Re: [PATCH 1/2] x86: x86_64_defconfig: Enable KSM.
From: Austin S. Hemmelgarn
Date: Fri Jun 15 2018 - 08:23:50 EST
On 2018-06-14 18:50, Daniel DÃaz wrote:
As per the documentation, Kernel Samepage Merging (availableAs pointed out by a couple of others, this doesn't explain why this is a
good idea. All you're doing here is giving a reason that it won't have
a negative impact on most users.
since 2.6.32) is a memory-saving de-duplication feature,
enabled by CONFIG_KSM=y and activated via sysfs. More
information can be found here:
When enabled in the kernel, the default is to not do anything
at all, until it is activated at run-time with:
echo 1 > /sys/kernel/mm/ksm/run
Two points that may be worth adding, but also don't really argue for it
being a significant improvement:
* Pretty much all of the major distributions that use pre-built kernels
have it enabled in their kernels (At minimum, Debian, Ubuntu, Fedora
(and by extension RHEL and CentOS), openSUSE (and by extension SLES),
Arch, and Alpine have it enabled), so enabling this in defconfig would
bring it a bit closer to parity with distribution kernels in terms of
* Software other than QEMU is starting to take advantage of it if
available (for example, Netdata  can mark it's in-memory TSDB's for
deduplication, which usually cuts it's memory usage roughly in half).