From: Vlastimil Babka <vbabka@suse.cz>
To: Nicholas Piggin <npiggin@gmail.com>,
David Laight <David.Laight@ACULAB.COM>
Cc: Jason Baron <jbaron@akamai.com>,
Hillf Danton <hillf.zj@alibaba-inc.com>,
'Alexander Viro' <viro@zeniv.linux.org.uk>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
'Michal Hocko' <mhocko@kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Eric Dumazet <eric.dumazet@gmail.com>
Subject: Re: [PATCH] fs/select: add vmalloc fallback for select(2)
Date: Tue, 27 Sep 2016 13:51:03 +0200 [thread overview]
Message-ID: <92d1ec2c-3246-bd1f-eae5-53ca425ab315@suse.cz> (raw)
In-Reply-To: <20160927214229.2b0b49ac@roar.ozlabs.ibm.com>
On 09/27/2016 01:42 PM, Nicholas Piggin wrote:
> On Tue, 27 Sep 2016 11:37:24 +0000
> David Laight <David.Laight@ACULAB.COM> wrote:
>
>> From: Nicholas Piggin
>> > Sent: 27 September 2016 12:25
>> > On Tue, 27 Sep 2016 10:44:04 +0200
>> > Vlastimil Babka <vbabka@suse.cz> wrote:
>> >
>> >
>> > What's your customer doing with those selects? If they care at all about
>> > performance, I doubt they want select to attempt order-4 allocations, fail,
>> > then use vmalloc :)
>>
>> If they care about performance they shouldn't be passing select() lists that
>> are anywhere near that large.
>> If the number of actual fd is small - use poll().
>
> Right. Presumably it's some old app they're still using, no?
Process name suggests it's part of db2 database. It seems it has to implement
its own interface to select() syscall, because glibc itself seems to have a
FD_SETSIZE limit of 1024, which is probably why this wasn't an issue for all the
years...
--
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>
next prev parent reply other threads:[~2016-09-27 11:51 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-22 15:28 Vlastimil Babka
2016-09-22 16:24 ` Eric Dumazet
2016-09-22 16:40 ` Vlastimil Babka
2016-09-23 6:42 ` Hillf Danton
2016-09-23 7:24 ` Nicholas Piggin
2016-09-23 16:47 ` Jason Baron
2016-09-27 8:44 ` Vlastimil Babka
2016-09-27 11:24 ` Nicholas Piggin
2016-09-27 11:37 ` David Laight
2016-09-27 11:42 ` Nicholas Piggin
2016-09-27 11:51 ` Vlastimil Babka [this message]
2016-09-28 16:30 ` David Laight
2016-09-28 20:04 ` Vlastimil Babka
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=92d1ec2c-3246-bd1f-eae5-53ca425ab315@suse.cz \
--to=vbabka@suse.cz \
--cc=David.Laight@ACULAB.COM \
--cc=eric.dumazet@gmail.com \
--cc=hillf.zj@alibaba-inc.com \
--cc=jbaron@akamai.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=npiggin@gmail.com \
--cc=viro@zeniv.linux.org.uk \
/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