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=-9.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,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 01146C4338F for ; Tue, 17 Aug 2021 00:40:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8F26860FC3 for ; Tue, 17 Aug 2021 00:40:04 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 8F26860FC3 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id D6C4D6B006C; Mon, 16 Aug 2021 20:40:03 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id D1C7B6B0072; Mon, 16 Aug 2021 20:40:03 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id C32706B0073; Mon, 16 Aug 2021 20:40:03 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0093.hostedemail.com [216.40.44.93]) by kanga.kvack.org (Postfix) with ESMTP id A5F0F6B006C for ; Mon, 16 Aug 2021 20:40:03 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 4C4908249980 for ; Tue, 17 Aug 2021 00:40:03 +0000 (UTC) X-FDA: 78482715486.28.C6D583C Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf27.hostedemail.com (Postfix) with ESMTP id 039EE70468D6 for ; Tue, 17 Aug 2021 00:40:02 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id BAD5F60240; Tue, 17 Aug 2021 00:40:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1629160802; bh=nNjbX5cWn1CMLFVoEdB7PkH+dxuHmFgEZzkDVdkXFW0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=yzbFLNT8gkFtcXHHIjJpr+XMUoCQTO4dGWnSn4NFeFwYSDXXdzkdEw004xSWr6fkw woX23uyu/EYJS/AJ0VZChyv02r2kYIHbMqQoL47rnWlb/X8X2RiPYE2j2B82YSrDet GVv4HEyvQ0DBoC1eq4vXyYhtHiF2mfCXs3xmsido= Date: Mon, 16 Aug 2021 17:39:59 -0700 From: Andrew Morton To: Mike Kravetz Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, David Hildenbrand , Michal Hocko , Oscar Salvador , Zi Yan , Muchun Song , Naoya Horiguchi , David Rientjes Subject: Re: [PATCH RESEND 0/8] hugetlb: add demote/split page functionality Message-Id: <20210816173959.950443c7516a2b178e2ec376@linux-foundation.org> In-Reply-To: <5dd4e07b-d2cf-63f2-fc0a-9b371b469a44@oracle.com> References: <20210816224953.157796-1-mike.kravetz@oracle.com> <20210816162305.b19bfa3f3ba7431a62ff205f@linux-foundation.org> <5dd4e07b-d2cf-63f2-fc0a-9b371b469a44@oracle.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.32; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 039EE70468D6 Authentication-Results: imf27.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=yzbFLNT8; spf=pass (imf27.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspamd-Server: rspam01 X-Stat-Signature: z9jhb8kw9afquqcjyuigesf4j75r3zh8 X-HE-Tag: 1629160802-758416 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 Mon, 16 Aug 2021 17:17:50 -0700 Mike Kravetz wrote: > > > > And how does one know the operation has completed so the sysfs files > > can be reloaded for another operation? > > > > When the write to the file is complete, the operation has completed. > Not exactly sure what you mean by reloading the sysfs files for > another operation? If userspace wishes to perform another demote operation, it must wait for the preceding one to complete. Presumably if thread A is blocked in a write to `demote' and thread B concurrently tries to perform a demotion, thread B will be blocked as well? Was this tested? Lots of things are to be added to changelogs & documentation, methinks.