From: ebiederm@xmission.com (Eric W. Biederman)
To: Sang Yan <sangyan@huawei.com>
Cc: luanjianhai@huawei.com, xiexiuqi@huawei.com,
kexec@lists.infradead.org, linux-kernel@vger.kernel.org,
luchunhua@huawei.com, guohanjun@huawei.com, zhuling8@huawei.com
Subject: Re: [PATCH 1/2] kexec: Add quick kexec support for kernel
Date: Fri, 14 Aug 2020 10:17:06 -0500 [thread overview]
Message-ID: <87tux5i7f1.fsf@x220.int.ebiederm.org> (raw)
In-Reply-To: <20200814055239.47348-1-sangyan@huawei.com> (Sang Yan's message of "Fri, 14 Aug 2020 01:52:38 -0400")
Sang Yan <sangyan@huawei.com> writes:
> In normal kexec, relocating kernel may cost 5 ~ 10 seconds, to
> copy all segments from vmalloced memory to kernel boot memory,
> because of disabled mmu.
I haven't seen kexec that slow since I tested on my 16Mhz 386.
That machine has an excuse it really is slow. Anything else
that takes seconds is almost certainly slow because someone
has misconfigured things to not cache the data copied by kexec.
I humbly suggest that you fix the arm64 code so that the data gets
cached.
Eric
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next prev parent reply other threads:[~2020-08-14 15:20 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-14 5:52 [PATCH 1/2] kexec: Add quick kexec support for kernel Sang Yan
2020-08-14 5:52 ` [PATCH 2/2] arm64: Reserve memory for quick kexec Sang Yan
2020-08-16 4:11 ` kernel test robot
2020-08-14 6:58 ` [PATCH 1/2] kexec: Add quick kexec support for kernel Dave Young
2020-08-14 8:21 ` Sang Yan
2020-08-14 11:24 ` Dave Young
2020-08-14 19:22 ` Pavel Tatashin
2020-08-17 12:14 ` James Morse
2020-08-19 12:37 ` Dave Young
2020-08-14 15:17 ` Eric W. Biederman [this message]
2020-08-17 13:42 ` Pavel Machek
2020-08-18 6:49 ` Sang Yan
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