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reserve some pages for the kernel, and some more especially 

for the pagedaemon allocating from kmem_object.  this should
prevent from the pagedaemon running out of memory and deadlocking.
fix counting of wired pages.
add some debugging code to detect attempts to reference free vm_pages.
This commit is contained in:
chs 1998-02-07 02:34:08 +00:00
parent 249efd73a1
commit c2f8ffc062
1 changed files with 49 additions and 17 deletions
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66
sys/uvm/uvm_page.c
View File

@ -1,4 +1,4 @@
/* $NetBSD: uvm_page.c,v 1.2 1998/02/06 22:32:13 thorpej Exp $ */ /* $NetBSD: uvm_page.c,v 1.3 1998/02/07 02:34:08 chs Exp $ */
/* /*
* XXXCDC: "ROUGH DRAFT" QUALITY UVM PRE-RELEASE FILE! * XXXCDC: "ROUGH DRAFT" QUALITY UVM PRE-RELEASE FILE!
@ -335,6 +335,13 @@ vm_offset_t *kvm_startp, *kvm_endp;
simple_lock_init(&uvm.pagedaemon_lock); simple_lock_init(&uvm.pagedaemon_lock);
/*
* step 7: init reserve thresholds
* XXXCDC - values may need adjusting
*/
uvmexp.reserve_pagedaemon = 1;
uvmexp.reserve_kernel = 5;
/* /*
* done! * done!
*/ */
@ -789,7 +796,7 @@ vm_offset_t off;
struct vm_anon *anon; struct vm_anon *anon;
{ {
int s, nfree; int s;
struct vm_page *pg; struct vm_page *pg;
#ifdef DIAGNOSTIC #ifdef DIAGNOSTIC
@ -802,23 +809,9 @@ struct vm_anon *anon;
uvm_lock_fpageq(); /* lock free page queue */ uvm_lock_fpageq(); /* lock free page queue */
if ((pg = uvm.page_free.tqh_first) == NULL) {
uvm_unlock_fpageq();
splx(s);
/* XXX: not waking pagedaemon, ok to assume it is already going? */
return(NULL);
}
TAILQ_REMOVE(&uvm.page_free, pg, pageq);
nfree = --uvmexp.free;
uvm_unlock_fpageq(); /* unlock free page queue */
splx(s);
/* /*
* check to see if we need to generate some free pages waking * check to see if we need to generate some free pages waking
* the pagedaemon. * the pagedaemon.
* XXX: we read uvm.free without locking
*/ */
if (uvmexp.free < uvmexp.freemin || if (uvmexp.free < uvmexp.freemin ||
@ -827,6 +820,32 @@ struct vm_anon *anon;
thread_wakeup(&uvm.pagedaemon); thread_wakeup(&uvm.pagedaemon);
} }
/*
* fail if any of these conditions is true:
* [1] there really are no free pages, or
* [2] only kernel "reserved" pages remain and
* the page isn't being allocated to a kernel object.
* [3] only pagedaemon "reserved" pages remain and
* the requestor isn't the pagedaemon.
*/
pg = uvm.page_free.tqh_first;
if (pg == NULL ||
(uvmexp.free <= uvmexp.reserve_kernel &&
!(obj && obj->uo_refs == UVM_OBJ_KERN)) ||
(uvmexp.free <= uvmexp.reserve_pagedaemon &&
!(obj == uvmexp.kmem_object && curproc == uvm.pagedaemon_proc))) {
uvm_unlock_fpageq();
splx(s);
return(NULL);
}
TAILQ_REMOVE(&uvm.page_free, pg, pageq);
uvmexp.free--;
uvm_unlock_fpageq(); /* unlock free page queue */
splx(s);
pg->offset = off; pg->offset = off;
pg->uobject = obj; pg->uobject = obj;
pg->uanon = anon; pg->uanon = anon;
@ -977,6 +996,15 @@ struct vm_page *pg;
uvmexp.inactive--; uvmexp.inactive--;
} }
/*
* if the page was wired, unwire it now.
*/
if (pg->wire_count)
{
pg->wire_count = 0;
uvmexp.wired--;
}
/* /*
* and put on free queue * and put on free queue
*/ */
@ -985,10 +1013,14 @@ struct vm_page *pg;
uvm_lock_fpageq(); uvm_lock_fpageq();
TAILQ_INSERT_TAIL(&uvm.page_free, pg, pageq); TAILQ_INSERT_TAIL(&uvm.page_free, pg, pageq);
pg->pqflags = PQ_FREE; pg->pqflags = PQ_FREE;
#ifdef DEBUG
pg->uobject = (void *)0xdeadbeef;
pg->offset = 0xdeadbeef;
pg->uanon = (void *)0xdeadbeef;
#endif
uvmexp.free++; uvmexp.free++;
uvm_unlock_fpageq(); uvm_unlock_fpageq();
splx(s); splx(s);
} }
#if defined(UVM_PAGE_TRKOWN) #if defined(UVM_PAGE_TRKOWN)