scftorture: Count single_rpc offline failures in statistics outputgrafted

scf_torture_stats_print() aggregates each invoker thread's counters
into a local scf_statistics structure before printing, but the
n_single_rpc_ofl field is missing from the aggregation loop.  As a
result, the "single_rpc_ofl" value printed in the statistics line is
always zero, even when smp_call_function_single() invocations for the
RPC test have failed due to offline CPUs and been counted by the
invoker threads.

Add the missing accumulation so that the printed value reflects the
actual counts.

Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 170 insertions, 0 deletions

diff --git a/net/rds/page.c b/net/rds/page.c
new file mode 100644
index 000000000..afb151eac
--- /dev/null
+++ b/net/rds/page.c
@@ -0,0 +1,170 @@
+/*
+ * Copyright (c) 2006 Oracle.  All rights reserved.
+ *
+ * This software is available to you under a choice of one of two
+ * licenses.  You may choose to be licensed under the terms of the GNU
+ * General Public License (GPL) Version 2, available from the file
+ * COPYING in the main directory of this source tree, or the
+ * OpenIB.org BSD license below:
+ *
+ *     Redistribution and use in source and binary forms, with or
+ *     without modification, are permitted provided that the following
+ *     conditions are met:
+ *
+ *      - Redistributions of source code must retain the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer.
+ *
+ *      - Redistributions in binary form must reproduce the above
+ *        copyright notice, this list of conditions and the following
+ *        disclaimer in the documentation and/or other materials
+ *        provided with the distribution.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
+ * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+#include <linux/highmem.h>
+#include <linux/gfp.h>
+#include <linux/cpu.h>
+#include <linux/export.h>
+
+#include "rds.h"
+
+struct rds_page_remainder {
+	struct page	*r_page;
+	unsigned long	r_offset;
+	local_lock_t	bh_lock;
+};
+
+static DEFINE_PER_CPU_SHARED_ALIGNED(struct rds_page_remainder, rds_page_remainders) = {
+	.bh_lock = INIT_LOCAL_LOCK(bh_lock),
+};
+
+/**
+ * rds_page_remainder_alloc - build up regions of a message.
+ *
+ * @scat: Scatter list for message
+ * @bytes: the number of bytes needed.
+ * @gfp: the waiting behaviour of the allocation
+ *
+ * @gfp is always ored with __GFP_HIGHMEM.  Callers must be prepared to
+ * kmap the pages, etc.
+ *
+ * If @bytes is at least a full page then this just returns a page from
+ * alloc_page().
+ *
+ * If @bytes is a partial page then this stores the unused region of the
+ * page in a per-cpu structure.  Future partial-page allocations may be
+ * satisfied from that cached region.  This lets us waste less memory on
+ * small allocations with minimal complexity.  It works because the transmit
+ * path passes read-only page regions down to devices.  They hold a page
+ * reference until they are done with the region.
+ */
+int rds_page_remainder_alloc(struct scatterlist *scat, unsigned long bytes,
+			     gfp_t gfp)
+{
+	struct rds_page_remainder *rem;
+	struct page *page;
+	int ret;
+
+	gfp |= __GFP_HIGHMEM;
+
+	/* jump straight to allocation if we're trying for a huge page */
+	if (bytes >= PAGE_SIZE) {
+		page = alloc_page(gfp);
+		if (!page) {
+			ret = -ENOMEM;
+		} else {
+			sg_set_page(scat, page, PAGE_SIZE, 0);
+			ret = 0;
+		}
+		goto out;
+	}
+
+	local_bh_disable();
+	local_lock_nested_bh(&rds_page_remainders.bh_lock);
+	rem = this_cpu_ptr(&rds_page_remainders);
+
+	while (1) {
+		/* avoid a tiny region getting stuck by tossing it */
+		if (rem->r_page && bytes > (PAGE_SIZE - rem->r_offset)) {
+			rds_stats_inc(s_page_remainder_miss);
+			__free_page(rem->r_page);
+			rem->r_page = NULL;
+		}
+
+		/* hand out a fragment from the cached page */
+		if (rem->r_page && bytes <= (PAGE_SIZE - rem->r_offset)) {
+			sg_set_page(scat, rem->r_page, bytes, rem->r_offset);
+			get_page(sg_page(scat));
+
+			if (rem->r_offset != 0)
+				rds_stats_inc(s_page_remainder_hit);
+
+			rem->r_offset += ALIGN(bytes, 8);
+			if (rem->r_offset >= PAGE_SIZE) {
+				__free_page(rem->r_page);
+				rem->r_page = NULL;
+			}
+			ret = 0;
+			break;
+		}
+
+		/* alloc if there is nothing for us to use */
+		local_unlock_nested_bh(&rds_page_remainders.bh_lock);
+		local_bh_enable();
+
+		page = alloc_page(gfp);
+
+		local_bh_disable();
+		local_lock_nested_bh(&rds_page_remainders.bh_lock);
+		rem = this_cpu_ptr(&rds_page_remainders);
+
+		if (!page) {
+			ret = -ENOMEM;
+			break;
+		}
+
+		/* did someone race to fill the remainder before us? */
+		if (rem->r_page) {
+			__free_page(page);
+			continue;
+		}
+
+		/* otherwise install our page and loop around to alloc */
+		rem->r_page = page;
+		rem->r_offset = 0;
+	}
+
+	local_unlock_nested_bh(&rds_page_remainders.bh_lock);
+	local_bh_enable();
+out:
+	rdsdebug("bytes %lu ret %d %p %u %u\n", bytes, ret,
+		 ret ? NULL : sg_page(scat), ret ? 0 : scat->offset,
+		 ret ? 0 : scat->length);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rds_page_remainder_alloc);
+
+void rds_page_exit(void)
+{
+	unsigned int cpu;
+
+	for_each_possible_cpu(cpu) {
+		struct rds_page_remainder *rem;
+
+		rem = &per_cpu(rds_page_remainders, cpu);
+		rdsdebug("cpu %u\n", cpu);
+
+		if (rem->r_page)
+			__free_page(rem->r_page);
+		rem->r_page = NULL;
+	}
+}