Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
MIME-Version: 1.0
References: <20210802215408.804942-1-pasha.tatashin@soleen.com>
 <20210824180555.GD623@arm.com> <CA+CK2bCakwsqS1RqXPJr+ewe=gsO98cOxhXye8-AcRLwtqhZ+g@mail.gmail.com>
 <YUMQZGLQl+82fL6G@arm.com>
In-Reply-To: <YUMQZGLQl+82fL6G@arm.com>
From:   Pasha Tatashin <pasha.tatashin@soleen.com>
Date:   Thu, 16 Sep 2021 18:32:14 -0400
Message-ID: <CA+CK2bB-BV2tzeq8M_B+5M9YRJX-GmT-9ZM0fnvrfnuWhSk46g@mail.gmail.com>
Subject: Re: [PATCH v16 00/15] arm64: MMU enabled kexec relocation
To:     Catalin Marinas <catalin.marinas@arm.com>
Cc:     James Morris <jmorris@namei.org>, Sasha Levin <sashal@kernel.org>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        kexec mailing list <kexec@lists.infradead.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Will Deacon <will@kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Marc Zyngier <maz@kernel.org>,
        James Morse <james.morse@arm.com>,
        Vladimir Murzin <vladimir.murzin@arm.com>,
        Matthias Brugger <matthias.bgg@gmail.com>,
        linux-mm <linux-mm@kvack.org>,
        Mark Rutland <mark.rutland@arm.com>, steve.capper@arm.com,
        rfontana@redhat.com, Thomas Gleixner <tglx@linutronix.de>,
        Selin Dag <selindag@gmail.com>,
        Tyler Hicks <tyhicks@linux.microsoft.com>,
        Pingfan Liu <kernelfans@gmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        madvenka@linux.microsoft.com
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

> > In case we are so low on memory that trans_pgd_create_copy() fails to
> > allocate the linear map that uses the large pages (the size of the
> > page table is tiny) the kexec fails during kexec load time (not during
> > reboot time), as out of memory. The MMU enabled kexec reboot is always
> > on, and we should not have several ways to do kexec reboot as it makes
> > the kexec reboot unpredictable in terms of performance, and also prone
> > to bugs by having a common MMU enabled path and less common path when
> > we are low on memory which is never tested.
>
> I think this makes sense, especially since it will fail during the kexec
> load time rather than reboot.
>
> I'm ok in principle with this series but I'd need to convince James
> Morse to have a another look since he followed it more closely than me.
> Could you please rebase it against 5.15-rc1?

Sure, I will send it out soon.

Thanks,
Pasha