Re: [PATCH 05/63] dyndbg: replace classmap list with a vector
On Tue, Feb 25, 2025 at 7:08 AM Louis Chauvet wrote:
>
>
>
> Le 25/01/2025 ą 07:45, Jim Cromie a écrit :
> > Classmaps are stored in an elf section/array, but are individually
> > list-linked onto dyndbg's per-module ddebug_table for operation.
> >
> > This is unnecessary; even when ddebug_attach_classmap() is handling
> > the builtin section (with classmaps for multiple builtin modules), its
> > contents are ordered, so a module's possibly multiple classmaps will
> > be consecutive in the section, and could be treated as a vector/block,
> > since both start-address and subrange length are in the ddebug_info arg.
> >
> > IOW, this treats classmaps similarly to _ddebugs, which are already
> > kept as vector-refs (address+len).
> >
> > So this changes:
> >
> > struct ddebug_class_map drops list-head link.
> >
> > struct ddebug_table drops the list-head maps, and gets: classes &
> > num_classes for the start-address and num_classes, placed to improve
> > struct packing.
> >
> > The loading: in ddebug_attach_module_classes(), replace the
> > for-the-modname list-add loop, with a forloop that finds the module's
> > subrange (start,length) of matching classmaps within the possibly
> > builtin classmaps vector, and saves those to the ddebug_table.
> >
> > The reading/using: change list-foreach loops in ddebug_class_name() &
> > ddebug_find_valid_class() to walk the array from start to length.
> >
> > Also:
> > Move #define __outvar up, above an added use in a fn-prototype.
> > Simplify ddebug_attach_module_classes args, ref has both address & len.
> >
> > no functional changes
> >
> > Signed-off-by: Jim Cromie
> > ---
> > include/linux/dynamic_debug.h | 1 -
> > lib/dynamic_debug.c | 61 ++-
> > 2 files changed, 32 insertions(+), 30 deletions(-)
> >
> > diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
> > index b9afc7731b7c..2b0057058ecf 100644
> > --- a/include/linux/dynamic_debug.h
> > +++ b/include/linux/dynamic_debug.h
> > @@ -83,7 +83,6 @@ enum class_map_type {
> > };
> >
> > struct ddebug_class_map {
> > - struct list_head link;
> > struct module *mod;
> > const char *mod_name; /* needed for builtins */
> > const char **class_names;
> > diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
> > index 55df35df093b..41cbaa96f83d 100644
> > --- a/lib/dynamic_debug.c
> > +++ b/lib/dynamic_debug.c
> > @@ -45,10 +45,11 @@ extern struct ddebug_class_map
> > __start___dyndbg_classes[];
> > extern struct ddebug_class_map __stop___dyndbg_classes[];
> >
> > struct ddebug_table {
> > - struct list_head link, maps;
> > + struct list_head link;
> > const char *mod_name;
> > - unsigned int num_ddebugs;
> > struct _ddebug *ddebugs;
> > + struct ddebug_class_map *classes;
> > + unsigned int num_ddebugs, num_classes;
> > };
> >
> > struct ddebug_query {
> > @@ -147,13 +148,15 @@ static void vpr_info_dq(const struct ddebug_query
> > *query, const char *msg)
> > query->first_lineno, query->last_lineno,
> > query->class_string);
> > }
> >
> > +#define __outvar /* filled by callee */
>
> Hi Jim,
>
> What is the goal of this __outvar define? I can't find any other #define
> of it in the kernel.
its basically a comment, trying to be more important.
if its misleading or overwrought, I can yank it :-)
>
> > static struct ddebug_class_map *ddebug_find_valid_class(struct
> > ddebug_table const *dt,
> > - const char
> > *class_string, int *class_id)
> > + const char
> > *class_string,
> > + __outvar int
> > *class_id)
>
> The order between __outvar and int is not important? Here you have
> __outvar before int, but later [1] the __outvar is after int.
>
I intended no difference, I used it where I thought it communicated best
in each case, and since the macro is empty, it makes none.
> [1]:https://elixir.bootlin.com/linux/v6.14-rc3/source/lib/dynamic_debug.c#L183
>
> Thanks,
> Louis Chauvet
>
> > {
> > struct ddebug_class_map *map;
> > - int idx;
> > + int i, idx;
> >
> > - list_for_each_entry(map, &dt->maps, link) {
> > + for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) {
> > idx = match_string(map->class_names, map->length,
> > class_string);
> > if (idx >= 0) {
> > *class_id = idx + map->base;
> > @@ -164,7 +167,6 @@ static struct ddebug_class_map
> > *ddebug_find_valid_class(struct ddebug_table cons
> > return NULL;
> > }
> >
> > -#define __outvar /* filled by callee */
> > /*
> >* Search the tables for _ddebug's which match the given `query' and
> >* apply the `flags' and `mask' to them. Returns number of matching
> > @@ -1114,9 +1116,10 @@ static void *ddebug_proc_next(struct seq_file *m,
> >
Re: [PATCH 05/63] dyndbg: replace classmap list with a vector
Le 25/01/2025 à 07:45, Jim Cromie a écrit :
Classmaps are stored in an elf section/array, but are individually
list-linked onto dyndbg's per-module ddebug_table for operation.
This is unnecessary; even when ddebug_attach_classmap() is handling
the builtin section (with classmaps for multiple builtin modules), its
contents are ordered, so a module's possibly multiple classmaps will
be consecutive in the section, and could be treated as a vector/block,
since both start-address and subrange length are in the ddebug_info arg.
IOW, this treats classmaps similarly to _ddebugs, which are already
kept as vector-refs (address+len).
So this changes:
struct ddebug_class_map drops list-head link.
struct ddebug_table drops the list-head maps, and gets: classes &
num_classes for the start-address and num_classes, placed to improve
struct packing.
The loading: in ddebug_attach_module_classes(), replace the
for-the-modname list-add loop, with a forloop that finds the module's
subrange (start,length) of matching classmaps within the possibly
builtin classmaps vector, and saves those to the ddebug_table.
The reading/using: change list-foreach loops in ddebug_class_name() &
ddebug_find_valid_class() to walk the array from start to length.
Also:
Move #define __outvar up, above an added use in a fn-prototype.
Simplify ddebug_attach_module_classes args, ref has both address & len.
no functional changes
Signed-off-by: Jim Cromie
---
include/linux/dynamic_debug.h | 1 -
lib/dynamic_debug.c | 61 ++-
2 files changed, 32 insertions(+), 30 deletions(-)
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h
index b9afc7731b7c..2b0057058ecf 100644
--- a/include/linux/dynamic_debug.h
+++ b/include/linux/dynamic_debug.h
@@ -83,7 +83,6 @@ enum class_map_type {
};
struct ddebug_class_map {
- struct list_head link;
struct module *mod;
const char *mod_name; /* needed for builtins */
const char **class_names;
diff --git a/lib/dynamic_debug.c b/lib/dynamic_debug.c
index 55df35df093b..41cbaa96f83d 100644
--- a/lib/dynamic_debug.c
+++ b/lib/dynamic_debug.c
@@ -45,10 +45,11 @@ extern struct ddebug_class_map __start___dyndbg_classes[];
extern struct ddebug_class_map __stop___dyndbg_classes[];
struct ddebug_table {
- struct list_head link, maps;
+ struct list_head link;
const char *mod_name;
- unsigned int num_ddebugs;
struct _ddebug *ddebugs;
+ struct ddebug_class_map *classes;
+ unsigned int num_ddebugs, num_classes;
};
struct ddebug_query {
@@ -147,13 +148,15 @@ static void vpr_info_dq(const struct ddebug_query *query,
const char *msg)
query->first_lineno, query->last_lineno, query->class_string);
}
+#define __outvar /* filled by callee */
Hi Jim,
What is the goal of this __outvar define? I can't find any other #define
of it in the kernel.
static struct ddebug_class_map *ddebug_find_valid_class(struct ddebug_table
const *dt,
- const char
*class_string, int *class_id)
+ const char
*class_string,
+ __outvar int *class_id)
The order between __outvar and int is not important? Here you have
__outvar before int, but later [1] the __outvar is after int.
[1]:https://elixir.bootlin.com/linux/v6.14-rc3/source/lib/dynamic_debug.c#L183
Thanks,
Louis Chauvet
{
struct ddebug_class_map *map;
- int idx;
+ int i, idx;
- list_for_each_entry(map, &dt->maps, link) {
+ for (map = dt->classes, i = 0; i < dt->num_classes; i++, map++) {
idx = match_string(map->class_names, map->length, class_string);
if (idx >= 0) {
*class_id = idx + map->base;
@@ -164,7 +167,6 @@ static struct ddebug_class_map
*ddebug_find_valid_class(struct ddebug_table cons
return NULL;
}
-#define __outvar /* filled by callee */
/*
* Search the tables for _ddebug's which match the given `query' and
* apply the `flags' and `mask' to them. Returns number of matching
@@ -1114,9 +1116,10 @@ static void *ddebug_proc_next(struct seq_file *m, void
*p, loff_t *pos)
static const char *ddebug_class_name(struct ddebug_iter *iter, struct _ddebug *dp)
{
- struct ddebug_class_map *map;
+ struct ddebug_class_map *map = iter->table->classes;
+ int i, nc = iter->table->num_classes;
- list_for_each_entry(map, &iter->table->maps, link)
+ for (i = 0; i < nc; i++, map++)
if (class_in_range(dp->class_id, map))
return map->class_names[dp->class_id - map->base];
@@ -1200,30 +1203,31 @@ static const struct proc_ops proc_fops = {
.proc_write = ddebug_proc_write
};
-static void ddebug_attach_module_classes(struct ddebug_table *dt,
-
