![Tejun Heo](/assets/img/avatar_default.png)
percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
270 lines
6.1 KiB
C
270 lines
6.1 KiB
C
/*
|
|
* IPVS: Source Hashing scheduling module
|
|
*
|
|
* Authors: Wensong Zhang <wensong@gnuchina.org>
|
|
*
|
|
* This program is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU General Public License
|
|
* as published by the Free Software Foundation; either version
|
|
* 2 of the License, or (at your option) any later version.
|
|
*
|
|
* Changes:
|
|
*
|
|
*/
|
|
|
|
/*
|
|
* The sh algorithm is to select server by the hash key of source IP
|
|
* address. The pseudo code is as follows:
|
|
*
|
|
* n <- servernode[src_ip];
|
|
* if (n is dead) OR
|
|
* (n is overloaded) or (n.weight <= 0) then
|
|
* return NULL;
|
|
*
|
|
* return n;
|
|
*
|
|
* Notes that servernode is a 256-bucket hash table that maps the hash
|
|
* index derived from packet source IP address to the current server
|
|
* array. If the sh scheduler is used in cache cluster, it is good to
|
|
* combine it with cache_bypass feature. When the statically assigned
|
|
* server is dead or overloaded, the load balancer can bypass the cache
|
|
* server and send requests to the original server directly.
|
|
*
|
|
*/
|
|
|
|
#define KMSG_COMPONENT "IPVS"
|
|
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
|
|
|
|
#include <linux/ip.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/module.h>
|
|
#include <linux/kernel.h>
|
|
#include <linux/skbuff.h>
|
|
|
|
#include <net/ip_vs.h>
|
|
|
|
|
|
/*
|
|
* IPVS SH bucket
|
|
*/
|
|
struct ip_vs_sh_bucket {
|
|
struct ip_vs_dest *dest; /* real server (cache) */
|
|
};
|
|
|
|
/*
|
|
* for IPVS SH entry hash table
|
|
*/
|
|
#ifndef CONFIG_IP_VS_SH_TAB_BITS
|
|
#define CONFIG_IP_VS_SH_TAB_BITS 8
|
|
#endif
|
|
#define IP_VS_SH_TAB_BITS CONFIG_IP_VS_SH_TAB_BITS
|
|
#define IP_VS_SH_TAB_SIZE (1 << IP_VS_SH_TAB_BITS)
|
|
#define IP_VS_SH_TAB_MASK (IP_VS_SH_TAB_SIZE - 1)
|
|
|
|
|
|
/*
|
|
* Returns hash value for IPVS SH entry
|
|
*/
|
|
static inline unsigned ip_vs_sh_hashkey(int af, const union nf_inet_addr *addr)
|
|
{
|
|
__be32 addr_fold = addr->ip;
|
|
|
|
#ifdef CONFIG_IP_VS_IPV6
|
|
if (af == AF_INET6)
|
|
addr_fold = addr->ip6[0]^addr->ip6[1]^
|
|
addr->ip6[2]^addr->ip6[3];
|
|
#endif
|
|
return (ntohl(addr_fold)*2654435761UL) & IP_VS_SH_TAB_MASK;
|
|
}
|
|
|
|
|
|
/*
|
|
* Get ip_vs_dest associated with supplied parameters.
|
|
*/
|
|
static inline struct ip_vs_dest *
|
|
ip_vs_sh_get(int af, struct ip_vs_sh_bucket *tbl,
|
|
const union nf_inet_addr *addr)
|
|
{
|
|
return (tbl[ip_vs_sh_hashkey(af, addr)]).dest;
|
|
}
|
|
|
|
|
|
/*
|
|
* Assign all the hash buckets of the specified table with the service.
|
|
*/
|
|
static int
|
|
ip_vs_sh_assign(struct ip_vs_sh_bucket *tbl, struct ip_vs_service *svc)
|
|
{
|
|
int i;
|
|
struct ip_vs_sh_bucket *b;
|
|
struct list_head *p;
|
|
struct ip_vs_dest *dest;
|
|
|
|
b = tbl;
|
|
p = &svc->destinations;
|
|
for (i=0; i<IP_VS_SH_TAB_SIZE; i++) {
|
|
if (list_empty(p)) {
|
|
b->dest = NULL;
|
|
} else {
|
|
if (p == &svc->destinations)
|
|
p = p->next;
|
|
|
|
dest = list_entry(p, struct ip_vs_dest, n_list);
|
|
atomic_inc(&dest->refcnt);
|
|
b->dest = dest;
|
|
|
|
p = p->next;
|
|
}
|
|
b++;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* Flush all the hash buckets of the specified table.
|
|
*/
|
|
static void ip_vs_sh_flush(struct ip_vs_sh_bucket *tbl)
|
|
{
|
|
int i;
|
|
struct ip_vs_sh_bucket *b;
|
|
|
|
b = tbl;
|
|
for (i=0; i<IP_VS_SH_TAB_SIZE; i++) {
|
|
if (b->dest) {
|
|
atomic_dec(&b->dest->refcnt);
|
|
b->dest = NULL;
|
|
}
|
|
b++;
|
|
}
|
|
}
|
|
|
|
|
|
static int ip_vs_sh_init_svc(struct ip_vs_service *svc)
|
|
{
|
|
struct ip_vs_sh_bucket *tbl;
|
|
|
|
/* allocate the SH table for this service */
|
|
tbl = kmalloc(sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE,
|
|
GFP_ATOMIC);
|
|
if (tbl == NULL) {
|
|
pr_err("%s(): no memory\n", __func__);
|
|
return -ENOMEM;
|
|
}
|
|
svc->sched_data = tbl;
|
|
IP_VS_DBG(6, "SH hash table (memory=%Zdbytes) allocated for "
|
|
"current service\n",
|
|
sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE);
|
|
|
|
/* assign the hash buckets with the updated service */
|
|
ip_vs_sh_assign(tbl, svc);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int ip_vs_sh_done_svc(struct ip_vs_service *svc)
|
|
{
|
|
struct ip_vs_sh_bucket *tbl = svc->sched_data;
|
|
|
|
/* got to clean up hash buckets here */
|
|
ip_vs_sh_flush(tbl);
|
|
|
|
/* release the table itself */
|
|
kfree(svc->sched_data);
|
|
IP_VS_DBG(6, "SH hash table (memory=%Zdbytes) released\n",
|
|
sizeof(struct ip_vs_sh_bucket)*IP_VS_SH_TAB_SIZE);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
static int ip_vs_sh_update_svc(struct ip_vs_service *svc)
|
|
{
|
|
struct ip_vs_sh_bucket *tbl = svc->sched_data;
|
|
|
|
/* got to clean up hash buckets here */
|
|
ip_vs_sh_flush(tbl);
|
|
|
|
/* assign the hash buckets with the updated service */
|
|
ip_vs_sh_assign(tbl, svc);
|
|
|
|
return 0;
|
|
}
|
|
|
|
|
|
/*
|
|
* If the dest flags is set with IP_VS_DEST_F_OVERLOAD,
|
|
* consider that the server is overloaded here.
|
|
*/
|
|
static inline int is_overloaded(struct ip_vs_dest *dest)
|
|
{
|
|
return dest->flags & IP_VS_DEST_F_OVERLOAD;
|
|
}
|
|
|
|
|
|
/*
|
|
* Source Hashing scheduling
|
|
*/
|
|
static struct ip_vs_dest *
|
|
ip_vs_sh_schedule(struct ip_vs_service *svc, const struct sk_buff *skb)
|
|
{
|
|
struct ip_vs_dest *dest;
|
|
struct ip_vs_sh_bucket *tbl;
|
|
struct ip_vs_iphdr iph;
|
|
|
|
ip_vs_fill_iphdr(svc->af, skb_network_header(skb), &iph);
|
|
|
|
IP_VS_DBG(6, "ip_vs_sh_schedule(): Scheduling...\n");
|
|
|
|
tbl = (struct ip_vs_sh_bucket *)svc->sched_data;
|
|
dest = ip_vs_sh_get(svc->af, tbl, &iph.saddr);
|
|
if (!dest
|
|
|| !(dest->flags & IP_VS_DEST_F_AVAILABLE)
|
|
|| atomic_read(&dest->weight) <= 0
|
|
|| is_overloaded(dest)) {
|
|
IP_VS_ERR_RL("SH: no destination available\n");
|
|
return NULL;
|
|
}
|
|
|
|
IP_VS_DBG_BUF(6, "SH: source IP address %s --> server %s:%d\n",
|
|
IP_VS_DBG_ADDR(svc->af, &iph.saddr),
|
|
IP_VS_DBG_ADDR(svc->af, &dest->addr),
|
|
ntohs(dest->port));
|
|
|
|
return dest;
|
|
}
|
|
|
|
|
|
/*
|
|
* IPVS SH Scheduler structure
|
|
*/
|
|
static struct ip_vs_scheduler ip_vs_sh_scheduler =
|
|
{
|
|
.name = "sh",
|
|
.refcnt = ATOMIC_INIT(0),
|
|
.module = THIS_MODULE,
|
|
.n_list = LIST_HEAD_INIT(ip_vs_sh_scheduler.n_list),
|
|
.init_service = ip_vs_sh_init_svc,
|
|
.done_service = ip_vs_sh_done_svc,
|
|
.update_service = ip_vs_sh_update_svc,
|
|
.schedule = ip_vs_sh_schedule,
|
|
};
|
|
|
|
|
|
static int __init ip_vs_sh_init(void)
|
|
{
|
|
return register_ip_vs_scheduler(&ip_vs_sh_scheduler);
|
|
}
|
|
|
|
|
|
static void __exit ip_vs_sh_cleanup(void)
|
|
{
|
|
unregister_ip_vs_scheduler(&ip_vs_sh_scheduler);
|
|
}
|
|
|
|
|
|
module_init(ip_vs_sh_init);
|
|
module_exit(ip_vs_sh_cleanup);
|
|
MODULE_LICENSE("GPL");
|