Adding upstream version 4.19.249.upstream/4.19.249upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 236 insertions, 0 deletions

diff --git a/mm/percpu-stats.c b/mm/percpu-stats.c
new file mode 100644
index 000000000..b5fdd43b6
--- /dev/null
+++ b/mm/percpu-stats.c
@@ -0,0 +1,236 @@
+/*
+ * mm/percpu-debug.c
+ *
+ * Copyright (C) 2017		Facebook Inc.
+ * Copyright (C) 2017		Dennis Zhou <dennisz@fb.com>
+ *
+ * This file is released under the GPLv2.
+ *
+ * Prints statistics about the percpu allocator and backing chunks.
+ */
+#include <linux/debugfs.h>
+#include <linux/list.h>
+#include <linux/percpu.h>
+#include <linux/seq_file.h>
+#include <linux/sort.h>
+#include <linux/vmalloc.h>
+
+#include "percpu-internal.h"
+
+#define P(X, Y) \
+	seq_printf(m, "  %-20s: %12lld\n", X, (long long int)Y)
+
+struct percpu_stats pcpu_stats;
+struct pcpu_alloc_info pcpu_stats_ai;
+
+static int cmpint(const void *a, const void *b)
+{
+	return *(int *)a - *(int *)b;
+}
+
+/*
+ * Iterates over all chunks to find the max nr_alloc entries.
+ */
+static int find_max_nr_alloc(void)
+{
+	struct pcpu_chunk *chunk;
+	int slot, max_nr_alloc;
+
+	max_nr_alloc = 0;
+	for (slot = 0; slot < pcpu_nr_slots; slot++)
+		list_for_each_entry(chunk, &pcpu_slot[slot], list)
+			max_nr_alloc = max(max_nr_alloc, chunk->nr_alloc);
+
+	return max_nr_alloc;
+}
+
+/*
+ * Prints out chunk state. Fragmentation is considered between
+ * the beginning of the chunk to the last allocation.
+ *
+ * All statistics are in bytes unless stated otherwise.
+ */
+static void chunk_map_stats(struct seq_file *m, struct pcpu_chunk *chunk,
+			    int *buffer)
+{
+	int i, last_alloc, as_len, start, end;
+	int *alloc_sizes, *p;
+	/* statistics */
+	int sum_frag = 0, max_frag = 0;
+	int cur_min_alloc = 0, cur_med_alloc = 0, cur_max_alloc = 0;
+
+	alloc_sizes = buffer;
+
+	/*
+	 * find_last_bit returns the start value if nothing found.
+	 * Therefore, we must determine if it is a failure of find_last_bit
+	 * and set the appropriate value.
+	 */
+	last_alloc = find_last_bit(chunk->alloc_map,
+				   pcpu_chunk_map_bits(chunk) -
+				   chunk->end_offset / PCPU_MIN_ALLOC_SIZE - 1);
+	last_alloc = test_bit(last_alloc, chunk->alloc_map) ?
+		     last_alloc + 1 : 0;
+
+	as_len = 0;
+	start = chunk->start_offset / PCPU_MIN_ALLOC_SIZE;
+
+	/*
+	 * If a bit is set in the allocation map, the bound_map identifies
+	 * where the allocation ends.  If the allocation is not set, the
+	 * bound_map does not identify free areas as it is only kept accurate
+	 * on allocation, not free.
+	 *
+	 * Positive values are allocations and negative values are free
+	 * fragments.
+	 */
+	while (start < last_alloc) {
+		if (test_bit(start, chunk->alloc_map)) {
+			end = find_next_bit(chunk->bound_map, last_alloc,
+					    start + 1);
+			alloc_sizes[as_len] = 1;
+		} else {
+			end = find_next_bit(chunk->alloc_map, last_alloc,
+					    start + 1);
+			alloc_sizes[as_len] = -1;
+		}
+
+		alloc_sizes[as_len++] *= (end - start) * PCPU_MIN_ALLOC_SIZE;
+
+		start = end;
+	}
+
+	/*
+	 * The negative values are free fragments and thus sorting gives the
+	 * free fragments at the beginning in largest first order.
+	 */
+	if (as_len > 0) {
+		sort(alloc_sizes, as_len, sizeof(int), cmpint, NULL);
+
+		/* iterate through the unallocated fragments */
+		for (i = 0, p = alloc_sizes; *p < 0 && i < as_len; i++, p++) {
+			sum_frag -= *p;
+			max_frag = max(max_frag, -1 * (*p));
+		}
+
+		cur_min_alloc = alloc_sizes[i];
+		cur_med_alloc = alloc_sizes[(i + as_len - 1) / 2];
+		cur_max_alloc = alloc_sizes[as_len - 1];
+	}
+
+	P("nr_alloc", chunk->nr_alloc);
+	P("max_alloc_size", chunk->max_alloc_size);
+	P("empty_pop_pages", chunk->nr_empty_pop_pages);
+	P("first_bit", chunk->first_bit);
+	P("free_bytes", chunk->free_bytes);
+	P("contig_bytes", chunk->contig_bits * PCPU_MIN_ALLOC_SIZE);
+	P("sum_frag", sum_frag);
+	P("max_frag", max_frag);
+	P("cur_min_alloc", cur_min_alloc);
+	P("cur_med_alloc", cur_med_alloc);
+	P("cur_max_alloc", cur_max_alloc);
+	seq_putc(m, '\n');
+}
+
+static int percpu_stats_show(struct seq_file *m, void *v)
+{
+	struct pcpu_chunk *chunk;
+	int slot, max_nr_alloc;
+	int *buffer;
+
+alloc_buffer:
+	spin_lock_irq(&pcpu_lock);
+	max_nr_alloc = find_max_nr_alloc();
+	spin_unlock_irq(&pcpu_lock);
+
+	/* there can be at most this many free and allocated fragments */
+	buffer = vmalloc(array_size(sizeof(int), (2 * max_nr_alloc + 1)));
+	if (!buffer)
+		return -ENOMEM;
+
+	spin_lock_irq(&pcpu_lock);
+
+	/* if the buffer allocated earlier is too small */
+	if (max_nr_alloc < find_max_nr_alloc()) {
+		spin_unlock_irq(&pcpu_lock);
+		vfree(buffer);
+		goto alloc_buffer;
+	}
+
+#define PL(X) \
+	seq_printf(m, "  %-20s: %12lld\n", #X, (long long int)pcpu_stats_ai.X)
+
+	seq_printf(m,
+			"Percpu Memory Statistics\n"
+			"Allocation Info:\n"
+			"----------------------------------------\n");
+	PL(unit_size);
+	PL(static_size);
+	PL(reserved_size);
+	PL(dyn_size);
+	PL(atom_size);
+	PL(alloc_size);
+	seq_putc(m, '\n');
+
+#undef PL
+
+#define PU(X) \
+	seq_printf(m, "  %-20s: %12llu\n", #X, (unsigned long long)pcpu_stats.X)
+
+	seq_printf(m,
+			"Global Stats:\n"
+			"----------------------------------------\n");
+	PU(nr_alloc);
+	PU(nr_dealloc);
+	PU(nr_cur_alloc);
+	PU(nr_max_alloc);
+	PU(nr_chunks);
+	PU(nr_max_chunks);
+	PU(min_alloc_size);
+	PU(max_alloc_size);
+	P("empty_pop_pages", pcpu_nr_empty_pop_pages);
+	seq_putc(m, '\n');
+
+#undef PU
+
+	seq_printf(m,
+			"Per Chunk Stats:\n"
+			"----------------------------------------\n");
+
+	if (pcpu_reserved_chunk) {
+		seq_puts(m, "Chunk: <- Reserved Chunk\n");
+		chunk_map_stats(m, pcpu_reserved_chunk, buffer);
+	}
+
+	for (slot = 0; slot < pcpu_nr_slots; slot++) {
+		list_for_each_entry(chunk, &pcpu_slot[slot], list) {
+			if (chunk == pcpu_first_chunk) {
+				seq_puts(m, "Chunk: <- First Chunk\n");
+				chunk_map_stats(m, chunk, buffer);
+
+
+			} else {
+				seq_puts(m, "Chunk:\n");
+				chunk_map_stats(m, chunk, buffer);
+			}
+
+		}
+	}
+
+	spin_unlock_irq(&pcpu_lock);
+
+	vfree(buffer);
+
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(percpu_stats);
+
+static int __init init_percpu_stats_debugfs(void)
+{
+	debugfs_create_file("percpu_stats", 0444, NULL, NULL,
+			&percpu_stats_fops);
+
+	return 0;
+}
+
+late_initcall(init_percpu_stats_debugfs);