From 2f55f070e5b80f130f5b161931ca91ce9cb2e625 Mon Sep 17 00:00:00 2001
From: Miaohe Lin <linmiaohe@huawei.com>
Date: Sat, 25 Jun 2022 17:28:13 +0800
Subject: [PATCH] mm/khugepaged: minor cleanup for collapse_file
nr_none is always 0 for non-shmem case because the page can be read from
the backend store. So when nr_none ! = 0, it must be in is_shmem case.
Also only adjust the nrpages and uncharge shmem when nr_none != 0 to save
cpu cycles.
Link: https://lkml.kernel.org/r/20220625092816.4856-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: Zach O'Keefe <zokeefe@google.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: NeilBrown <neilb@suse.de>
Cc: Peter Xu <peterx@redhat.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/khugepaged.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)
diff --git a/mm/khugepaged.c b/mm/khugepaged.c
index e237c5ec59bbb..35f87bd2af282 100644
--- a/mm/khugepaged.c
+++ b/mm/khugepaged.c
@@ -1881,8 +1881,8 @@ out_unlock:
if (nr_none) {
__mod_lruvec_page_state(new_page, NR_FILE_PAGES, nr_none);
- if (is_shmem)
- __mod_lruvec_page_state(new_page, NR_SHMEM, nr_none);
+ /* nr_none is always 0 for non-shmem. */
+ __mod_lruvec_page_state(new_page, NR_SHMEM, nr_none);
}
/* Join all the small entries into a single multi-index entry */
@@ -1946,10 +1946,10 @@ xa_unlocked:
/* Something went wrong: roll back page cache changes */
xas_lock_irq(&xas);
- mapping->nrpages -= nr_none;
-
- if (is_shmem)
+ if (nr_none) {
+ mapping->nrpages -= nr_none;
shmem_uncharge(mapping->host, nr_none);
+ }
xas_set(&xas, start);
xas_for_each(&xas, page, end - 1) {
--
2.30.2