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-rw-r--r--mm/vmscan.c21
1 files changed, 5 insertions, 16 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 10f9c59..5c59665 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -495,15 +495,6 @@ static pageout_t pageout(struct page *page, struct address_space *mapping,
return PAGE_ACTIVATE;
}
- /*
- * Wait on writeback if requested to. This happens when
- * direct reclaiming a large contiguous area and the
- * first attempt to free a range of pages fails.
- */
- if (PageWriteback(page) &&
- (sc->reclaim_mode & RECLAIM_MODE_SYNC))
- wait_on_page_writeback(page);
-
if (!PageWriteback(page)) {
/* synchronous write or broken a_ops? */
ClearPageReclaim(page);
@@ -804,12 +795,10 @@ static unsigned long shrink_page_list(struct list_head *page_list,
if (PageWriteback(page)) {
/*
- * Synchronous reclaim is performed in two passes,
- * first an asynchronous pass over the list to
- * start parallel writeback, and a second synchronous
- * pass to wait for the IO to complete. Wait here
- * for any page for which writeback has already
- * started.
+ * Synchronous reclaim cannot queue pages for
+ * writeback due to the possibility of stack overflow
+ * but if it encounters a page under writeback, wait
+ * for the IO to complete.
*/
if ((sc->reclaim_mode & RECLAIM_MODE_SYNC) &&
may_enter_fs)
@@ -1414,7 +1403,7 @@ static noinline_for_stack void update_isolated_counts(struct zone *zone,
}
/*
- * Returns true if the caller should wait to clean dirty/writeback pages.
+ * Returns true if a direct reclaim should wait on pages under writeback.
*
* If we are direct reclaiming for contiguous pages and we do not reclaim
* everything in the list, try again and wait for writeback IO to complete.