linux-kernel - [PATCH] mm/zsmalloc: strength reduce zspage

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Date:   Mon, 26 Feb 2018 02:21:26 -1000
From:   Joey Pabalinas <joeypabalinas@...il.com>
To:     linux-mm@...ck.org
Cc:     Minchan Kim <minchan@...nel.org>, Nitin Gupta <ngupta@...are.org>,
        linux-kernel@...r.kernel.org,
        Joey Pabalinas <joeypabalinas@...il.com>
Subject: [PATCH] mm/zsmalloc: strength reduce zspage_size calculation

Replace the repeated multiplication in the main loop
body calculation of zspage_size with an equivalent
(and cheaper) addition operation.

Signed-off-by: Joey Pabalinas <joeypabalinas@...il.com>

 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index c3013505c30527dc42..647a1a2728634b5194 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -821,15 +821,15 @@ static enum fullness_group fix_fullness_group(struct size_class *class,
  */
 static int get_pages_per_zspage(int class_size)
 {
+	int zspage_size = 0;
 	int i, max_usedpc = 0;
 	/* zspage order which gives maximum used size per KB */
 	int max_usedpc_order = 1;
 
 	for (i = 1; i <= ZS_MAX_PAGES_PER_ZSPAGE; i++) {
-		int zspage_size;
 		int waste, usedpc;
 
-		zspage_size = i * PAGE_SIZE;
+		zspage_size += PAGE_SIZE;
 		waste = zspage_size % class_size;
 		usedpc = (zspage_size - waste) * 100 / zspage_size;
 
-- 
2.16.2

Download attachment "signature.asc" of type "application/pgp-signature" (834 bytes)