Re: [PATCH 2.43] malloc: Show hugetlb tunable default in --list-tunables

Wilco Dijkstra <[email protected]>
Newsgroups gmane.comp.lib.glibc.alpha
Message-ID <PAWPR08MB8982D72C5881F50559CA553E83DA2@PAWPR08MB8982.eurprd08.prod.outlook.com>
Hi Alexander,

> On Thu, 2026-08-13 at 13:52 +0000, Wilco Dijkstra wrote:
>> The backport looks fine - I can do the commit if you don't have write access.
>
> sure, thank you for the quick reaction! (no, I don't have write access)

OK, committed as 7d26579873791748c20d874adb66e877412175dd

> I believe the pages are getting accessed, but the side effect comes on the systems
> which always had
>
> /sys/kernel/mm/transparent_hugepage/enabled: [always] madvise never
>
> so madvise() syscall plays no role for them, but padding does.

If you set THP to [always], you explicitly state that you want hugepages to be used as
much as possible. You will always get hugepages for large allocations or as a result of
background page coalescing. Other allocators are far more aggressive than GLIBC -
this work is reducing these obvious gaps.

Cheers,
Wilco
lmpx.com only provides a reader for public news (NNTP) servers. It is not affiliated with the servers or forums shown here and is not responsible for the content of articles, which is written by their respective authors.