From: Thomas Graf <tgraf@suug.ch>
To: lkp@lists.01.org
Subject: Re: rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation
Date: Wed, 09 Dec 2015 03:42:48 +0100 [thread overview]
Message-ID: <20151209024248.GA20213@pox.localdomain> (raw)
In-Reply-To: <20151209023844.GA24736@gondor.apana.org.au>
[-- Attachment #1: Type: text/plain, Size: 698 bytes --]
On 12/09/15 at 10:38am, Herbert Xu wrote:
> On Wed, Dec 09, 2015 at 03:36:32AM +0100, Thomas Graf wrote:
> >
> > Without knowing your exact implementation plans: introducing an
> > additional reference indirection for every lookup will have a
> > huge performance penalty as well.
> >
> > Is your plan to only introduce the master table after an
> > allocation has failed?
>
> Right, obviously the extra indirections would only come into play
> after a failed allocation. As soon as we can run the worker thread
> it'll try to remove the extra indirections by doing vmalloc.
OK, this sounds like a good compromise. The penalty is isolated
for the duration of the atomic burst.
WARNING: multiple messages have this Message-ID (diff)
From: Thomas Graf <tgraf@suug.ch>
To: Herbert Xu <herbert@gondor.apana.org.au>
Cc: David Miller <davem@davemloft.net>, Phil Sutter <phil@nwl.cc>,
Eric Dumazet <eric.dumazet@gmail.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
fengguang.wu@intel.com, wfg@linux.intel.com, lkp@01.org
Subject: Re: rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation
Date: Wed, 9 Dec 2015 03:42:48 +0100 [thread overview]
Message-ID: <20151209024248.GA20213@pox.localdomain> (raw)
In-Reply-To: <20151209023844.GA24736@gondor.apana.org.au>
On 12/09/15 at 10:38am, Herbert Xu wrote:
> On Wed, Dec 09, 2015 at 03:36:32AM +0100, Thomas Graf wrote:
> >
> > Without knowing your exact implementation plans: introducing an
> > additional reference indirection for every lookup will have a
> > huge performance penalty as well.
> >
> > Is your plan to only introduce the master table after an
> > allocation has failed?
>
> Right, obviously the extra indirections would only come into play
> after a failed allocation. As soon as we can run the worker thread
> it'll try to remove the extra indirections by doing vmalloc.
OK, this sounds like a good compromise. The penalty is isolated
for the duration of the atomic burst.
next prev parent reply other threads:[~2015-12-09 2:42 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-11-20 17:17 [PATCH v2 0/4] improve fault-tolerance of rhashtable runtime-test Phil Sutter
2015-11-20 17:17 ` [PATCH v2 1/4] rhashtable-test: add cond_resched() to thread test Phil Sutter
2015-11-20 17:17 ` [PATCH v2 2/4] rhashtable-test: retry insert operations Phil Sutter
2015-11-20 17:17 ` [PATCH v2 3/4] rhashtable-test: calculate max_entries value by default Phil Sutter
2015-11-20 17:17 ` [PATCH v2 4/4] rhashtable-test: allow to retry even if -ENOMEM was returned Phil Sutter
2015-11-20 17:28 ` Phil Sutter
2015-11-23 17:38 ` [PATCH v2 0/4] improve fault-tolerance of rhashtable runtime-test David Miller
2015-11-23 17:38 ` David Miller
2015-11-30 9:37 ` Herbert Xu
2015-11-30 9:37 ` Herbert Xu
2015-11-30 10:14 ` Phil Sutter
2015-11-30 10:18 ` Herbert Xu
2015-11-30 10:18 ` Herbert Xu
2015-12-03 12:41 ` rhashtable: Prevent spurious EBUSY errors on insertion Herbert Xu
2015-12-03 12:41 ` Herbert Xu
2015-12-03 15:38 ` Phil Sutter
2015-12-04 19:38 ` David Miller
2015-12-04 19:38 ` David Miller
2015-12-17 8:46 ` Xin Long
2015-12-17 8:48 ` Herbert Xu
2015-12-17 8:48 ` Herbert Xu
2015-12-17 9:00 ` Xin Long
2015-12-17 16:07 ` Xin Long
2015-12-18 2:26 ` Herbert Xu
2015-12-18 2:26 ` Herbert Xu
2015-12-18 8:18 ` Xin Long
2015-12-17 17:00 ` David Miller
2015-12-17 17:00 ` David Miller
2015-12-03 12:51 ` rhashtable: ENOMEM errors when hit with a flood of insertions Herbert Xu
2015-12-03 12:51 ` Herbert Xu
2015-12-03 15:08 ` David Laight
2015-12-03 15:08 ` David Laight
2015-12-03 16:08 ` Eric Dumazet
2015-12-03 16:08 ` Eric Dumazet
2015-12-04 0:07 ` Herbert Xu
2015-12-04 0:07 ` Herbert Xu
2015-12-04 14:39 ` rhashtable: Use __vmalloc with GFP_ATOMIC for table allocation Herbert Xu
2015-12-04 14:39 ` Herbert Xu
2015-12-04 17:01 ` Phil Sutter
2015-12-04 17:45 ` Eric Dumazet
2015-12-04 17:45 ` Eric Dumazet
2015-12-04 18:15 ` Phil Sutter
2015-12-05 7:06 ` Herbert Xu
2015-12-05 7:06 ` Herbert Xu
2015-12-07 15:35 ` Thomas Graf
2015-12-07 15:35 ` Thomas Graf
2015-12-07 19:29 ` David Miller
2015-12-07 19:29 ` David Miller
2015-12-09 2:18 ` Thomas Graf
2015-12-09 2:18 ` Thomas Graf
2015-12-09 2:24 ` Herbert Xu
2015-12-09 2:24 ` Herbert Xu
2015-12-09 2:36 ` Thomas Graf
2015-12-09 2:36 ` Thomas Graf
2015-12-09 2:38 ` Herbert Xu
2015-12-09 2:38 ` Herbert Xu
2015-12-09 2:42 ` Thomas Graf [this message]
2015-12-09 2:42 ` Thomas Graf
2015-12-04 21:53 ` David Miller
2015-12-04 21:53 ` David Miller
2015-12-05 7:03 ` Herbert Xu
2015-12-05 7:03 ` Herbert Xu
2015-12-06 3:48 ` David Miller
2015-12-06 3:48 ` David Miller
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