From: Rusty Russell <rusty@au1.ibm.com>
To: Ravikiran G Thirumalai <kiran@in.ibm.com>
Cc: dipankar@in.ibm.com, linux-kernel@vger.kernel.org, akpm@zip.com.au
Subject: Re: [PATCH] kmalloc_percpu
Date: Tue, 06 May 2003 18:03:15 +1000 [thread overview]
Message-ID: <20030506082949.F2A3217DE0@ozlabs.au.ibm.com> (raw)
In-Reply-To: Your message of "Tue, 06 May 2003 10:37:44 +0530." <20030506050744.GA29352@in.ibm.com>
In message <20030506050744.GA29352@in.ibm.com> you write:
> On Mon, May 05, 2003 at 08:46:58AM +0000, Andrew Morton wrote:
> Andrew,
> Here is a comparision of kmalloc_percpu techniques as I see it,
>
> Current Implementation:
> 1. Two dereferences to get to the per-cpu data
> 2. Allocates for cpu_possible cpus only, and can deal with sparse cpu nos
>
> Rusty's Implementation
> 1. One extra memory reference (__per_cpu_offset)
> 2. allocates for NR_CPUS and probably breaks with sparse cpu nos?
> 3. Let you do per-cpu data in modules
> 4. fragmentation
And #3 is, in fact, the one I care about. The extra memory reference
is already probably cachehot (all static per-cpu use it), and might be
in a register on some archs.
Doesn't break with sparce CPU #s, but yes, it is inefficient.
Cheers,
Rusty.
--
Anyone who quotes me in their sig is an idiot. -- Rusty Russell.
next prev parent reply other threads:[~2003-05-06 8:18 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-05-05 8:08 [PATCH] kmalloc_percpu Rusty Russell
2003-05-05 8:47 ` Andrew Morton
2003-05-06 0:47 ` Rusty Russell
2003-05-06 1:52 ` Andrew Morton
2003-05-06 2:11 ` David S. Miller
2003-05-06 4:08 ` Rusty Russell
2003-05-06 3:40 ` David S. Miller
2003-05-06 5:02 ` Andrew Morton
2003-05-06 4:16 ` David S. Miller
2003-05-06 5:48 ` Andrew Morton
2003-05-06 5:35 ` David S. Miller
2003-05-06 6:55 ` Andrew Morton
2003-05-06 5:57 ` David S. Miller
2003-05-06 7:22 ` Andrew Morton
2003-05-06 6:15 ` David S. Miller
2003-05-06 7:34 ` Andrew Morton
2003-05-06 8:42 ` William Lee Irwin III
2003-05-06 14:38 ` Martin J. Bligh
2003-05-06 7:20 ` Dipankar Sarma
2003-05-06 8:28 ` Rusty Russell
2003-05-06 8:47 ` Andrew Morton
2003-05-07 1:57 ` Rusty Russell
2003-05-07 2:41 ` William Lee Irwin III
2003-05-07 4:03 ` Paul Mackerras
2003-05-07 4:22 ` William Lee Irwin III
2003-05-07 4:56 ` Paul Mackerras
2003-05-07 5:19 ` William Lee Irwin III
2003-05-07 4:10 ` Martin J. Bligh
2003-05-07 12:13 ` William Lee Irwin III
2003-05-07 4:15 ` Rusty Russell
2003-05-07 5:37 ` Andrew Morton
2003-05-08 0:53 ` Rusty Russell
2003-05-06 14:41 ` Martin J. Bligh
2003-05-06 6:42 ` Andrew Morton
2003-05-06 5:39 ` David S. Miller
2003-05-06 6:57 ` Andrew Morton
2003-05-06 7:25 ` Jens Axboe
2003-05-06 10:41 ` Ingo Oeser
2003-05-06 16:05 ` Bryan O'Sullivan
2003-05-06 8:06 ` Rusty Russell
2003-05-06 5:03 ` Dipankar Sarma
2003-05-06 4:28 ` Andrew Morton
2003-05-06 3:37 ` David S. Miller
2003-05-06 4:11 ` Rusty Russell
2003-05-06 5:07 ` Ravikiran G Thirumalai
2003-05-06 8:03 ` Rusty Russell [this message]
2003-05-06 9:23 ` David S. Miller
2003-05-06 9:34 ` Ravikiran G Thirumalai
2003-05-06 9:38 ` Dipankar Sarma
2003-05-07 2:14 ` Rusty Russell
2003-05-07 5:51 ` Ravikiran G Thirumalai
2003-05-07 6:16 ` Rusty Russell
2003-05-08 7:42 ` Ravikiran G Thirumalai
2003-05-08 7:47 ` Rusty Russell
-- strict thread matches above, loose matches on Subject: below --
2002-10-31 16:06 [patch] kmalloc_percpu Ravikiran G Thirumalai
2002-11-01 8:33 ` Rusty Russell
2002-11-05 16:00 ` Dipankar Sarma
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