From: Andi Kleen <andi@firstfloor.org>
To: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, mhocko@kernel.org
Subject: Re: [v4 1/1] mm: Adaptive hash table scaling
Date: Sat, 20 May 2017 19:07:29 -0700 [thread overview]
Message-ID: <87h90faroe.fsf@firstfloor.org> (raw)
In-Reply-To: <1495300013-653283-2-git-send-email-pasha.tatashin@oracle.com> (Pavel Tatashin's message of "Sat, 20 May 2017 13:06:53 -0400")
Pavel Tatashin <pasha.tatashin@oracle.com> writes:
> Allow hash tables to scale with memory but at slower pace, when HASH_ADAPT
> is provided every time memory quadruples the sizes of hash tables will only
> double instead of quadrupling as well. This algorithm starts working only
> when memory size reaches a certain point, currently set to 64G.
>
> This is example of dentry hash table size, before and after four various
> memory configurations:
IMHO the scale is still too aggressive. I find it very unlikely
that a 1TB machine really needs 256MB of hash table because
number of used files are unlikely to directly scale with memory.
Perhaps should just cap it at some large size, e.g. 32M
-Andi
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Andi Kleen <andi@firstfloor.org>
To: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, mhocko@kernel.org
Subject: Re: [v4 1/1] mm: Adaptive hash table scaling
Date: Sat, 20 May 2017 19:07:29 -0700 [thread overview]
Message-ID: <87h90faroe.fsf@firstfloor.org> (raw)
In-Reply-To: <1495300013-653283-2-git-send-email-pasha.tatashin@oracle.com> (Pavel Tatashin's message of "Sat, 20 May 2017 13:06:53 -0400")
Pavel Tatashin <pasha.tatashin@oracle.com> writes:
> Allow hash tables to scale with memory but at slower pace, when HASH_ADAPT
> is provided every time memory quadruples the sizes of hash tables will only
> double instead of quadrupling as well. This algorithm starts working only
> when memory size reaches a certain point, currently set to 64G.
>
> This is example of dentry hash table size, before and after four various
> memory configurations:
IMHO the scale is still too aggressive. I find it very unlikely
that a 1TB machine really needs 256MB of hash table because
number of used files are unlikely to directly scale with memory.
Perhaps should just cap it at some large size, e.g. 32M
-Andi
next prev parent reply other threads:[~2017-05-21 2:07 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-20 17:06 [v4 0/1] mm: Adaptive hash table scaling Pavel Tatashin
2017-05-20 17:06 ` Pavel Tatashin
2017-05-20 17:06 ` [v4 1/1] " Pavel Tatashin
2017-05-20 17:06 ` Pavel Tatashin
2017-05-21 2:07 ` Andi Kleen [this message]
2017-05-21 2:07 ` Andi Kleen
2017-05-21 12:58 ` Pasha Tatashin
2017-05-21 12:58 ` Pasha Tatashin
2017-05-21 16:35 ` Andi Kleen
2017-05-21 16:35 ` Andi Kleen
2017-05-22 6:17 ` Michael Ellerman
2017-05-22 6:17 ` Michael Ellerman
2017-05-22 9:29 ` Michal Hocko
2017-05-22 9:29 ` Michal Hocko
2017-05-22 13:18 ` Pasha Tatashin
2017-05-22 13:18 ` Pasha Tatashin
2017-05-22 13:38 ` Michal Hocko
2017-05-22 13:38 ` Michal Hocko
2017-05-22 13:41 ` Pasha Tatashin
2017-05-22 13:41 ` Pasha Tatashin
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=87h90faroe.fsf@firstfloor.org \
--to=andi@firstfloor.org \
--cc=akpm@linux-foundation.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=pasha.tatashin@oracle.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.