| Message ID | 20250320185238.447458-11-jim.cromie@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Fix CONFIG_DRM_USE_DYNAMIC_DEBUG=y | expand |
Le 20/03/2025 à 19:51, Jim Cromie a écrit : > Classmaps are stored in an elf section/array, but currently are > individually list-linked onto dyndbg's per-module ddebug_table for > operation. This is unnecessary. > > Just like dyndbg's descriptors, classes are packed in compile order; > so even with many builtin modules employing multiple classmaps, each > modules' maps are packed contiguously, and can be treated as a > array-start-address & array-length. > > So this drops the whole list building operation done in > ddebug_attach_module_classes(), and removes the list-head members. > The "select-by-modname" condition is reused to find the start,end of > the subrange. > > NOTE: This "filter-by-modname" on classmaps should really be done in > ddebug_add_module(1); ie at least one step closer to ddebug_init(2), > which already splits up pr-debug descriptors into subranges by > modname, then calls (1) on each. (2) knows nothing of classmaps > currently, and doesn't need to. For now, just add comment. > > Signed-off-by: Jim Cromie <jim.cromie@gmail.com> > --- > 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 ac199293d203..e458d4b838ac 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 dd7320b9616d..d5572712ce55 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 */ > 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) Thanks for your explanation of __outvar! It makes sense. I never seen this pattern anywhere in the kernel, maybe a simple doc comment is enough to carry the information: /** * ddebug_find_valid_class - Find a valid class for a * given string * @dt: debug table to inspect * @class_string: string to match on * @class_id: output pointer for the class_id value * * Returns: Pointer to the ddebug_class_map instance, if found. * @class_id will be set to the id of this class. If no class * matching @class_string is found, returns NULL and class_id is * set to -ENOENT. */ Or at maybe change the documentation of __outvar to be a bit more explicit about how it works (I had difficulties to understand because a lot of "magic macro" exist in the kernel and sometimes carry information to the compiler, but this one is always empty): /** * __outvar - Denotes that an argument is used as an output * value * This macro does nothing apart clarify for the reader that * the parameter will be filled by the callee */ With any of the modifications (feel free to reword them as you want): Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com> > { > 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 > @@ -1122,9 +1124,10 @@ 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]; > > @@ -1208,30 +1211,31 @@ static const struct proc_ops proc_fops = { > .proc_write = ddebug_proc_write > }; > > -static void ddebug_attach_module_classes(struct ddebug_table *dt, > - struct ddebug_class_map *classes, > - int num_classes) > +static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di) > { > struct ddebug_class_map *cm; > - int i, j, ct = 0; > + int i, nc = 0; > > - for (cm = classes, i = 0; i < num_classes; i++, cm++) { > + /* > + * Find this module's classmaps in a subrange/wholerange of > + * the builtin/modular classmap vector/section. Save the start > + * and length of the subrange at its edges. > + */ > + for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) { > > if (!strcmp(cm->mod_name, dt->mod_name)) { > - > - v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i, > - cm->mod_name, cm->base, cm->length, cm->map_type); > - > - for (j = 0; j < cm->length; j++) > - v3pr_info(" %d: %d %s\n", j + cm->base, j, > - cm->class_names[j]); > - > - list_add(&cm->link, &dt->maps); > - ct++; > + if (!nc) { > + v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n", > + i, cm->mod_name, cm->base, cm->length, cm->map_type); > + dt->classes = cm; > + } > + nc++; > } > } > - if (ct) > - vpr_info("module:%s attached %d classes\n", dt->mod_name, ct); > + if (nc) { > + dt->num_classes = nc; > + vpr_info("module:%s attached %d classes\n", dt->mod_name, nc); > + } > } > > /* > @@ -1263,10 +1267,9 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname) > dt->num_ddebugs = di->num_descs; > > INIT_LIST_HEAD(&dt->link); > - INIT_LIST_HEAD(&dt->maps); > > if (di->classes && di->num_classes) > - ddebug_attach_module_classes(dt, di->classes, di->num_classes); > + ddebug_attach_module_classes(dt, di); > > mutex_lock(&ddebug_lock); > list_add_tail(&dt->link, &ddebug_tables); > @@ -1379,8 +1382,8 @@ static void ddebug_remove_all_tables(void) > mutex_lock(&ddebug_lock); > while (!list_empty(&ddebug_tables)) { > struct ddebug_table *dt = list_entry(ddebug_tables.next, > - struct ddebug_table, > - link); > + struct ddebug_table, > + link); > ddebug_table_free(dt); > } > mutex_unlock(&ddebug_lock);
On Mon, Mar 24, 2025 at 9:08 AM Louis Chauvet <louis.chauvet@bootlin.com> wrote: > > > > Le 20/03/2025 à 19:51, Jim Cromie a écrit : > Thanks for your explanation of __outvar! It makes sense. I never seen > this pattern anywhere in the kernel, maybe a simple doc comment is > enough to carry the information: Im gonna pull it - Ive decided its misleading, since it looks like it does something that it cant do. a plain old comment would be enough, if its needed at all. __outvar was at least brief ;-) In fact I did, but in a later patch. cleaning now. > /** > * ddebug_find_valid_class - Find a valid class for a > * given string > * @dt: debug table to inspect > * @class_string: string to match on > * @class_id: output pointer for the class_id value > * > * Returns: Pointer to the ddebug_class_map instance, if found. > * @class_id will be set to the id of this class. If no class > * matching @class_string is found, returns NULL and class_id is > * set to -ENOENT. > */ > > Or at maybe change the documentation of __outvar to be a bit more > explicit about how it works (I had difficulties to understand because a > lot of "magic macro" exist in the kernel and sometimes carry information > to the compiler, but this one is always empty): > > /** > * __outvar - Denotes that an argument is used as an output > * value > * This macro does nothing apart clarify for the reader that > * the parameter will be filled by the callee > */ > > With any of the modifications (feel free to reword them as you want): > > Reviewed-by: Louis Chauvet <louis.chauvet@bootlin.com> > > > { > > 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 > > @@ -1122,9 +1124,10 @@ 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]; > > > > @@ -1208,30 +1211,31 @@ static const struct proc_ops proc_fops = { > > .proc_write = ddebug_proc_write > > }; > > > > -static void ddebug_attach_module_classes(struct ddebug_table *dt, > > - struct ddebug_class_map *classes, > > - int num_classes) > > +static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di) > > { > > struct ddebug_class_map *cm; > > - int i, j, ct = 0; > > + int i, nc = 0; > > > > - for (cm = classes, i = 0; i < num_classes; i++, cm++) { > > + /* > > + * Find this module's classmaps in a subrange/wholerange of > > + * the builtin/modular classmap vector/section. Save the start > > + * and length of the subrange at its edges. > > + */ > > + for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) { > > > > if (!strcmp(cm->mod_name, dt->mod_name)) { > > - > > - v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i, > > - cm->mod_name, cm->base, cm->length, cm->map_type); > > - > > - for (j = 0; j < cm->length; j++) > > - v3pr_info(" %d: %d %s\n", j + cm->base, j, > > - cm->class_names[j]); > > - > > - list_add(&cm->link, &dt->maps); > > - ct++; > > + if (!nc) { > > + v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n", > > + i, cm->mod_name, cm->base, cm->length, cm->map_type); > > + dt->classes = cm; > > + } > > + nc++; > > } > > } > > - if (ct) > > - vpr_info("module:%s attached %d classes\n", dt->mod_name, ct); > > + if (nc) { > > + dt->num_classes = nc; > > + vpr_info("module:%s attached %d classes\n", dt->mod_name, nc); > > + } > > } > > > > /* > > @@ -1263,10 +1267,9 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname) > > dt->num_ddebugs = di->num_descs; > > > > INIT_LIST_HEAD(&dt->link); > > - INIT_LIST_HEAD(&dt->maps); > > > > if (di->classes && di->num_classes) > > - ddebug_attach_module_classes(dt, di->classes, di->num_classes); > > + ddebug_attach_module_classes(dt, di); > > > > mutex_lock(&ddebug_lock); > > list_add_tail(&dt->link, &ddebug_tables); > > @@ -1379,8 +1382,8 @@ static void ddebug_remove_all_tables(void) > > mutex_lock(&ddebug_lock); > > while (!list_empty(&ddebug_tables)) { > > struct ddebug_table *dt = list_entry(ddebug_tables.next, > > - struct ddebug_table, > > - link); > > + struct ddebug_table, > > + link); > > ddebug_table_free(dt); > > } > > mutex_unlock(&ddebug_lock); > > -- > Louis Chauvet, Bootlin > Embedded Linux and Kernel engineering > https://bootlin.com > >
diff --git a/include/linux/dynamic_debug.h b/include/linux/dynamic_debug.h index ac199293d203..e458d4b838ac 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 dd7320b9616d..d5572712ce55 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 */ 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) { 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 @@ -1122,9 +1124,10 @@ 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]; @@ -1208,30 +1211,31 @@ static const struct proc_ops proc_fops = { .proc_write = ddebug_proc_write }; -static void ddebug_attach_module_classes(struct ddebug_table *dt, - struct ddebug_class_map *classes, - int num_classes) +static void ddebug_attach_module_classes(struct ddebug_table *dt, struct _ddebug_info *di) { struct ddebug_class_map *cm; - int i, j, ct = 0; + int i, nc = 0; - for (cm = classes, i = 0; i < num_classes; i++, cm++) { + /* + * Find this module's classmaps in a subrange/wholerange of + * the builtin/modular classmap vector/section. Save the start + * and length of the subrange at its edges. + */ + for (cm = di->classes, i = 0; i < di->num_classes; i++, cm++) { if (!strcmp(cm->mod_name, dt->mod_name)) { - - v2pr_info("class[%d]: module:%s base:%d len:%d ty:%d\n", i, - cm->mod_name, cm->base, cm->length, cm->map_type); - - for (j = 0; j < cm->length; j++) - v3pr_info(" %d: %d %s\n", j + cm->base, j, - cm->class_names[j]); - - list_add(&cm->link, &dt->maps); - ct++; + if (!nc) { + v2pr_info("start subrange, class[%d]: module:%s base:%d len:%d ty:%d\n", + i, cm->mod_name, cm->base, cm->length, cm->map_type); + dt->classes = cm; + } + nc++; } } - if (ct) - vpr_info("module:%s attached %d classes\n", dt->mod_name, ct); + if (nc) { + dt->num_classes = nc; + vpr_info("module:%s attached %d classes\n", dt->mod_name, nc); + } } /* @@ -1263,10 +1267,9 @@ static int ddebug_add_module(struct _ddebug_info *di, const char *modname) dt->num_ddebugs = di->num_descs; INIT_LIST_HEAD(&dt->link); - INIT_LIST_HEAD(&dt->maps); if (di->classes && di->num_classes) - ddebug_attach_module_classes(dt, di->classes, di->num_classes); + ddebug_attach_module_classes(dt, di); mutex_lock(&ddebug_lock); list_add_tail(&dt->link, &ddebug_tables); @@ -1379,8 +1382,8 @@ static void ddebug_remove_all_tables(void) mutex_lock(&ddebug_lock); while (!list_empty(&ddebug_tables)) { struct ddebug_table *dt = list_entry(ddebug_tables.next, - struct ddebug_table, - link); + struct ddebug_table, + link); ddebug_table_free(dt); } mutex_unlock(&ddebug_lock);
Classmaps are stored in an elf section/array, but currently are individually list-linked onto dyndbg's per-module ddebug_table for operation. This is unnecessary. Just like dyndbg's descriptors, classes are packed in compile order; so even with many builtin modules employing multiple classmaps, each modules' maps are packed contiguously, and can be treated as a array-start-address & array-length. So this drops the whole list building operation done in ddebug_attach_module_classes(), and removes the list-head members. The "select-by-modname" condition is reused to find the start,end of the subrange. NOTE: This "filter-by-modname" on classmaps should really be done in ddebug_add_module(1); ie at least one step closer to ddebug_init(2), which already splits up pr-debug descriptors into subranges by modname, then calls (1) on each. (2) knows nothing of classmaps currently, and doesn't need to. For now, just add comment. Signed-off-by: Jim Cromie <jim.cromie@gmail.com> --- include/linux/dynamic_debug.h | 1 - lib/dynamic_debug.c | 61 ++++++++++++++++++----------------- 2 files changed, 32 insertions(+), 30 deletions(-)