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From: Eric Dumazet <eric.dumazet@gmail.com>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Linux 4.9-rc6
Date: Sun, 20 Nov 2016 14:27:53 -0800	[thread overview]
Message-ID: <1479680873.8455.386.camel@edumazet-glaptop3.roam.corp.google.com> (raw)
In-Reply-To: <CA+55aFw00NZUf37F4cDo99ymcki336TAzfp6C505z9yP-2oRQQ@mail.gmail.com>

On Sun, 2016-11-20 at 14:05 -0800, Linus Torvalds wrote:

> That said, nothing particular is bothering me all that much, but we've
> had some of the VMALLOC_STACK fixups continue to trickle in, so I
> worry that we're not quite done there yet. And let's see what
> Thorsten's regression list looks like next week. So no decision yet,
> it could still go either way.

Hosts with ~100,000 threads have an issue with /prov/vmallocinfo

It can take about 800 usec to skip over ~100,000 struct vmap_area
in s_start(), while holding vmap_area_lock spinlock, and therefore
blocking fork()/pthread_create().

I presume we can not switch to the rbtree (vmap_area_root)
for /proc/vmallocinfo, because this file is seek-able, right ?

  reply	other threads:[~2016-11-20 22:34 UTC|newest]

Thread overview: 12+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-11-20 22:05 Linus Torvalds
2016-11-20 22:27 ` Eric Dumazet [this message]
2016-11-20 23:27   ` Linus Torvalds
2016-11-21  1:35     ` Al Viro
2016-11-21  4:59       ` Eric Dumazet
2016-11-21  8:34         ` David Rientjes
2016-11-21 13:32           ` Eric Dumazet
2016-11-21 13:51             ` Eric Dumazet
2016-11-21 16:49               ` Eric Dumazet
2016-12-04 10:43               ` Thorsten Leemhuis
     [not found]                 ` <CA+55aFzPiZW4FfWbvM-+AFraa0fkUHv4C1Y9SCzHdXEcUSPqdg@mail.gmail.com>
2016-12-04 17:17                   ` Eric Dumazet
2016-12-21 15:30                     ` Eric Dumazet

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