Module Name: src
Committed By: ad
Date: Sun Dec 22 16:37:36 UTC 2019
Modified Files:
src/sys/uvm: uvm_page.c
Log Message:
uvm_pagealloc_strat(): Tweak the locking to allow for lazy dequeue of pages
in the pdpolicy code. This means taking pg->interlock if assigning to
an object. The remaining barrier to lazy dequeue is having a dedicated
TAILQ_ENTRY in the page (it's currently shared with the page allocator).
To generate a diff of this commit:
cvs rdiff -u -r1.211 -r1.212 src/sys/uvm/uvm_page.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/uvm/uvm_page.c
diff -u src/sys/uvm/uvm_page.c:1.211 src/sys/uvm/uvm_page.c:1.212
--- src/sys/uvm/uvm_page.c:1.211 Sat Dec 21 15:16:14 2019
+++ src/sys/uvm/uvm_page.c Sun Dec 22 16:37:36 2019
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_page.c,v 1.211 2019/12/21 15:16:14 ad Exp $ */
+/* $NetBSD: uvm_page.c,v 1.212 2019/12/22 16:37:36 ad Exp $ */
/*
* Copyright (c) 1997 Charles D. Cranor and Washington University.
@@ -66,7 +66,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.211 2019/12/21 15:16:14 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_page.c,v 1.212 2019/12/22 16:37:36 ad Exp $");
#include "opt_ddb.h"
#include "opt_uvm.h"
@@ -829,10 +829,6 @@ uvm_pagealloc_pgfl(struct uvm_cpu *ucpu,
LIST_REMOVE(pg, listq.list); /* per-cpu list */
uvmexp.free--;
- /* update zero'd page count */
- if (pg->flags & PG_ZERO)
- CPU_COUNT(CPU_COUNT_ZEROPAGES, -1);
-
if (color == trycolor)
CPU_COUNT(CPU_COUNT_COLORHIT, 1);
else {
@@ -996,34 +992,43 @@ uvm_pagealloc_strat(struct uvm_object *o
ucpu->page_idle_zero = vm_page_zero_enable;
}
}
+ if (pg->flags & PG_ZERO) {
+ CPU_COUNT(CPU_COUNT_ZEROPAGES, -1);
+ }
+ if (anon) {
+ CPU_COUNT(CPU_COUNT_ANONPAGES, 1);
+ }
KASSERT((pg->flags & ~(PG_ZERO|PG_FREE)) == 0);
- /*
- * For now check this - later on we may do lazy dequeue, but need
- * to get page.queue used only by the pagedaemon policy first.
- */
- KASSERT(!uvmpdpol_pageisqueued_p(pg));
+ /* mark the page as allocated and then drop uvm_fpageqlock. */
+ pg->flags &= ~PG_FREE;
+ mutex_spin_exit(&uvm_fpageqlock);
/*
- * assign the page to the object. we don't need to lock the page's
- * identity to do this, as the caller holds the objects locked, and
- * the page is not on any paging queues at this time.
+ * assign the page to the object. as the page was free, we know
+ * that pg->uobject and pg->uanon are NULL. we only need to take
+ * the page's interlock if we are changing the values.
*/
+ if (anon != NULL || obj != NULL) {
+ mutex_enter(&pg->interlock);
+ }
pg->offset = off;
pg->uobject = obj;
pg->uanon = anon;
KASSERT(uvm_page_locked_p(pg));
pg->flags = PG_BUSY|PG_CLEAN|PG_FAKE;
- mutex_spin_exit(&uvm_fpageqlock);
if (anon) {
anon->an_page = pg;
pg->flags |= PG_ANON;
- cpu_count(CPU_COUNT_ANONPAGES, 1);
+ mutex_exit(&pg->interlock);
} else if (obj) {
uvm_pageinsert_object(obj, pg);
+ mutex_exit(&pg->interlock);
error = uvm_pageinsert_tree(obj, pg);
if (error != 0) {
+ mutex_enter(&pg->interlock);
uvm_pageremove_object(obj, pg);
+ mutex_exit(&pg->interlock);
uvm_pagefree(pg);
return NULL;
}
