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From: Manfred Spraul <manfred@colorfullife.com>
To: Ravikiran G Thirumalai <kiran@in.ibm.com>
Cc: akpm@osdl.org, linux-kernel@vger.kernel.org,
	Robert Love <rml@tech9.net>,
	dipankar@in.ibm.com
Subject: Re: [patch] Make slab allocator work with SLAB_MUST_HWCACHE_ALIGN
Date: Sat, 13 Sep 2003 22:06:08 +0200	[thread overview]
Message-ID: <3F6378B0.8040606@colorfullife.com> (raw)
In-Reply-To: <20030912085921.GB1128@llm08.in.ibm.com>

Ravikiran G Thirumalai wrote:

>I am working on a simplistic allocator for alloc_percpu which
>1. Minimises cache footprint (simple pointer arithmetic to get to each cpus 
>   version
>2. Does numa aware allocation
>3. Does not fragment
>4. Is simple and extends simple pointer arithmetic to get to cpus offsets
>
>I wouldn't be using the slab at all because using slabs would mean using
>NR_CPUs pointers and one extra dereference which is bad as we had found out
>earlier.  But I guess slab will have to do node local allocations for
>other applications.
>  
>
Interesting. Slab internally uses lots of large per-cpu arrays. 
Alltogether something like around 40 kB/cpu. Right now implemented with 
NR_CPUs pointers. In the long run I'll try to switch to your allocator.

But back to the patch that started this thread: Do you still need the 
ability to set an explicit alignment for slab allocations? If yes, then 
I'd polish my patch, double check all kmem_cache_create callers and then 
send the patch to akpm. Otherwise I'd wait - the patch is not a bugfix.

--
    Manfred


  parent reply	other threads:[~2003-09-13 20:06 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-09-10  8:16 How reliable is SLAB_HWCACHE_ALIGN? Ravikiran G Thirumalai
2003-09-10 15:41 ` Robert Love
2003-09-11  5:54   ` Ravikiran G Thirumalai
2003-09-11 11:08     ` [patch] Make slab allocator work with SLAB_MUST_HWCACHE_ALIGN Ravikiran G Thirumalai
2003-09-11 16:19       ` Manfred Spraul
2003-09-11 21:49         ` Manfred Spraul
2003-09-12  8:59         ` Ravikiran G Thirumalai
2003-09-12  9:10           ` Arjan van de Ven
2003-09-13 20:06           ` Manfred Spraul [this message]
2003-09-13 20:58             ` Dipankar Sarma
2003-09-14  8:09             ` Ravikiran G Thirumalai
2003-09-14 13:00               ` Dipankar Sarma
2003-09-15  5:13                 ` Ravikiran G Thirumalai
     [not found] <u8mV.so.19@gated-at.bofh.it>
     [not found] ` <ufor.30e.21@gated-at.bofh.it>
     [not found]   ` <usvj.6s9.17@gated-at.bofh.it>
     [not found]     ` <uxv1.5D5.23@gated-at.bofh.it>
     [not found]       ` <uCuI.5hY.13@gated-at.bofh.it>
     [not found]         ` <uRWI.xK.5@gated-at.bofh.it>
     [not found]           ` <voSF.8l7.17@gated-at.bofh.it>
2003-09-13 22:18             ` Arnd Bergmann

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