Re: [PATCH] Shrinks sizeof(files_struct) and better layout

[Eric Dumazet]

Andi Kleen a écrit :
> On Wednesday 04 January 2006 12:13, Eric Dumazet wrote:
> > Andi Kleen a écrit :
> > > Eric Dumazet <dada1@xxxxxxxxxxxxx> writes:
> > > > 1) Reduces the size of (struct fdtable) to exactly 64 bytes on 32bits
> > > > platforms, lowering kmalloc() allocated space by 50%.
> > > It should be probably a kmem_cache_alloc() instead of a kmalloc
> > > in the first place anyways. This would reduce fragmentation.
> > Well in theory yes, if you really expect thousand of tasks running...
> > But for most machines, number of concurrent tasks is < 200, and using a 
> > special cache for this is not a win.
>
> It is because it avoids fragmentation because objects with similar livetimes
> are clustered together. In general caches are a win
> if the data is nearly a page or more.

I dont undertand your last sentence. Do you mean 'if the object size is near 
PAGE_SIZE' ?

Eric
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/