mirror of
https://git.openwrt.org/openwrt/openwrt.git
synced 2024-06-13 10:49:13 +02:00
708a507af0
Refresh kernel patches for generic kernel 5.15 due to new backport version of MGLRU patchset. Signed-off-by: Christian Marangi <ansuelsmth@gmail.com>
125 lines
4.3 KiB
Diff
125 lines
4.3 KiB
Diff
From 6f315879ad750391a0b1fab8c9170bc054a5f5d7 Mon Sep 17 00:00:00 2001
|
|
From: Yu Zhao <yuzhao@google.com>
|
|
Date: Tue, 15 Nov 2022 18:38:07 -0700
|
|
Subject: [PATCH 14/29] mm: multi-gen LRU: retry pages written back while
|
|
isolated
|
|
|
|
The page reclaim isolates a batch of pages from the tail of one of the
|
|
LRU lists and works on those pages one by one. For a suitable
|
|
swap-backed page, if the swap device is async, it queues that page for
|
|
writeback. After the page reclaim finishes an entire batch, it puts back
|
|
the pages it queued for writeback to the head of the original LRU list.
|
|
|
|
In the meantime, the page writeback flushes the queued pages also by
|
|
batches. Its batching logic is independent from that of the page reclaim.
|
|
For each of the pages it writes back, the page writeback calls
|
|
rotate_reclaimable_page() which tries to rotate a page to the tail.
|
|
|
|
rotate_reclaimable_page() only works for a page after the page reclaim
|
|
has put it back. If an async swap device is fast enough, the page
|
|
writeback can finish with that page while the page reclaim is still
|
|
working on the rest of the batch containing it. In this case, that page
|
|
will remain at the head and the page reclaim will not retry it before
|
|
reaching there.
|
|
|
|
This patch adds a retry to evict_pages(). After evict_pages() has
|
|
finished an entire batch and before it puts back pages it cannot free
|
|
immediately, it retries those that may have missed the rotation.
|
|
|
|
Before this patch, ~60% of pages swapped to an Intel Optane missed
|
|
rotate_reclaimable_page(). After this patch, ~99% of missed pages were
|
|
reclaimed upon retry.
|
|
|
|
This problem affects relatively slow async swap devices like Samsung 980
|
|
Pro much less and does not affect sync swap devices like zram or zswap at
|
|
all.
|
|
|
|
Link: https://lkml.kernel.org/r/20221116013808.3995280-1-yuzhao@google.com
|
|
Fixes: ac35a4902374 ("mm: multi-gen LRU: minimal implementation")
|
|
Signed-off-by: Yu Zhao <yuzhao@google.com>
|
|
Cc: "Yin, Fengwei" <fengwei.yin@intel.com>
|
|
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
|
|
---
|
|
mm/vmscan.c | 48 +++++++++++++++++++++++++++++++++++++-----------
|
|
1 file changed, 37 insertions(+), 11 deletions(-)
|
|
|
|
--- a/mm/vmscan.c
|
|
+++ b/mm/vmscan.c
|
|
@@ -4723,10 +4723,13 @@ static int evict_pages(struct lruvec *lr
|
|
int scanned;
|
|
int reclaimed;
|
|
LIST_HEAD(list);
|
|
+ LIST_HEAD(clean);
|
|
struct page *page;
|
|
+ struct page *next;
|
|
enum vm_event_item item;
|
|
struct reclaim_stat stat;
|
|
struct lru_gen_mm_walk *walk;
|
|
+ bool skip_retry = false;
|
|
struct mem_cgroup *memcg = lruvec_memcg(lruvec);
|
|
struct pglist_data *pgdat = lruvec_pgdat(lruvec);
|
|
|
|
@@ -4743,20 +4746,37 @@ static int evict_pages(struct lruvec *lr
|
|
|
|
if (list_empty(&list))
|
|
return scanned;
|
|
-
|
|
+retry:
|
|
reclaimed = shrink_page_list(&list, pgdat, sc, &stat, false);
|
|
+ sc->nr_reclaimed += reclaimed;
|
|
|
|
- list_for_each_entry(page, &list, lru) {
|
|
- /* restore LRU_REFS_FLAGS cleared by isolate_page() */
|
|
- if (PageWorkingset(page))
|
|
- SetPageReferenced(page);
|
|
+ list_for_each_entry_safe_reverse(page, next, &list, lru) {
|
|
+ if (!page_evictable(page)) {
|
|
+ list_del(&page->lru);
|
|
+ putback_lru_page(page);
|
|
+ continue;
|
|
+ }
|
|
|
|
- /* don't add rejected pages to the oldest generation */
|
|
if (PageReclaim(page) &&
|
|
- (PageDirty(page) || PageWriteback(page)))
|
|
- ClearPageActive(page);
|
|
- else
|
|
- SetPageActive(page);
|
|
+ (PageDirty(page) || PageWriteback(page))) {
|
|
+ /* restore LRU_REFS_FLAGS cleared by isolate_page() */
|
|
+ if (PageWorkingset(page))
|
|
+ SetPageReferenced(page);
|
|
+ continue;
|
|
+ }
|
|
+
|
|
+ if (skip_retry || PageActive(page) || PageReferenced(page) ||
|
|
+ page_mapped(page) || PageLocked(page) ||
|
|
+ PageDirty(page) || PageWriteback(page)) {
|
|
+ /* don't add rejected pages to the oldest generation */
|
|
+ set_mask_bits(&page->flags, LRU_REFS_MASK | LRU_REFS_FLAGS,
|
|
+ BIT(PG_active));
|
|
+ continue;
|
|
+ }
|
|
+
|
|
+ /* retry pages that may have missed rotate_reclaimable_page() */
|
|
+ list_move(&page->lru, &clean);
|
|
+ sc->nr_scanned -= thp_nr_pages(page);
|
|
}
|
|
|
|
spin_lock_irq(&lruvec->lru_lock);
|
|
@@ -4778,7 +4798,13 @@ static int evict_pages(struct lruvec *lr
|
|
mem_cgroup_uncharge_list(&list);
|
|
free_unref_page_list(&list);
|
|
|
|
- sc->nr_reclaimed += reclaimed;
|
|
+ INIT_LIST_HEAD(&list);
|
|
+ list_splice_init(&clean, &list);
|
|
+
|
|
+ if (!list_empty(&list)) {
|
|
+ skip_retry = true;
|
|
+ goto retry;
|
|
+ }
|
|
|
|
if (need_swapping && type == LRU_GEN_ANON)
|
|
*need_swapping = true;
|