From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4CD62C433EF for ; Fri, 22 Apr 2022 12:08:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1447256AbiDVMK6 (ORCPT ); Fri, 22 Apr 2022 08:10:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34170 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1384839AbiDVMK6 (ORCPT ); Fri, 22 Apr 2022 08:10:58 -0400 X-Greylist: delayed 467 seconds by postgrey-1.37 at lindbergh.monkeyblade.net; Fri, 22 Apr 2022 05:08:03 PDT Received: from mail.sberdevices.ru (mail.sberdevices.ru [45.89.227.171]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 65A0C56435; Fri, 22 Apr 2022 05:08:03 -0700 (PDT) Received: from s-lin-edge02.sberdevices.ru (localhost [127.0.0.1]) by mail.sberdevices.ru (Postfix) with ESMTP id 36B415FD02; Fri, 22 Apr 2022 15:00:13 +0300 (MSK) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sberdevices.ru; s=mail; t=1650628813; bh=WGcfw8+jkSEDAp7PzGBXGL+KYgoLrJlmcpYGAiTjh9c=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type; b=mWKkDqU9zd+6jMn6LF34ds5F5QWus3BbqYxRfe++y7ule4ejyYTRNq1Zsq3rIguMn uum8aHOz75sbkv2eU1+w7t8IIFScyB3urtkSkeaxpKhYSvG5jumJHtGhdgJOujBF0z zvufrnkAmB1A9qxtFzjL7QyQtdeJ2h7mY/JU2+QIWrDD+W6c+xyL+XGoaCdSh57nRw Sw6EcfbCtAUD7cm0uu8o0wy/W0ep607QASvT3HtndHd5Rw8WEB6jPIemFOua/Dy76t iA6mGyepFswjQhpJBlF1Wa/xwufbfzEAEuehOu8bwAKYInvr3nnMBKHGiiqtwPVwad x7eadFKcsfqqg== Received: from S-MS-EXCH01.sberdevices.ru (S-MS-EXCH01.sberdevices.ru [172.16.1.4]) by mail.sberdevices.ru (Postfix) with ESMTP; Fri, 22 Apr 2022 15:00:12 +0300 (MSK) From: Alexey Romanov To: , , , CC: , , , , Alexey Romanov , Dmitry Rokosov Subject: [PATCH v1] zram: don't retry compress incompressible page Date: Fri, 22 Apr 2022 14:59:59 +0300 Message-ID: <20220422115959.3313-1-avromanov@sberdevices.ru> X-Mailer: git-send-email 2.33.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-Originating-IP: [172.16.1.6] X-ClientProxiedBy: S-MS-EXCH01.sberdevices.ru (172.16.1.4) To S-MS-EXCH01.sberdevices.ru (172.16.1.4) X-KSMG-Rule-ID: 4 X-KSMG-Message-Action: clean X-KSMG-AntiSpam-Status: not scanned, disabled by settings X-KSMG-AntiSpam-Interceptor-Info: not scanned X-KSMG-AntiPhishing: not scanned, disabled by settings X-KSMG-AntiVirus: Kaspersky Secure Mail Gateway, version 1.1.2.30, bases: 2022/04/22 06:12:00 #19330442 X-KSMG-AntiVirus-Status: Clean, skipped Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org It doesn't make sense for us to retry to compress an uncompressible page (comp_len == PAGE_SIZE) in zsmalloc slowpath, because we will be storing it uncompressed anyway. We can avoid wasting time on another compression attempt. It is enough to take lock (zcomp_stream_get) and execute the code below. Signed-off-by: Alexey Romanov Signed-off-by: Dmitry Rokosov --- drivers/block/zram/zram_drv.c | 15 +++++++++++++-- 1 file changed, 13 insertions(+), 2 deletions(-) diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index cb253d80d72b..bb9dd8b64176 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1413,9 +1413,20 @@ static int __zram_bvec_write(struct zram *zram, struct bio_vec *bvec, handle = zs_malloc(zram->mem_pool, comp_len, GFP_NOIO | __GFP_HIGHMEM | __GFP_MOVABLE); - if (handle) + if (!handle) + return -ENOMEM; + + if (comp_len != PAGE_SIZE) goto compress_again; - return -ENOMEM; + + /* + * If the page is not compressible, you need to acquire the lock and + * execute the code below. The zcomp_stream_get() call is needed to + * disable the cpu hotplug and grab the zstrm buffer back. + * It is necessary that the dereferencing of the zstrm variable below + * occurs correctly. + */ + zstrm = zcomp_stream_get(zram->comp); } alloced_pages = zs_get_total_pages(zram->mem_pool); -- 2.30.1