From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f177.google.com (mail-pd0-f177.google.com [209.85.192.177]) by kanga.kvack.org (Postfix) with ESMTP id 456966B006E for ; Tue, 24 Mar 2015 11:24:37 -0400 (EDT) Received: by pdbop1 with SMTP id op1so224381080pdb.2 for ; Tue, 24 Mar 2015 08:24:37 -0700 (PDT) Received: from mail-pd0-x22f.google.com (mail-pd0-x22f.google.com. [2607:f8b0:400e:c02::22f]) by mx.google.com with ESMTPS id in5si5843688pbd.231.2015.03.24.08.24.36 for (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 24 Mar 2015 08:24:36 -0700 (PDT) Received: by pdbcz9 with SMTP id cz9so224292734pdb.3 for ; Tue, 24 Mar 2015 08:24:36 -0700 (PDT) From: 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> 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: owner-linux-mm@kvack.org List-ID: To: Andrew Morton , Minchan Kim Cc: Nitin Gupta , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Sergey Senozhatsky , Sergey Senozhatsky 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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org