linux-kernel - [PATCH v2] mm: use kvzalloc for swap_info

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Message-ID: <fc23172d-3c75-21e2-d551-8b1808cbe593@virtuozzo.com>
Date:   Mon, 5 Nov 2018 14:17:01 +0300
From:   Vasily Averin <vvs@...tuozzo.com>
To:     linux-mm@...ck.org, Andrew Morton <akpm@...ux-foundation.org>
Cc:     Huang Ying <ying.huang@...el.com>, linux-kernel@...r.kernel.org,
        Aaron Lu <aaron.lu@...el.com>
Subject: [PATCH v2] mm: use kvzalloc for swap_info_struct allocation

commit a2468cc9bfdf ("swap: choose swap device according to numa node")
changed 'avail_lists' field of 'struct swap_info_struct' to an array.
In popular linux distros it increased size of swap_info_struct up to
40 Kbytes and now swap_info_struct allocation requires order-4 page.
Switch to kvzmalloc allows to avoid unexpected allocation failures.

Acked-by: Aaron Lu <aaron.lu@...el.com>
Signed-off-by: Vasily Averin <vvs@...tuozzo.com>
---
 mm/swapfile.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/mm/swapfile.c b/mm/swapfile.c
index 644f746e167a..8688ae65ef58 100644
--- a/mm/swapfile.c
+++ b/mm/swapfile.c
@@ -2813,7 +2813,7 @@ static struct swap_info_struct *alloc_swap_info(void)
 	unsigned int type;
 	int i;
 
-	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	p = kvzalloc(sizeof(*p), GFP_KERNEL);
 	if (!p)
 		return ERR_PTR(-ENOMEM);
 
@@ -2824,7 +2824,7 @@ static struct swap_info_struct *alloc_swap_info(void)
 	}
 	if (type >= MAX_SWAPFILES) {
 		spin_unlock(&swap_lock);
-		kfree(p);
+		kvfree(p);
 		return ERR_PTR(-EPERM);
 	}
 	if (type >= nr_swapfiles) {
@@ -2838,7 +2838,7 @@ static struct swap_info_struct *alloc_swap_info(void)
 		smp_wmb();
 		nr_swapfiles++;
 	} else {
-		kfree(p);
+		kvfree(p);
 		p = swap_info[type];
 		/*
 		 * Do not memset this entry: a racing procfs swap_next()
-- 
2.17.1