[Crash-utility] [PATCH 2/2] tree: add an option to dump the tree sorted
Daniel Vacek
neelx at redhat.com
Thu Apr 12 14:51:37 UTC 2018
On Thu, Apr 12, 2018 at 3:57 PM, Dave Anderson <anderson at redhat.com> wrote:
>
> Daniel,
>
> Hmmm, when looking at your example, I just noticed it didn't use the -t argument,
> but then looking at the code realized that the command defaults to rbtrees. I
> actually don't think that was the original intent, but maybe that fact should
> should be indicated in the help page? Although I can't come up with a compelling
> argument why one should be the default. Either that, or -t should be enforced.
Wow. I didn't know this was not intended. I thought that red-black is
default as radix trees are only used in address_space of mapped files
(page cache), AFAIK. I usually do not need to specify the type as all
the major trees are red-black - being it cgroups, scheduler entities,
memory mappings, inodes, you name it.
Again, I didn't change anything with regards to this behavior.
> Anyway, you probably didn't notice that all help page output is constrained
> to 80 columns. Your example command alone is 162 bytes long, making it way
> too confusing to figure out what the command is doing. Can you just show
> the command output without piping it to an external command, or make a much
> simpler example? And also keep it to 80 columns or less,
I was thinking about wrapping the command to a second line but that's
what terminal will do anyways if narrower so I left it that way. The
rest of the pipe is just formatting/pretty printing the table.
Otherwise the output would be waaaay toooo loooong and not really
human readable. I do not think it can get any simpler than that. I can
get rid of one of the columns though, it does not need to contain both
the start and the end of the VMA range.
As an added value it also teaches eventual readers some advanced usage
techniques in general so I believe it can be useful. There is enough
simple examples already. Would you rather prefer something like this?
crash> task -R mm
PID: 28682 TASK: ffff880036d4af10 CPU: 0 COMMAND: "crash"
mm = 0xffff880074b5be80,
crash> tree -lp -o vm_area_struct.vm_rb -r mm_struct.mm_rb 0xffff880074b5be80
ffff88001f2c50e0
position: root/l/l/l/l/l
ffff88001f2c5290
position: root/l/l/l/l
ffff880074bfc6c0
position: root/l/l/l/l/r
ffff88001f2c4bd0
position: root/l/l/l
ffff880074bfc948
position: root/l/l/l/r/l/l
ffff880036e54510
position: root/l/l/l/r/l/l/r
ffff88001f2c5bd8
position: root/l/l/l/r/l
ffff880036e54af8
position: root/l/l/l/r/l/r/l
ffff880036e54f30
position: root/l/l/l/r/l/r
ffff88000e06aa20
position: root/l/l/l/r/l/r/r
ffff88000e06b368
position: root/l/l/l/r
ffff88000e06ba28
position: root/l/l/l/r/r/l
ffff88000e06ae58
position: root/l/l/l/r/r
ffff88000e06a6c0
position: root/l/l/l/r/r/r
...
ffff88001f2c51b8
position: root/l/r/r/r/l
ffff88001f2c4d80
position: root/l/r/r/r
ffff880074bfd878
position: root/l/r/r/r/r
ffff88001f2c5a28
position: root
ffff88001f2c4a20
position: root/r/l/l/l
ffff88001f2c4360
position: root/r/l/l
ffff880074bfcaf8
position: root/r/l/l/r
...
ffff88001f2c5e60
position: root/r/r/l/l/l
ffff88001f2c4ca8
position: root/r/r/l/l
ffff88001f2c5008
position: root/r/r/l
ffff88001f2c5d88
position: root/r/r/l/r
ffff880074bfd6c8
position: root/r/r/l/r/r
ffff88001f2c4288
position: root/r/r
ffff88001f2c4510
position: root/r/r/r
ffff88001f2c5b00
position: root/r/r/r/r
This is not as readable in my opinion. And also it does not show why
would one care about the order in the first place. See?
I do not believe a hard limit of 80 columns is useful for any serious
kernel debugging. For developing and maintaining a source code, yes.
For dumping a lot of debugging data in a human readable form, no.
For example if I type 'timer -r' I already get an output which is over
eighty. How would you copy/paste this to help? Or how do you feel
about the output itself?
CLOCK: 1 HRTIMER_CLOCK_BASE: ffff8805ed82d9a0 [ktime_get_real]
CURRENT
1522436617507394900
SOFTEXPIRES EXPIRES HRTIMER FUNCTION
1522436624101007000 1522436624101057000 ffff8805e08ebd60
ffffffff810a95c0 <hrtimer_wakeup>
1522436628203647900 1522436628203697900 ffff8805e33fbd60
ffffffff810a95c0 <hrtimer_wakeup>
1522436635368413000 1522436635368463000 ffff8805e07cfd60
ffffffff810a95c0 <hrtimer_wakeup>
1522436652248574300 1522436652248624300 ffff8805e1acfd60
ffffffff810a95c0 <hrtimer_wakeup>
1522436652257417000 1522436652257467000 ffff8805e07a3d60
ffffffff810a95c0 <hrtimer_wakeup>
1522436664228364000 1522436664228414000 ffff8805e1347d60
ffffffff810a95c0 <hrtimer_wakeup>
That's about the same width as my example.
What do you suggest?
> and put the "l" argument in the synopsis line at the top.
Nah. I missed that one. Will fix it. Or you can just amend it yourself.
--nX
> Thanks,
> Dave
>
>
>
> ----- Original Message -----
>> ---
>> defs.h | 1 +
>> help.c | 80
>> +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
>> tools.c | 16 +++++++++++--
>> 3 files changed, 95 insertions(+), 2 deletions(-)
>>
>> diff --git a/defs.h b/defs.h
>> index adddb9f2748d..ec298cbd70be 100644
>> --- a/defs.h
>> +++ b/defs.h
>> @@ -2480,6 +2480,7 @@ struct tree_data {
>> #define TREE_STRUCT_RADIX_16 (VERBOSE << 6)
>> #define TREE_PARSE_MEMBER (VERBOSE << 7)
>> #define TREE_READ_MEMBER (VERBOSE << 8)
>> +#define TREE_LINEAR_ORDER (VERBOSE << 9)
>>
>> #define ALIAS_RUNTIME (1)
>> #define ALIAS_RCLOCAL (2)
>> diff --git a/help.c b/help.c
>> index c5cec5365962..e7df50fa2ef4 100644
>> --- a/help.c
>> +++ b/help.c
>> @@ -5698,6 +5698,8 @@ char *help_tree[] = {
>> " indicates \"root/l/r\" means that the node is the right
>> child",
>> " of the left child of the root node. For radix trees, the
>> height",
>> " and slot index values are shown with respect to the root.",
>> +" -l Dump the tree sorted in linear order starting with the
>> leftmost",
>> +" node and progressing to the right.",
>> " ",
>> " The meaning of the \"start\" argument, which can be expressed either in",
>> " hexadecimal format or symbolically, depends upon whether the -N option",
>> @@ -5823,6 +5825,84 @@ char *help_tree[] = {
>> " ffffea000407de58",
>> " position: root/3/28",
>> "",
>> +" List the tree in linear order from the leftmost node progressing",
>> +" to the right using the -l option:\n",
>> +" %s> tree -lps vm_area_struct.vm_start,vm_end -o vm_area_struct.vm_rb -r
>> mm_struct.mm_rb 0xffff8805dee5e400 | sed 's/^ //' | paste - - - - | column
>> -ts' '",
>> +" ffff8805e108f008 position: root/l/l/l/l/l/l/l/l/l vm_start =
>> 0x7f6f9ca5f000 vm_end = 0x7f6f9d44c000",
>> +" ffff880540d35d88 position: root/l/l/l/l/l/l/l/l vm_start =
>> 0x7f6f9d44c000 vm_end = 0x7f6f9d454000",
>> +" ffff8805def64d80 position: root/l/l/l/l/l/l/l vm_start =
>> 0x7f6f9d454000 vm_end = 0x7f6f9d653000",
>> +" ffff8805e0b46510 position: root/l/l/l/l/l/l/l/r/l vm_start =
>> 0x7f6f9d653000 vm_end = 0x7f6f9d654000",
>> +" ffff8805e108e288 position: root/l/l/l/l/l/l/l/r vm_start =
>> 0x7f6f9d654000 vm_end = 0x7f6f9d655000",
>> +" ffff8805def65bd8 position: root/l/l/l/l/l/l/l/r/r vm_start =
>> 0x7f6f9d655000 vm_end = 0x7f6f9d661000",
>> +" ffff8805def64ca8 position: root/l/l/l/l/l/l vm_start =
>> 0x7f6f9d661000 vm_end = 0x7f6f9d860000",
>> +" ffff8805def641b0 position: root/l/l/l/l/l/l/r/l vm_start =
>> 0x7f6f9d860000 vm_end = 0x7f6f9d861000",
>> +" ffff8805def64438 position: root/l/l/l/l/l/l/r/l/r vm_start =
>> 0x7f6f9d861000 vm_end = 0x7f6f9d862000",
>> +" ffff8805def65368 position: root/l/l/l/l/l/l/r vm_start =
>> 0x7f6f9d862000 vm_end = 0x7f6f9d868000",
>> +" ffff880540ec2e58 position: root/l/l/l/l/l/l/r/r vm_start =
>> 0x7f6f9d868000 vm_end = 0x7f6f9d88c000",
>> +" ...",
>> +" ffff8805dfc08e58 position: root/l/r/r/l/r/l vm_start =
>> 0x7f6fa020f000 vm_end = 0x7f6fa0216000",
>> +" ffff880540ec35f0 position: root/l/r/r/l/r vm_start =
>> 0x7f6fa0216000 vm_end = 0x7f6fa0217000",
>> +" ffff8805dfc09cb0 position: root/l/r/r/l/r/r vm_start =
>> 0x7f6fa0217000 vm_end = 0x7f6fa0338000",
>> +" ffff8805dfc08360 position: root/l/r/r vm_start =
>> 0x7f6fa0338000 vm_end = 0x7f6fa0538000",
>> +" ffff8805dfc08bd0 position: root vm_start =
>> 0x7f6fa07af000 vm_end = 0x7f6fa09ae000",
>> +" ffff8805dfc08288 position: root/r/l/l/l/l/l vm_start =
>> 0x7f6fa09ae000 vm_end = 0x7f6fa09b2000",
>> +" ffff880540ec31b8 position: root/r/l/l/l/l/l/r vm_start =
>> 0x7f6fa09b2000 vm_end = 0x7f6fa09b3000",
>> +" ffff8805dfc08ca8 position: root/r/l/l/l/l vm_start =
>> 0x7f6fa09b3000 vm_end = 0x7f6fa09b4000",
>> +" ffff8800f78c15f0 position: root/r/l/l/l/l/r vm_start =
>> 0x7f6fa09b4000 vm_end = 0x7f6fa0b6c000",
>> +" ...",
>> +" ffff8805def651b8 position: root/r/r/r/r/l/l vm_start =
>> 0x7f6fa2f42000 vm_end = 0x7f6fa2f43000",
>> +" ffff880540d35e60 position: root/r/r/r/r/l vm_start =
>> 0x7f6fa2f43000 vm_end = 0x7f6fa2f44000",
>> +" ffff880540d35518 position: root/r/r/r/r/l/r vm_start =
>> 0x7f6fa2f44000 vm_end = 0x7f6fa2f85000",
>> +" ffff880540d356c8 position: root/r/r/r/r vm_start =
>> 0x7f6fa3185000 vm_end = 0x7f6fa3187000",
>> +" ffff8805def64000 position: root/r/r/r/r/r/l/l vm_start =
>> 0x7f6fa3187000 vm_end = 0x7f6fa3188000",
>> +" ffff880540d35cb0 position: root/r/r/r/r/r/l vm_start =
>> 0x7f6fa3188000 vm_end = 0x7f6fa3189000",
>> +" ffff8805def64798 position: root/r/r/r/r/r/l/r vm_start =
>> 0x7f6fa4bf9000 vm_end = 0x7f6fa4c1a000",
>> +" ffff880540d340d8 position: root/r/r/r/r/r vm_start =
>> 0x7ffc2b386000 vm_end = 0x7ffc2b3a8000",
>> +" ffff880540d35950 position: root/r/r/r/r/r/r vm_start =
>> 0x7ffc2b3c2000 vm_end = 0x7ffc2b3c4000",
>> +"",
>> +" Compared to the top/down order:\n",
>> +" %s> tree -ps vm_area_struct.vm_start,vm_end -o vm_area_struct.vm_rb -r
>> mm_struct.mm_rb 0xffff8805dee5e400 | sed 's/^ //' | paste - - - - | column
>> -ts' '",
>> +" ffff8805dfc08bd0 position: root vm_start =
>> 0x7f6fa07af000 vm_end = 0x7f6fa09ae000",
>> +" ffff8805e0b79b00 position: root/l vm_start =
>> 0x7f6f9f585000 vm_end = 0x7f6f9f785000",
>> +" ffff8805e0b79e60 position: root/l/l vm_start =
>> 0x7f6f9ec2b000 vm_end = 0x7f6f9ee2b000",
>> +" ffff8805e0b78bd0 position: root/l/l/l vm_start =
>> 0x7f6f9e2c1000 vm_end = 0x7f6f9e4c0000",
>> +" ffff8805e07f0bd0 position: root/l/l/l/l vm_start =
>> 0x7f6f9da92000 vm_end = 0x7f6f9dc91000",
>> +" ffff880540ec20d8 position: root/l/l/l/l/l vm_start =
>> 0x7f6f9d88c000 vm_end = 0x7f6f9da8b000",
>> +" ffff8805def64ca8 position: root/l/l/l/l/l/l vm_start =
>> 0x7f6f9d661000 vm_end = 0x7f6f9d860000",
>> +" ffff8805def64d80 position: root/l/l/l/l/l/l/l vm_start =
>> 0x7f6f9d454000 vm_end = 0x7f6f9d653000",
>> +" ffff880540d35d88 position: root/l/l/l/l/l/l/l/l vm_start =
>> 0x7f6f9d44c000 vm_end = 0x7f6f9d454000",
>> +" ffff8805e108f008 position: root/l/l/l/l/l/l/l/l/l vm_start =
>> 0x7f6f9ca5f000 vm_end = 0x7f6f9d44c000",
>> +" ffff8805e108e288 position: root/l/l/l/l/l/l/l/r vm_start =
>> 0x7f6f9d654000 vm_end = 0x7f6f9d655000",
>> +" ffff8805e0b46510 position: root/l/l/l/l/l/l/l/r/l vm_start =
>> 0x7f6f9d653000 vm_end = 0x7f6f9d654000",
>> +" ffff8805def65bd8 position: root/l/l/l/l/l/l/l/r/r vm_start =
>> 0x7f6f9d655000 vm_end = 0x7f6f9d661000",
>> +" ...",
>> +" ffff8805dfc08360 position: root/l/r/r vm_start =
>> 0x7f6fa0338000 vm_end = 0x7f6fa0538000",
>> +" ffff8805dfc096c8 position: root/l/r/r/l vm_start =
>> 0x7f6fa0010000 vm_end = 0x7f6fa020f000",
>> +" ffff880540ec2870 position: root/l/r/r/l/l vm_start =
>> 0x7f6f9ffe9000 vm_end = 0x7f6f9ffea000",
>> +" ffff8805dfc09440 position: root/l/r/r/l/l/l vm_start =
>> 0x7f6f9ffe8000 vm_end = 0x7f6f9ffe9000",
>> +" ffff8805dfc09290 position: root/l/r/r/l/l/r vm_start =
>> 0x7f6f9ffea000 vm_end = 0x7f6fa0010000",
>> +" ffff880540ec35f0 position: root/l/r/r/l/r vm_start =
>> 0x7f6fa0216000 vm_end = 0x7f6fa0217000",
>> +" ffff8805dfc08e58 position: root/l/r/r/l/r/l vm_start =
>> 0x7f6fa020f000 vm_end = 0x7f6fa0216000",
>> +" ffff8805dfc09cb0 position: root/l/r/r/l/r/r vm_start =
>> 0x7f6fa0217000 vm_end = 0x7f6fa0338000",
>> +" ffff880540d346c0 position: root/r vm_start =
>> 0x7f6fa1f5a000 vm_end = 0x7f6fa2159000",
>> +" ffff8800f78c10e0 position: root/r/l vm_start =
>> 0x7f6fa135f000 vm_end = 0x7f6fa155f000",
>> +" ffff8800f78c1440 position: root/r/l/l vm_start =
>> 0x7f6fa0d8d000 vm_end = 0x7f6fa0f8d000",
>> +" ffff8800f78c1950 position: root/r/l/l/l vm_start =
>> 0x7f6fa0b6c000 vm_end = 0x7f6fa0d6c000",
>> +" ffff8805dfc08ca8 position: root/r/l/l/l/l vm_start =
>> 0x7f6fa09b3000 vm_end = 0x7f6fa09b4000",
>> +" ffff8805dfc08288 position: root/r/l/l/l/l/l vm_start =
>> 0x7f6fa09ae000 vm_end = 0x7f6fa09b2000",
>> +" ffff880540ec31b8 position: root/r/l/l/l/l/l/r vm_start =
>> 0x7f6fa09b2000 vm_end = 0x7f6fa09b3000",
>> +" ffff8800f78c15f0 position: root/r/l/l/l/l/r vm_start =
>> 0x7f6fa09b4000 vm_end = 0x7f6fa0b6c000",
>> +" ...",
>> +" ffff880540d356c8 position: root/r/r/r/r vm_start =
>> 0x7f6fa3185000 vm_end = 0x7f6fa3187000",
>> +" ffff880540d35e60 position: root/r/r/r/r/l vm_start =
>> 0x7f6fa2f43000 vm_end = 0x7f6fa2f44000",
>> +" ffff8805def651b8 position: root/r/r/r/r/l/l vm_start =
>> 0x7f6fa2f42000 vm_end = 0x7f6fa2f43000",
>> +" ffff880540d35518 position: root/r/r/r/r/l/r vm_start =
>> 0x7f6fa2f44000 vm_end = 0x7f6fa2f85000",
>> +" ffff880540d340d8 position: root/r/r/r/r/r vm_start =
>> 0x7ffc2b386000 vm_end = 0x7ffc2b3a8000",
>> +" ffff880540d35cb0 position: root/r/r/r/r/r/l vm_start =
>> 0x7f6fa3188000 vm_end = 0x7f6fa3189000",
>> +" ffff8805def64000 position: root/r/r/r/r/r/l/l vm_start =
>> 0x7f6fa3187000 vm_end = 0x7f6fa3188000",
>> +" ffff8805def64798 position: root/r/r/r/r/r/l/r vm_start =
>> 0x7f6fa4bf9000 vm_end = 0x7f6fa4c1a000",
>> +" ffff880540d35950 position: root/r/r/r/r/r/r vm_start =
>> 0x7ffc2b3c2000 vm_end = 0x7ffc2b3c4000",
>> +"",
>> " Alternatively, take the address of the radix_tree_node from the",
>> " radix_tree_root structure in the address_space structure above,",
>> " and display the tree with the -N option:\n",
>> diff --git a/tools.c b/tools.c
>> index 992f4776281a..1970e8bb136b 100644
>> --- a/tools.c
>> +++ b/tools.c
>> @@ -3926,7 +3926,7 @@ cmd_tree()
>> td = &tree_data;
>> BZERO(td, sizeof(struct tree_data));
>>
>> - while ((c = getopt(argcnt, args, "xdt:r:o:s:S:pN")) != EOF) {
>> + while ((c = getopt(argcnt, args, "xdt:r:o:s:S:plN")) != EOF) {
>> switch (c)
>> {
>> case 't':
>> @@ -3993,6 +3993,10 @@ cmd_tree()
>> td->flags |= TREE_POSITION_DISPLAY;
>> break;
>>
>> + case 'l':
>> + td->flags |= TREE_LINEAR_ORDER;
>> + break;
>> +
>> case 'N':
>> td->flags |= TREE_NODE_POINTER;
>> break;
>> @@ -4399,6 +4403,13 @@ rbtree_iteration(ulong node_p, struct tree_data *td,
>> char *pos)
>>
>> struct_p = node_p - td->node_member_offset;
>>
>> + if (td->flags & TREE_LINEAR_ORDER &&
>> + readmem(node_p+OFFSET(rb_node_rb_left), KVADDR, &new_p,
>> + sizeof(void *), "rb_node rb_left", RETURN_ON_ERROR)) {
>> + sprintf(new_pos, "%s/l", pos);
>> + rbtree_iteration(new_p, td, new_pos);
>> + }
>> +
>> if (td->flags & VERBOSE)
>> fprintf(fp, "%lx\n", struct_p);
>>
>> @@ -4430,7 +4441,8 @@ rbtree_iteration(ulong node_p, struct tree_data *td,
>> char *pos)
>> }
>> }
>>
>> - if ( readmem(node_p+OFFSET(rb_node_rb_left), KVADDR, &new_p,
>> + if (!(td->flags & TREE_LINEAR_ORDER) &&
>> + readmem(node_p+OFFSET(rb_node_rb_left), KVADDR, &new_p,
>> sizeof(void *), "rb_node rb_left", RETURN_ON_ERROR)) {
>> sprintf(new_pos, "%s/l", pos);
>> rbtree_iteration(new_p, td, new_pos);
>> --
>> 2.16.2
>>
>> --
>> Crash-utility mailing list
>> Crash-utility at redhat.com
>> https://www.redhat.com/mailman/listinfo/crash-utility
>>
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