* [PATCH,RFC] [NET] ALIGN
@ 2004-02-09 4:45 YOSHIFUJI Hideaki / 吉藤英明
2004-02-09 19:20 ` David S. Miller
0 siblings, 1 reply; 4+ messages in thread
From: YOSHIFUJI Hideaki / 吉藤英明 @ 2004-02-09 4:45 UTC (permalink / raw)
To: davem; +Cc: netdev, yoshfuji
D: Use ALIGN() where appricable.
BTW,
1. do we really need this ALIGN?
2. should 16 be BYTES_PER_WORD (in mm/slab.c)?
===== net/core/neighbour.c 1.24 vs edited =====
--- 1.24/net/core/neighbour.c Tue Jan 20 14:31:23 2004
+++ edited/net/core/neighbour.c Mon Feb 9 13:13:37 2004
@@ -1164,8 +1164,7 @@
if (!tbl->kmem_cachep)
tbl->kmem_cachep = kmem_cache_create(tbl->id,
- (tbl->entry_size +
- 15) & ~15,
+ ALIGN(tbl->entry_size, 16),
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
tbl->lock = RW_LOCK_UNLOCKED;
--
Hideaki YOSHIFUJI @ USAGI Project <yoshfuji@linux-ipv6.org>
GPG FP: 9022 65EB 1ECF 3AD1 0BDF 80D8 4807 F894 E062 0EEA
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH,RFC] [NET] ALIGN
2004-02-09 4:45 [PATCH,RFC] [NET] ALIGN YOSHIFUJI Hideaki / 吉藤英明
@ 2004-02-09 19:20 ` David S. Miller
2004-02-10 4:05 ` YOSHIFUJI Hideaki / 吉藤英明
0 siblings, 1 reply; 4+ messages in thread
From: David S. Miller @ 2004-02-09 19:20 UTC (permalink / raw)
To: yoshfuji; +Cc: netdev
On Mon, 09 Feb 2004 13:45:28 +0900 (JST)
YOSHIFUJI Hideaki / ^[$B5HF#1QL@^[(B <yoshfuji@linux-ipv6.org> wrote:
> D: Use ALIGN() where appricable.
>
> BTW,
> 1. do we really need this ALIGN?
> 2. should 16 be BYTES_PER_WORD (in mm/slab.c)?
Let's hold on this patch.
Why does it want to align the table entry size to 16 bytes
anyways?
I think this is complete nonsense, and that the alignment is not
necessary. I can't even come up with a performance reason as SLAB
is going to align things to hw cache line size anyways.
Can anybody come up with some theory ? :-)
Else let's just remove this bogus 16 byte alignment in the
kmem_cache_create() call.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH,RFC] [NET] ALIGN
2004-02-09 19:20 ` David S. Miller
@ 2004-02-10 4:05 ` YOSHIFUJI Hideaki / 吉藤英明
2004-02-11 18:42 ` David S. Miller
0 siblings, 1 reply; 4+ messages in thread
From: YOSHIFUJI Hideaki / 吉藤英明 @ 2004-02-10 4:05 UTC (permalink / raw)
To: davem; +Cc: netdev
In article <20040209112007.08023ba6.davem@redhat.com> (at Mon, 9 Feb 2004 11:20:07 -0800), "David S. Miller" <davem@redhat.com> says:
> > BTW,
> > 1. do we really need this ALIGN?
> > 2. should 16 be BYTES_PER_WORD (in mm/slab.c)?
:
> I think this is complete nonsense, and that the alignment is not
> necessary. I can't even come up with a performance reason as SLAB
> is going to align things to hw cache line size anyways.
Agreed.
> Else let's just remove this bogus 16 byte alignment in the
> kmem_cache_create() call.
Let's kill it. It is very likely safe.
===== net/core/neighbour.c 1.24 vs edited =====
--- 1.24/net/core/neighbour.c Tue Jan 20 14:31:23 2004
+++ edited/net/core/neighbour.c Tue Feb 10 13:01:15 2004
@@ -1164,8 +1164,7 @@
if (!tbl->kmem_cachep)
tbl->kmem_cachep = kmem_cache_create(tbl->id,
- (tbl->entry_size +
- 15) & ~15,
+ tbl->entry_size,
0, SLAB_HWCACHE_ALIGN,
NULL, NULL);
tbl->lock = RW_LOCK_UNLOCKED;
--
Hideaki YOSHIFUJI @ USAGI Project <yoshfuji@linux-ipv6.org>
GPG FP: 9022 65EB 1ECF 3AD1 0BDF 80D8 4807 F894 E062 0EEA
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH,RFC] [NET] ALIGN
2004-02-10 4:05 ` YOSHIFUJI Hideaki / 吉藤英明
@ 2004-02-11 18:42 ` David S. Miller
0 siblings, 0 replies; 4+ messages in thread
From: David S. Miller @ 2004-02-11 18:42 UTC (permalink / raw)
To: yoshfuji; +Cc: netdev
On Tue, 10 Feb 2004 13:05:43 +0900 (JST)
YOSHIFUJI Hideaki / ^[$B5HF#1QL@^[(B <yoshfuji@linux-ipv6.org> wrote:
> In article <20040209112007.08023ba6.davem@redhat.com> (at Mon, 9 Feb 2004 11:20:07 -0800), "David S. Miller" <davem@redhat.com> says:
>
> > I think this is complete nonsense, and that the alignment is not
> > necessary. I can't even come up with a performance reason as SLAB
> > is going to align things to hw cache line size anyways.
>
> Agreed.
Patch applied, arigato Yoshfuji-san.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2004-02-09 4:45 [PATCH,RFC] [NET] ALIGN YOSHIFUJI Hideaki / 吉藤英明
2004-02-09 19:20 ` David S. Miller
2004-02-10 4:05 ` YOSHIFUJI Hideaki / 吉藤英明
2004-02-11 18:42 ` David S. Miller
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