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-rw-r--r--mm/swapfile.c16
1 files changed, 8 insertions, 8 deletions
diff --git a/mm/swapfile.c b/mm/swapfile.c
index 2b8d9c3fbb47..bf4ef2e40f23 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2023,7 +2023,6 @@ static unsigned int find_next_to_unuse(struct swap_info_struct *si,
* If the boolean frontswap is true, only unuse pages_to_unuse pages;
* pages_to_unuse==0 means all pages; ignored if frontswap is false
*/
-#define SWAP_UNUSE_MAX_TRIES 3
int try_to_unuse(unsigned int type, bool frontswap,
unsigned long pages_to_unuse)
{
@@ -2035,7 +2034,6 @@ int try_to_unuse(unsigned int type, bool frontswap,
struct page *page;
swp_entry_t entry;
unsigned int i;
- int retries = 0;
if (!si->inuse_pages)
return 0;
@@ -2117,14 +2115,16 @@ retry:
* If yes, we would need to do retry the unuse logic again.
* Under global memory pressure, swap entries can be reinserted back
* into process space after the mmlist loop above passes over them.
- * Its not worth continuosuly retrying to unuse the swap in this case.
- * So we try SWAP_UNUSE_MAX_TRIES times.
+ *
+ * Limit the number of retries? No: when shmem_unuse()'s igrab() fails,
+ * a shmem inode using swap is being evicted; and when mmget_not_zero()
+ * above fails, that mm is likely to be freeing swap from exit_mmap().
+ * Both proceed at their own independent pace: we could move them to
+ * separate lists, and wait for those lists to be emptied; but it's
+ * easier and more robust (though cpu-intensive) just to keep retrying.
*/
- if (++retries >= SWAP_UNUSE_MAX_TRIES)
- retval = -EBUSY;
- else if (si->inuse_pages)
+ if (si->inuse_pages)
goto retry;
-
out:
return (retval == FRONTSWAP_PAGES_UNUSED) ? 0 : retval;
}