Author: alc
Date: Mon Oct 29 06:15:04 2012
New Revision: 242300
URL: http://svn.freebsd.org/changeset/base/242300
Log:
Replace the page hold queue, PQ_HOLD, by a new page flag, PG_UNHOLDFREE,
because the queue itself serves no purpose. When a held page is freed,
inserting the page into the hold queue has the side effect of setting the
page's "queue" field to PQ_HOLD. Later, when the page is unheld, it will
be freed because the "queue" field is PQ_HOLD. In other words, PQ_HOLD is
used as a flag, not a queue. So, this change replaces it with a flag.
To accomodate the new page flag, make the page's "flags" field wider and
"oflags" field narrower.
Reviewed by: kib
Modified:
head/sys/vm/vm_page.c
head/sys/vm/vm_page.h
Modified: head/sys/vm/vm_page.c
==============================================================================
--- head/sys/vm/vm_page.c Mon Oct 29 04:51:51 2012 (r242299)
+++ head/sys/vm/vm_page.c Mon Oct 29 06:15:04 2012 (r242300)
@@ -308,7 +308,6 @@ vm_page_startup(vm_offset_t vaddr)
TAILQ_INIT(&vm_page_queues[i].pl);
vm_page_queues[PQ_INACTIVE].cnt = &cnt.v_inactive_count;
vm_page_queues[PQ_ACTIVE].cnt = &cnt.v_active_count;
- vm_page_queues[PQ_HOLD].cnt = &cnt.v_active_count;
/*
* Allocate memory for use when boot strapping the kernel memory
@@ -540,7 +539,7 @@ vm_page_unhold(vm_page_t mem)
vm_page_lock_assert(mem, MA_OWNED);
--mem->hold_count;
KASSERT(mem->hold_count >= 0, ("vm_page_unhold: hold count < 0!!!"));
- if (mem->hold_count == 0 && mem->queue == PQ_HOLD)
+ if (mem->hold_count == 0 && (mem->flags & PG_UNHOLDFREE) != 0)
vm_page_free_toq(mem);
}
@@ -2042,9 +2041,9 @@ vm_page_free_toq(vm_page_t m)
panic("vm_page_free: freeing wired page %p", m);
if (m->hold_count != 0) {
m->flags &= ~PG_ZERO;
- vm_page_lock_queues();
- vm_page_enqueue(PQ_HOLD, m);
- vm_page_unlock_queues();
+ KASSERT((m->flags & PG_UNHOLDFREE) == 0,
+ ("vm_page_free: freeing PG_UNHOLDFREE page %p", m));
+ m->flags |= PG_UNHOLDFREE;
} else {
/*
* Restore the default memory attribute to the page.
Modified: head/sys/vm/vm_page.h
==============================================================================
--- head/sys/vm/vm_page.h Mon Oct 29 04:51:51 2012 (r242299)
+++ head/sys/vm/vm_page.h Mon Oct 29 06:15:04 2012 (r242300)
@@ -145,8 +145,8 @@ struct vm_page {
u_short cow; /* page cow mapping count (P) */
u_int wire_count; /* wired down maps refs (P) */
uint8_t aflags; /* access is atomic */
- uint8_t flags; /* see below, often immutable after
alloc */
- u_short oflags; /* page flags (O) */
+ uint8_t oflags; /* page VPO_* flags (O) */
+ uint16_t flags; /* page PG_* flags (P) */
u_char act_count; /* page usage count (O) */
u_char busy; /* page busy count (O) */
/* NOTE that these must support one bit per DEV_BSIZE in a page!!! */
@@ -169,17 +169,16 @@ struct vm_page {
* mappings, and such pages are also not on any PQ queue.
*
*/
-#define VPO_BUSY 0x0001 /* page is in transit */
-#define VPO_WANTED 0x0002 /* someone is waiting for page */
-#define VPO_UNMANAGED 0x0004 /* No PV management for page */
-#define VPO_SWAPINPROG 0x0200 /* swap I/O in progress on page */
-#define VPO_NOSYNC 0x0400 /* do not collect for syncer */
+#define VPO_BUSY 0x01 /* page is in transit */
+#define VPO_WANTED 0x02 /* someone is waiting for page
*/
+#define VPO_UNMANAGED 0x04 /* no PV management for page */
+#define VPO_SWAPINPROG 0x08 /* swap I/O in progress on page
*/
+#define VPO_NOSYNC 0x10 /* do not collect for syncer */
#define PQ_NONE 255
#define PQ_INACTIVE 0
#define PQ_ACTIVE 1
-#define PQ_HOLD 2
-#define PQ_COUNT 3
+#define PQ_COUNT 2
struct vpgqueues {
struct pglist pl;
@@ -263,14 +262,15 @@ extern struct vpglocks pa_lock[];
* Page flags. If changed at any other time than page allocation or
* freeing, the modification must be protected by the vm_page lock.
*/
-#define PG_CACHED 0x01 /* page is cached */
-#define PG_FREE 0x02 /* page is free */
-#define PG_FICTITIOUS 0x04 /* physical page doesn't exist
*/
-#define PG_ZERO 0x08 /* page is zeroed */
-#define PG_MARKER 0x10 /* special queue marker page */
-#define PG_SLAB 0x20 /* object pointer is actually a
slab */
-#define PG_WINATCFLS 0x40 /* flush dirty page on inactive
q */
-#define PG_NODUMP 0x80 /* don't include this page in a
dump */
+#define PG_CACHED 0x0001 /* page is cached */
+#define PG_FREE 0x0002 /* page is free */
+#define PG_FICTITIOUS 0x0004 /* physical page doesn't exist
*/
+#define PG_ZERO 0x0008 /* page is zeroed */
+#define PG_MARKER 0x0010 /* special queue marker page */
+#define PG_SLAB 0x0020 /* object pointer is actually a
slab */
+#define PG_WINATCFLS 0x0040 /* flush dirty page on inactive
q */
+#define PG_NODUMP 0x0080 /* don't include this page in a
dump */
+#define PG_UNHOLDFREE 0x0100 /* delayed free of a held page
*/
/*
* Misc constants.
_______________________________________________
svn-src-head@freebsd.org mailing list
http://lists.freebsd.org/mailman/listinfo/svn-src-head
To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
