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 873FBE728C5 for ; Fri, 29 Sep 2023 16:09:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 166CC8D0023; Fri, 29 Sep 2023 12:09:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 117B48D00E3; Fri, 29 Sep 2023 12:09:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 0102A8D0023; Fri, 29 Sep 2023 12:09:45 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) by kanga.kvack.org (Postfix) with ESMTP id E5ADB8D0023 for ; Fri, 29 Sep 2023 12:09:45 -0400 (EDT) Received: from smtpin03.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id B6E744050F for ; Fri, 29 Sep 2023 16:09:45 +0000 (UTC) X-FDA: 81290120730.03.2C26765 Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by imf22.hostedemail.com (Postfix) with ESMTP id E902EC002B for ; Fri, 29 Sep 2023 16:09:42 +0000 (UTC) Authentication-Results: imf22.hostedemail.com; dkim=pass header.d=linux.microsoft.com header.s=default header.b=Lv3AqhUO; spf=pass (imf22.hostedemail.com: domain of skinsburskii@linux.microsoft.com designates 13.77.154.182 as permitted sender) smtp.mailfrom=skinsburskii@linux.microsoft.com; dmarc=pass (policy=none) header.from=linux.microsoft.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1696003783; 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: in-reply-to:in-reply-to:references:references:dkim-signature; bh=hBRFFChWfIJKYy72bpQH7xKGGzU+r4Wzml1eGPFHEBs=; b=8BHX18DIw1GArKaQiwZZcktQT+00bvz96ONIlouPt7/WMBEfZLzPCMnrNf1Ah0hY0x9kBP xJ0Wv7gLBZeW43Tb7KkMtZIWtfLDVxnok82fAn95KGWEOJ3FkfJdvKCStruSS6elwM4TvD cgYD0r9DvYy2oviKG/lEjtt3ZX4GqOs= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1696003783; a=rsa-sha256; cv=none; b=K1S4UG/vasKpgR0tEqlxASI4n3Y4rYosTztRttj12K5SV7Ose6yC5+7UlQFBtBL7ulD+7A ZcViM78FP4QYBS4u9txQO/rWcR/rPoh+da63rZT6P1aJ75W+HIYdBOH0TLuVPN+yGUb7Cb HhYWXaHi2DU95li727aFQIV26Y/AoxI= ARC-Authentication-Results: i=1; imf22.hostedemail.com; dkim=pass header.d=linux.microsoft.com header.s=default header.b=Lv3AqhUO; spf=pass (imf22.hostedemail.com: domain of skinsburskii@linux.microsoft.com designates 13.77.154.182 as permitted sender) smtp.mailfrom=skinsburskii@linux.microsoft.com; dmarc=pass (policy=none) header.from=linux.microsoft.com Received: from skinsburskii. (c-67-170-100-148.hsd1.wa.comcast.net [67.170.100.148]) by linux.microsoft.com (Postfix) with ESMTPSA id 1E11020B74C0; Fri, 29 Sep 2023 09:09:41 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1E11020B74C0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1696003781; bh=hBRFFChWfIJKYy72bpQH7xKGGzU+r4Wzml1eGPFHEBs=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Lv3AqhUOg8n151/bqh1okWzXQRnbJgv18TSyBOBoKBUSs7z96qc9wIslOfmYcIj20 CX5yJ/0tbuQmucA2aTIQJ3ol3I886vdUGrp40UFE1NeZwEgGJi/tVjsIKiezjtqnti YKg4s4TCMmGlxuZx+vugASYdS7colcK7Tnp+TSbs= Date: Thu, 28 Sep 2023 02:16:41 -0700 From: Stanislav Kinsburskii To: "Shutemov, Kirill" Cc: Dave Hansen , Baoquan He , tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, ebiederm@xmission.com, akpm@linux-foundation.org, stanislav.kinsburskii@gmail.com, corbet@lwn.net, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, kys@microsoft.com, jgowans@amazon.com, wei.liu@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org, graf@amazon.de, pbonzini@redhat.com Subject: Re: [RFC PATCH v2 0/7] Introduce persistent memory pool Message-ID: <20230928091641.GA20562@skinsburskii.> References: <20230927161319.GA19976@skinsburskii.> <20230927232548.GA20221@skinsburskii.> <20230928000230.GA20259@skinsburskii.> <760bbb08-83b4-7bb1-822f-2ceba26278a6@intel.com> <20230928003831.GA20366@skinsburskii.> <340596c9-d55d-5f8a-fa27-d95b0e10b20a@intel.com> <20230928024636.GA20423@skinsburskii.> <20230929101324.jgixt4jmqialchno@box.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20230929101324.jgixt4jmqialchno@box.shutemov.name> X-Stat-Signature: mgxjb4mip6ii1r6kfashfyzktscb85wi X-Rspamd-Server: rspam10 X-Rspamd-Queue-Id: E902EC002B X-Rspam-User: X-HE-Tag: 1696003782-646611 X-HE-Meta: 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 COCmwTAM ud++JJ8FZhKom8TduJ448MbSpDGq0LngRGmmDAzRjo8maR1KSqZTgo86RZx8tQpB3kmE0i0Wb//sr7hzAWAmKqy1cDuZ2EHRUj2ZUdOoodpYWCiNYv5kP3SuXpUbOsNQQZDrV/wddEV6S12y8Q7uiiwH/OYOOTJlWbnYc9rrjjyT3c+W3DLhtSU2s94LyQxfAn1ddKwrY4RWnI8KejjmRvknVmjuAX8gIZJVv9FlmKZAwKoq5zK04fNJbgkxMELyO8SKUbyli6hfSy58Fs2P4kggZCcBWTRBZsVom 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 Fri, Sep 29, 2023 at 01:13:24PM +0300, Shutemov, Kirill wrote: > On Wed, Sep 27, 2023 at 07:46:36PM -0700, Stanislav Kinsburskii wrote: > > I'd answer yes, "System MAP" must be persisted across kexec. > > Could you elaborate on why there should be a mechanism to tell the > > kernel anything special about the existent "System map" in this context? > > Say, one can reserve a CMA region (or a crash kernel region, etc), store > > there some data, and then pass it across kexec. Reserved CMA region will > > still be a part of the "System MAP", won't it? > > Em. When crash kernel starts all System RAM of the the first kernel > becomes E820_TYPE_RESERVED and only memory pre-allocated for crash > scenario becomes E820_TYPE_RAM. See crash_setup_memmap_entries(). > > Can't you go the same path? Report all deposited memory as > E820_TYPE_RESERVED. > Sure I can. This approach will have the corresponding command line option as a requirement, and therefore is less flexible. But if passing device tree across kexec on x86 is the major concern, then of course I can change it the way you suggest. > Or do you have too many deposited memory ranges, so we would run out of > e820 entries? > No, I don't think I have. I can imagine how such a pool with a lot of regions can exhaust e820 table, but the implementation currently proposed is based on CMA and thus limited by 19 entires by default, so I guess running out of e820 entries is unlikely in real world scenarios. Thanks, Stanislav > -- > Kiryl Shutsemau / Kirill A. Shutemov