From c7d03a00b56fc23c3a01a8353789ad257363e281 Mon Sep 17 00:00:00 2001 From: Alexey Dobriyan Date: Thu, 17 Nov 2016 04:58:21 +0300 Subject: netns: make struct pernet_operations::id unsigned int Make struct pernet_operations::id unsigned. There are 2 reasons to do so: 1) This field is really an index into an zero based array and thus is unsigned entity. Using negative value is out-of-bound access by definition. 2) On x86_64 unsigned 32-bit data which are mixed with pointers via array indexing or offsets added or subtracted to pointers are preffered to signed 32-bit data. "int" being used as an array index needs to be sign-extended to 64-bit before being used. void f(long *p, int i) { g(p[i]); } roughly translates to movsx rsi, esi mov rdi, [rsi+...] call g MOVSX is 3 byte instruction which isn't necessary if the variable is unsigned because x86_64 is zero extending by default. Now, there is net_generic() function which, you guessed it right, uses "int" as an array index: static inline void *net_generic(const struct net *net, int id) { ... ptr = ng->ptr[id - 1]; ... } And this function is used a lot, so those sign extensions add up. Patch snipes ~1730 bytes on allyesconfig kernel (without all junk messing with code generation): add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730) Unfortunately some functions actually grow bigger. This is a semmingly random artefact of code generation with register allocator being used differently. gcc decides that some variable needs to live in new r8+ registers and every access now requires REX prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be used which is longer than [r8] However, overall balance is in negative direction: add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730) function old new delta nfsd4_lock 3886 3959 +73 tipc_link_build_proto_msg 1096 1140 +44 mac80211_hwsim_new_radio 2776 2808 +32 tipc_mon_rcv 1032 1058 +26 svcauth_gss_legacy_init 1413 1429 +16 tipc_bcbase_select_primary 379 392 +13 nfsd4_exchange_id 1247 1260 +13 nfsd4_setclientid_confirm 782 793 +11 ... put_client_renew_locked 494 480 -14 ip_set_sockfn_get 730 716 -14 geneve_sock_add 829 813 -16 nfsd4_sequence_done 721 703 -18 nlmclnt_lookup_host 708 686 -22 nfsd4_lockt 1085 1063 -22 nfs_get_client 1077 1050 -27 tcf_bpf_init 1106 1076 -30 nfsd4_encode_fattr 5997 5930 -67 Total: Before=154856051, After=154854321, chg -0.00% Signed-off-by: Alexey Dobriyan Signed-off-by: David S. Miller --- net/sched/act_bpf.c | 2 +- net/sched/act_connmark.c | 2 +- net/sched/act_csum.c | 2 +- net/sched/act_gact.c | 2 +- net/sched/act_ife.c | 2 +- net/sched/act_ipt.c | 4 ++-- net/sched/act_mirred.c | 2 +- net/sched/act_nat.c | 2 +- net/sched/act_pedit.c | 2 +- net/sched/act_police.c | 2 +- net/sched/act_simple.c | 2 +- net/sched/act_skbedit.c | 2 +- net/sched/act_skbmod.c | 2 +- net/sched/act_tunnel_key.c | 2 +- net/sched/act_vlan.c | 2 +- 15 files changed, 16 insertions(+), 16 deletions(-) (limited to 'net/sched') diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c index 9ff06cfbcdec..1aa4ecf41baf 100644 --- a/net/sched/act_bpf.c +++ b/net/sched/act_bpf.c @@ -33,7 +33,7 @@ struct tcf_bpf_cfg { bool is_ebpf; }; -static int bpf_net_id; +static unsigned int bpf_net_id; static struct tc_action_ops act_bpf_ops; static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act, diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c index eae07a2e774d..ab8062909962 100644 --- a/net/sched/act_connmark.c +++ b/net/sched/act_connmark.c @@ -30,7 +30,7 @@ #define CONNMARK_TAB_MASK 3 -static int connmark_net_id; +static unsigned int connmark_net_id; static struct tc_action_ops act_connmark_ops; static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a, diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c index e0defcef376d..a0edd80a44db 100644 --- a/net/sched/act_csum.c +++ b/net/sched/act_csum.c @@ -42,7 +42,7 @@ static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = { [TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), }, }; -static int csum_net_id; +static unsigned int csum_net_id; static struct tc_action_ops act_csum_ops; static int tcf_csum_init(struct net *net, struct nlattr *nla, diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c index e0aa30f83c6c..e6c874a2b283 100644 --- a/net/sched/act_gact.c +++ b/net/sched/act_gact.c @@ -25,7 +25,7 @@ #define GACT_TAB_MASK 15 -static int gact_net_id; +static unsigned int gact_net_id; static struct tc_action_ops act_gact_ops; #ifdef CONFIG_GACT_PROB diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c index 95c463cbb9a6..80b848d3f096 100644 --- a/net/sched/act_ife.c +++ b/net/sched/act_ife.c @@ -35,7 +35,7 @@ #define IFE_TAB_MASK 15 -static int ife_net_id; +static unsigned int ife_net_id; static int max_metacnt = IFE_META_MAX + 1; static struct tc_action_ops act_ife_ops; diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c index ce7ea6c1c50d..992ef8d624f1 100644 --- a/net/sched/act_ipt.c +++ b/net/sched/act_ipt.c @@ -30,10 +30,10 @@ #define IPT_TAB_MASK 15 -static int ipt_net_id; +static unsigned int ipt_net_id; static struct tc_action_ops act_ipt_ops; -static int xt_net_id; +static unsigned int xt_net_id; static struct tc_action_ops act_xt_ops; static int ipt_init_target(struct xt_entry_target *t, char *table, diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c index 6073a1132725..b2d417b8f46c 100644 --- a/net/sched/act_mirred.c +++ b/net/sched/act_mirred.c @@ -70,7 +70,7 @@ static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = { [TCA_MIRRED_PARMS] = { .len = sizeof(struct tc_mirred) }, }; -static int mirred_net_id; +static unsigned int mirred_net_id; static struct tc_action_ops act_mirred_ops; static bool dev_is_mac_header_xmit(const struct net_device *dev) diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c index 8e8b0cc30704..9b6aec665495 100644 --- a/net/sched/act_nat.c +++ b/net/sched/act_nat.c @@ -31,7 +31,7 @@ #define NAT_TAB_MASK 15 -static int nat_net_id; +static unsigned int nat_net_id; static struct tc_action_ops act_nat_ops; static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = { diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c index b54d56d4959b..eda322045e75 100644 --- a/net/sched/act_pedit.c +++ b/net/sched/act_pedit.c @@ -25,7 +25,7 @@ #define PEDIT_TAB_MASK 15 -static int pedit_net_id; +static unsigned int pedit_net_id; static struct tc_action_ops act_pedit_ops; static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = { diff --git a/net/sched/act_police.c b/net/sched/act_police.c index d1bd248fe146..c990b73a6c85 100644 --- a/net/sched/act_police.c +++ b/net/sched/act_police.c @@ -55,7 +55,7 @@ struct tc_police_compat { /* Each policer is serialized by its individual spinlock */ -static int police_net_id; +static unsigned int police_net_id; static struct tc_action_ops act_police_ops; static int tcf_act_police_walker(struct net *net, struct sk_buff *skb, diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c index 289af6f9bb3b..823a73ad0c60 100644 --- a/net/sched/act_simple.c +++ b/net/sched/act_simple.c @@ -26,7 +26,7 @@ #define SIMP_TAB_MASK 7 -static int simp_net_id; +static unsigned int simp_net_id; static struct tc_action_ops act_simp_ops; #define SIMP_MAX_DATA 32 diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c index 024f3a3afeff..06ccae3c12ee 100644 --- a/net/sched/act_skbedit.c +++ b/net/sched/act_skbedit.c @@ -29,7 +29,7 @@ #define SKBEDIT_TAB_MASK 15 -static int skbedit_net_id; +static unsigned int skbedit_net_id; static struct tc_action_ops act_skbedit_ops; static int tcf_skbedit(struct sk_buff *skb, const struct tc_action *a, diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c index e7d96381c908..3b7074e23024 100644 --- a/net/sched/act_skbmod.c +++ b/net/sched/act_skbmod.c @@ -22,7 +22,7 @@ #define SKBMOD_TAB_MASK 15 -static int skbmod_net_id; +static unsigned int skbmod_net_id; static struct tc_action_ops act_skbmod_ops; #define MAX_EDIT_LEN ETH_HLEN diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c index edc720f11687..7af712526f01 100644 --- a/net/sched/act_tunnel_key.c +++ b/net/sched/act_tunnel_key.c @@ -22,7 +22,7 @@ #define TUNNEL_KEY_TAB_MASK 15 -static int tunnel_key_net_id; +static unsigned int tunnel_key_net_id; static struct tc_action_ops act_tunnel_key_ops; static int tunnel_key_act(struct sk_buff *skb, const struct tc_action *a, diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c index b57fcbcefea1..19e0dba305ce 100644 --- a/net/sched/act_vlan.c +++ b/net/sched/act_vlan.c @@ -21,7 +21,7 @@ #define VLAN_TAB_MASK 15 -static int vlan_net_id; +static unsigned int vlan_net_id; static struct tc_action_ops act_vlan_ops; static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a, -- cgit v1.2.3