From 565f0fa902b64020d5d147ff1708567e9e0b6e49 Mon Sep 17 00:00:00 2001 From: Mathias Krause Date: Thu, 3 May 2018 10:55:07 +0200 Subject: xfrm: use a dedicated slab cache for struct xfrm_state 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 Signed-off-by: Steffen Klassert --- net/xfrm/xfrm_state.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) (limited to 'net/xfrm') diff --git a/net/xfrm/xfrm_state.c b/net/xfrm/xfrm_state.c index f9d2f2233f09..f595797a20ce 100644 --- a/net/xfrm/xfrm_state.c +++ b/net/xfrm/xfrm_state.c @@ -42,6 +42,7 @@ static void xfrm_state_gc_task(struct work_struct *work); static unsigned int xfrm_state_hashmax __read_mostly = 1 * 1024 * 1024; static __read_mostly seqcount_t xfrm_state_hash_generation = SEQCNT_ZERO(xfrm_state_hash_generation); +static struct kmem_cache *xfrm_state_cache __ro_after_init; static DECLARE_WORK(xfrm_state_gc_work, xfrm_state_gc_task); static HLIST_HEAD(xfrm_state_gc_list); @@ -451,7 +452,7 @@ static void xfrm_state_gc_destroy(struct xfrm_state *x) } xfrm_dev_state_free(x); security_xfrm_state_free(x); - kfree(x); + kmem_cache_free(xfrm_state_cache, x); } static void xfrm_state_gc_task(struct work_struct *work) @@ -563,7 +564,7 @@ struct xfrm_state *xfrm_state_alloc(struct net *net) { struct xfrm_state *x; - x = kzalloc(sizeof(struct xfrm_state), GFP_ATOMIC); + x = kmem_cache_alloc(xfrm_state_cache, GFP_ATOMIC | __GFP_ZERO); if (x) { write_pnet(&x->xs_net, net); @@ -2307,6 +2308,10 @@ int __net_init xfrm_state_init(struct net *net) { unsigned int sz; + if (net_eq(net, &init_net)) + xfrm_state_cache = KMEM_CACHE(xfrm_state, + SLAB_HWCACHE_ALIGN | SLAB_PANIC); + INIT_LIST_HEAD(&net->xfrm.state_all); sz = sizeof(struct hlist_head) * 8; -- cgit v1.2.3