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 0EC60C36008 for ; Wed, 26 Mar 2025 09:17:02 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 62A1E28006D; Wed, 26 Mar 2025 05:17:01 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5DBF9280069; Wed, 26 Mar 2025 05:17:01 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 47A9428006D; Wed, 26 Mar 2025 05:17:01 -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 245E9280069 for ; Wed, 26 Mar 2025 05:17:01 -0400 (EDT) Received: from smtpin10.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay08.hostedemail.com (Postfix) with ESMTP id 9C30A141C7F for ; Wed, 26 Mar 2025 09:17:00 +0000 (UTC) X-FDA: 83263147800.10.FEF0DBB Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by imf05.hostedemail.com (Postfix) with ESMTP id 066A5100008 for ; Wed, 26 Mar 2025 09:16:57 +0000 (UTC) Authentication-Results: imf05.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=aXXGggez; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf05.hostedemail.com: domain of ruyang@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=ruyang@redhat.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1742980618; a=rsa-sha256; cv=none; b=gZAyY55dzfZoX0yApHX2X2JmxktfKoFf+lmlsnYzO8JgS/vQAdRwjoEKEBFV+vp8tfRJRT jhRaEeVF4EarK5LwopMFQfTwC1nfXaISnTB6KDfI4ISfJRsy3woF3yWw5YHMFJdYhlEz/c YjCN4j139atsbhfrUVAzTxRt5TqVmeM= ARC-Authentication-Results: i=1; imf05.hostedemail.com; dkim=pass header.d=redhat.com header.s=mimecast20190719 header.b=aXXGggez; dmarc=pass (policy=quarantine) header.from=redhat.com; spf=pass (imf05.hostedemail.com: domain of ruyang@redhat.com designates 170.10.133.124 as permitted sender) smtp.mailfrom=ruyang@redhat.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1742980618; 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=ow6AGnrr84AMQ0ah/Xi6PJkaHmTpZO5eKBmQQUtOVkg=; b=CU1Lg8yVc7AH9nvR5aRqW+fRFNk1Dj418SkM2A6HFwXAr3+mY8fO1sWc7n0AFZ1PYiUTui nKfMoIG+6jy/bX7lRH1eGVOdGjbia82znw6bF1KdkAB6yD6PlJjEiT4+7CDqEYmsWUcey8 /YukmCMDINMcNJf0ZQYgEUtPOm3aV5k= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1742980617; h=from:from:reply-to:subject:subject: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=ow6AGnrr84AMQ0ah/Xi6PJkaHmTpZO5eKBmQQUtOVkg=; b=aXXGggezF1ezh1XJYmGlQHRi6ALyjONB/kYJclvM0jGnTfYcGc8hvzkxYVZrTCyBsIVYd8 /waOH0SPjr0KnaRz9Sc10rQrXWsrx+VLu3Xp4JjrT4dq58x6MMsQKJB0uYJ6lC+dbnagOf tWBc9XFIK/E3SRQxwU6+1JmiglbSbDo= Received: from mail-il1-f200.google.com (mail-il1-f200.google.com [209.85.166.200]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-196-32ilZVJCMNCmCYraLRbeeA-1; Wed, 26 Mar 2025 05:16:56 -0400 X-MC-Unique: 32ilZVJCMNCmCYraLRbeeA-1 X-Mimecast-MFC-AGG-ID: 32ilZVJCMNCmCYraLRbeeA_1742980615 Received: by mail-il1-f200.google.com with SMTP id e9e14a558f8ab-3d5bb1708e4so31428055ab.3 for ; Wed, 26 Mar 2025 02:16:55 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1742980615; x=1743585415; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=ow6AGnrr84AMQ0ah/Xi6PJkaHmTpZO5eKBmQQUtOVkg=; b=jyYSG6/MUxIwGaaRm4/1FlO38gUSDUiQJfUOTXwaVR8fnnmnt2KXNUwz3v74emJcmC RDn2fx79bMSRXFnSWZNUpxWMhYvJ+JyDttN0kFVBXdxZWtWdgQpJi4wOTe4epWo9tEgS IWQUCNOBra9WCqUzv8jjHNnTva4+cT74P2R34nNwzVYuuklg+PcKcDd+J15fG+I6fOV5 o67YUckkmsEb+2OwuTzlmGNBsPNbQ8MOcMBCgLWYwxhKsUKDxsaLgtnH5aAviwukulRv 3uqTsjpuHJggc9dg2r7m1ytuFsTxFi0Y4C/DGe8Bmbqw2KIyuydiwMVyd55rLJYgTY5b zU8g== X-Forwarded-Encrypted: i=1; AJvYcCWZ+ax8Oo9YmESx1e3hutaRhdbAiGFO2L9KhunuGuBF04Rne6fbk2i0O70t3ltTN1mbJT1gRG0Xjg==@kvack.org X-Gm-Message-State: AOJu0YzpQ0EMqfqG7LlX5d9z1nVPmcdhwhdYSUQvXR9r/iJOIrcGGuqA b4FiEjNaIv/u0f+EwFsxEZEraLyj/tcnUXukZWnuHd8riWlIkfWKu9kGO3t3rHp/o4i1nUvvgBo gv2nFCI2InaP/cD1RZyEWR8uiGfewvMoJlSd03I9trlVCWAUQTfPNC6sZOBnWZ3jxdh7z5J0TH/ ESHcQCTSdLwSw0rNKb17jbw/w= X-Gm-Gg: ASbGncuR1WMcrZLs3z1GzhftXTU0K/72X4BbFR3GG2ZuwmT/0M5FM0bkMsVtFY/nA+m +a+SU82tekaFGihnnDIPpKzjfRVpFNiJPs3rzxrtKIZb9S3XcfnSIAGbyoC+sd4Z7s+815P59gQ == X-Received: by 2002:a05:6e02:3e03:b0:3d4:2409:ce6 with SMTP id e9e14a558f8ab-3d59612bc91mr234170265ab.5.1742980615148; Wed, 26 Mar 2025 02:16:55 -0700 (PDT) X-Google-Smtp-Source: AGHT+IHJ1vGph9A3VJepHAKEDwhyEi3HEUoYZg9GSD20aZ5PWU5QdCBZemC86Ee43E1W8Lw5ALFAPfq+RTfo03e4kyA= X-Received: by 2002:a05:6e02:3e03:b0:3d4:2409:ce6 with SMTP id e9e14a558f8ab-3d59612bc91mr234169465ab.5.1742980614659; Wed, 26 Mar 2025 02:16:54 -0700 (PDT) MIME-Version: 1.0 References: <20250320015551.2157511-1-changyuanl@google.com> <20250320015551.2157511-12-changyuanl@google.com> In-Reply-To: From: Dave Young Date: Wed, 26 Mar 2025 17:17:16 +0800 X-Gm-Features: AQ5f1Jpq9GZncvPHkaxZJh8I7FiGahHb1rvcGNvIVWbnRM_2M_RRWQiPj2LtDHg Message-ID: Subject: Re: [PATCH v5 11/16] kexec: add config option for KHO To: Baoquan He Cc: Changyuan Lyu , linux-kernel@vger.kernel.org, graf@amazon.com, akpm@linux-foundation.org, luto@kernel.org, anthony.yznaga@oracle.com, arnd@arndb.de, ashish.kalra@amd.com, benh@kernel.crashing.org, bp@alien8.de, catalin.marinas@arm.com, dave.hansen@linux.intel.com, dwmw2@infradead.org, ebiederm@xmission.com, mingo@redhat.com, jgowans@amazon.com, corbet@lwn.net, krzk@kernel.org, rppt@kernel.org, mark.rutland@arm.com, pbonzini@redhat.com, pasha.tatashin@soleen.com, hpa@zytor.com, peterz@infradead.org, ptyadav@amazon.de, robh+dt@kernel.org, robh@kernel.org, saravanak@google.com, skinsburskii@linux.microsoft.com, rostedt@goodmis.org, tglx@linutronix.de, thomas.lendacky@amd.com, usama.arif@bytedance.com, will@kernel.org, devicetree@vger.kernel.org, kexec@lists.infradead.org, linux-arm-kernel@lists.infradead.org, linux-doc@vger.kernel.org, linux-mm@kvack.org, x86@kernel.org X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: zjXah6TApVmUqZK1jXV7oDMIUMU_0UXB6Yfkv6uRiKM_1742980615 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 066A5100008 X-Stat-Signature: h5nee1d5yg8epbn1fqkan1g85673wu6h X-Rspam-User: X-HE-Tag: 1742980617-104258 X-HE-Meta: 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 1kZ5i0Gv 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 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000001, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, 25 Mar 2025 at 16:36, Dave Young wrote: > > > > > > > Have you tested kdump? In my mind there are two issues, one is with > > > CMA enabled, it could cause kdump crashkernel memory reservation > > > failures more often due to the fragmented low memory. Secondly, in > > > > kho scracth memorys are reserved much later than crashkernel, we may not > > need to worry about it. > > ==================== > > start_kernel() > > ...... > > -->setup_arch(&command_line); > > -->arch_reserve_crashkernel(); > > ...... > > -->mm_core_init(); > > -->kho_memory_init(); > > > > > kdump kernel dump the crazy scratch memory in vmcore is not very > > > meaningful. Otherwise I suspect this is not tested under kdump. If > > > so please disable this option for kdump. > > Ok, it is fine if this is the case, thanks Baoquan for clearing this worry. > > But the other concerns are still need to address, eg. KHO use cases > are not good for kdump. > There could be more to think about. > eg. the issues talked in thread: > https://lore.kernel.org/lkml/Z7dc9Cd8KX3b_brB@dwarf.suse.cz/T/ Rethink about this, other than previous concerns. Transferring the old kernel state to kdump kernel makes no sense since the old state is not stable as the kernel has crashed.