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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 ACA2FC433E0 for ; Wed, 6 Jan 2021 17:07:59 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 420B92311E for ; Wed, 6 Jan 2021 17:07:59 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 420B92311E Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6A5396B02A8; Wed, 6 Jan 2021 12:07:58 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 6553B6B02AA; Wed, 6 Jan 2021 12:07:58 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 51C846B02AB; Wed, 6 Jan 2021 12:07:58 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0160.hostedemail.com [216.40.44.160]) by kanga.kvack.org (Postfix) with ESMTP id 3CE336B02A8 for ; Wed, 6 Jan 2021 12:07:58 -0500 (EST) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 092711E0A for ; Wed, 6 Jan 2021 17:07:58 +0000 (UTC) X-FDA: 77675982636.12.rice72_07111a6274e3 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin12.hostedemail.com (Postfix) with ESMTP id D6F0618023A8A for ; Wed, 6 Jan 2021 17:07:57 +0000 (UTC) X-HE-Tag: rice72_07111a6274e3 X-Filterd-Recvd-Size: 2478 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf13.hostedemail.com (Postfix) with ESMTP for ; Wed, 6 Jan 2021 17:07:57 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1609952876; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=tMDGStXu5aOKdSM+cuLv8ZbVcDEjNhgE+EM0ieJw6OE=; b=k7JyX+a5xGNYm2Iavk9sgx0VgM1jAxWJ6msI+j+XiFr+f8TmPCqw6zeWXFuo3wv4XDg8TO DMHVdhCkirqO1aAzlzu5OsrB5jHtJQd1N1JbykFzlwXPKt46FyUKqK2LgOTudJZB5MGygF n/GTy4xQufCeCTRQt/b1Aj+YE6I9G6M= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 116E0ACAF; Wed, 6 Jan 2021 17:07:56 +0000 (UTC) Date: Wed, 6 Jan 2021 18:07:54 +0100 From: Michal Hocko To: Muchun Song Cc: mike.kravetz@oracle.com, akpm@linux-foundation.org, n-horiguchi@ah.jp.nec.com, ak@linux.intel.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 4/6] mm: hugetlb: add return -EAGAIN for dissolve_free_huge_page Message-ID: <20210106170754.GU13207@dhcp22.suse.cz> References: <20210106084739.63318-1-songmuchun@bytedance.com> <20210106084739.63318-5-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210106084739.63318-5-songmuchun@bytedance.com> 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 Wed 06-01-21 16:47:37, Muchun Song wrote: > When dissolve_free_huge_page() races with __free_huge_page(), we can > do a retry. Because the race window is small. Is this a bug fix or mere optimization. I have hard time to tell from the description. > Signed-off-by: Muchun Song > --- > mm/hugetlb.c | 26 +++++++++++++++++++++----- > 1 file changed, 21 insertions(+), 5 deletions(-) > > diff --git a/mm/hugetlb.c b/mm/hugetlb.c [...] > @@ -1825,6 +1828,14 @@ int dissolve_free_huge_page(struct page *page) > } > out: > spin_unlock(&hugetlb_lock); > + > + /* > + * If the freeing of the HugeTLB page is put on a work queue, we should > + * flush the work before retrying. > + */ > + if (unlikely(rc == -EAGAIN)) > + flush_work(&free_hpage_work); Is it safe to wait for the work to finish from this context? -- Michal Hocko SUSE Labs