* High-level RPC service routines
*
* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
+ *
+ * Multiple threads pools and NUMAisation
+ * Copyright (c) 2006 Silicon Graphics, Inc.
+ * by Greg Banks <gnb@melbourne.sgi.com>
*/
#include <linux/linkage.h>
#define RPCDBG_FACILITY RPCDBG_SVCDSP
#define RPC_PARANOIA 1
+/*
+ * Mode for mapping cpus to pools.
+ */
+enum {
+ SVC_POOL_NONE = -1, /* uninitialised, choose one of the others */
+ SVC_POOL_GLOBAL, /* no mapping, just a single global pool
+ * (legacy & UP mode) */
+ SVC_POOL_PERCPU, /* one pool per cpu */
+ SVC_POOL_PERNODE /* one pool per numa node */
+};
+
+/*
+ * Structure for mapping cpus to pools and vice versa.
+ * Setup once during sunrpc initialisation.
+ */
+static struct svc_pool_map {
+ int mode; /* Note: int not enum to avoid
+ * warnings about "enumeration value
+ * not handled in switch" */
+ unsigned int npools;
+ unsigned int *pool_to; /* maps pool id to cpu or node */
+ unsigned int *to_pool; /* maps cpu or node to pool id */
+} svc_pool_map = {
+ .mode = SVC_POOL_NONE
+};
+
+
+/*
+ * Detect best pool mapping mode heuristically,
+ * according to the machine's topology.
+ */
+static int
+svc_pool_map_choose_mode(void)
+{
+ unsigned int node;
+
+ if (num_online_nodes() > 1) {
+ /*
+ * Actually have multiple NUMA nodes,
+ * so split pools on NUMA node boundaries
+ */
+ return SVC_POOL_PERNODE;
+ }
+
+ node = any_online_node(node_online_map);
+ if (nr_cpus_node(node) > 2) {
+ /*
+ * Non-trivial SMP, or CONFIG_NUMA on
+ * non-NUMA hardware, e.g. with a generic
+ * x86_64 kernel on Xeons. In this case we
+ * want to divide the pools on cpu boundaries.
+ */
+ return SVC_POOL_PERCPU;
+ }
+
+ /* default: one global pool */
+ return SVC_POOL_GLOBAL;
+}
+
+/*
+ * Allocate the to_pool[] and pool_to[] arrays.
+ * Returns 0 on success or an errno.
+ */
+static int
+svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
+{
+ m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
+ if (!m->to_pool)
+ goto fail;
+ m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
+ if (!m->pool_to)
+ goto fail_free;
+
+ return 0;
+
+fail_free:
+ kfree(m->to_pool);
+fail:
+ return -ENOMEM;
+}
+
+/*
+ * Initialise the pool map for SVC_POOL_PERCPU mode.
+ * Returns number of pools or <0 on error.
+ */
+static int
+svc_pool_map_init_percpu(struct svc_pool_map *m)
+{
+ unsigned int maxpools = highest_possible_processor_id()+1;
+ unsigned int pidx = 0;
+ unsigned int cpu;
+ int err;
+
+ err = svc_pool_map_alloc_arrays(m, maxpools);
+ if (err)
+ return err;
+
+ for_each_online_cpu(cpu) {
+ BUG_ON(pidx > maxpools);
+ m->to_pool[cpu] = pidx;
+ m->pool_to[pidx] = cpu;
+ pidx++;
+ }
+ /* cpus brought online later all get mapped to pool0, sorry */
+
+ return pidx;
+};
+
+
+/*
+ * Initialise the pool map for SVC_POOL_PERNODE mode.
+ * Returns number of pools or <0 on error.
+ */
+static int
+svc_pool_map_init_pernode(struct svc_pool_map *m)
+{
+ unsigned int maxpools = highest_possible_node_id()+1;
+ unsigned int pidx = 0;
+ unsigned int node;
+ int err;
+
+ err = svc_pool_map_alloc_arrays(m, maxpools);
+ if (err)
+ return err;
+
+ for_each_node_with_cpus(node) {
+ /* some architectures (e.g. SN2) have cpuless nodes */
+ BUG_ON(pidx > maxpools);
+ m->to_pool[node] = pidx;
+ m->pool_to[pidx] = node;
+ pidx++;
+ }
+ /* nodes brought online later all get mapped to pool0, sorry */
+
+ return pidx;
+}
+
+
+/*
+ * Build the global map of cpus to pools and vice versa.
+ */
+static unsigned int
+svc_pool_map_init(void)
+{
+ struct svc_pool_map *m = &svc_pool_map;
+ int npools = -1;
+
+ if (m->mode != SVC_POOL_NONE)
+ return m->npools;
+
+ m->mode = svc_pool_map_choose_mode();
+
+ switch (m->mode) {
+ case SVC_POOL_PERCPU:
+ npools = svc_pool_map_init_percpu(m);
+ break;
+ case SVC_POOL_PERNODE:
+ npools = svc_pool_map_init_pernode(m);
+ break;
+ }
+
+ if (npools < 0) {
+ /* default, or memory allocation failure */
+ npools = 1;
+ m->mode = SVC_POOL_GLOBAL;
+ }
+ m->npools = npools;
+
+ return m->npools;
+}
+
+/*
+ * Set the current thread's cpus_allowed mask so that it
+ * will only run on cpus in the given pool.
+ *
+ * Returns 1 and fills in oldmask iff a cpumask was applied.
+ */
+static inline int
+svc_pool_map_set_cpumask(unsigned int pidx, cpumask_t *oldmask)
+{
+ struct svc_pool_map *m = &svc_pool_map;
+ unsigned int node; /* or cpu */
+
+ /*
+ * The caller checks for sv_nrpools > 1, which
+ * implies that we've been initialized and the
+ * map mode is not NONE.
+ */
+ BUG_ON(m->mode == SVC_POOL_NONE);
+
+ switch (m->mode)
+ {
+ default:
+ return 0;
+ case SVC_POOL_PERCPU:
+ node = m->pool_to[pidx];
+ *oldmask = current->cpus_allowed;
+ set_cpus_allowed(current, cpumask_of_cpu(node));
+ return 1;
+ case SVC_POOL_PERNODE:
+ node = m->pool_to[pidx];
+ *oldmask = current->cpus_allowed;
+ set_cpus_allowed(current, node_to_cpumask(node));
+ return 1;
+ }
+}
+
+/*
+ * Use the mapping mode to choose a pool for a given CPU.
+ * Used when enqueueing an incoming RPC. Always returns
+ * a non-NULL pool pointer.
+ */
+struct svc_pool *
+svc_pool_for_cpu(struct svc_serv *serv, int cpu)
+{
+ struct svc_pool_map *m = &svc_pool_map;
+ unsigned int pidx = 0;
+
+ /*
+ * SVC_POOL_NONE happens in a pure client when
+ * lockd is brought up, so silently treat it the
+ * same as SVC_POOL_GLOBAL.
+ */
+
+ switch (m->mode) {
+ case SVC_POOL_PERCPU:
+ pidx = m->to_pool[cpu];
+ break;
+ case SVC_POOL_PERNODE:
+ pidx = m->to_pool[cpu_to_node(cpu)];
+ break;
+ }
+ return &serv->sv_pools[pidx % serv->sv_nrpools];
+}
+
+
/*
* Create an RPC service
*/
svc_thread_fn func, int sig, struct module *mod)
{
struct svc_serv *serv;
+ unsigned int npools = svc_pool_map_init();
- serv = __svc_create(prog, bufsize, /*npools*/1, shutdown);
+ serv = __svc_create(prog, bufsize, npools, shutdown);
if (serv != NULL) {
serv->sv_function = func;
/*
* Create a thread in the given pool. Caller must hold BKL.
+ * On a NUMA or SMP machine, with a multi-pool serv, the thread
+ * will be restricted to run on the cpus belonging to the pool.
*/
static int
__svc_create_thread(svc_thread_fn func, struct svc_serv *serv,
{
struct svc_rqst *rqstp;
int error = -ENOMEM;
+ int have_oldmask = 0;
+ cpumask_t oldmask;
rqstp = kzalloc(sizeof(*rqstp), GFP_KERNEL);
if (!rqstp)
spin_unlock_bh(&pool->sp_lock);
rqstp->rq_server = serv;
rqstp->rq_pool = pool;
+
+ if (serv->sv_nrpools > 1)
+ have_oldmask = svc_pool_map_set_cpumask(pool->sp_id, &oldmask);
+
error = kernel_thread((int (*)(void *)) func, rqstp, 0);
+
+ if (have_oldmask)
+ set_cpus_allowed(current, oldmask);
+
if (error < 0)
goto out_thread;
svc_sock_update_bufs(serv);
projects / linux-2.6 / commitdiff