Johannes pointed out TTU_LZFREE is unnecessary. It's true because we
always have the flag set if we want to do an unmap. For cases we don't
do an unmap, the TTU_LZFREE part of code should never run.
Also the TTU_UNMAP is unnecessary. If no other flags set (for
example, TTU_MIGRATION), an unmap is implied.
Cc: Michal Hocko <mho...@suse.com>
Cc: Minchan Kim <minc...@kernel.org>
Cc: Hugh Dickins <hu...@google.com>
Cc: Rik van Riel <r...@redhat.com>
Cc: Mel Gorman <mgor...@techsingularity.net>
Cc: Andrew Morton <a...@linux-foundation.org>
Suggested-by: Johannes Weiner <han...@cmpxchg.org>
Signed-off-by: Shaohua Li <s...@fb.com>
---
include/linux/rmap.h | 2 --
mm/memory-failure.c | 2 +-
mm/rmap.c | 2 +-
mm/vmscan.c | 11 ++++-------
4 files changed, 6 insertions(+), 11 deletions(-)
diff --git a/include/linux/rmap.h b/include/linux/rmap.h
index 8c89e90..e2cd8f9 100644
--- a/include/linux/rmap.h
+++ b/include/linux/rmap.h
@@ -83,10 +83,8 @@ struct anon_vma_chain {
};
enum ttu_flags {
- TTU_UNMAP = 1, /* unmap mode */
TTU_MIGRATION = 2, /* migration mode */
TTU_MUNLOCK = 4, /* munlock mode */
- TTU_LZFREE = 8, /* lazy free mode */
TTU_SPLIT_HUGE_PMD = 16, /* split huge PMD if any */
TTU_IGNORE_MLOCK = (1 << 8), /* ignore mlock */
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 3d0f2fd..b78d080 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -906,7 +906,7 @@ EXPORT_SYMBOL_GPL(get_hwpoison_page);
static int hwpoison_user_mappings(struct page *p, unsigned long pfn,
int trapno, int flags, struct page **hpagep)
{
- enum ttu_flags ttu = TTU_UNMAP | TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
+ enum ttu_flags ttu = TTU_IGNORE_MLOCK | TTU_IGNORE_ACCESS;
struct address_space *mapping;
LIST_HEAD(tokill);
int ret;
diff --git a/mm/rmap.c b/mm/rmap.c
index 8774791..96eb85c 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -1418,7 +1418,7 @@ static int try_to_unmap_one(struct page *page, struct
vm_area_struct *vma,
*/
VM_BUG_ON_PAGE(!PageSwapCache(page), page);
- if (!PageDirty(page) && (flags & TTU_LZFREE)) {
+ if (!PageDirty(page)) {
/* It's a freeable page by MADV_FREE */
dec_mm_counter(mm, MM_ANONPAGES);
rp->lazyfreed++;
diff --git a/mm/vmscan.c b/mm/vmscan.c
index 26c3b40..68ea50d 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -971,7 +971,6 @@ static unsigned long shrink_page_list(struct list_head
*page_list,
int may_enter_fs;
enum page_references references = PAGEREF_RECLAIM_CLEAN;
bool dirty, writeback;
- bool lazyfree = false;
int ret = SWAP_SUCCESS;
cond_resched();
@@ -1125,7 +1124,6 @@ static unsigned long shrink_page_list(struct list_head
*page_list,
goto keep_locked;
if (!add_to_swap(page, page_list))
goto activate_locked;
- lazyfree = true;
may_enter_fs = 1;
/* Adding to swap updated mapping */
@@ -1143,9 +1141,8 @@ static unsigned long shrink_page_list(struct list_head
*page_list,
* processes. Try to unmap it here.
*/
if (page_mapped(page) && mapping) {
- switch (ret = try_to_unmap(page, lazyfree ?
- (ttu_flags | TTU_BATCH_FLUSH | TTU_LZFREE) :
- (ttu_flags | TTU_BATCH_FLUSH))) {
+ switch (ret = try_to_unmap(page,
+ ttu_flags | TTU_BATCH_FLUSH)) {
case SWAP_FAIL:
nr_unmap_fail++;
goto activate_locked;
@@ -1353,7 +1350,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone
*zone,
}
ret = shrink_page_list(&clean_pages, zone->zone_pgdat, &sc,
- TTU_UNMAP|TTU_IGNORE_ACCESS, NULL, true);
+ TTU_IGNORE_ACCESS, NULL, true);
list_splice(&clean_pages, page_list);
mod_node_page_state(zone->zone_pgdat, NR_ISOLATED_FILE, -ret);
return ret;
@@ -1760,7 +1757,7 @@ shrink_inactive_list(unsigned long nr_to_scan, struct
lruvec *lruvec,
if (nr_taken == 0)
return 0;
- nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, TTU_UNMAP,
+ nr_reclaimed = shrink_page_list(&page_list, pgdat, sc, 0,
&stat, false);
spin_lock_irq(&pgdat->lru_lock);
--
2.9.3
