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Add support for the VM_ALLOC_COUNT() hint to vm_page_alloc(). Consequently,

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the maintenance of vm_pageout_deficit can be localized to just two places:
vm_page_alloc() and vm_pageout_scan().

This change also corrects an off-by-one error in the maintenance of
vm_pageout_deficit.  Historically, the buffer cache functions, allocbuf()
and vm_hold_load_pages(), have not taken into account that vm_page_alloc()
already increments vm_pageout_deficit by one.

Reviewed by:	kib
This commit is contained in:
Alan Cox 2010-07-09 19:38:30 +00:00
parent c8ed14e2d8
commit b99348e5ea
3 changed files with 5 additions and 10 deletions
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5
sys/kern/vfs_bio.c
View File

@ -3752,10 +3752,9 @@ vm_hold_load_pages(struct buf *bp, vm_offset_t from, vm_offset_t to)
* process we are.
*/
p = vm_page_alloc(NULL, pg >> PAGE_SHIFT, VM_ALLOC_NOOBJ |
VM_ALLOC_SYSTEM | VM_ALLOC_WIRED);
VM_ALLOC_SYSTEM | VM_ALLOC_WIRED |
VM_ALLOC_COUNT((to - pg) >> PAGE_SHIFT));
if (!p) {
atomic_add_int(&vm_pageout_deficit,
(to - pg) >> PAGE_SHIFT);
VM_WAIT;
goto tryagain;
}

9
sys/vm/vm_page.c
View File

@ -1264,7 +1264,8 @@ vm_page_alloc(vm_object_t object, vm_pindex_t pindex, int req)
* Not allocatable, give up.
*/
mtx_unlock(&vm_page_queue_free_mtx);
atomic_add_int(&vm_pageout_deficit, 1);
atomic_add_int(&vm_pageout_deficit,
MAX((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
pagedaemon_wakeup();
return (NULL);
}
@ -2041,7 +2042,6 @@ vm_page_t
vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
{
vm_page_t m;
u_int count;
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
KASSERT((allocflags & VM_ALLOC_RETRY) != 0,
@ -2071,12 +2071,9 @@ vm_page_grab(vm_object_t object, vm_pindex_t pindex, int allocflags)
}
}
m = vm_page_alloc(object, pindex, allocflags & ~(VM_ALLOC_RETRY |
VM_ALLOC_IGN_SBUSY | VM_ALLOC_COUNT_MASK));
VM_ALLOC_IGN_SBUSY));
if (m == NULL) {
VM_OBJECT_UNLOCK(object);
count = (u_int)allocflags >> VM_ALLOC_COUNT_SHIFT;
if (count > 0)
atomic_add_int(&vm_pageout_deficit, count);
VM_WAIT;
VM_OBJECT_LOCK(object);
goto retrylookup;

1
sys/vm/vm_page.h
View File

@ -321,7 +321,6 @@ extern struct vpglocks vm_page_queue_lock;
#define VM_ALLOC_COUNT_SHIFT 16
#define VM_ALLOC_COUNT(count) ((count) << VM_ALLOC_COUNT_SHIFT)
#define VM_ALLOC_COUNT_MASK VM_ALLOC_COUNT(0xffff)
void vm_page_flag_set(vm_page_t m, unsigned short bits);
void vm_page_flag_clear(vm_page_t m, unsigned short bits);