Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754114AbbHRTVt (ORCPT ); Tue, 18 Aug 2015 15:21:49 -0400 Received: from mail-qg0-f52.google.com ([209.85.192.52]:33759 "EHLO mail-qg0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750780AbbHRTVq (ORCPT ); Tue, 18 Aug 2015 15:21:46 -0400 From: Dan Streetman To: Seth Jennings , Andrew Morton Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Sergey Senozhatsky , Dan Streetman Subject: [PATCH] zswap: move zswap_pool frequently-used fields together Date: Tue, 18 Aug 2015 15:21:41 -0400 Message-Id: <1439925701-29678-1-git-send-email-ddstreet@ieee.org> X-Mailer: git-send-email 2.1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2260 Lines: 68 Move the "tfm" field in struct zswap_pool to the top, after the "zpool" field. As suggested by Sergey Senozhatsky: >> > ->tfm will be access pretty often, right? did you intentionally put it >> > at the bottom offset of `struct zswap_pool'? >> >> no it wasn't intentional; does moving it up provide a benefit? > > well, I just prefer to keep 'read mostly' pointers together. all > those cache lines, etc. > > gcc 5.1, x86_64 > > struct zswap_pool { > struct zpool *zpool; > + struct crypto_comp * __percpu *tfm; > struct kref kref; > struct list_head list; > struct rcu_head rcu_head; > struct notifier_block notifier; > char tfm_name[CRYPTO_MAX_ALG_NAME]; > - struct crypto_comp * __percpu *tfm; > }; > > ../scripts/bloat-o-meter zswap.o.old zswap.o > add/remove: 0/0 grow/shrink: 0/6 up/down: 0/-27 (-27) > function old new delta > zswap_writeback_entry 659 656 -3 > zswap_frontswap_store 1445 1442 -3 > zswap_frontswap_load 417 414 -3 > zswap_pool_create 438 432 -6 > __zswap_cpu_comp_notifier.part 152 146 -6 > __zswap_cpu_comp_notifier 122 116 -6 Suggested-by: Sergey Senozhatsky Signed-off-by: Dan Streetman --- mm/zswap.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/zswap.c b/mm/zswap.c index b198081..4043df7 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -120,12 +120,12 @@ module_param_named(max_pool_percent, zswap_max_pool_percent, uint, 0644); struct zswap_pool { struct zpool *zpool; + struct crypto_comp * __percpu *tfm; struct kref kref; struct list_head list; struct rcu_head rcu_head; struct notifier_block notifier; char tfm_name[CRYPTO_MAX_ALG_NAME]; - struct crypto_comp * __percpu *tfm; }; /* -- 2.1.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/