From: Wilco Dijkstra <Wilco.Dijkstra@arm.com>
To: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>,
"libc-alpha@sourceware.org" <libc-alpha@sourceware.org>,
Cupertino Miranda <cupertino.miranda@oracle.com>
Subject: Re: [PATCH] nptl: Disable THP on thread stack if it incurs in large RSS usage
Date: Wed, 17 May 2023 12:49:42 +0000 [thread overview]
Message-ID: <PAWPR08MB898213ECDCF7D98E89370654837E9@PAWPR08MB8982.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <f0b2fca5-f21d-b538-329f-7795e85ad4f1@linaro.org>
Hi Adhemerval,
>> The question is, under what circumstances are huge pages in stacks beneficial and
>> in which cases are they not? If have a good answer to that, then we can automatically
>> do the right thing without needing a tuning.
>>
>
> Afaiu the issue is not whether huge page in stacks is beneficial, but rather
> when kernel will fall back to default pages anyway which will be just waste
> cycles. Another option would be tune the default stack and guard size
> to avoid this issue, but this might require some more heuristics to find a
> good spot to avoid too much VMA waste.
The kernel won't fallback to standard pages - like I said, it really allocates a huge
page when it can (based on alignment of the stack) and that is what causes the
increase of RSS size. But that's not evidence of an issue.
So the real question is when do huge pages make sense for stacks?
Cheers,
Wilco
next prev parent reply other threads:[~2023-05-17 12:49 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-20 17:24 Adhemerval Zanella
2023-05-03 12:42 ` Wilco Dijkstra
2023-05-15 17:57 ` Adhemerval Zanella Netto
2023-05-16 15:38 ` Wilco Dijkstra
2023-05-16 16:35 ` Adhemerval Zanella Netto
2023-05-17 12:49 ` Wilco Dijkstra [this message]
2023-05-17 13:12 ` Cupertino Miranda
2023-05-17 13:20 ` Adhemerval Zanella Netto
2023-05-17 14:22 ` Wilco Dijkstra
2023-05-17 16:50 ` Adhemerval Zanella Netto
2023-05-17 18:16 ` Wilco Dijkstra
2023-05-18 13:04 ` Adhemerval Zanella Netto
2023-05-23 9:48 ` Wilco Dijkstra
2024-01-31 2:03 ` Cristian Rodríguez
2024-01-31 7:54 ` Florian Weimer
2024-01-31 11:30 ` Adhemerval Zanella Netto
2024-01-31 11:43 ` Florian Weimer
2024-03-12 0:55 ` Cristian Rodríguez
2024-01-31 15:18 ` Cristian Rodríguez
2024-02-01 1:26 ` Cristian Rodríguez
2023-05-16 14:30 ` Cupertino Miranda
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=PAWPR08MB898213ECDCF7D98E89370654837E9@PAWPR08MB8982.eurprd08.prod.outlook.com \
--to=wilco.dijkstra@arm.com \
--cc=adhemerval.zanella@linaro.org \
--cc=cupertino.miranda@oracle.com \
--cc=libc-alpha@sourceware.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).