linux-kernel - [PATCH 2/3] swap: call free_swap_slot() in __swap_entry

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Date:   Mon, 27 Aug 2018 15:55:34 +0800
From:   Huang Ying <ying.huang@...el.com>
To:     Andrew Morton <akpm@...ux-foundation.org>
Cc:     linux-mm@...ck.org, linux-kernel@...r.kernel.org,
        Huang Ying <ying.huang@...el.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Michal Hocko <mhocko@...e.com>,
        Johannes Weiner <hannes@...xchg.org>,
        Shaohua Li <shli@...nel.org>, Hugh Dickins <hughd@...gle.com>,
        Minchan Kim <minchan@...nel.org>
Subject: [PATCH 2/3] swap: call free_swap_slot() in __swap_entry_free()

This is a code cleanup patch without functionality change.

Originally, when __swap_entry_free() is called, and its return value
is 0, free_swap_slot() will always be called to free the swap entry to
the per-CPU pool.  So move the call to free_swap_slot() to
__swap_entry_free() to simplify the code.

Signed-off-by: "Huang, Ying" <ying.huang@...el.com>
Cc: Dave Hansen <dave.hansen@...ux.intel.com>
Cc: Michal Hocko <mhocko@...e.com>
Cc: Johannes Weiner <hannes@...xchg.org>
Cc: Shaohua Li <shli@...nel.org>
Cc: Hugh Dickins <hughd@...gle.com>
Cc: Minchan Kim <minchan@...nel.org>
---
 mm/swapfile.c | 10 ++++------
 1 file changed, 4 insertions(+), 6 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 409926079607..ef974bbd7715 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -1241,6 +1241,8 @@ static unsigned char __swap_entry_free(struct swap_info_struct *p,
 	ci = lock_cluster_or_swap_info(p, offset);
 	usage = __swap_entry_free_locked(p, offset, usage);
 	unlock_cluster_or_swap_info(p, ci);
+	if (!usage)
+		free_swap_slot(entry);
 
 	return usage;
 }
@@ -1271,10 +1273,8 @@ void swap_free(swp_entry_t entry)
 	struct swap_info_struct *p;
 
 	p = _swap_info_get(entry);
-	if (p) {
-		if (!__swap_entry_free(p, entry, 1))
-			free_swap_slot(entry);
-	}
+	if (p)
+		__swap_entry_free(p, entry, 1);
 }
 
 /*
@@ -1705,8 +1705,6 @@ int free_swap_and_cache(swp_entry_t entry)
 		    !swap_page_trans_huge_swapped(p, entry))
 			__try_to_reclaim_swap(p, swp_offset(entry),
 					      TTRS_UNMAPPED | TTRS_FULL);
-		else if (!count)
-			free_swap_slot(entry);
 	}
 	return p != NULL;
 }
-- 
2.16.4