_t start, stop;
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UVMHIST_FUNC("uvm_shareprot"); UVMHIST_CALLED(maphist);
if (UVM_ET_ISSUBMAP(entry))
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panic("uvm_shareprot: non-object attached");
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start = entry->offset;
stop = start + (entry->end - entry->start);
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/*
* traverse list of pages in object. if page in range, pmap_prot it
*/
for (pp = uobj->memq.tqh_first ; pp != NULL ; pp = pp->listq.tqe_next) {
if (pp->offset >= start && pp->offset < stop)
pmap_page_protect(PMAP_PGARG(pp), prot);
}
UVMHIST_LOG(maphist, "<- done",0,0,0,0);
}
/*
* 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).
*/
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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 */
vaddr_t start, stop; /* IN, IN */
{
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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;
}
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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:
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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, 0);
/* if (uobj): object still locked, as per
* return-state item #3 */
}
return (result);
}
/*
* a pager error occured. if we have clustered, we drop the
* cluster and try again.
*/
if (*npages > 1 || pg == NULL) {
if (uobj)
simple_lock(&uobj->vmobjlock);
uvm_pager_dropcluster(uobj, pg, ppsp, npages, PGO_REALLOCSWAP,
swblk);
if (pg != NULL)
goto ReTry;
}
/*
* 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, swblk)
struct uvm_object *uobj; /* IN */
struct vm_page *pg, **ppsp; /* IN, IN/OUT */
int *npages; /* IN/OUT */
int flags;
int swblk; /* valid if (uobj == NULL && PGO_REALLOCSWAP) */
{
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int lcv;
boolean_t obj_is_alive;
struct uvm_object *saved_uobj;
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/*
* if we need to reallocate swap space for the cluster we are dropping
* (true if swap-backed and PGO_REALLOCSWAP) then free the old
* allocation now. save a block for "pg" if it is non-NULL.
*
* note that we will zap the object's pointer to swap in the "for" loop
* below...
*/
if (uobj == NULL && (flags & PGO_REALLOCSWAP)) {
if (pg)
uvm_swap_free(swblk + 1, *npages - 1);
else
uvm_swap_free(swblk, *npages);
}
/*
* drop all pages but "pg"
*/
for (lcv = 0 ; lcv < *npages ; lcv++) {
if (ppsp[lcv] == pg) /* skip "pg" */
continue;
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/*
* 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);
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}
}
/* did someone want the page while we had it busy-locked? */
if (ppsp[lcv]->flags & PG_WANTED)
/* still holding obj lock */
thread_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(PMAP_PGARG(ppsp[lcv]),
VM_PROT_NONE); /* be safe */
simple_unlock(&ppsp[lcv]->uanon->an_lock);
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/* kills anon and frees pg */
uvm_anfree(ppsp[lcv]->uanon);
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continue;
}
/*
* pgo_releasepg will dump the page for us
*/
#ifdef DIAGNOSTIC
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if (ppsp[lcv]->uobject->pgops->pgo_releasepg == NULL)
panic("uvm_pager_dropcluster: no releasepg "
"function");
#endif
saved_uobj = ppsp[lcv]->uobject;
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obj_is_alive =
saved_uobj->pgops->pgo_releasepg(ppsp[lcv], NULL);
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#ifdef DIAGNOSTIC
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/* 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 */
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} 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) {
/* XXX: with PMAP_NEW ref should already be clear,
* but don't trust! */
pmap_clear_reference(PMAP_PGARG(ppsp[lcv]));
pmap_clear_modify(PMAP_PGARG(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);
}
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}
/*
* drop to a cluster of 1 page ("pg") if requested
*/
if (pg && (flags & PGO_PDFREECLUST) == 0) {
/*
* if we are not a successful pageout, we make a 1 page cluster.
*/
ppsp[0] = pg;
*npages = 1;
/*
* assign new swap block to new cluster, if anon backed
*/
if (uobj == NULL && (flags & PGO_REALLOCSWAP)) {
if (pg->pqflags & PQ_ANON) {
simple_lock(&pg->uanon->an_lock);
pg->uanon->an_swslot = swblk; /* reassign */
simple_unlock(&pg->uanon->an_lock);
} else {
simple_lock(&pg->uobject->vmobjlock);
uao_set_swslot(pg->uobject,
pg->offset >> PAGE_SHIFT, swblk);
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simple_unlock(&pg->uobject->vmobjlock);
}
}
}
}