[Crash-utility] [PATCH 1/2] Support for "dev -d|-D" options by parsing bitmap in blk-mq layer
Lianbo Jiang
lijiang at redhat.com
Wed Apr 27 03:37:03 UTC 2022
Currently, crash doesn't support to display disk I/O statistics
for blk-mq devices. For more details, please refer to the following
commit: <98b417fc6346> ("Handle blk_mq_ctx member changes for kernels
5.16-rc1 and later").
Lets parse the bitmap in blk-mq layer to achieve it.
Signed-off-by: Lianbo Jiang <lijiang at redhat.com>
---
defs.h | 13 +++
dev.c | 302 +++++++++++++++++++++++++++++++++++++++++++++++-------
symbols.c | 26 +++++
3 files changed, 302 insertions(+), 39 deletions(-)
diff --git a/defs.h b/defs.h
index 81ac0498dac7..f3c05fb44e62 100644
--- a/defs.h
+++ b/defs.h
@@ -2168,6 +2168,18 @@ struct offset_table { /* stash of commonly-used offsets */
long sbitmap_queue_min_shallow_depth;
long sbq_wait_state_wait_cnt;
long sbq_wait_state_wait;
+ long request_q;
+ long request_cmd_flags;
+ long request_queue_queue_hw_ctx;
+ long request_queue_nr_hw_queues;
+ long blk_mq_hw_ctx_tags;
+ long blk_mq_hw_ctx_sched_tags;
+ long blk_mq_tags_bitmap_tags;
+ long blk_mq_tags_breserved_tags;
+ long blk_mq_tags_nr_reserved_tags;
+ long blk_mq_tags_nr_tags;
+ long blk_mq_tags_rqs;
+ long blk_mq_tags_static_rqs;
};
struct size_table { /* stash of commonly-used sizes */
@@ -2337,6 +2349,7 @@ struct size_table { /* stash of commonly-used sizes */
long sbitmap;
long sbitmap_queue;
long sbq_wait_state;
+ long blk_mq_tags;
};
struct array_table {
diff --git a/dev.c b/dev.c
index a493e51ac95c..4d574f06494f 100644
--- a/dev.c
+++ b/dev.c
@@ -4238,19 +4238,224 @@ get_one_mctx_diskio(unsigned long mctx, struct diskio *io)
io->write = (dispatch[1] - comp[1]);
}
+struct blk_mq_tags_context {
+ uint nr_tags;
+ uint nr_reserved_tags;
+ ulong bitmap_tags;
+ ulong breserved_tags;
+ ulong rqs;
+ ulong static_rqs;
+};
+
+static void load_blk_mq_tags_context(ulong addr, struct blk_mq_tags_context *bmtc)
+{
+ char *tag_buf = NULL;
+
+ tag_buf = GETBUF(SIZE(blk_mq_tags));
+ if (!tag_buf)
+ error(FATAL, "fail to get memory for blk_mq_tags\n");
+
+ if (!readmem(addr, KVADDR, tag_buf, SIZE(blk_mq_tags), "blk_mq_tags", RETURN_ON_ERROR)) {
+ FREEBUF(tag_buf);
+ error(FATAL, "cannot read blk_mq_tags\n");
+ }
+
+ bmtc->nr_tags = UINT(tag_buf + OFFSET(blk_mq_tags_nr_tags));
+ bmtc->nr_reserved_tags = UINT(tag_buf + OFFSET(blk_mq_tags_nr_reserved_tags));
+ bmtc->bitmap_tags = addr + OFFSET(blk_mq_tags_bitmap_tags);
+ bmtc->breserved_tags = addr + OFFSET(blk_mq_tags_breserved_tags);
+ bmtc->rqs = ULONG(tag_buf + OFFSET(blk_mq_tags_rqs));
+ bmtc->static_rqs = ULONG(tag_buf + OFFSET(blk_mq_tags_static_rqs));
+
+ FREEBUF(tag_buf);
+}
+
+static void load_blk_mq_rqs(ulong rqs_addr, uint counts, ulong **rqs)
+{
+ char *rqs_buf = NULL;
+ uint rqs_buf_size = sizeof(void *) * counts;
+
+ if (!IS_KVADDR(rqs_addr)) {
+ *rqs = NULL;
+ return;
+ }
+
+ rqs_buf = GETBUF(rqs_buf_size);
+ if (!rqs_buf)
+ error(FATAL, "fail to get memory for the rqs buf\n");
+
+ if (!readmem(rqs_addr, KVADDR, rqs_buf, rqs_buf_size,
+ "blk_mq_tags.[static_]rqs", RETURN_ON_ERROR)) {
+ FREEBUF(rqs_buf);
+ error(FATAL, "fail to load blk_mq_tags.[static_]rqs\n");
+ }
+
+ *rqs = (ulong*)rqs_buf;
+}
+
+static uint op_is_write(uint op)
+{
+#define REQ_OP_BITS 8
+#define REQ_OP_MASK ((1 << REQ_OP_BITS) - 1)
+
+ return (op & REQ_OP_MASK) & 1;
+}
+
+static void find_mq_diskio_by_parsing_bitmap(ulong q, ulong tags, uint offset, ulong *rqs, struct diskio **io_counts)
+{
+ int i,j;
+ char *sbitmap_word_buf = NULL;
+ ulong depth = 0, word = 0, cleared = 0;
+ struct sbitmap_context sc = {0};
+ uint idx = offset;
+ ulong addr = tags + OFFSET(sbitmap_queue_sb);
+ ulong sbitmap_word_size = SIZE(sbitmap_word);
+
+ sbitmap_word_buf = GETBUF(sbitmap_word_size);
+ if (!sbitmap_word_buf)
+ error(FATAL, "fail to get memory for the sbitmap word\n");
+
+ sbitmap_context_load(addr, &sc);
+ if (sc.map_nr == 0 || !IS_KVADDR(sc.map_addr))
+ goto sbitmap_word_buf_free;
+
+ addr = sc.map_addr;
+ for (i = 0; i < sc.map_nr; i++, addr += sbitmap_word_size) {
+ if (!readmem(addr, KVADDR, sbitmap_word_buf, sbitmap_word_size,
+ "sbitmap_word", RETURN_ON_ERROR)) {
+ error(INFO, "cannot read sbitmap_word\n");
+ goto sbitmap_word_buf_free;
+ }
+
+ word = ULONG(sbitmap_word_buf + OFFSET(sbitmap_word_word));
+ cleared = ULONG(sbitmap_word_buf + OFFSET(sbitmap_word_cleared));
+ word = word & ~cleared;
+ if (!word)
+ continue;
+
+ if (i == sc.map_nr - 1)
+ depth = sc.depth - (i << sc.shift);
+ else
+ depth = 1U << sc.shift;
+
+ for (j = 0; j < depth; j++) {
+ if ((word & 1) && (rqs[idx])) {
+ ulong queue = 0;
+ uint cmd_flags = 0;
+
+ if (!readmem(rqs[idx] + OFFSET(request_q), KVADDR, &queue,
+ sizeof(ulong), "request.q", RETURN_ON_ERROR))
+ goto next;
+
+ if (!readmem(rqs[idx] + OFFSET(request_cmd_flags), KVADDR, &cmd_flags,
+ sizeof(uint), "request.cmd_flags", RETURN_ON_ERROR))
+ goto next;
+
+ if (q == queue) {
+ if (op_is_write(cmd_flags))
+ (*io_counts)->write++;
+ else
+ (*io_counts)->read++;
+ }
+
+ }
+ next:
+ idx++;
+ word >>= 1;
+ }
+ }
+
+sbitmap_word_buf_free:
+ FREEBUF(sbitmap_word_buf);
+}
+
+static void get_mq_diskio_from_hw_queues(unsigned long q, struct diskio *io_counts)
+{
+ unsigned long *queue_hw_ctx = NULL;
+ unsigned long addr = 0;
+ unsigned int i, nr_hw_queues;
+
+ addr = q + OFFSET(request_queue_nr_hw_queues);
+ readmem(addr, KVADDR, &nr_hw_queues, sizeof(uint),
+ "request_queue.nr_hw_queues", FAULT_ON_ERROR);
+
+ queue_hw_ctx = (ulong *)GETBUF(sizeof(void *) * nr_hw_queues);
+ if (!queue_hw_ctx)
+ error(FATAL, "fail to get memory for the queue_hw_ctx\n");
+
+ addr = q + OFFSET(request_queue_queue_hw_ctx);
+ if (!readmem(addr, KVADDR, queue_hw_ctx, sizeof(void *) * nr_hw_queues,
+ "request_queue.queue_hw_ctx", RETURN_ON_ERROR))
+ goto queue_hw_ctx_free;
+
+ for (i = 0; i < nr_hw_queues; i++) {
+ ulong tags = 0, sched_tags = 0, queue_hw_ctx_addr = 0;
+ unsigned long *rqs = NULL, *static_rqs = NULL;
+ struct blk_mq_tags_context tags_ctx = {0};
+ struct blk_mq_tags_context sched_tags_ctx = {0};
+
+ if(!IS_KVADDR(queue_hw_ctx[i]))
+ continue;
+
+ if (!readmem(queue_hw_ctx[i], KVADDR, &queue_hw_ctx_addr,
+ sizeof(ulong), "blk_mq_hw_ctx", RETURN_ON_ERROR))
+ goto queue_hw_ctx_free;
+
+ if(!IS_KVADDR(queue_hw_ctx_addr))
+ continue;
+
+ addr = queue_hw_ctx_addr + OFFSET(blk_mq_hw_ctx_tags);
+ if (!readmem(addr, KVADDR, &tags, sizeof(ulong),
+ "blk_mq_hw_ctx.tags", RETURN_ON_ERROR))
+ goto queue_hw_ctx_free;
+
+ addr = queue_hw_ctx_addr + OFFSET(blk_mq_hw_ctx_sched_tags);
+ if (!readmem(addr, KVADDR, &sched_tags, sizeof(ulong),
+ "blk_mq_hw_ctx.sched_tags", RETURN_ON_ERROR))
+ goto queue_hw_ctx_free;
+
+ if (IS_KVADDR(tags)) {
+ load_blk_mq_tags_context(tags, &tags_ctx);
+ load_blk_mq_rqs(tags_ctx.rqs, tags_ctx.nr_tags, &rqs);
+ if (!rqs)
+ goto next;
+ find_mq_diskio_by_parsing_bitmap(q, tags_ctx.breserved_tags, 0, rqs, &io_counts);
+ find_mq_diskio_by_parsing_bitmap(q, tags_ctx.bitmap_tags, tags_ctx.nr_reserved_tags, rqs, &io_counts);
+ FREEBUF(rqs);
+ }
+
+ next:
+ if (IS_KVADDR(sched_tags)) {
+ load_blk_mq_tags_context(sched_tags, &sched_tags_ctx);
+ load_blk_mq_rqs(sched_tags_ctx.static_rqs, sched_tags_ctx.nr_tags, &static_rqs);
+ if (!static_rqs)
+ continue;
+ find_mq_diskio_by_parsing_bitmap(q, sched_tags_ctx.breserved_tags, 0, static_rqs, &io_counts);
+ find_mq_diskio_by_parsing_bitmap(q, sched_tags_ctx.bitmap_tags, sched_tags_ctx.nr_reserved_tags,
+ static_rqs, &io_counts);
+ FREEBUF(static_rqs);
+ }
+ }
+
+queue_hw_ctx_free:
+ FREEBUF(queue_hw_ctx);
+}
+
static void
get_mq_diskio(unsigned long q, unsigned long *mq_count)
{
int cpu;
unsigned long queue_ctx;
unsigned long mctx_addr;
- struct diskio tmp;
+ struct diskio tmp = {0};
if (INVALID_MEMBER(blk_mq_ctx_rq_dispatched) ||
- INVALID_MEMBER(blk_mq_ctx_rq_completed))
+ INVALID_MEMBER(blk_mq_ctx_rq_completed)) {
+ get_mq_diskio_from_hw_queues(q, &tmp);
+ mq_count[0] = tmp.read;
+ mq_count[1] = tmp.write;
return;
-
- memset(&tmp, 0x00, sizeof(struct diskio));
+ }
readmem(q + OFFSET(request_queue_queue_ctx), KVADDR, &queue_ctx,
sizeof(ulong), "request_queue.queue_ctx",
@@ -4479,41 +4684,24 @@ display_one_diskio(struct iter *i, unsigned long gendisk, ulong flags)
&& (io.read + io.write == 0))
return;
- if (use_mq_interface(queue_addr) &&
- (INVALID_MEMBER(blk_mq_ctx_rq_dispatched) ||
- INVALID_MEMBER(blk_mq_ctx_rq_completed)))
- fprintf(fp, "%s%s%s %s%s%s%s %s%s%s",
- mkstring(buf0, 5, RJUST|INT_DEC, (char *)(unsigned long)major),
- space(MINSPACE),
- mkstring(buf1, VADDR_PRLEN, LJUST|LONG_HEX, (char *)gendisk),
- space(MINSPACE),
- mkstring(buf2, 10, LJUST, disk_name),
- space(MINSPACE),
- mkstring(buf3, VADDR_PRLEN <= 11 ? 11 : VADDR_PRLEN,
- LJUST|LONG_HEX, (char *)queue_addr),
- space(MINSPACE),
- mkstring(buf4, 17, RJUST, "(not supported)"),
- space(MINSPACE));
-
- else
- fprintf(fp, "%s%s%s %s%s%s%s %s%5d%s%s%s%s%s",
- mkstring(buf0, 5, RJUST|INT_DEC, (char *)(unsigned long)major),
- space(MINSPACE),
- mkstring(buf1, VADDR_PRLEN, LJUST|LONG_HEX, (char *)gendisk),
- space(MINSPACE),
- mkstring(buf2, 10, LJUST, disk_name),
- space(MINSPACE),
- mkstring(buf3, VADDR_PRLEN <= 11 ? 11 : VADDR_PRLEN,
- LJUST|LONG_HEX, (char *)queue_addr),
- space(MINSPACE),
- io.read + io.write,
- space(MINSPACE),
- mkstring(buf4, 5, RJUST|INT_DEC,
- (char *)(unsigned long)io.read),
- space(MINSPACE),
- mkstring(buf5, 5, RJUST|INT_DEC,
- (char *)(unsigned long)io.write),
- space(MINSPACE));
+ fprintf(fp, "%s%s%s %s%s%s%s %s%5d%s%s%s%s%s",
+ mkstring(buf0, 5, RJUST|INT_DEC, (char *)(unsigned long)major),
+ space(MINSPACE),
+ mkstring(buf1, VADDR_PRLEN, LJUST|LONG_HEX, (char *)gendisk),
+ space(MINSPACE),
+ mkstring(buf2, 10, LJUST, disk_name),
+ space(MINSPACE),
+ mkstring(buf3, VADDR_PRLEN <= 11 ? 11 : VADDR_PRLEN,
+ LJUST|LONG_HEX, (char *)queue_addr),
+ space(MINSPACE),
+ io.read + io.write,
+ space(MINSPACE),
+ mkstring(buf4, 5, RJUST|INT_DEC,
+ (char *)(unsigned long)io.read),
+ space(MINSPACE),
+ mkstring(buf5, 5, RJUST|INT_DEC,
+ (char *)(unsigned long)io.write),
+ space(MINSPACE));
if (VALID_MEMBER(request_queue_in_flight)) {
if (!use_mq_interface(queue_addr)) {
@@ -4603,15 +4791,51 @@ void diskio_init(void)
MEMBER_OFFSET_INIT(request_queue_rq, "request_queue", "rq");
else
MEMBER_OFFSET_INIT(request_queue_rq, "request_queue", "root_rl");
+ if (MEMBER_EXISTS("request", "q"))
+ MEMBER_OFFSET_INIT(request_q, "request", "q");
+ if (MEMBER_EXISTS("request", "cmd_flags"))
+ MEMBER_OFFSET_INIT(request_cmd_flags, "request", "cmd_flags");
if (MEMBER_EXISTS("request_queue", "mq_ops")) {
MEMBER_OFFSET_INIT(request_queue_mq_ops, "request_queue",
"mq_ops");
ANON_MEMBER_OFFSET_INIT(request_queue_queue_ctx,
"request_queue", "queue_ctx");
+ MEMBER_OFFSET_INIT(request_queue_queue_hw_ctx,
+ "request_queue", "queue_hw_ctx");
+ MEMBER_OFFSET_INIT(request_queue_nr_hw_queues,
+ "request_queue", "nr_hw_queues");
MEMBER_OFFSET_INIT(blk_mq_ctx_rq_dispatched, "blk_mq_ctx",
"rq_dispatched");
MEMBER_OFFSET_INIT(blk_mq_ctx_rq_completed, "blk_mq_ctx",
"rq_completed");
+ MEMBER_OFFSET_INIT(blk_mq_hw_ctx_tags, "blk_mq_hw_ctx",
+ "tags");
+ MEMBER_OFFSET_INIT(blk_mq_hw_ctx_sched_tags, "blk_mq_hw_ctx",
+ "sched_tags");
+ MEMBER_OFFSET_INIT(blk_mq_tags_bitmap_tags, "blk_mq_tags",
+ "bitmap_tags");
+ MEMBER_OFFSET_INIT(blk_mq_tags_breserved_tags, "blk_mq_tags",
+ "breserved_tags");
+ MEMBER_OFFSET_INIT(blk_mq_tags_nr_reserved_tags, "blk_mq_tags",
+ "nr_reserved_tags");
+ MEMBER_OFFSET_INIT(blk_mq_tags_nr_tags, "blk_mq_tags",
+ "nr_tags");
+ MEMBER_OFFSET_INIT(blk_mq_tags_rqs, "blk_mq_tags",
+ "rqs");
+ MEMBER_OFFSET_INIT(blk_mq_tags_static_rqs, "blk_mq_tags",
+ "static_rqs");
+ STRUCT_SIZE_INIT(blk_mq_tags, "blk_mq_tags");
+ STRUCT_SIZE_INIT(sbitmap, "sbitmap");
+ STRUCT_SIZE_INIT(sbitmap_word, "sbitmap_word");
+ MEMBER_OFFSET_INIT(sbitmap_word_depth, "sbitmap_word", "depth");
+ MEMBER_OFFSET_INIT(sbitmap_word_word, "sbitmap_word", "word");
+ MEMBER_OFFSET_INIT(sbitmap_word_cleared, "sbitmap_word", "cleared");
+ MEMBER_OFFSET_INIT(sbitmap_depth, "sbitmap", "depth");
+ MEMBER_OFFSET_INIT(sbitmap_shift, "sbitmap", "shift");
+ MEMBER_OFFSET_INIT(sbitmap_map_nr, "sbitmap", "map_nr");
+ MEMBER_OFFSET_INIT(sbitmap_map, "sbitmap", "map");
+ MEMBER_OFFSET_INIT(sbitmap_queue_sb, "sbitmap_queue", "sb");
+
}
MEMBER_OFFSET_INIT(subsys_private_klist_devices, "subsys_private",
"klist_devices");
diff --git a/symbols.c b/symbols.c
index ba5e2741347d..0612255b6e34 100644
--- a/symbols.c
+++ b/symbols.c
@@ -10385,6 +10385,10 @@ dump_offset_table(char *spec, ulong makestruct)
OFFSET(kset_list));
fprintf(fp, " request_list_count: %ld\n",
OFFSET(request_list_count));
+ fprintf(fp, " request_q: %ld\n",
+ OFFSET(request_q));
+ fprintf(fp, " request_cmd_flags: %ld\n",
+ OFFSET(request_cmd_flags));
fprintf(fp, " request_queue_in_flight: %ld\n",
OFFSET(request_queue_in_flight));
fprintf(fp, " request_queue_rq: %ld\n",
@@ -10393,10 +10397,31 @@ dump_offset_table(char *spec, ulong makestruct)
OFFSET(request_queue_mq_ops));
fprintf(fp, " request_queue_queue_ctx: %ld\n",
OFFSET(request_queue_queue_ctx));
+ fprintf(fp, " request_queue_queue_hw_ctx: %ld\n",
+ OFFSET(request_queue_queue_hw_ctx));
+ fprintf(fp, " request_queue_nr_hw_queues: %ld\n",
+ OFFSET(request_queue_nr_hw_queues));
fprintf(fp, " blk_mq_ctx_rq_dispatched: %ld\n",
OFFSET(blk_mq_ctx_rq_dispatched));
fprintf(fp, " blk_mq_ctx_rq_completed: %ld\n",
OFFSET(blk_mq_ctx_rq_completed));
+ fprintf(fp, " blk_mq_hw_ctx_tags: %ld\n",
+ OFFSET(blk_mq_hw_ctx_tags));
+ fprintf(fp, " blk_mq_hw_ctx_sched_tags: %ld\n",
+ OFFSET(blk_mq_hw_ctx_sched_tags));
+ fprintf(fp, " blk_mq_tags_bitmap_tags: %ld\n",
+ OFFSET(blk_mq_tags_bitmap_tags));
+ fprintf(fp, " blk_mq_tags_breserved_tags: %ld\n",
+ OFFSET(blk_mq_tags_breserved_tags));
+ fprintf(fp, " blk_mq_tags_nr_reserved_tags: %ld\n",
+ OFFSET(blk_mq_tags_nr_reserved_tags));
+ fprintf(fp, " blk_mq_tags_nr_tags: %ld\n",
+ OFFSET(blk_mq_tags_nr_tags));
+ fprintf(fp, " blk_mq_tags_rqs: %ld\n",
+ OFFSET(blk_mq_tags_rqs));
+ fprintf(fp, " blk_mq_tags_static_rqs: %ld\n",
+ OFFSET(blk_mq_tags_static_rqs));
+
fprintf(fp, " subsys_private_klist_devices: %ld\n",
OFFSET(subsys_private_klist_devices));
fprintf(fp, " subsystem_kset: %ld\n",
@@ -10999,6 +11024,7 @@ dump_offset_table(char *spec, ulong makestruct)
fprintf(fp, " sbitmap: %ld\n", SIZE(sbitmap));
fprintf(fp, " sbitmap_queue: %ld\n", SIZE(sbitmap_queue));
fprintf(fp, " sbq_wait_state: %ld\n", SIZE(sbq_wait_state));
+ fprintf(fp, " blk_mq_tags: %ld\n", SIZE(blk_mq_tags));
fprintf(fp, "\n array_table:\n");
/*
--
2.20.1
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