From d37d8ac17d38d389375060416ceedd5b19d5255c Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 17 Mar 2014 20:20:49 -0700 Subject: [PATCH] net: sched: use no more than one page in struct fw_head In commit b4e9b520ca5d ("[NET_SCHED]: Add mask support to fwmark classifier") Patrick added an u32 field in fw_head, making it slightly bigger than one page. Lets use 256 slots to make fw_hash() more straight forward, and move @mask to the beginning of the structure as we often use a small number of skb->mark. @mask and first hash buckets share the same cache line. This brings back the memory usage to less than 4000 bytes, and permits John to add a rcu_head at the end of the structure later without any worry. Signed-off-by: Eric Dumazet Cc: Thomas Graf Cc: John Fastabend Acked-by: Thomas Graf Signed-off-by: David S. Miller --- net/sched/cls_fw.c | 33 +++++++-------------------------- 1 file changed, 7 insertions(+), 26 deletions(-) diff --git a/net/sched/cls_fw.c b/net/sched/cls_fw.c index a366537f82c6..63a3ce75c02e 100644 --- a/net/sched/cls_fw.c +++ b/net/sched/cls_fw.c @@ -29,11 +29,11 @@ #include #include -#define HTSIZE (PAGE_SIZE/sizeof(struct fw_filter *)) +#define HTSIZE 256 struct fw_head { - struct fw_filter *ht[HTSIZE]; - u32 mask; + u32 mask; + struct fw_filter *ht[HTSIZE]; }; struct fw_filter { @@ -46,30 +46,11 @@ struct fw_filter { struct tcf_exts exts; }; -static inline int fw_hash(u32 handle) +static u32 fw_hash(u32 handle) { - if (HTSIZE == 4096) - return ((handle >> 24) & 0xFFF) ^ - ((handle >> 12) & 0xFFF) ^ - (handle & 0xFFF); - else if (HTSIZE == 2048) - return ((handle >> 22) & 0x7FF) ^ - ((handle >> 11) & 0x7FF) ^ - (handle & 0x7FF); - else if (HTSIZE == 1024) - return ((handle >> 20) & 0x3FF) ^ - ((handle >> 10) & 0x3FF) ^ - (handle & 0x3FF); - else if (HTSIZE == 512) - return (handle >> 27) ^ - ((handle >> 18) & 0x1FF) ^ - ((handle >> 9) & 0x1FF) ^ - (handle & 0x1FF); - else if (HTSIZE == 256) { - u8 *t = (u8 *) &handle; - return t[0] ^ t[1] ^ t[2] ^ t[3]; - } else - return handle & (HTSIZE - 1); + handle ^= (handle >> 16); + handle ^= (handle >> 8); + return handle % HTSIZE; } static int fw_classify(struct sk_buff *skb, const struct tcf_proto *tp, -- 2.20.1