[Crash-utility] [PATCH v4 2/2] Fix for "dev -d|-D" options to correctly display disk I/O statistics on linux v5.18-rc1
Kernel commit 4e5cc99e1e48 ("blk-mq: manage hctx map via xarray") removed
the "queue_hw_ctx" member from struct request_queue at Linux v5.18-rc1,
and replaced it with a struct xarray "hctx_table". Without the patch, the
"dev -d|-D" options will print an error:
crash> dev -d
MAJOR GENDISK NAME REQUEST_QUEUE TOTAL READ WRITE
dev: invalid structure member offset: request_queue_queue_hw_ctx
With the patch:
crash> dev -d
MAJOR GENDISK NAME REQUEST_QUEUE TOTAL READ WRITE
8 ffff8e99d0a1ae00 sda ffff8e9c14c59980 10 6 4
Signed-off-by: Lianbo Jiang <lijiang(a)redhat.com>
---
defs.h | 1 +
dev.c | 42 +++++++++++++++++++++++++++++++++---------
symbols.c | 2 ++
3 files changed, 36 insertions(+), 9 deletions(-)
diff --git a/defs.h b/defs.h
index 2681586a33dc..7d3b73422f48 100644
--- a/defs.h
+++ b/defs.h
@@ -2180,6 +2180,7 @@ struct offset_table { /* stash of commonly-used
offsets */
long blk_mq_tags_breserved_tags;
long blk_mq_tags_nr_reserved_tags;
long blk_mq_tags_rqs;
+ long request_queue_hctx_table;
};
struct size_table { /* stash of commonly-used sizes */
diff --git a/dev.c b/dev.c
index 4be4c96df8b0..0172c83ffaea 100644
--- a/dev.c
+++ b/dev.c
@@ -4369,20 +4369,42 @@ static void get_mq_diskio_from_hw_queues(ulong q, struct diskio
*dio)
uint cnt = 0;
ulong addr = 0, hctx_addr = 0;
ulong *hctx_array = NULL;
+ struct list_pair *lp = NULL;
+
+ if (VALID_MEMBER(request_queue_hctx_table)) {
+ addr = q + OFFSET(request_queue_hctx_table);
+ cnt = do_xarray(addr, XARRAY_COUNT, NULL);
+ lp = (struct list_pair *)GETBUF(sizeof(struct list_pair) * (cnt + 1));
+ if (!lp)
+ error(FATAL, "fail to get memory for list_pair.\n");
+ lp[0].index = cnt;
+ cnt = do_xarray(addr, XARRAY_GATHER, lp);
+ } else {
+ addr = q + OFFSET(request_queue_nr_hw_queues);
+ readmem(addr, KVADDR, &cnt, sizeof(uint),
+ "request_queue.nr_hw_queues", FAULT_ON_ERROR);
- addr = q + OFFSET(request_queue_nr_hw_queues);
- readmem(addr, KVADDR, &cnt, sizeof(uint),
- "request_queue.nr_hw_queues", FAULT_ON_ERROR);
-
- addr = q + OFFSET(request_queue_queue_hw_ctx);
- readmem(addr, KVADDR, &hctx_addr, sizeof(void *),
- "request_queue.queue_hw_ctx", FAULT_ON_ERROR);
+ addr = q + OFFSET(request_queue_queue_hw_ctx);
+ readmem(addr, KVADDR, &hctx_addr, sizeof(void *),
+ "request_queue.queue_hw_ctx", FAULT_ON_ERROR);
+ }
hctx_array = (ulong *)GETBUF(sizeof(void *) * cnt);
- if (!hctx_array)
+ if (!hctx_array) {
+ if (lp)
+ FREEBUF(lp);
error(FATAL, "fail to get memory for the hctx_array\n");
+ }
+
+ if (lp && hctx_array) {
+ uint i;
+
+ /* copy it from list_pair to hctx_array */
+ for (i = 0; i < cnt; i++)
+ hctx_array[i] = (ulong)lp[i].value;
- if (!readmem(hctx_addr, KVADDR, hctx_array, sizeof(void *) * cnt,
+ FREEBUF(lp);
+ } else if (!readmem(hctx_addr, KVADDR, hctx_array, sizeof(void *) * cnt,
"request_queue.queue_hw_ctx[]", RETURN_ON_ERROR)) {
FREEBUF(hctx_array);
return;
@@ -4755,6 +4777,8 @@ void diskio_init(void)
"request_queue", "queue_hw_ctx");
MEMBER_OFFSET_INIT(request_queue_nr_hw_queues,
"request_queue", "nr_hw_queues");
+ MEMBER_OFFSET_INIT(request_queue_hctx_table,
+ "request_queue", "hctx_table");
MEMBER_OFFSET_INIT(blk_mq_ctx_rq_dispatched, "blk_mq_ctx",
"rq_dispatched");
MEMBER_OFFSET_INIT(blk_mq_ctx_rq_completed, "blk_mq_ctx",
diff --git a/symbols.c b/symbols.c
index c1f09556d710..bee1faf92c83 100644
--- a/symbols.c
+++ b/symbols.c
@@ -10403,6 +10403,8 @@ dump_offset_table(char *spec, ulong makestruct)
OFFSET(request_queue_queue_hw_ctx));
fprintf(fp, " request_queue_nr_hw_queues: %ld\n",
OFFSET(request_queue_nr_hw_queues));
+ fprintf(fp, " request_queue_hctx_table: %ld\n",
+ OFFSET(request_queue_hctx_table));
fprintf(fp, " blk_mq_ctx_rq_dispatched: %ld\n",
OFFSET(blk_mq_ctx_rq_dispatched));
fprintf(fp, " blk_mq_ctx_rq_completed: %ld\n",
--
2.20.1