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From: Eric Dumazet <dada1@cosmosbay.com>
To: Ravikiran G Thirumalai <kiran@scalex86.org>
Cc: Andrew Morton <akpm@osdl.org>,
	davem@davemloft.net, linux-kernel@vger.kernel.org,
	shai@scalex86.org, netdev@vger.kernel.org,
	pravins@calsoftinc.com
Subject: Re: [patch 3/4] net: Percpufy frequently used variables -- proto.sockets_allocated
Date: Sat, 28 Jan 2006 00:21:07 +0100	[thread overview]
Message-ID: <43DAAAE3.2030107@cosmosbay.com> (raw)
In-Reply-To: <20060127225036.GC3565@localhost.localdomain>

Ravikiran G Thirumalai a écrit :
> On Fri, Jan 27, 2006 at 11:30:23PM +0100, Eric Dumazet wrote:
>> There are several issues here :
>>
>> alloc_percpu() current implementation is a a waste of ram. (because it uses 
>> slab allocations that have a minimum size of 32 bytes)
> 
> Oh there was a solution for that :).  
> 
> http://lwn.net/Articles/119532/
> 
> I can quickly revive it if there is interest.
> 

Well, nice work ! :)

Maybe a litle bit complicated if expected percpu space is 50 KB per cpu ?

Why not use a boot time allocated percpu area (as done today in 
setup_per_cpu_areas()), but instead of reserving extra space for module's 
percpu data, being able to serve alloc_percpu() from this reserved area (ie no 
kmalloced data anymore), and keeping your

#define per_cpu_ptr(ptr, cpu)  ((__typeof__(ptr))         \
	(RELOC_HIDE(ptr,  PCPU_BLKSIZE * cpu)))

Some code from kernel/module.c could be reworked to serve both as an allocator 
when a module percpudata must be relocated (insmod)/freed (rmmod), and serve 
alloc_percpu() for 'dynamic allocations'

Eric

  reply	other threads:[~2006-01-27 23:21 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-01-26 18:56 [patch 0/4] net: Percpufy frequently used variables on struct proto Ravikiran G Thirumalai
2006-01-26 18:59 ` [patch 1/4] net: Percpufy frequently used variables -- add percpu_counter_mod_bh Ravikiran G Thirumalai
2006-01-26 19:02 ` [patch 2/4] net: Percpufy frequently used variables -- struct proto.memory_allocated Ravikiran G Thirumalai
2006-01-27  9:01   ` Eric Dumazet
2006-01-26 19:03 ` [patch 3/4] net: Percpufy frequently used variables -- proto.sockets_allocated Ravikiran G Thirumalai
2006-01-27  8:53   ` Eric Dumazet
2006-01-27 19:52     ` Ravikiran G Thirumalai
2006-01-27 20:16       ` Andrew Morton
2006-01-27 22:30         ` Eric Dumazet
2006-01-27 22:50           ` Ravikiran G Thirumalai
2006-01-27 23:21             ` Eric Dumazet [this message]
2006-01-28  0:40               ` Ravikiran G Thirumalai
2006-01-27 22:44         ` Ravikiran G Thirumalai
2006-01-27 22:58           ` Eric Dumazet
2006-01-27 23:16             ` Andrew Morton
2006-01-28  0:28               ` Eric Dumazet
2006-01-28  0:35                 ` Eric Dumazet
2006-01-28  4:52                   ` Ravikiran G Thirumalai
2006-01-28  7:19                     ` Eric Dumazet
2006-01-28  0:43                 ` Andrew Morton
2006-01-28  1:10                   ` Eric Dumazet
2006-01-28  1:18                     ` Andrew Morton
2006-01-29  0:44                 ` Benjamin LaHaise
2006-01-29  0:55                   ` Andrew Morton
2006-01-29  1:19                     ` Benjamin LaHaise
2006-01-29  1:29                       ` Andrew Morton
2006-01-29  1:45                       ` Kyle McMartin
2006-01-29  5:38                     ` Andi Kleen
2006-01-29  6:54                   ` Eric Dumazet
2006-01-29 19:52                     ` Benjamin LaHaise
2006-01-27 23:01           ` Andrew Morton
2006-01-27 23:08             ` Andrew Morton
2006-01-28  0:01               ` Ravikiran G Thirumalai
2006-01-28  0:26                 ` Andrew Morton
2006-02-03  3:05             ` Ravikiran G Thirumalai
2006-02-03  3:16               ` Andrew Morton
2006-02-03 19:37                 ` Ravikiran G Thirumalai
2006-02-03 20:13                   ` Andrew Morton
2006-01-26 19:05 ` [patch 4/4] net: Percpufy frequently used variables -- proto.inuse Ravikiran G Thirumalai

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