Re: [PATCH] mm: compaction: optimize compact_memory to comply with the admin-guide

[Andrew Morton]

On Wed, 12 Apr 2023 02:24:26 +0800 wenyang.linux@xxxxxxxxxxx wrote:

> For the /proc/sys/vm/compact_memory file, the admin-guide states:
> When 1 is written to the file, all zones are compacted such that free
> memory is available in contiguous blocks where possible. This can be
> important for example in the allocation of huge pages although processes
> will also directly compact memory as required
> 
> But it was not strictly followed, writing any value would cause all
> zones to be compacted. In some critical scenarios, some applications
> operating it, such as echo 0, have caused serious problems.

Really?  You mean someone actually did this and didn't observe the
effect during their testing?

> It has been slightly optimized to comply with the admin-guide.