perf record: Adapt affinity to machines with #CPUs > 1K

Use struct mmap_cpu_mask type for the tool's thread and mmap data
buffers to overcome current 1024 CPUs mask size limitation of cpu_set_t
type.

Currently glibc's cpu_set_t type has an internal mask size limit of 1024
CPUs.

Moving to the 'struct mmap_cpu_mask' type allows overcoming that limit.

The tools bitmap API is used to manipulate objects of 'struct mmap_cpu_mask'
type.

Committer notes:

To print the 'nbits' struct member we must use %zd, since it is a
size_t, this fixes the build in some toolchains/arches.

Reported-by: Andi Kleen <[e-mail]>
Signed-off-by: Alexey Budankov <[e-mail]>
Acked-by: Jiri Olsa <[e-mail]>
Cc: Alexander Shishkin <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lore.kernel.org/lkml/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/builtin-record.c

···
 #include <linux/string.h>
 #include <linux/time64.h>
 #include <linux/zalloc.h>
+#include <linux/bitmap.h>
 
 struct switch_output {
 	bool		 enabled;
···
 	bool			timestamp_boundary;
 	struct switch_output	switch_output;
 	unsigned long long	samples;
-	cpu_set_t		affinity_mask;
+	struct mmap_cpu_mask	affinity_mask;
 	unsigned long		output_max_size;	/* = 0: unlimited */
 };
 
···
 static void record__adjust_affinity(struct record *rec, struct mmap *map)
 {
 	if (rec->opts.affinity != PERF_AFFINITY_SYS &&
-	    !CPU_EQUAL(&rec->affinity_mask, &map->affinity_mask)) {
-		CPU_ZERO(&rec->affinity_mask);
-		CPU_OR(&rec->affinity_mask, &rec->affinity_mask, &map->affinity_mask);
-		sched_setaffinity(0, sizeof(rec->affinity_mask), &rec->affinity_mask);
+	    !bitmap_equal(rec->affinity_mask.bits, map->affinity_mask.bits,
+			  rec->affinity_mask.nbits)) {
+		bitmap_zero(rec->affinity_mask.bits, rec->affinity_mask.nbits);
+		bitmap_or(rec->affinity_mask.bits, rec->affinity_mask.bits,
+			  map->affinity_mask.bits, rec->affinity_mask.nbits);
+		sched_setaffinity(0, MMAP_CPU_MASK_BYTES(&rec->affinity_mask),
+				  (cpu_set_t *)rec->affinity_mask.bits);
+		if (verbose == 2)
+			mmap_cpu_mask__scnprintf(&rec->affinity_mask, "thread");
 	}
 }
 
···
 # undef REASON
 #endif
 
-	CPU_ZERO(&rec->affinity_mask);
 	rec->opts.affinity = PERF_AFFINITY_SYS;
 
 	rec->evlist = evlist__new();
···
 	symbol_conf.allow_aliases = true;
 
 	symbol__init(NULL);
+
+	if (rec->opts.affinity != PERF_AFFINITY_SYS) {
+		rec->affinity_mask.nbits = cpu__max_cpu();
+		rec->affinity_mask.bits = bitmap_alloc(rec->affinity_mask.nbits);
+		if (!rec->affinity_mask.bits) {
+			pr_err("Failed to allocate thread mask for %zd cpus\n", rec->affinity_mask.nbits);
+			return -ENOMEM;
+		}
+		pr_debug2("thread mask[%zd]: empty\n", rec->affinity_mask.nbits);
+	}
 
 	err = record__auxtrace_init(rec);
 	if (err)
···
 
 	err = __cmd_record(&record, argc, argv);
 out:
+	bitmap_free(rec->affinity_mask.bits);
 	evlist__delete(rec->evlist);
 	symbol__exit();
 	auxtrace_record__free(rec->itr);

tools/perf/util/mmap.c

···
 
 void mmap__munmap(struct mmap *map)
 {
+	bitmap_free(map->affinity_mask.bits);
+
 	perf_mmap__aio_munmap(map);
 	if (map->data != NULL) {
 		munmap(map->data, mmap__mmap_len(map));
···
 	auxtrace_mmap__munmap(&map->auxtrace_mmap);
 }
 
-static void build_node_mask(int node, cpu_set_t *mask)
+static void build_node_mask(int node, struct mmap_cpu_mask *mask)
 {
 	int c, cpu, nr_cpus;
 	const struct perf_cpu_map *cpu_map = NULL;
···
 	for (c = 0; c < nr_cpus; c++) {
 		cpu = cpu_map->map[c]; /* map c index to online cpu index */
 		if (cpu__get_node(cpu) == node)
-			CPU_SET(cpu, mask);
+			set_bit(cpu, mask->bits);
 	}
 }
 
-static void perf_mmap__setup_affinity_mask(struct mmap *map, struct mmap_params *mp)
+static int perf_mmap__setup_affinity_mask(struct mmap *map, struct mmap_params *mp)
 {
-	CPU_ZERO(&map->affinity_mask);
+	map->affinity_mask.nbits = cpu__max_cpu();
+	map->affinity_mask.bits = bitmap_alloc(map->affinity_mask.nbits);
+	if (!map->affinity_mask.bits)
+		return -1;
+
 	if (mp->affinity == PERF_AFFINITY_NODE && cpu__max_node() > 1)
 		build_node_mask(cpu__get_node(map->core.cpu), &map->affinity_mask);
 	else if (mp->affinity == PERF_AFFINITY_CPU)
-		CPU_SET(map->core.cpu, &map->affinity_mask);
+		set_bit(map->core.cpu, map->affinity_mask.bits);
+
+	return 0;
 }
 
 int mmap__mmap(struct mmap *map, struct mmap_params *mp, int fd, int cpu)
···
 		return -1;
 	}
 
-	perf_mmap__setup_affinity_mask(map, mp);
+	if (mp->affinity != PERF_AFFINITY_SYS &&
+		perf_mmap__setup_affinity_mask(map, mp)) {
+		pr_debug2("failed to alloc mmap affinity mask, error %d\n",
+			  errno);
+		return -1;
+	}
+
+	if (verbose == 2)
+		mmap_cpu_mask__scnprintf(&map->affinity_mask, "mmap");
 
 	map->core.flush = mp->flush;
 

tools/perf/util/mmap.h

···
 		int		 nr_cblocks;
 	} aio;
 #endif
-	cpu_set_t	affinity_mask;
+	struct mmap_cpu_mask	affinity_mask;
 	void		*data;
 	int		comp_level;
 };