linux-kernel - [PATCH] mm/swap_slots.c: don't reset the cache slot after use

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Message-Id: <20200309090940.34130-1-richard.weiyang@linux.alibaba.com>
Date:   Mon,  9 Mar 2020 17:09:40 +0800
From:   Wei Yang <richard.weiyang@...ux.alibaba.com>
To:     akpm@...ux-foundation.org
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Wei Yang <richard.weiyang@...ux.alibaba.com>
Subject: [PATCH] mm/swap_slots.c: don't reset the cache slot after use

Currently we would clear the cache slot if it is used. While this is not
necessary, since this entry would not be used until refilled.

Leave it untouched and assigned the value directly to entry which makes
the code little more neat.

Also this patch merges the else and if, since this is the only case we
refill and repeat swap cache.

Signed-off-by: Wei Yang <richard.weiyang@...ux.alibaba.com>
---
 mm/swap_slots.c | 11 ++++-------
 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/mm/swap_slots.c b/mm/swap_slots.c
index 63a7b4563a57..ff695df3db26 100644
--- a/mm/swap_slots.c
+++ b/mm/swap_slots.c
@@ -309,7 +309,7 @@ int free_swap_slot(swp_entry_t entry)
 
 swp_entry_t get_swap_page(struct page *page)
 {
-	swp_entry_t entry, *pentry;
+	swp_entry_t entry;
 	struct swap_slots_cache *cache;
 
 	entry.val = 0;
@@ -336,13 +336,10 @@ swp_entry_t get_swap_page(struct page *page)
 		if (cache->slots) {
 repeat:
 			if (cache->nr) {
-				pentry = &cache->slots[cache->cur++];
-				entry = *pentry;
-				pentry->val = 0;
+				entry = cache->slots[cache->cur++];
 				cache->nr--;
-			} else {
-				if (refill_swap_slots_cache(cache))
-					goto repeat;
+			} else if (refill_swap_slots_cache(cache)) {
+				goto repeat;
 			}
 		}
 		mutex_unlock(&cache->alloc_lock);
-- 
2.20.1 (Apple Git-117)