于 2012年08月25日 02:17, Dave Anderson 写道:
>
>
> ----- Original Message -----
>>
>>
>> ----- Original Message -----
>>> Hello Dave,
>>>
>>> In runq command, when dumping cfs and rt runqueues,
>>> it seems that we get the wrong nr_running values of rq
>>> and cfs_rq.
>>>
>>> Please refer to the attached patch.
>>>
>>> Thanks
>>> Zhang Yanfei
>>
>> Hello Zhang,
>>
>> I understand what you are trying to accomplish with this patch, but
>> none of my test dumpfiles can actually verify it because there is no
>> difference with or without your patch. What failure mode did you see
>> in your testing? I presume that it just showed "[no tasks queued]"
>> for the RT runqueue when there were actually tasks queued there?
>>
>> The reason I ask is that I'm thinking that a better solution would
>> be to simplify dump_CFS_runqueues() by *not* accessing and using
>> rq_nr_running, cfs_rq_nr_running or cfs_rq_h_nr_running.
>>
>> Those counters are only read to determine the "active" argument to
>> pass to dump_RT_prio_array(), which returns immediately if it is
>> FALSE. However, if we get rid of the "active" argument and simply
>> allow dump_RT_prio_array() to always check its queues every time,
>> it still works just fine.
>>
>> For example, I tested my set of sample dumpfiles with this patch:
>>
>> diff -u -r1.205 task.c
>> --- task.c 12 Jul 2012 20:04:00 -0000 1.205
>> +++ task.c 22 Aug 2012 15:33:32 -0000
>> @@ -7636,7 +7636,7 @@
>> OFFSET(cfs_rq_tasks_timeline));
>> }
>>
>> - dump_RT_prio_array(nr_running != cfs_rq_nr_running,
>> + dump_RT_prio_array(TRUE,
>> runq + OFFSET(rq_rt) + OFFSET(rt_rq_active),
>> &runqbuf[OFFSET(rq_rt) +
>> OFFSET(rt_rq_active)]);
>>
>> and the output is identical to testing with, and without, your patch.
>>
>> So the question is whether dump_CFS_runqueues() should be needlessly
>> complicated with all of the "nr_running" references?
>>
>> In fact, it also seems possible that a crash could happen at a point in
>> the scheduler code where those counters are not
>> valid/current/trustworthy.
>>
>> So unless you can convince me otherwise, I'd prefer to just remove
>> the "nr_running" business completely.
>
> Hello Zhang,
>
> Here's the patch I've got queued, which resolves the bug you encountered
> by simplifying things:
>
OK. I see.
And based on this patch, I made a new patch to solve the problem when
dumping rt runqueues. Currently dump_RT_prio_array() doesn't support
rt group scheduler.
In my test, I put some rt tasks into one group, just like below:
mkdir /cgroup/cpu/test1
echo 850000 > /cgroup/cpu/test1/cpu.rt_runtime_us
./rtloop1 &
echo $! > /cgroup/cpu/test1/tasks
./rtloop1 &
echo $! > /cgroup/cpu/test1/tasks
./rtloop1 &
echo $! > /cgroup/cpu/test1/tasks
./rtloop98 &
echo $! > /cgroup/cpu/test1/tasks
./rtloop45 &
echo $! > /cgroup/cpu/test1/tasks
./rtloop99 &
echo $! > /cgroup/cpu/test1/tasks
Using crash to analyse the vmcore:
crash> runq
CPU 0 RUNQUEUE: ffff880028216680
CURRENT: PID: 5125 TASK: ffff88010799d540 COMMAND: "sh"
RT PRIO_ARRAY: ffff880028216808
[ 0] PID: 5136 TASK: ffff8801153cc040 COMMAND: "rtloop99"
PID: 6 TASK: ffff88013d7c6080 COMMAND: "watchdog/0"
PID: 3 TASK: ffff88013d7ba040 COMMAND: "migration/0"
[ 1] PID: 5134 TASK: ffff8801153cd500 COMMAND: "rtloop98"
PID: 5135 TASK: ffff8801153ccaa0 COMMAND: "rtloop98"
CFS RB_ROOT: ffff880028216718
[120] PID: 5109 TASK: ffff880037923500 COMMAND: "sh"
[120] PID: 5107 TASK: ffff88006eeccaa0 COMMAND: "sh"
[120] PID: 5123 TASK: ffff880107a4caa0 COMMAND: "sh"
CPU 1 RUNQUEUE: ffff880028296680
CURRENT: PID: 5086 TASK: ffff88006eecc040 COMMAND: "bash"
RT PRIO_ARRAY: ffff880028296808
[ 0] PID: 5137 TASK: ffff880107b35540 COMMAND: "rtloop99"
PID: 10 TASK: ffff88013cc2cae0 COMMAND: "watchdog/1"
PID: 2852 TASK: ffff88013bd5aae0 COMMAND: "rtkit-daemon"
[ 54] CFS RB_ROOT: ffff880028296718
[120] PID: 5115 TASK: ffff8801152b1500 COMMAND: "sh"
[120] PID: 5113 TASK: ffff880139530080 COMMAND: "sh"
[120] PID: 5111 TASK: ffff88011bd86080 COMMAND: "sh"
[120] PID: 5121 TASK: ffff880115a9e080 COMMAND: "sh"
[120] PID: 5117 TASK: ffff8801152b0040 COMMAND: "sh"
[120] PID: 5119 TASK: ffff880115a9eae0 COMMAND: "sh"
We can see that the output is kind of incorrect.
After applying the attached patch, crash seems to work well:
crash> runq
CPU 0 RUNQUEUE: ffff880028216680
CURRENT: PID: 5125 TASK: ffff88010799d540 COMMAND: "sh"
RT PRIO_ARRAY: ffff880028216808
[ 0] PID: 5136 TASK: ffff8801153cc040 COMMAND: "rtloop99"
CHILD RT PRIO_ARRAY: ffff88013b050000
[ 0] PID: 5133 TASK: ffff88010799c080 COMMAND: "rtloop99"
[ 1] PID: 5131 TASK: ffff880037922aa0 COMMAND: "rtloop98"
[ 98] PID: 5128 TASK: ffff88011bd87540 COMMAND: "rtloop1"
PID: 5130 TASK: ffff8801396e7500 COMMAND: "rtloop1"
PID: 5129 TASK: ffff88011bf5a080 COMMAND: "rtloop1"
PID: 6 TASK: ffff88013d7c6080 COMMAND: "watchdog/0"
PID: 3 TASK: ffff88013d7ba040 COMMAND: "migration/0"
[ 1] PID: 5134 TASK: ffff8801153cd500 COMMAND: "rtloop98"
PID: 5135 TASK: ffff8801153ccaa0 COMMAND: "rtloop98"
CFS RB_ROOT: ffff880028216718
[120] PID: 5109 TASK: ffff880037923500 COMMAND: "sh"
[120] PID: 5107 TASK: ffff88006eeccaa0 COMMAND: "sh"
[120] PID: 5123 TASK: ffff880107a4caa0 COMMAND: "sh"
CPU 1 RUNQUEUE: ffff880028296680
CURRENT: PID: 5086 TASK: ffff88006eecc040 COMMAND: "bash"
RT PRIO_ARRAY: ffff880028296808
[ 0] PID: 5137 TASK: ffff880107b35540 COMMAND: "rtloop99"
PID: 10 TASK: ffff88013cc2cae0 COMMAND: "watchdog/1"
PID: 2852 TASK: ffff88013bd5aae0 COMMAND: "rtkit-daemon"
[ 54] CHILD RT PRIO_ARRAY: ffff880138978000
[ 54] PID: 5132 TASK: ffff88006eecd500 COMMAND: "rtloop45"
CFS RB_ROOT: ffff880028296718
[120] PID: 5115 TASK: ffff8801152b1500 COMMAND: "sh"
[120] PID: 5113 TASK: ffff880139530080 COMMAND: "sh"
[120] PID: 5111 TASK: ffff88011bd86080 COMMAND: "sh"
[120] PID: 5121 TASK: ffff880115a9e080 COMMAND: "sh"
[120] PID: 5117 TASK: ffff8801152b0040 COMMAND: "sh"
[120] PID: 5119 TASK: ffff880115a9eae0 COMMAND: "sh"
Is this kind of output for rt runqueues ok? Or do you have any suggestion?
Thanks
Zhang Yanfei
>From 550d428cbb6d9d22837e3ef138e1de59e7ccc1b3 Mon Sep 17 00:00:00 2001
From: zhangyanfei <zhangyanfei@xxxxxxxxxxxxxx>
Date: Sat, 25 Aug 2012 11:17:37 +0800
Subject: [PATCH] Fix rt not support group sched bug
Signed-off-by: zhangyanfei <zhangyanfei@xxxxxxxxxxxxxx>
---
defs.h | 2 ++
symbols.c | 4 ++++
task.c | 47 ++++++++++++++++++++++++++++++++++++++++-------
3 files changed, 46 insertions(+), 7 deletions(-)
diff --git a/defs.h b/defs.h
index 4a8e2e3..4af670d 100755
--- a/defs.h
+++ b/defs.h
@@ -1785,6 +1785,7 @@ struct offset_table { /* stash of commonly-used offsets */
long log_level;
long log_flags_level;
long timekeeper_xtime_sec;
+ long sched_rt_entity_my_q;
};
struct size_table { /* stash of commonly-used sizes */
@@ -1919,6 +1920,7 @@ struct size_table { /* stash of commonly-used sizes */
long msg_queue;
long log;
long log_level;
+ long rt_rq;
};
struct array_table {
diff --git a/symbols.c b/symbols.c
index 2646ff8..bbadd5e 100755
--- a/symbols.c
+++ b/symbols.c
@@ -8812,6 +8812,8 @@ dump_offset_table(char *spec, ulong makestruct)
OFFSET(log_level));
fprintf(fp, " log_flags_level: %ld\n",
OFFSET(log_flags_level));
+ fprintf(fp, " sched_rt_entity_my_q: %ld\n",
+ OFFSET(sched_rt_entity_my_q));
fprintf(fp, "\n size_table:\n");
fprintf(fp, " page: %ld\n", SIZE(page));
@@ -9027,6 +9029,8 @@ dump_offset_table(char *spec, ulong makestruct)
SIZE(log));
fprintf(fp, " log_level: %ld\n",
SIZE(log_level));
+ fprintf(fp, " rt_rq: %ld\n",
+ SIZE(rt_rq));
fprintf(fp, "\n array_table:\n");
/*
diff --git a/task.c b/task.c
index 6e4cfec..eeaad60 100755
--- a/task.c
+++ b/task.c
@@ -7552,6 +7552,7 @@ dump_CFS_runqueues(void)
if (!VALID_STRUCT(cfs_rq)) {
STRUCT_SIZE_INIT(cfs_rq, "cfs_rq");
+ STRUCT_SIZE_INIT(rt_rq, "rt_rq");
MEMBER_OFFSET_INIT(rq_rt, "rq", "rt");
MEMBER_OFFSET_INIT(rq_nr_running, "rq", "nr_running");
MEMBER_OFFSET_INIT(task_struct_se, "task_struct", "se");
@@ -7562,6 +7563,8 @@ dump_CFS_runqueues(void)
"cfs_rq");
MEMBER_OFFSET_INIT(sched_entity_my_q, "sched_entity",
"my_q");
+ MEMBER_OFFSET_INIT(sched_rt_entity_my_q, "sched_rt_entity",
+ "my_q");
MEMBER_OFFSET_INIT(sched_entity_on_rq, "sched_entity", "on_rq");
MEMBER_OFFSET_INIT(cfs_rq_rb_leftmost, "cfs_rq", "rb_leftmost");
MEMBER_OFFSET_INIT(cfs_rq_nr_running, "cfs_rq", "nr_running");
@@ -7648,6 +7651,8 @@ dump_CFS_runqueues(void)
FREEBUF(cfs_rq_buf);
}
+static int depth = 0;
+
static void
dump_RT_prio_array(ulong k_prio_array, char *u_prio_array)
{
@@ -7657,8 +7662,11 @@ dump_RT_prio_array(ulong k_prio_array, char *u_prio_array)
struct list_data list_data, *ld;
struct task_context *tc;
ulong *tlist;
+ ulong my_q, task_addr;
+ char *rt_rq_buf;
- fprintf(fp, " RT PRIO_ARRAY: %lx\n", k_prio_array);
+ if (!depth)
+ fprintf(fp, " RT PRIO_ARRAY: %lx\n", k_prio_array);
qheads = (i = ARRAY_LENGTH(rt_prio_array_queue)) ?
i : get_array_length("rt_prio_array.queue", NULL, SIZE(list_head));
@@ -7678,14 +7686,14 @@ dump_RT_prio_array(ulong k_prio_array, char *u_prio_array)
if ((list_head[0] == kvaddr) && (list_head[1] == kvaddr))
continue;
- fprintf(fp, " [%3d] ", i);
+ INDENT(5 + 9 * depth);
+ fprintf(fp, "[%3d] ", i);
BZERO(ld, sizeof(struct list_data));
ld->start = list_head[0];
if (VALID_MEMBER(task_struct_rt) &&
VALID_MEMBER(sched_rt_entity_run_list))
- ld->list_head_offset = OFFSET(task_struct_rt) +
- OFFSET(sched_rt_entity_run_list);
+ ld->list_head_offset = OFFSET(sched_rt_entity_run_list);
else
ld->list_head_offset = OFFSET(task_struct_run_list);
ld->end = kvaddr;
@@ -7695,10 +7703,35 @@ dump_RT_prio_array(ulong k_prio_array, char *u_prio_array)
tlist = (ulong *)GETBUF((cnt) * sizeof(ulong));
cnt = retrieve_list(tlist, cnt);
for (c = 0; c < cnt; c++) {
- if (!(tc = task_to_context(tlist[c])))
+ task_addr = tlist[c];
+ if (VALID_MEMBER(sched_rt_entity_my_q)) {
+ readmem(tlist[c] + OFFSET(sched_rt_entity_my_q),
+ KVADDR, &my_q, sizeof(ulong), "my_q",
+ FAULT_ON_ERROR);
+ if (my_q) {
+ rt_rq_buf = GETBUF(SIZE(rt_rq));
+ readmem(my_q, KVADDR, rt_rq_buf,
+ SIZE(rt_rq), "rt_rq",
+ FAULT_ON_ERROR);
+ if (c)
+ INDENT(11 + 9 * depth);
+ fprintf(fp, "CHILD RT PRIO_ARRAY: %lx\n",
+ my_q + OFFSET(rt_rq_active));
+ tot++;
+ depth++;
+ dump_RT_prio_array(
+ my_q + OFFSET(rt_rq_active),
+ &rt_rq_buf[OFFSET(rt_rq_active)]);
+ depth--;
+ continue;
+ } else {
+ task_addr -= OFFSET(task_struct_rt);
+ }
+ }
+ if (!(tc = task_to_context(task_addr)))
continue;
if (c)
- INDENT(11);
+ INDENT(11 + 9 * depth);
fprintf(fp, "PID: %-5ld TASK: %lx COMMAND: \"%s\"\n",
tc->pid, tc->task, tc->comm);
tot++;
@@ -7707,7 +7740,7 @@ dump_RT_prio_array(ulong k_prio_array, char *u_prio_array)
}
if (!tot) {
- INDENT(5);
+ INDENT(5 + 9 * depth);
fprintf(fp, "[no tasks queued]\n");
}
}
--
1.7.1
--
Crash-utility mailing list
Crash-utility@xxxxxxxxxx
https://www.redhat.com/mailman/listinfo/crash-utility
