Module Name: src
Committed By: ad
Date: Fri May 15 22:27:04 UTC 2020
Modified Files:
src/sys/uvm: uvm_aobj.c
Log Message:
PR kern/55268: tmpfs is slow
uao_get(): in the PGO_LOCKED case, we're okay to allocate a new page as long
as the caller holds a write lock. PGO_NOBUSY doesn't put a stop to that.
To generate a diff of this commit:
cvs rdiff -u -r1.139 -r1.140 src/sys/uvm/uvm_aobj.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_aobj.c
diff -u src/sys/uvm/uvm_aobj.c:1.139 src/sys/uvm/uvm_aobj.c:1.140
--- src/sys/uvm/uvm_aobj.c:1.139 Sun Mar 22 18:32:42 2020
+++ src/sys/uvm/uvm_aobj.c Fri May 15 22:27:04 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: uvm_aobj.c,v 1.139 2020/03/22 18:32:42 ad Exp $ */
+/* $NetBSD: uvm_aobj.c,v 1.140 2020/05/15 22:27:04 ad Exp $ */
/*
* Copyright (c) 1998 Chuck Silvers, Charles D. Cranor and
@@ -38,7 +38,7 @@
*/
#include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: uvm_aobj.c,v 1.139 2020/03/22 18:32:42 ad Exp $");
+__KERNEL_RCSID(0, "$NetBSD: uvm_aobj.c,v 1.140 2020/05/15 22:27:04 ad Exp $");
#ifdef _KERNEL_OPT
#include "opt_uvmhist.h"
@@ -827,6 +827,7 @@ uao_get(struct uvm_object *uobj, voff_t
*/
if (flags & PGO_LOCKED) {
+ krw_t lktype = rw_lock_op(uobj->vmobjlock);
/*
* step 1a: get pages that are already resident. only do
@@ -845,11 +846,11 @@ uao_get(struct uvm_object *uobj, voff_t
/*
* if page is new, attempt to allocate the page,
- * zero-fill'd. we can only do this if busying
- * pages, as otherwise the object is read locked.
+ * zero-fill'd. we can only do this if the caller
+ * holds a write lock.
*/
- if ((flags & PGO_NOBUSY) == 0 && ptmp == NULL &&
+ if (ptmp == NULL && lktype == RW_WRITER &&
uao_find_swslot(uobj,
current_offset >> PAGE_SHIFT) == 0) {
ptmp = uao_pagealloc(uobj, current_offset,
@@ -859,6 +860,8 @@ uao_get(struct uvm_object *uobj, voff_t
ptmp->flags &= ~(PG_FAKE);
uvm_pagemarkdirty(ptmp,
UVM_PAGE_STATUS_UNKNOWN);
+ if ((flags & PGO_NOBUSY) != 0)
+ ptmp->flags &= ~PG_BUSY;
goto gotpage;
}
}
