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net: snmp mib cleanup

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There is no point to align or pad mibs to cache lines, they are per cpu
allocated with a 8 bytes alignment anyway.
This wastes space for no gain. This patch removes __SNMP_MIB_ALIGN__

Since SNMP mibs contain "unsigned long" fields only, we can relax the
allocation alignment from "unsigned long long" to "unsigned long"

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Eric Dumazet 2010-03-18 20:36:06 +00:00 committed by David S. Miller
parent 62c97ac04a
commit ec733b15a3
4 changed files with 11 additions and 26 deletions
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2
include/net/sctp/sctp.h
View file

@ -268,7 +268,7 @@ enum {
#define SCTP_MIB_MAX __SCTP_MIB_MAX
struct sctp_mib {
unsigned long mibs[SCTP_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
/* Print debugging messages. */

29
include/net/snmp.h
View file

@ -52,26 +52,11 @@ struct snmp_mib {
* count on the 20Gb/s + networks people expect in a few years time!
*/
/*
* The rule for padding:
* Best is power of two because then the right structure can be found by a
* simple shift. The structure should be always cache line aligned.
* gcc needs n=alignto(cachelinesize, popcnt(sizeof(bla_mib))) shift/add
* instructions to emulate multiply in case it is not power-of-two.
* Currently n is always <=3 for all sizes so simple cache line alignment
* is enough.
*
* The best solution would be a global CPU local area , especially on 64
* and 128byte cacheline machine it makes a *lot* of sense -AK
*/
#define __SNMP_MIB_ALIGN__ ____cacheline_aligned
/* IPstats */
#define IPSTATS_MIB_MAX __IPSTATS_MIB_MAX
struct ipstats_mib {
unsigned long mibs[IPSTATS_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
/* ICMP */
#define ICMP_MIB_DUMMY __ICMP_MIB_MAX
@ -79,36 +64,36 @@ struct ipstats_mib {
struct icmp_mib {
unsigned long mibs[ICMP_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
#define ICMPMSG_MIB_MAX __ICMPMSG_MIB_MAX
struct icmpmsg_mib {
unsigned long mibs[ICMPMSG_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
/* ICMP6 (IPv6-ICMP) */
#define ICMP6_MIB_MAX __ICMP6_MIB_MAX
struct icmpv6_mib {
unsigned long mibs[ICMP6_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
#define ICMP6MSG_MIB_MAX __ICMP6MSG_MIB_MAX
struct icmpv6msg_mib {
unsigned long mibs[ICMP6MSG_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
/* TCP */
#define TCP_MIB_MAX __TCP_MIB_MAX
struct tcp_mib {
unsigned long mibs[TCP_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
/* UDP */
#define UDP_MIB_MAX __UDP_MIB_MAX
struct udp_mib {
unsigned long mibs[UDP_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
/* Linux */
#define LINUX_MIB_MAX __LINUX_MIB_MAX

2
net/dccp/dccp.h
View file

@ -189,7 +189,7 @@ enum {
#define DCCP_MIB_MAX __DCCP_MIB_MAX
struct dccp_mib {
unsigned long mibs[DCCP_MIB_MAX];
} __SNMP_MIB_ALIGN__;
};
DECLARE_SNMP_STAT(struct dccp_mib, dccp_statistics);
#define DCCP_INC_STATS(field) SNMP_INC_STATS(dccp_statistics, field)

4
net/ipv4/af_inet.c
View file

@ -1401,10 +1401,10 @@ EXPORT_SYMBOL_GPL(snmp_fold_field);
int snmp_mib_init(void __percpu *ptr[2], size_t mibsize)
{
BUG_ON(ptr == NULL);
ptr[0] = __alloc_percpu(mibsize, __alignof__(unsigned long long));
ptr[0] = __alloc_percpu(mibsize, __alignof__(unsigned long));
if (!ptr[0])
goto err0;
ptr[1] = __alloc_percpu(mibsize, __alignof__(unsigned long long));
ptr[1] = __alloc_percpu(mibsize, __alignof__(unsigned long));
if (!ptr[1])
goto err1;
return 0;