Re: [PATCH][RFC] slub: increasing order reduces memory usage of somekey caches

From: Christoph Lameter
Date: Fri Jul 18 2008 - 10:19:21 EST


Richard Kennedy wrote:

> Slabcache: dentry Aliases: 0 Order : 0 Objects: 22553
> ** Reclaim accounting active
>
> Sizes (bytes) Slabs Debug Memory
> ------------------------------------------------------------------------
> Object : 208 Total : 1188 Sanity Checks : Off Total: 4866048
> SlabObj: 208 Full : 1186 Redzoning : Off Used : 4691024
> SlabSiz: 4096 Partial: 0 Poisoning : Off Loss : 175024
> Loss : 0 CpuSlab: 2 Tracking : Off Lalig: 0
> Align : 8 Objects: 19 Tracing : Off Lpadd: 171072

So we are using 1188 pages before make

> and after a make kernel & a small delay

2399 pages after make

> on 2.6.26 + my patch

579 * 2 = 1158 (saved 30 pages even before doing anything) before make


> after the make

2025 *2 = 4050 pages which are much more than the 2399 with order 0.
So we are wasting a lot more space. You'd probably need to run slab defrag to get that memory back.

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