Removal of PG_launder.
It's not obvious (to me) why this ever existed. If it's to prevent
deadlocks then I'd like to know who was performing __GFP_FS allocations
while holding a page lock?
But in 2.5, the only memory allocations which are performed when the
caller holds PG_writeback against an unsubmitted page are those which
occur inside submit_bh(). There will be no __GFS_FS allocations in
that call chain.
Removing PG_launder means that memory allocators can block on any
PageWriteback() page at all, which reduces the risk of very long list
walks inside pagemap_lru_lock in shrink_cache().
=====================================
--- 2.5.16/mm/vmscan.c~pg_launder Sun May 19 11:49:50 2002
+++ 2.5.16-akpm/mm/vmscan.c Sun May 19 11:49:50 2002
@@ -424,11 +424,10 @@ static int shrink_cache(int nr_pages, zo
goto page_mapped;
/*
- * The page is locked. IO in progress?
- * Move it to the back of the list.
+ * IO in progress? Leave it at the back of the list.
*/
if (unlikely(PageWriteback(page))) {
- if (PageLaunder(page) && (gfp_mask & __GFP_FS)) {
+ if (gfp_mask & __GFP_FS) {
page_cache_get(page);
spin_unlock(&pagemap_lru_lock);
wait_on_page_writeback(page);
--- 2.5.16/mm/page-writeback.c~pg_launder Sun May 19 11:49:50 2002
+++ 2.5.16-akpm/mm/page-writeback.c Sun May 19 11:49:50 2002
@@ -373,8 +373,6 @@ int generic_writeback_mapping(struct add
}
spin_unlock(&pagemap_lru_lock);
}
- if (current->flags & PF_MEMALLOC)
- SetPageLaunder(page);
err = writepage(page);
if (!ret)
ret = err;
--- 2.5.16/mm/shmem.c~pg_launder Sun May 19 11:49:50 2002
+++ 2.5.16-akpm/mm/shmem.c Sun May 19 11:49:50 2002
@@ -438,7 +438,8 @@ static int shmem_writepage(struct page *
if (!PageLocked(page))
BUG();
- if (!PageLaunder(page))
+
+ if (!(current->flags & PF_MEMALLOC))
return fail_writepage(page);
mapping = page->mapping;
--- 2.5.16/mm/filemap.c~pg_launder Sun May 19 11:49:50 2002
+++ 2.5.16-akpm/mm/filemap.c Sun May 19 11:49:50 2002
@@ -432,7 +432,7 @@ void invalidate_inode_pages2(struct addr
int fail_writepage(struct page *page)
{
/* Only activate on memory-pressure, not fsync.. */
- if (PageLaunder(page)) {
+ if (current->flags & PF_MEMALLOC) {
activate_page(page);
SetPageReferenced(page);
}
@@ -652,7 +652,6 @@ void unlock_page(struct page *page)
void end_page_writeback(struct page *page)
{
wait_queue_head_t *waitqueue = page_waitqueue(page);
- ClearPageLaunder(page);
smp_mb__before_clear_bit();
if (!TestClearPageWriteback(page))
BUG();
--- 2.5.16/include/linux/page-flags.h~pg_launder Sun May 19 11:49:50 2002
+++ 2.5.16-akpm/include/linux/page-flags.h Sun May 19 11:49:50 2002
@@ -62,9 +62,8 @@
#define PG_arch_1 10
#define PG_reserved 11
-#define PG_launder 12 /* written out by VM pressure.. */
-#define PG_private 13 /* Has something at ->private */
-#define PG_writeback 14 /* Page is under writeback */
+#define PG_private 12 /* Has something at ->private */
+#define PG_writeback 13 /* Page is under writeback */
/*
* Global page accounting. One instance per CPU.
@@ -172,10 +171,6 @@ extern void get_page_state(struct page_s
#define SetPageReserved(page) set_bit(PG_reserved, &(page)->flags)
#define ClearPageReserved(page) clear_bit(PG_reserved, &(page)->flags)
-#define PageLaunder(page) test_bit(PG_launder, &(page)->flags)
-#define SetPageLaunder(page) set_bit(PG_launder, &(page)->flags)
-#define ClearPageLaunder(page) clear_bit(PG_launder, &(page)->flags)
-
#define SetPagePrivate(page) set_bit(PG_private, &(page)->flags)
#define ClearPagePrivate(page) clear_bit(PG_private, &(page)->flags)
#define PagePrivate(page) test_bit(PG_private, &(page)->flags)
-
-
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This archive was generated by hypermail 2b29 : Thu May 23 2002 - 22:00:17 EST