svcrdma: Convert rdma_stat_recv to a per-CPU counter
Receives are frequent events. Avoid the overhead of a memory bus lock cycle for counting a value that is hardly every used. Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
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Родитель
59a00257c6
Коммит
df971cd853
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@ -49,6 +49,7 @@
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#include <linux/sunrpc/rpc_rdma_cid.h>
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#include <linux/sunrpc/svc_rdma_pcl.h>
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#include <linux/percpu_counter.h>
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#include <rdma/ib_verbs.h>
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#include <rdma/rdma_cm.h>
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@ -65,7 +66,7 @@ extern unsigned int svcrdma_max_requests;
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extern unsigned int svcrdma_max_bc_requests;
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extern unsigned int svcrdma_max_req_size;
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extern atomic_t rdma_stat_recv;
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extern struct percpu_counter svcrdma_stat_recv;
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extern atomic_t rdma_stat_read;
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extern atomic_t rdma_stat_write;
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extern atomic_t rdma_stat_sq_starve;
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@ -63,7 +63,7 @@ unsigned int svcrdma_max_req_size = RPCRDMA_DEF_INLINE_THRESH;
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static unsigned int min_max_inline = RPCRDMA_DEF_INLINE_THRESH;
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static unsigned int max_max_inline = RPCRDMA_MAX_INLINE_THRESH;
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atomic_t rdma_stat_recv;
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struct percpu_counter svcrdma_stat_recv;
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atomic_t rdma_stat_read;
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atomic_t rdma_stat_write;
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atomic_t rdma_stat_sq_starve;
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@ -110,6 +110,42 @@ static int read_reset_stat(struct ctl_table *table, int write,
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return 0;
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}
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enum {
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SVCRDMA_COUNTER_BUFSIZ = sizeof(unsigned long long),
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};
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static int svcrdma_counter_handler(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct percpu_counter *stat = (struct percpu_counter *)table->data;
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char tmp[SVCRDMA_COUNTER_BUFSIZ + 1];
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int len;
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if (write) {
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percpu_counter_set(stat, 0);
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return 0;
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}
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len = snprintf(tmp, SVCRDMA_COUNTER_BUFSIZ, "%lld\n",
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percpu_counter_sum_positive(stat));
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if (len >= SVCRDMA_COUNTER_BUFSIZ)
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return -EFAULT;
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len = strlen(tmp);
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if (*ppos > len) {
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*lenp = 0;
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return 0;
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}
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len -= *ppos;
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if (len > *lenp)
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len = *lenp;
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if (len)
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memcpy(buffer, tmp, len);
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*lenp = len;
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*ppos += len;
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return 0;
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}
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static struct ctl_table_header *svcrdma_table_header;
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static struct ctl_table svcrdma_parm_table[] = {
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{
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@ -149,10 +185,10 @@ static struct ctl_table svcrdma_parm_table[] = {
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},
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{
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.procname = "rdma_stat_recv",
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.data = &rdma_stat_recv,
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.maxlen = sizeof(atomic_t),
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.data = &svcrdma_stat_recv,
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.maxlen = SVCRDMA_COUNTER_BUFSIZ,
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.mode = 0644,
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.proc_handler = read_reset_stat,
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.proc_handler = svcrdma_counter_handler,
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},
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{
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.procname = "rdma_stat_write",
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@ -230,15 +266,26 @@ static void svc_rdma_proc_cleanup(void)
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return;
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unregister_sysctl_table(svcrdma_table_header);
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svcrdma_table_header = NULL;
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percpu_counter_destroy(&svcrdma_stat_recv);
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}
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static int svc_rdma_proc_init(void)
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{
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int rc;
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if (svcrdma_table_header)
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return 0;
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rc = percpu_counter_init(&svcrdma_stat_recv, 0, GFP_KERNEL);
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if (rc)
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goto out_err;
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svcrdma_table_header = register_sysctl_table(svcrdma_root_table);
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return 0;
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out_err:
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return rc;
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}
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void svc_rdma_cleanup(void)
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@ -845,8 +845,7 @@ int svc_rdma_recvfrom(struct svc_rqst *rqstp)
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}
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list_del(&ctxt->rc_list);
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spin_unlock(&rdma_xprt->sc_rq_dto_lock);
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atomic_inc(&rdma_stat_recv);
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percpu_counter_inc(&svcrdma_stat_recv);
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svc_rdma_build_arg_xdr(rqstp, ctxt);
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