Re: [PATCH v3 4/6] alloc_tag: add accuracy based filtering to ioctl
From: Hao Ge
Date: Mon Jun 08 2026 - 04:27:31 EST
On 2026/6/8 14:22, Hao Ge wrote:
Hi AbhishekAnd I've reviewed the issue reported by Sashiko, and I think it's valid.
On 2026/6/6 07:36, Abhishek Bapat wrote:
Extend the allocinfo filtering mechanism to allow users to filter tags
based on their accuracy.
Signed-off-by: Abhishek Bapat <abhishekbapat@xxxxxxxxxx>
---
include/uapi/linux/alloc_tag.h | 3 +++
lib/alloc_tag.c | 8 ++++++++
2 files changed, 11 insertions(+)
diff --git a/include/uapi/linux/alloc_tag.h b/include/uapi/linux/alloc_tag.h
index 0e648192df4d..42445bdb11c5 100644
--- a/include/uapi/linux/alloc_tag.h
+++ b/include/uapi/linux/alloc_tag.h
@@ -20,6 +20,7 @@ struct allocinfo_tag {
char function[ALLOCINFO_STR_SIZE];
char filename[ALLOCINFO_STR_SIZE];
__u64 lineno;
+ __u64 inaccurate;
I was wondering if it would make sense to define inaccurate as a flags field
(e.g. __u64 flags with ALLOCINFO_TAG_F_INACCURATE (1 <<0)),
so that only bit 0 is used today and the upper bits are reserved for future use,
aligning with current kernel codebase.
This design also allows for better extensibility if we need to
add new flags for any reason in the future.
We also need to add flag validity checks if we go this route.
When we expand the allocinfo_tag_data structure
struct allocinfo_tag_data{
char modname[64];
char function[64];
char filename[64];
__u64 lineno;
__u64 inaccurate;
__u64 bytes;
__u64 calls;
__u8 accurate;
/* padding */
}
I think user space may see two fields related to inaccuracy.
How do you like these modifications?
diff --git a/include/uapi/linux/alloc_tag.h b/include/uapi/linux/alloc_tag.h
--- a/include/uapi/linux/alloc_tag.h
+++ b/include/uapi/linux/alloc_tag.h
@@ -20,7 +20,6 @@ struct allocinfo_tag {
char function[ALLOCINFO_STR_SIZE];
char filename[ALLOCINFO_STR_SIZE];
__u64 lineno;
- __u64 inaccurate;
};
/* The alignment ensures 32-bit compatible interfaces are not broken */
@@ -40,7 +39,7 @@ enum {
ALLOCINFO_FILTER_FUNCTION,
ALLOCINFO_FILTER_FILENAME,
ALLOCINFO_FILTER_LINENO,
- ALLOCINFO_FILTER_INACCURATE,
+ ALLOCINFO_FILTER_FLAGS,
ALLOCINFO_FILTER_MIN_SIZE,
ALLOCINFO_FILTER_MAX_SIZE,
__ALLOCINFO_FILTER_LAST = ALLOCINFO_FILTER_MAX_SIZE
@@ -50,16 +49,20 @@ enum {
#define ALLOCINFO_FILTER_MASK_FUNCTION (1 << ALLOCINFO_FILTER_FUNCTION)
#define ALLOCINFO_FILTER_MASK_FILENAME (1 << ALLOCINFO_FILTER_FILENAME)
#define ALLOCINFO_FILTER_MASK_LINENO (1 << ALLOCINFO_FILTER_LINENO)
-#define ALLOCINFO_FILTER_MASK_INACCURATE (1 << ALLOCINFO_FILTER_INACCURATE)
+#define ALLOCINFO_FILTER_MASK_FLAGS (1 << ALLOCINFO_FILTER_FLAGS)
#define ALLOCINFO_FILTER_MASK_MIN_SIZE (1 << ALLOCINFO_FILTER_MIN_SIZE)
#define ALLOCINFO_FILTER_MASK_MAX_SIZE (1 << ALLOCINFO_FILTER_MAX_SIZE)
#define ALLOCINFO_FILTER_MASKS \
((1 << (__ALLOCINFO_FILTER_LAST + 1)) - 1)
+#define ALLOCINFO_FILTER_F_INACCURATE (1ULL << 0)
+#define ALLOCINFO_FILTER_FLAGS_ALL ALLOCINFO_FILTER_F_INACCURATE
+
struct allocinfo_filter {
__u64 mask; /* bitmask of the filter fields used */
struct allocinfo_tag fields;
+ __u64 flags; /* bitmask of ALLOCINFO_FILTER_F_* */
__u64 min_size;
__u64 max_size;
};
diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
--- a/lib/alloc_tag.c
+++ b/lib/alloc_tag.c
@@ -249,8 +249,6 @@ static bool matches_filter(struct codetag *ct, struct allocinfo_filter *filter,
struct alloc_tag_counters *counters,
bool *fetched_counters)
{
- bool inaccurate;
-
if (!filter || !filter->mask)
return true;
@@ -277,10 +275,11 @@ static bool matches_filter(struct codetag *ct, struct allocinfo_filter *filter,
ct->lineno != filter->fields.lineno)
return false;
- if (filter->mask & ALLOCINFO_FILTER_MASK_INACCURATE) {
- inaccurate = !!(ct->flags & CODETAG_FLAG_INACCURATE);
- if (inaccurate != !!(filter->fields.inaccurate))
- return false;
+ if (filter->mask & ALLOCINFO_FILTER_MASK_FLAGS) {
+ if (filter->flags & ALLOCINFO_FILTER_F_INACCURATE) {
+ if (!(ct->flags & CODETAG_FLAG_INACCURATE))
+ return false;
+ }
}
if (filter->mask & (ALLOCINFO_FILTER_MASK_MIN_SIZE | ALLOCINFO_FILTER_MASK_MAX_SIZE)) {
@@ -318,6 +317,10 @@ static int allocinfo_ioctl_get_at(struct seq_file *m, void __user *arg)
if (params.filter.mask & ~ALLOCINFO_FILTER_MASKS)
return -EINVAL;
+ if ((params.filter.mask & ALLOCINFO_FILTER_MASK_FLAGS) &&
+ (params.filter.flags & ~ALLOCINFO_FILTER_FLAGS_ALL))
+ return -EINVAL;
+
if ((params.filter.mask & ALLOCINFO_FILTER_MASK_MIN_SIZE) &&
(params.filter.mask & ALLOCINFO_FILTER_MASK_MAX_SIZE) &&
params.filter.min_size > params.filter.max_size)
Thanks
Best Regards
Hao
Thanks
Best Regards
Hao
};
/* The alignment ensures 32-bit compatible interfaces are not broken */
@@ -39,6 +40,7 @@ enum {
ALLOCINFO_FILTER_FUNCTION,
ALLOCINFO_FILTER_FILENAME,
ALLOCINFO_FILTER_LINENO,
+ ALLOCINFO_FILTER_INACCURATE,
ALLOCINFO_FILTER_MIN_SIZE,
ALLOCINFO_FILTER_MAX_SIZE,
__ALLOCINFO_FILTER_LAST = ALLOCINFO_FILTER_MAX_SIZE
@@ -48,6 +50,7 @@ enum {
#define ALLOCINFO_FILTER_MASK_FUNCTION (1 << ALLOCINFO_FILTER_FUNCTION)
#define ALLOCINFO_FILTER_MASK_FILENAME (1 << ALLOCINFO_FILTER_FILENAME)
#define ALLOCINFO_FILTER_MASK_LINENO (1 << ALLOCINFO_FILTER_LINENO)
+#define ALLOCINFO_FILTER_MASK_INACCURATE (1 << ALLOCINFO_FILTER_INACCURATE)
#define ALLOCINFO_FILTER_MASK_MIN_SIZE (1 << ALLOCINFO_FILTER_MIN_SIZE)
#define ALLOCINFO_FILTER_MASK_MAX_SIZE (1 << ALLOCINFO_FILTER_MAX_SIZE)
diff --git a/lib/alloc_tag.c b/lib/alloc_tag.c
index ddc6946f56ab..cbcd12c4ef9c 100644
--- a/lib/alloc_tag.c
+++ b/lib/alloc_tag.c
@@ -249,6 +249,8 @@ static bool matches_filter(struct codetag *ct, struct allocinfo_filter *filter,
struct alloc_tag_counters *counters,
bool *fetched_counters)
{
+ bool inaccurate;
+
if (!filter || !filter->mask)
return true;
@@ -275,6 +277,12 @@ static bool matches_filter(struct codetag *ct, struct allocinfo_filter *filter,
ct->lineno != filter->fields.lineno)
return false;
+ if (filter->mask & ALLOCINFO_FILTER_MASK_INACCURATE) {
+ inaccurate = !!(ct->flags & CODETAG_FLAG_INACCURATE);
+ if (inaccurate != !!(filter->fields.inaccurate))
+ return false;
+ }
+
if (filter->mask & (ALLOCINFO_FILTER_MASK_MIN_SIZE | ALLOCINFO_FILTER_MASK_MAX_SIZE)) {
if (!*fetched_counters) {
*counters = allocinfo_prefetch_counters(ct);