[PATCH] SwapMig: Switch error handling in migrate_pages to use -Exx
Use -Exxx instead of numeric return codes and cleanup the code in migrate_pages() using -Exx error codes. Consolidate successful migration handling Signed-off-by: Christoph Lameter <clameter@sgi.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
This commit is contained in:
parent
d498471133
commit
d0d963281c
1 changed files with 34 additions and 22 deletions
56
mm/vmscan.c
56
mm/vmscan.c
|
@ -606,10 +606,6 @@ int putback_lru_pages(struct list_head *l)
|
|||
/*
|
||||
* swapout a single page
|
||||
* page is locked upon entry, unlocked on exit
|
||||
*
|
||||
* return codes:
|
||||
* 0 = complete
|
||||
* 1 = retry
|
||||
*/
|
||||
static int swap_page(struct page *page)
|
||||
{
|
||||
|
@ -650,7 +646,7 @@ static int swap_page(struct page *page)
|
|||
unlock_page(page);
|
||||
|
||||
retry:
|
||||
return 1;
|
||||
return -EAGAIN;
|
||||
}
|
||||
/*
|
||||
* migrate_pages
|
||||
|
@ -669,6 +665,8 @@ static int swap_page(struct page *page)
|
|||
* is only swapping out pages and never touches the second
|
||||
* list. The direct migration patchset
|
||||
* extends this function to avoid the use of swap.
|
||||
*
|
||||
* Return: Number of pages not migrated when "to" ran empty.
|
||||
*/
|
||||
int migrate_pages(struct list_head *from, struct list_head *to,
|
||||
struct list_head *moved, struct list_head *failed)
|
||||
|
@ -679,6 +677,7 @@ int migrate_pages(struct list_head *from, struct list_head *to,
|
|||
struct page *page;
|
||||
struct page *page2;
|
||||
int swapwrite = current->flags & PF_SWAPWRITE;
|
||||
int rc;
|
||||
|
||||
if (!swapwrite)
|
||||
current->flags |= PF_SWAPWRITE;
|
||||
|
@ -689,22 +688,23 @@ int migrate_pages(struct list_head *from, struct list_head *to,
|
|||
list_for_each_entry_safe(page, page2, from, lru) {
|
||||
cond_resched();
|
||||
|
||||
if (page_count(page) == 1) {
|
||||
rc = 0;
|
||||
if (page_count(page) == 1)
|
||||
/* page was freed from under us. So we are done. */
|
||||
list_move(&page->lru, moved);
|
||||
continue;
|
||||
}
|
||||
goto next;
|
||||
|
||||
/*
|
||||
* Skip locked pages during the first two passes to give the
|
||||
* functions holding the lock time to release the page. Later we
|
||||
* use lock_page() to have a higher chance of acquiring the
|
||||
* lock.
|
||||
*/
|
||||
rc = -EAGAIN;
|
||||
if (pass > 2)
|
||||
lock_page(page);
|
||||
else
|
||||
if (TestSetPageLocked(page))
|
||||
goto retry_later;
|
||||
goto next;
|
||||
|
||||
/*
|
||||
* Only wait on writeback if we have already done a pass where
|
||||
|
@ -713,18 +713,19 @@ int migrate_pages(struct list_head *from, struct list_head *to,
|
|||
if (pass > 0) {
|
||||
wait_on_page_writeback(page);
|
||||
} else {
|
||||
if (PageWriteback(page)) {
|
||||
unlock_page(page);
|
||||
goto retry_later;
|
||||
}
|
||||
if (PageWriteback(page))
|
||||
goto unlock_page;
|
||||
}
|
||||
|
||||
/*
|
||||
* Anonymous pages must have swap cache references otherwise
|
||||
* the information contained in the page maps cannot be
|
||||
* preserved.
|
||||
*/
|
||||
if (PageAnon(page) && !PageSwapCache(page)) {
|
||||
if (!add_to_swap(page, GFP_KERNEL)) {
|
||||
unlock_page(page);
|
||||
list_move(&page->lru, failed);
|
||||
nr_failed++;
|
||||
continue;
|
||||
rc = -ENOMEM;
|
||||
goto unlock_page;
|
||||
}
|
||||
}
|
||||
|
||||
|
@ -732,12 +733,23 @@ int migrate_pages(struct list_head *from, struct list_head *to,
|
|||
* Page is properly locked and writeback is complete.
|
||||
* Try to migrate the page.
|
||||
*/
|
||||
if (!swap_page(page)) {
|
||||
rc = swap_page(page);
|
||||
goto next;
|
||||
|
||||
unlock_page:
|
||||
unlock_page(page);
|
||||
|
||||
next:
|
||||
if (rc == -EAGAIN) {
|
||||
retry++;
|
||||
} else if (rc) {
|
||||
/* Permanent failure */
|
||||
list_move(&page->lru, failed);
|
||||
nr_failed++;
|
||||
} else {
|
||||
/* Success */
|
||||
list_move(&page->lru, moved);
|
||||
continue;
|
||||
}
|
||||
retry_later:
|
||||
retry++;
|
||||
}
|
||||
if (retry && pass++ < 10)
|
||||
goto redo;
|
||||
|
|
Loading…
Reference in a new issue