[Crash-utility] [PATCH] dev: Fix display disk I/O statistics for 4.20
Masayoshi Mizuma
msys.mizuma at gmail.com
Mon Jan 7 15:18:02 UTC 2019
Fix for the "dev -d|-D" command on Linux 4.20 and later kernels.
In Linux 4.20, in_flight member in struct request_queue is disappeared.
And also struct request_list is removed. So, dev -d|-D doesn't work.
Unfortunately, it seems that there is no alternative information
which shows the number of I/Os issued to disk driver. So this patch
gets DRV column removed if in_flight member in struct request_queue
isn't valid.
Without the patch, the command fails with the error message
"dev: -d option not supported or applicable on this architecture
or kernel".
Signed-off-by: Masayoshi Mizuma <m.mizuma at jp.fujitsu.com>
---
defs.h | 2 ++
dev.c | 73 ++++++++++++++++++++++++++++++++++++++++---------------
symbols.c | 4 +++
3 files changed, 59 insertions(+), 20 deletions(-)
diff --git a/defs.h b/defs.h
index a3cb5a4..9ebdde6 100644
--- a/defs.h
+++ b/defs.h
@@ -2064,6 +2064,8 @@ struct offset_table { /* stash of commonly-used offsets */
long xarray_xa_head;
long xa_node_slots;
long xa_node_shift;
+ long hd_struct_dkstats;
+ long disk_stats_in_flight;
};
struct size_table { /* stash of commonly-used sizes */
diff --git a/dev.c b/dev.c
index 7ce2422..24efea2 100644
--- a/dev.c
+++ b/dev.c
@@ -3974,7 +3974,7 @@ struct iter {
* this function reads request_list.count[2], and the first argument
* is the address of request_queue.
*/
- void (*get_diskio)(unsigned long , struct diskio *);
+ void (*get_diskio)(unsigned long , unsigned long, struct diskio *);
/*
* check if device.type == &disk_type
@@ -4187,24 +4187,55 @@ get_mq_diskio(unsigned long q, unsigned long *mq_count)
}
}
+static void
+get_one_diskio_from_dkstats(unsigned long dkstats, unsigned long *count)
+{
+ int cpu;
+ unsigned long dkstats_addr;
+ unsigned long in_flight[2];
+
+ for (cpu = 0; cpu < kt->cpus; cpu++) {
+ if ((kt->flags & SMP) && (kt->flags & PER_CPU_OFF)) {
+ dkstats_addr = dkstats + kt->__per_cpu_offset[cpu];
+ readmem(dkstats_addr + OFFSET(disk_stats_in_flight),
+ KVADDR, in_flight, sizeof(long) * 2,
+ "disk_stats.in_flight", FAULT_ON_ERROR);
+ count[0] += in_flight[0];
+ count[1] += in_flight[1];
+ }
+ }
+}
+
+
/* read request_queue.rq.count[2] */
static void
-get_diskio_1(unsigned long rq, struct diskio *io)
+get_diskio_1(unsigned long rq, unsigned long gendisk, struct diskio *io)
{
int count[2];
- unsigned long mq_count[2] = { 0 };
+ unsigned long io_counts[2] = { 0 };
+ unsigned long dkstats;
if (!use_mq_interface(rq)) {
- readmem(rq + OFFSET(request_queue_rq) +
- OFFSET(request_list_count), KVADDR, count,
- sizeof(int) * 2, "request_list.count", FAULT_ON_ERROR);
+ if (VALID_MEMBER(request_queue_rq)) {
+ readmem(rq + OFFSET(request_queue_rq) +
+ OFFSET(request_list_count), KVADDR, count,
+ sizeof(int) * 2, "request_list.count", FAULT_ON_ERROR);
+
+ io->read = count[0];
+ io->write = count[1];
+ } else {
+ readmem(gendisk + OFFSET(gendisk_part0) +
+ OFFSET(hd_struct_dkstats), KVADDR, &dkstats,
+ sizeof(ulong), "gendisk.part0.dkstats", FAULT_ON_ERROR);
+ get_one_diskio_from_dkstats(dkstats, io_counts);
- io->read = count[0];
- io->write = count[1];
+ io->read = io_counts[0];
+ io->write = io_counts[1];
+ }
} else {
- get_mq_diskio(rq, mq_count);
- io->read = mq_count[0];
- io->write = mq_count[1];
+ get_mq_diskio(rq, io_counts);
+ io->read = io_counts[0];
+ io->write = io_counts[1];
}
}
@@ -4250,9 +4281,6 @@ init_iter(struct iter *i)
i->get_in_flight = get_in_flight_1;
} else if (SIZE(rq_in_flight) == sizeof(int) * 2) {
i->get_in_flight = get_in_flight_2;
- } else {
- option_not_supported('d');
- return;
}
i->get_diskio = get_diskio_1;
@@ -4354,7 +4382,7 @@ display_one_diskio(struct iter *i, unsigned long gendisk, ulong flags)
sizeof(ulong), "gen_disk.queue", FAULT_ON_ERROR);
readmem(gendisk + OFFSET(gendisk_major), KVADDR, &major, sizeof(int),
"gen_disk.major", FAULT_ON_ERROR);
- i->get_diskio(queue_addr, &io);
+ i->get_diskio(queue_addr, gendisk, &io);
if ((flags & DIOF_NONZERO)
&& (io.read + io.write == 0))
@@ -4379,11 +4407,14 @@ display_one_diskio(struct iter *i, unsigned long gendisk, ulong flags)
(char *)(unsigned long)io.write),
space(MINSPACE));
- if (!use_mq_interface(queue_addr)) {
- in_flight = i->get_in_flight(queue_addr);
- fprintf(fp, "%5u\n", in_flight);
+ if (VALID_MEMBER(request_queue_in_flight)) {
+ if (!use_mq_interface(queue_addr)) {
+ in_flight = i->get_in_flight(queue_addr);
+ fprintf(fp, "%5u\n", in_flight);
+ } else
+ fprintf(fp, "%s\n", "N/A(MQ)");
} else
- fprintf(fp, "%s\n", "N/A(MQ)");
+ fprintf(fp, "\n");
}
static void
@@ -4418,7 +4449,7 @@ display_all_diskio(ulong flags)
i.sync_count ? mkstring(buf4, 5, RJUST, "SYNC") :
mkstring(buf4, 5, RJUST, "WRITE"),
space(MINSPACE),
- mkstring(buf5, 5, RJUST, "DRV"));
+ VALID_MEMBER(request_queue_in_flight) ? mkstring(buf5, 5, RJUST, "DRV") : "");
while ((gendisk = i.next_disk(&i)) != 0)
display_one_diskio(&i, gendisk, flags);
@@ -4446,6 +4477,7 @@ void diskio_init(void)
MEMBER_OFFSET_INIT(gendisk_part0, "gendisk", "part0");
MEMBER_OFFSET_INIT(gendisk_queue, "gendisk", "queue");
MEMBER_OFFSET_INIT(hd_struct_dev, "hd_struct", "__dev");
+ MEMBER_OFFSET_INIT(hd_struct_dkstats, "hd_struct", "dkstats");
MEMBER_OFFSET_INIT(klist_k_list, "klist", "k_list");
MEMBER_OFFSET_INIT(klist_node_n_klist, "klist_node", "n_klist");
MEMBER_OFFSET_INIT(klist_node_n_node, "klist_node", "n_node");
@@ -4476,6 +4508,7 @@ void diskio_init(void)
MEMBER_SIZE_INIT(rq_in_flight, "request_queue", "in_flight");
MEMBER_SIZE_INIT(class_private_devices, "class_private",
"class_devices");
+ MEMBER_OFFSET_INIT(disk_stats_in_flight, "disk_stats", "in_flight");
dt->flags |= DISKIO_INIT;
}
diff --git a/symbols.c b/symbols.c
index ef6f934..5f77e27 100644
--- a/symbols.c
+++ b/symbols.c
@@ -10101,6 +10101,10 @@ dump_offset_table(char *spec, ulong makestruct)
OFFSET(gendisk_queue));
fprintf(fp, " hd_struct_dev: %ld\n",
OFFSET(hd_struct_dev));
+ fprintf(fp, " hd_struct_dkstats: %ld\n",
+ OFFSET(hd_struct_dkstats));
+ fprintf(fp, " disk_stats_in_flight: %ld\n",
+ OFFSET(disk_stats_in_flight));
fprintf(fp, " klist_k_list: %ld\n",
OFFSET(klist_k_list));
fprintf(fp, " klist_node_n_klist: %ld\n",
--
2.18.1
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