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 X-Spam-Level: X-Spam-Status: No, score=-8.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BD82FC433E1 for ; Thu, 25 Mar 2021 09:54:22 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3806D61A23 for ; Thu, 25 Mar 2021 09:54:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3806D61A23 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=suse.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id A706C6B0070; Thu, 25 Mar 2021 05:54:21 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A474A6B0071; Thu, 25 Mar 2021 05:54:21 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 912376B0072; Thu, 25 Mar 2021 05:54:21 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0060.hostedemail.com [216.40.44.60]) by kanga.kvack.org (Postfix) with ESMTP id 76BD86B0070 for ; Thu, 25 Mar 2021 05:54:21 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 37F741815A833 for ; Thu, 25 Mar 2021 09:54:21 +0000 (UTC) X-FDA: 77957936322.07.154C50B Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf16.hostedemail.com (Postfix) with ESMTP id 5F5C580192D9 for ; Thu, 25 Mar 2021 09:54:19 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 041C6AA55; Thu, 25 Mar 2021 09:54:18 +0000 (UTC) Date: Thu, 25 Mar 2021 10:54:10 +0100 From: Oscar Salvador To: Michal Hocko Cc: Mike Kravetz , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Roman Gushchin , Shakeel Butt , David Hildenbrand , Muchun Song , David Rientjes , Miaohe Lin , Peter Zijlstra , Matthew Wilcox , HORIGUCHI NAOYA , "Aneesh Kumar K . V" , Waiman Long , Peter Xu , Mina Almasry , Hillf Danton , Andrew Morton Subject: Re: [PATCH 1/8] mm: cma: introduce cma_release_nowait() Message-ID: References: <20210325002835.216118-1-mike.kravetz@oracle.com> <20210325002835.216118-2-mike.kravetz@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 5F5C580192D9 X-Stat-Signature: ccfhuir379s9w7zjtsoggcd7n5kmqcsj Received-SPF: none (suse.de>: No applicable sender policy available) receiver=imf16; identity=mailfrom; envelope-from=""; helo=mx2.suse.de; client-ip=195.135.220.15 X-HE-DKIM-Result: none/none X-HE-Tag: 1616666059-133348 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 Thu, Mar 25, 2021 at 10:45:18AM +0100, Michal Hocko wrote: > On Wed 24-03-21 17:28:28, Mike Kravetz wrote: > [...] > > phys_addr_t cma_get_base(const struct cma *cma) > > { > > return PFN_PHYS(cma->base_pfn); > > @@ -146,6 +155,10 @@ static int __init cma_init_reserved_areas(void) > > for (i = 0; i < cma_area_count; i++) > > cma_activate_area(&cma_areas[i]); > > > > + cma_release_wq = create_workqueue("cma_release"); > > Considering the workqueue is used to free up memory it should likely be > WQ_MEM_RECLAIM to prevent from long stalls when WQs are overloaded. I might be missing something but the worqueue->func() seems to not be anything for memory related purposes. The worqueue calls cma_clear_bitmap_fn(), and the only think that does is freeing one page, and clearing the bitmap. I might be reading the CMA code wrongly, but I cannot see any freeing up of memory in cma_clear_bitmap()->__bitmap_clear() (or its siblings). The actual freeing of memory seems to happen in cma_release_no_wait() with: if (count > 1) free_contig_range(pfn + 1, count - 1); -- Oscar Salvador SUSE L3