From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753150AbbCXPYj (ORCPT ); Tue, 24 Mar 2015 11:24:39 -0400 Received: from mail-pa0-f43.google.com ([209.85.220.43]:33350 "EHLO mail-pa0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752661AbbCXPYg (ORCPT ); Tue, 24 Mar 2015 11:24:36 -0400 From: Sergey Senozhatsky To: Andrew Morton , Minchan Kim Cc: Nitin Gupta , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky Subject: [PATCH 1/2] zsmalloc: do not remap dst page while prepare next src page Date: Wed, 25 Mar 2015 00:24:46 +0900 Message-Id: <1427210687-6634-2-git-send-email-sergey.senozhatsky@gmail.com> X-Mailer: git-send-email 2.3.4.263.gf53fc38 In-Reply-To: <1427210687-6634-1-git-send-email-sergey.senozhatsky@gmail.com> References: <1427210687-6634-1-git-send-email-sergey.senozhatsky@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org object may belong to different pages. zs_object_copy() handles this case and maps a new source page (get_next_page() and kmap_atomic()) when object crosses boundaries of the current source page. But it also performs unnecessary kunmap/kmap_atomic of the destination page (it remains unchanged), which can be avoided. Signed-off-by: Sergey Senozhatsky --- mm/zsmalloc.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c index d920e8b..7af4456 100644 --- a/mm/zsmalloc.c +++ b/mm/zsmalloc.c @@ -1536,12 +1536,10 @@ static void zs_object_copy(unsigned long src, unsigned long dst, break; if (s_off + size >= PAGE_SIZE) { - kunmap_atomic(d_addr); kunmap_atomic(s_addr); s_page = get_next_page(s_page); BUG_ON(!s_page); s_addr = kmap_atomic(s_page); - d_addr = kmap_atomic(d_page); s_size = class->size - written; s_off = 0; } else { -- 2.3.4