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Make vm_contig_grow_cache() extern, and use it when vm_phys_alloc_contig()

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fails to allocate MIPS page table pages.  The current usage of VM_WAIT in
case of vm_phys_alloc_contig() failure is not correct, because:

"There is no guarantee that any of the available free (or cached) pages
after the VM_WAIT will fall within the range of suitable physical
addresses.  Every time this function sleeps and a single page is freed
(or cached) by someone else, this function will be reawakened.  With
a little bad luck, you could spin indefinitely."

We also add low and high parameters to vm_contig_grow_cache() and
vm_contig_launder() so that we restrict vm_contig_launder() to the range
of pages we are interested in.

Reported by: alc

Reviewed by:	alc
Approved by:	rrs (mentor)
This commit is contained in:
Jayachandran C. 2010-06-04 06:35:36 +00:00
parent 28c0f4ec05
commit 17dca144a2
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=208794
3 changed files with 24 additions and 16 deletions
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18
sys/mips/mips/pmap.c
View File

@ -967,19 +967,23 @@ pmap_ptpgzone_allocf(uma_zone_t zone, int bytes, u_int8_t *flags, int wait)
{
vm_page_t m;
vm_paddr_t paddr;
int tries;
KASSERT(bytes == PAGE_SIZE,
("pmap_ptpgzone_allocf: invalid allocation size %d", bytes));
*flags = UMA_SLAB_PRIV;
for (;;) {
m = vm_phys_alloc_contig(1, 0, MIPS_KSEG0_LARGEST_PHYS,
PAGE_SIZE, PAGE_SIZE);
if (m != NULL)
break;
if ((wait & M_WAITOK) == 0)
tries = 0;
retry:
m = vm_phys_alloc_contig(1, 0, MIPS_KSEG0_LARGEST_PHYS,
PAGE_SIZE, PAGE_SIZE);
if (m == NULL) {
if (tries < ((wait & M_NOWAIT) != 0 ? 1 : 3)) {
vm_contig_grow_cache(tries, 0, MIPS_KSEG0_LARGEST_PHYS);
tries++;
goto retry;
} else
return (NULL);
VM_WAIT;
}
paddr = VM_PAGE_TO_PHYS(m);

21
sys/vm/vm_contig.c
View File

@ -87,8 +87,6 @@ __FBSDID("$FreeBSD$");
#include <vm/vm_phys.h>
#include <vm/vm_extern.h>
static void vm_contig_grow_cache(int tries);
static int
vm_contig_launder_page(vm_page_t m, vm_page_t *next)
{
@ -157,9 +155,10 @@ vm_contig_launder_page(vm_page_t m, vm_page_t *next)
}
static int
vm_contig_launder(int queue)
vm_contig_launder(int queue, vm_paddr_t low, vm_paddr_t high)
{
vm_page_t m, next;
vm_paddr_t pa;
int error;
TAILQ_FOREACH_SAFE(m, &vm_page_queues[queue].pl, pageq, next) {
@ -168,6 +167,10 @@ vm_contig_launder(int queue)
if ((m->flags & PG_MARKER) != 0)
continue;
pa = VM_PAGE_TO_PHYS(m);
if (pa < low || pa + PAGE_SIZE > high)
continue;
if (!vm_pageout_page_lock(m, &next)) {
vm_page_unlock(m);
continue;
@ -203,8 +206,8 @@ vm_page_release_contig(vm_page_t m, vm_pindex_t count)
/*
* Increase the number of cached pages.
*/
static void
vm_contig_grow_cache(int tries)
void
vm_contig_grow_cache(int tries, vm_paddr_t low, vm_paddr_t high)
{
int actl, actmax, inactl, inactmax;
@ -214,11 +217,11 @@ vm_contig_grow_cache(int tries)
actl = 0;
actmax = tries < 2 ? 0 : cnt.v_active_count;
again:
if (inactl < inactmax && vm_contig_launder(PQ_INACTIVE)) {
if (inactl < inactmax && vm_contig_launder(PQ_INACTIVE, low, high)) {
inactl++;
goto again;
}
if (actl < actmax && vm_contig_launder(PQ_ACTIVE)) {
if (actl < actmax && vm_contig_launder(PQ_ACTIVE, low, high)) {
actl++;
goto again;
}
@ -261,7 +264,7 @@ kmem_alloc_attr(vm_map_t map, vm_size_t size, int flags, vm_paddr_t low,
if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) {
VM_OBJECT_UNLOCK(object);
vm_map_unlock(map);
vm_contig_grow_cache(tries);
vm_contig_grow_cache(tries, low, high);
vm_map_lock(map);
VM_OBJECT_LOCK(object);
goto retry;
@ -368,7 +371,7 @@ kmem_alloc_contig(vm_map_t map, vm_size_t size, int flags, vm_paddr_t low,
pages = vm_phys_alloc_contig(npgs, low, high, alignment, boundary);
if (pages == NULL) {
if (tries < ((flags & M_NOWAIT) != 0 ? 1 : 3)) {
vm_contig_grow_cache(tries);
vm_contig_grow_cache(tries, low, high);
tries++;
goto retry;
}

1
sys/vm/vm_pageout.h
View File

@ -105,5 +105,6 @@ boolean_t vm_pageout_fallback_object_lock(vm_page_t, vm_page_t *);
int vm_pageout_flush(vm_page_t *, int, int);
void vm_pageout_oom(int shortage);
boolean_t vm_pageout_page_lock(vm_page_t, vm_page_t *);
void vm_contig_grow_cache(int, vm_paddr_t, vm_paddr_t);
#endif
#endif /* _VM_VM_PAGEOUT_H_ */