The following patch sets the ref count on all pages of an
allocation. This allows an allocation with order>0 to be freed
via individual __free_page() calls within vfree().
This is important on non cache coherent processors which
have a pci_alloc_consistent/consistent_alloc() implementation
that involves creating a vmalloc area cache inhibited mapping
of allocated pages.
Because of this implementation, the implementation
of pci_free_consistent/consistent_free is done via
a vfree(). Without this patch only the first page
of the allocated memory is freed since successive pages
all have ref counts of zero.
-Matt
===== mm/page_alloc.c 1.56 vs edited =====
--- 1.56/mm/page_alloc.c Tue Aug 20 04:39:48 2002
+++ edited/mm/page_alloc.c Tue Nov 26 12:03:38 2002
@@ -203,6 +203,7 @@
struct list_head *head, *curr;
unsigned long flags;
struct page *page;
+ int i;
spin_lock_irqsave(&zone->lock, flags);
do {
@@ -224,7 +225,10 @@
page = expand(zone, page, index, order, curr_order, area);
spin_unlock_irqrestore(&zone->lock, flags);
- set_page_count(page, 1);
+ /* Set ref count on all pages */
+ for (i = 0; i < (1 << order); i++)
+ set_page_count(page+i, 1);
+
if (BAD_RANGE(zone,page))
BUG();
if (PageLRU(page))
-- Matt Porter porter@cox.net This is Linux Country. On a quiet night, you can hear Windows reboot. -- Matt Porter porter@cox.net This is Linux Country. On a quiet night, you can hear Windows reboot. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sat Nov 30 2002 - 22:00:15 EST