Vitaly Kuznetsov bba072d162 hv_balloon: fix bugs in num_pages_onlined accounting
Our num_pages_onlined accounting is buggy:
1) In case we're offlining a memory block which was present at boot (e.g.
   when there was no hotplug at all) we subtract 32k from 0 and as
   num_pages_onlined is unsigned get a very big positive number.

2) Commit 6df8d9aaf3 ("Drivers: hv: balloon: Correctly update onlined
   page count") made num_pages_onlined counter accurate on onlining but
   totally incorrect on offlining for partly populated regions: no matter
   how many pages were onlined and what was actually added to
   num_pages_onlined counter we always subtract the full region (32k) so
   again, num_pages_onlined can wrap around zero. By onlining/offlining
   the same partly populated region multiple times we can make the
   situation worse.

Solve these issues by doing accurate accounting on offlining: walk HAS
list, check for covered range and gaps.

Fixes: 6df8d9aaf3 ("Drivers: hv: balloon: Correctly update onlined page count")
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2018-03-06 09:57:17 -08:00
2018-01-06 10:59:44 -07:00
2018-03-04 14:54:11 -08:00

Linux kernel
============

This file was moved to Documentation/admin-guide/README.rst

Please notice that there are several guides for kernel developers and users.
These guides can be rendered in a number of formats, like HTML and PDF.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
See Documentation/00-INDEX for a list of what is contained in each file.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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