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From: Cliff Wickman <cpw@sgi.com>
To: kexec@lists.infradead.org
Subject: [PATCH 0/2] time and space saving patches for large memories
Date: Tue, 9 Dec 2014 16:04:27 -0600	[thread overview]
Message-ID: <20141209220427.GA18652@sgi.com> (raw)

From: Cliff Wickman <cpw@sgi.com>

Back in early 2014 I submitted several patches for your consideration, most of
which concerned saving time and disk space when dumping very large memories.

I offer two of them again, as being the most important elements for the
practical dumping of very large memories.

[PATCH 1/2] use raw i/o and root device to use less memory
[PATCH 2/2] exclude page structures of non-dumped pages
  The second patch has a few dependencies on the first. But they are logically
  separate.  
  They apply to the 1.5.7 source.

As an example of the importance of these two concepts:
 We dump a 2TB system using crashkernel=450M.
 Without the patches we write a 3.6G dump in about 12 minutes.
 With the patches we write a 590M dump in about 4 minutes.
And the savings multiply as memory size grows.

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                 reply	other threads:[~2014-12-09 22:04 UTC|newest]

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