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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 41F0FC433FE for ; Tue, 22 Nov 2022 01:56:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id DE01C8E0001; Mon, 21 Nov 2022 20:56:23 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id D90416B0074; Mon, 21 Nov 2022 20:56:23 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C7F038E0001; Mon, 21 Nov 2022 20:56:23 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0012.hostedemail.com [216.40.44.12]) by kanga.kvack.org (Postfix) with ESMTP id BB2766B0073 for ; Mon, 21 Nov 2022 20:56:23 -0500 (EST) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 95EDCAAA58 for ; Tue, 22 Nov 2022 01:56:23 +0000 (UTC) X-FDA: 80159413446.27.CCA1985 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf05.hostedemail.com (Postfix) with ESMTP id 34A48100002 for ; Tue, 22 Nov 2022 01:56:22 +0000 (UTC) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 3C04561529; Tue, 22 Nov 2022 01:56:21 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CDDDC433D6; Tue, 22 Nov 2022 01:56:20 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1669082180; bh=JGk0ZxCYS42fSPPpUoBTd3yoEazg4HSkfZ8gjdsUELw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=suWLKTl+EwRj/3rirO4twtMpjXhSrKSOovRtn/X9D4P2KQYm2HqFS6FPdHrSVAy3M oBnzNHYoYWO/5h2yVzfsUL61mQ2uEM1nrTgy17XghzfOZbpDpUklxl4+XaPMRiFm0G +O5DCgC2zqudAl4TsFQnO10jvW8R6CDL8EMLSdhs= Date: Mon, 21 Nov 2022 17:56:19 -0800 From: Andrew Morton To: Sergey Senozhatsky Cc: Seth Jennings , Dan Streetman , Vitaly Wool , Nhat Pham , Johannes Weiner , Minchan Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] zswap: do not allocate from atomic pool Message-Id: <20221121175619.f38259bac177de86bd9eb558@linux-foundation.org> In-Reply-To: <20221122013338.3696079-1-senozhatsky@chromium.org> References: <20221122013338.3696079-1-senozhatsky@chromium.org> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669082182; a=rsa-sha256; cv=none; b=rljjLg8bg31Dt2NE+ZHNeuAo5cBU4OEKldcueOl7w/u2aF20bALdGlyVTeIWSfUArDYNEm pzsvvjwl1cZ7CHnyoegsTBqn9wDWrLrS5AQe78MyG0somTMxPYoZlDlpX39zyNseqW+Dry snnXN7eovyViec7/QUniOvTbqmonGe0= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=suWLKTl+; spf=pass (imf05.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1669082182; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=t4j3SlCdBkp3/8RFyXNasQREu1l57bvs2+dRI/rRbps=; b=EI6fVXrsONYR6cJbvYFy+o4K3YSlw9OXgFQ8tyI5qSZYMWtOqaRN/yhwo65l7HjmYJbhQA xxirkZmIwKAsSTWi7brJSf1NhXep709KnUHO8ZtkU38gpovlelH0NGqmJBDLRJsv7CST2f c1PbS+Rw8fx3OZSbkrut5/fj4FaZWPQ= X-Rspam-User: X-Stat-Signature: g6diiizb37ihucco1jahenztyyery4f3 X-Rspamd-Queue-Id: 34A48100002 Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=suWLKTl+; spf=pass (imf05.hostedemail.com: domain of akpm@linux-foundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspamd-Server: rspam07 X-HE-Tag: 1669082182-614603 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, 22 Nov 2022 10:33:38 +0900 Sergey Senozhatsky wrote: > zswap_frontswap_load() should be called from preemptible > context (we even call mutex_lock() there) and it does not > look like we need to do GFP_ATOMIC allocaion for temp > buffer there. Use GFP_KERNEL instead. > > ... > > --- a/mm/zswap.c > +++ b/mm/zswap.c > @@ -1314,7 +1314,7 @@ static int zswap_frontswap_load(unsigned type, pgoff_t offset, > } > > if (!zpool_can_sleep_mapped(entry->pool->zpool)) { > - tmp = kmalloc(entry->length, GFP_ATOMIC); > + tmp = kmalloc(entry->length, GFP_KERNEL); > if (!tmp) { > ret = -ENOMEM; > goto freeentry; It seems strange to do if (! can sleep) do something which can sleep or am I misreading the intent of zpool_driver.sleep_mapped? If so, perhaps some explanatory code comments will help.