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author | Eric Dumazet <eric.dumazet@gmail.com> | 2010-11-19 09:49:59 -0800 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2010-11-19 09:49:59 -0800 |
commit | 93aaae2e01e57483256b7da05c9a7ebd65ad4686 (patch) | |
tree | b3e4117bbf39814ef58ce1d012d977d2d5393c38 /drivers/isdn/i4l/isdn_ppp.c | |
parent | 0a80410dc53cf68e56456bef1ca66949b87412f9 (diff) | |
download | linux-93aaae2e01e57483256b7da05c9a7ebd65ad4686.tar.bz2 |
filter: optimize sk_run_filter
Remove pc variable to avoid arithmetic to compute fentry at each filter
instruction. Jumps directly manipulate fentry pointer.
As the last instruction of filter[] is guaranteed to be a RETURN, and
all jumps are before the last instruction, we dont need to check filter
bounds (number of instructions in filter array) at each iteration, so we
remove it from sk_run_filter() params.
On x86_32 remove f_k var introduced in commit 57fe93b374a6b871
(filter: make sure filters dont read uninitialized memory)
Note : We could use a CONFIG_ARCH_HAS_{FEW|MANY}_REGISTERS in order to
avoid too many ifdefs in this code.
This helps compiler to use cpu registers to hold fentry and A
accumulator.
On x86_32, this saves 401 bytes, and more important, sk_run_filter()
runs much faster because less register pressure (One less conditional
branch per BPF instruction)
# size net/core/filter.o net/core/filter_pre.o
text data bss dec hex filename
2948 0 0 2948 b84 net/core/filter.o
3349 0 0 3349 d15 net/core/filter_pre.o
on x86_64 :
# size net/core/filter.o net/core/filter_pre.o
text data bss dec hex filename
5173 0 0 5173 1435 net/core/filter.o
5224 0 0 5224 1468 net/core/filter_pre.o
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Acked-by: Changli Gao <xiaosuo@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/isdn/i4l/isdn_ppp.c')
-rw-r--r-- | drivers/isdn/i4l/isdn_ppp.c | 14 |
1 files changed, 6 insertions, 8 deletions
diff --git a/drivers/isdn/i4l/isdn_ppp.c b/drivers/isdn/i4l/isdn_ppp.c index 97c5cc2997f5..9e8162c80bb0 100644 --- a/drivers/isdn/i4l/isdn_ppp.c +++ b/drivers/isdn/i4l/isdn_ppp.c @@ -1147,15 +1147,14 @@ isdn_ppp_push_higher(isdn_net_dev * net_dev, isdn_net_local * lp, struct sk_buff } if (is->pass_filter - && sk_run_filter(skb, is->pass_filter, is->pass_len) == 0) { + && sk_run_filter(skb, is->pass_filter) == 0) { if (is->debug & 0x2) printk(KERN_DEBUG "IPPP: inbound frame filtered.\n"); kfree_skb(skb); return; } if (!(is->active_filter - && sk_run_filter(skb, is->active_filter, - is->active_len) == 0)) { + && sk_run_filter(skb, is->active_filter) == 0)) { if (is->debug & 0x2) printk(KERN_DEBUG "IPPP: link-active filter: reseting huptimer.\n"); lp->huptimer = 0; @@ -1294,15 +1293,14 @@ isdn_ppp_xmit(struct sk_buff *skb, struct net_device *netdev) } if (ipt->pass_filter - && sk_run_filter(skb, ipt->pass_filter, ipt->pass_len) == 0) { + && sk_run_filter(skb, ipt->pass_filter) == 0) { if (ipt->debug & 0x4) printk(KERN_DEBUG "IPPP: outbound frame filtered.\n"); kfree_skb(skb); goto unlock; } if (!(ipt->active_filter - && sk_run_filter(skb, ipt->active_filter, - ipt->active_len) == 0)) { + && sk_run_filter(skb, ipt->active_filter) == 0)) { if (ipt->debug & 0x4) printk(KERN_DEBUG "IPPP: link-active filter: reseting huptimer.\n"); lp->huptimer = 0; @@ -1492,9 +1490,9 @@ int isdn_ppp_autodial_filter(struct sk_buff *skb, isdn_net_local *lp) } drop |= is->pass_filter - && sk_run_filter(skb, is->pass_filter, is->pass_len) == 0; + && sk_run_filter(skb, is->pass_filter) == 0; drop |= is->active_filter - && sk_run_filter(skb, is->active_filter, is->active_len) == 0; + && sk_run_filter(skb, is->active_filter) == 0; skb_push(skb, IPPP_MAX_HEADER - 4); return drop; |