xfrm: use a dedicated slab cache for struct xfrm_state

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struct xfrm_state is rather large (768 bytes here) and therefore wastes
quite a lot of memory as it falls into the kmalloc-1024 slab cache,
leaving 256 bytes of unused memory per XFRM state object -- a net waste
of 25%.

Using a dedicated slab cache for struct xfrm_state reduces the level of
internal fragmentation to a minimum.

On my configuration SLUB chooses to create a slab cache covering 4
pages holding 21 objects, resulting in an average memory waste of ~13
bytes per object -- a net waste of only 1.6%.

In my tests this led to memory savings of roughly 2.3MB for 10k XFRM
states.

Signed-off-by: Mathias Krause <minipli@googlemail.com>
Signed-off-by: Steffen Klassert <steffen.klassert@secunet.com>

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Mathias Krause 2018-05-03 10:55:07 +02:00 • committed by Steffen Klassert

parent 154a8c46ba

commit 565f0fa902

1 changed files with 7 additions and 2 deletions

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net/xfrm/xfrm_state.c

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