Author: alc
Date: Sun Nov 6 02:03:27 2011
New Revision: 227127
URL: http://svn.freebsd.org/changeset/base/227127
Log:
Wake up the page daemon in vm_page_alloc_freelist() if it couldn't
allocate the requested page because too few pages are cached or free.
Document the VM_ALLOC_COUNT() option to vm_page_alloc() and
vm_page_alloc_freelist().
Make style changes to vm_page_alloc() and vm_page_alloc_freelist(),
such as using a variable name that more closely corresponds to the
comments.
Modified:
head/sys/vm/vm_page.c
Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c Sun Nov 6 00:44:40 2011 (r227126)
+++ head/sys/vm/vm_page.c Sun Nov 6 02:03:27 2011 (r227127)
@@ -1298,6 +1298,8 @@ vm_page_cache_transfer(vm_object_t orig_
* VM_ALLOC_INTERRUPT interrupt time request
*
* optional allocation flags:
+ * VM_ALLOC_COUNT(number) the number of additional pages that the caller
+ * intends to allocate
* VM_ALLOC_IFCACHED return page only if it is cached
* VM_ALLOC_IFNOTCACHED return NULL, do not reactivate if the page
* is cached
@@ -1315,27 +1317,26 @@ vm_page_alloc(vm_object_t object, vm_pin
struct vnode *vp = NULL;
vm_object_t m_object;
vm_page_t m;
- int flags, page_req;
+ int flags, req_class;
- if ((req & VM_ALLOC_NOOBJ) == 0) {
- KASSERT(object != NULL,
- ("vm_page_alloc: NULL object."));
+ KASSERT((object != NULL) == ((req & VM_ALLOC_NOOBJ) == 0),
+ ("vm_page_alloc: inconsistent object/req"));
+ if (object != NULL)
VM_OBJECT_LOCK_ASSERT(object, MA_OWNED);
- }
- page_req = req & VM_ALLOC_CLASS_MASK;
+ req_class = req & VM_ALLOC_CLASS_MASK;
/*
- * The pager is allowed to eat deeper into the free page list.
+ * The page daemon is allowed to dig deeper into the free page list.
*/
- if ((curproc == pageproc) && (page_req != VM_ALLOC_INTERRUPT))
- page_req = VM_ALLOC_SYSTEM;
+ if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
+ req_class = VM_ALLOC_SYSTEM;
mtx_lock(&vm_page_queue_free_mtx);
if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved ||
- (page_req == VM_ALLOC_SYSTEM &&
+ (req_class == VM_ALLOC_SYSTEM &&
cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) ||
- (page_req == VM_ALLOC_INTERRUPT &&
+ (req_class == VM_ALLOC_INTERRUPT &&
cnt.v_free_count + cnt.v_cache_count > 0)) {
/*
* Allocate from the free queue if the number of free pages
@@ -1383,7 +1384,7 @@ vm_page_alloc(vm_object_t object, vm_pin
*/
mtx_unlock(&vm_page_queue_free_mtx);
atomic_add_int(&vm_pageout_deficit,
- MAX((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
+ max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
pagedaemon_wakeup();
return (NULL);
}
@@ -1391,7 +1392,6 @@ vm_page_alloc(vm_object_t object, vm_pin
/*
* At this point we had better have found a good page.
*/
-
KASSERT(m != NULL, ("vm_page_alloc: missing page"));
KASSERT(m->queue == PQ_NONE,
("vm_page_alloc: page %p has unexpected queue %d", m, m->queue));
@@ -1403,6 +1403,8 @@ vm_page_alloc(vm_object_t object, vm_pin
("vm_page_alloc: page %p has unexpected memattr %d", m,
pmap_page_get_memattr(m)));
if ((m->flags & PG_CACHED) != 0) {
+ KASSERT((m->flags & PG_ZERO) == 0,
+ ("vm_page_alloc: cached page %p is PG_ZERO", m));
KASSERT(m->valid != 0,
("vm_page_alloc: cached page %p is invalid", m));
if (m->object == object && m->pindex == pindex)
@@ -1546,6 +1548,8 @@ vm_page_alloc_init(vm_page_t m)
* VM_ALLOC_INTERRUPT interrupt time request
*
* optional allocation flags:
+ * VM_ALLOC_COUNT(number) the number of additional pages that the caller
+ * intends to allocate
* VM_ALLOC_WIRED wire the allocated page
* VM_ALLOC_ZERO prefer a zeroed page
*
@@ -1557,20 +1561,32 @@ vm_page_alloc_freelist(int flind, int re
struct vnode *drop;
vm_page_t m;
u_int flags;
- int page_req;
+ int req_class;
+
+ req_class = req & VM_ALLOC_CLASS_MASK;
+
+ /*
+ * The page daemon is allowed to dig deeper into the free page list.
+ */
+ if (curproc == pageproc && req_class != VM_ALLOC_INTERRUPT)
+ req_class = VM_ALLOC_SYSTEM;
- m = NULL;
- page_req = req & VM_ALLOC_CLASS_MASK;
- mtx_lock(&vm_page_queue_free_mtx);
/*
* Do not allocate reserved pages unless the req has asked for it.
*/
+ mtx_lock(&vm_page_queue_free_mtx);
if (cnt.v_free_count + cnt.v_cache_count > cnt.v_free_reserved ||
- (page_req == VM_ALLOC_SYSTEM &&
+ (req_class == VM_ALLOC_SYSTEM &&
cnt.v_free_count + cnt.v_cache_count > cnt.v_interrupt_free_min) ||
- (page_req == VM_ALLOC_INTERRUPT &&
- cnt.v_free_count + cnt.v_cache_count > 0)) {
+ (req_class == VM_ALLOC_INTERRUPT &&
+ cnt.v_free_count + cnt.v_cache_count > 0))
m = vm_phys_alloc_freelist_pages(flind, VM_FREEPOOL_DIRECT, 0);
+ else {
+ mtx_unlock(&vm_page_queue_free_mtx);
+ atomic_add_int(&vm_pageout_deficit,
+ max((u_int)req >> VM_ALLOC_COUNT_SHIFT, 1));
+ pagedaemon_wakeup();
+ return (NULL);
}
if (m == NULL) {
mtx_unlock(&vm_page_queue_free_mtx);
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