The patch titled
Subject: mm/vmscan: __isolate_lru_page_prepare() cleanup
has been added to the -mm tree. Its filename is
mm-vmscan-__isolate_lru_page_prepare-clean-up.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/mm-vmscan-__isolate_lru_page_prepare-clean-up.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/mm-vmscan-__isolate_lru_page_prepare-clean-up.patch
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------------------------------------------------------
From: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Subject: mm/vmscan: __isolate_lru_page_prepare() cleanup
The function just returns 2 results, so using a 'switch' to deal with its
result is unnecessary. Also simplify it to a bool func as Vlastimil
suggested.
Also remove 'goto' by reusing list_move(), and take Matthew Wilcox's
suggestion to update comments in function.
Link: https://lkml.kernel.org/r/728874d7-2d93-4049-68c1-dcc3b2d52ccd@xxxxxxxxxxxxxxxxx
Signed-off-by: Alex Shi <alex.shi@xxxxxxxxxxxxxxxxx>
Reviewed-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/swap.h | 2 -
mm/compaction.c | 2 -
mm/vmscan.c | 68 ++++++++++++++++++-----------------------
3 files changed, 33 insertions(+), 39 deletions(-)
--- a/include/linux/swap.h~mm-vmscan-__isolate_lru_page_prepare-clean-up
+++ a/include/linux/swap.h
@@ -356,7 +356,7 @@ extern void lru_cache_add_inactive_or_un
extern unsigned long zone_reclaimable_pages(struct zone *zone);
extern unsigned long try_to_free_pages(struct zonelist *zonelist, int order,
gfp_t gfp_mask, nodemask_t *mask);
-extern int __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode);
+extern bool __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode);
extern unsigned long try_to_free_mem_cgroup_pages(struct mem_cgroup *memcg,
unsigned long nr_pages,
gfp_t gfp_mask,
--- a/mm/compaction.c~mm-vmscan-__isolate_lru_page_prepare-clean-up
+++ a/mm/compaction.c
@@ -988,7 +988,7 @@ isolate_migratepages_block(struct compac
if (unlikely(!get_page_unless_zero(page)))
goto isolate_fail;
- if (__isolate_lru_page_prepare(page, isolate_mode) != 0)
+ if (!__isolate_lru_page_prepare(page, isolate_mode))
goto isolate_fail_put;
/* Try isolate the page */
--- a/mm/vmscan.c~mm-vmscan-__isolate_lru_page_prepare-clean-up
+++ a/mm/vmscan.c
@@ -1536,19 +1536,17 @@ unsigned int reclaim_clean_pages_from_li
* page: page to consider
* mode: one of the LRU isolation modes defined above
*
- * returns 0 on success, -ve errno on failure.
+ * returns true on success, false on failure.
*/
-int __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode)
+bool __isolate_lru_page_prepare(struct page *page, isolate_mode_t mode)
{
- int ret = -EBUSY;
-
/* Only take pages on the LRU. */
if (!PageLRU(page))
- return ret;
+ return false;
/* Compaction should not handle unevictable pages but CMA can do so */
if (PageUnevictable(page) && !(mode & ISOLATE_UNEVICTABLE))
- return ret;
+ return false;
/*
* To minimise LRU disruption, the caller can indicate that it only
@@ -1561,7 +1559,7 @@ int __isolate_lru_page_prepare(struct pa
if (mode & ISOLATE_ASYNC_MIGRATE) {
/* All the caller can do on PageWriteback is block */
if (PageWriteback(page))
- return ret;
+ return false;
if (PageDirty(page)) {
struct address_space *mapping;
@@ -1577,20 +1575,20 @@ int __isolate_lru_page_prepare(struct pa
* from the page cache.
*/
if (!trylock_page(page))
- return ret;
+ return false;
mapping = page_mapping(page);
migrate_dirty = !mapping || mapping->a_ops->migratepage;
unlock_page(page);
if (!migrate_dirty)
- return ret;
+ return false;
}
}
if ((mode & ISOLATE_UNMAPPED) && page_mapped(page))
- return ret;
+ return false;
- return 0;
+ return true;
}
/*
@@ -1674,35 +1672,31 @@ static unsigned long isolate_lru_pages(u
* only when the page is being freed somewhere else.
*/
scan += nr_pages;
- switch (__isolate_lru_page_prepare(page, mode)) {
- case 0:
- /*
- * Be careful not to clear PageLRU until after we're
- * sure the page is not being freed elsewhere -- the
- * page release code relies on it.
- */
- if (unlikely(!get_page_unless_zero(page)))
- goto busy;
+ if (!__isolate_lru_page_prepare(page, mode)) {
+ /* It is being freed elsewhere */
+ list_move(&page->lru, src);
+ continue;
+ }
+ /*
+ * Be careful not to clear PageLRU until after we're
+ * sure the page is not being freed elsewhere -- the
+ * page release code relies on it.
+ */
+ if (unlikely(!get_page_unless_zero(page))) {
+ list_move(&page->lru, src);
+ continue;
+ }
- if (!TestClearPageLRU(page)) {
- /*
- * This page may in other isolation path,
- * but we still hold lru_lock.
- */
- put_page(page);
- goto busy;
- }
-
- nr_taken += nr_pages;
- nr_zone_taken[page_zonenum(page)] += nr_pages;
- list_move(&page->lru, dst);
- break;
-
- default:
-busy:
- /* else it is being freed elsewhere */
+ if (!TestClearPageLRU(page)) {
+ /* Another thread is already isolating this page */
+ put_page(page);
list_move(&page->lru, src);
+ continue;
}
+
+ nr_taken += nr_pages;
+ nr_zone_taken[page_zonenum(page)] += nr_pages;
+ list_move(&page->lru, dst);
}
/*
_
Patches currently in -mm which might be from alex.shi@xxxxxxxxxxxxxxxxx are
mm-filemap-add-static-for-function-__add_to_page_cache_locked.patch
fs-ntfs-remove-unused-varibles.patch
fs-ntfs-remove-unused-varible-attr_len.patch
mm-truncate-add-parameter-explanation-for-invalidate_mapping_pagevec.patch
mm-memcg-update-page-struct-member-in-comments.patch
mm-thp-move-lru_add_page_tail-func-to-huge_memoryc.patch
mm-thp-use-head-for-head-page-in-lru_add_page_tail.patch
mm-thp-simplify-lru_add_page_tail.patch
mm-thp-narrow-lru-locking.patch
mm-vmscan-remove-unnecessary-lruvec-adding.patch
mm-rmap-stop-store-reordering-issue-on-page-mapping.patch
mm-rmap-stop-store-reordering-issue-on-page-mapping-fix.patch
mm-memcg-add-debug-checking-in-lock_page_memcg.patch
mm-swapc-fold-vm-event-pgrotated-into-pagevec_move_tail_fn.patch
mm-lru-move-lock-into-lru_note_cost.patch
mm-vmscan-remove-lruvec-reget-in-move_pages_to_lru.patch
mm-mlock-remove-lru_lock-on-testclearpagemlocked.patch
mm-mlock-remove-__munlock_isolate_lru_page.patch
mm-lru-introduce-testclearpagelru.patch
mm-compaction-do-page-isolation-first-in-compaction.patch
mm-swapc-serialize-memcg-changes-in-pagevec_lru_move_fn.patch
mm-lru-replace-pgdat-lru_lock-with-lruvec-lock.patch
mm-lru-replace-pgdat-lru_lock-with-lruvec-lock-fix.patch
mm-lru-replace-pgdat-lru_lock-with-lruvec-lock-fix-2.patch
mm-lru-introduce-the-relock_page_lruvec-function-fix.patch
mm-memcg-remove-incorrect-comments.patch
mm-mapping_dirty_helpers-enhance-the-kernel-doc-markups.patch
mm-add-colon-to-fix-kernel-doc-markups-error-for-check_pte.patch
mm-vmalloc-add-align-parameter-explanation-for-pvm_determine_end_from_reverse.patch
docs-vm-remove-unused-3-items-explanation-for-proc-vmstat.patch
khugepaged-add-couples-parameter-explanation-for-kernel-doc-markup.patch
mm-vmscan-__isolate_lru_page_prepare-clean-up.patch
gcov-fix-kernel-doc-markup-issue.patch
mm-swapc-reduce-lock-contention-in-lru_cache_add.patch
mm-memcg-bail-early-from-swap-accounting-if-memcg-disabled.patch
mm-memcg-warning-on-memcg-after-readahead-page-charged.patch
mm-memcontrol-rewrite-mem_cgroup_page_lruvec-fix.patch
