* [PATCH dwarves] btf_encoder: dynamically allocate the vars array for percpu variables
@ 2024-03-01 12:41 Alan Maguire
2024-03-01 15:24 ` Jiri Olsa
0 siblings, 1 reply; 3+ messages in thread
From: Alan Maguire @ 2024-03-01 12:41 UTC (permalink / raw)
To: acme; +Cc: dwarves, bpf, Alan Maguire, John Hubbard, Jiri Olsa
Use consistent method across allocating function and per-cpu variable
representations, based around (re)allocating the arrays based on demand.
This avoids issues where the number of per-CPU variables exceeds the
hardcoded limit.
Reported-by: John Hubbard <jhubbard@nvidia.com>
Suggested-by: Jiri Olsa <olsajiri@gmail.com>
Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
---
btf_encoder.c | 38 +++++++++++++++++++++++++++++---------
1 file changed, 29 insertions(+), 9 deletions(-)
diff --git a/btf_encoder.c b/btf_encoder.c
index fd04008..a43d702 100644
--- a/btf_encoder.c
+++ b/btf_encoder.c
@@ -50,8 +50,6 @@ struct elf_function {
struct btf_encoder_state state;
};
-#define MAX_PERCPU_VAR_CNT 4096
-
struct var_info {
uint64_t addr;
const char *name;
@@ -80,8 +78,9 @@ struct btf_encoder {
is_rel;
uint32_t array_index_id;
struct {
- struct var_info vars[MAX_PERCPU_VAR_CNT];
+ struct var_info *vars;
int var_cnt;
+ int allocated;
uint32_t shndx;
uint64_t base_addr;
uint64_t sec_sz;
@@ -983,6 +982,16 @@ static int functions_cmp(const void *_a, const void *_b)
#define max(x, y) ((x) < (y) ? (y) : (x))
#endif
+static void *reallocarray_grow(void *ptr, int *nmemb, size_t size)
+{
+ int new_nmemb = max(1000, *nmemb * 3 / 2);
+ void *new = realloc(ptr, new_nmemb * size);
+
+ if (new)
+ *nmemb = new_nmemb;
+ return new;
+}
+
static int btf_encoder__collect_function(struct btf_encoder *encoder, GElf_Sym *sym)
{
struct elf_function *new;
@@ -995,8 +1004,9 @@ static int btf_encoder__collect_function(struct btf_encoder *encoder, GElf_Sym *
return 0;
if (encoder->functions.cnt == encoder->functions.allocated) {
- encoder->functions.allocated = max(1000, encoder->functions.allocated * 3 / 2);
- new = realloc(encoder->functions.entries, encoder->functions.allocated * sizeof(*encoder->functions.entries));
+ new = reallocarray_grow(encoder->functions.entries,
+ &encoder->functions.allocated,
+ sizeof(*encoder->functions.entries));
if (!new) {
/*
* The cleanup - delete_functions is called
@@ -1439,10 +1449,17 @@ static int btf_encoder__collect_percpu_var(struct btf_encoder *encoder, GElf_Sym
if (!encoder->is_rel)
addr -= encoder->percpu.base_addr;
- if (encoder->percpu.var_cnt == MAX_PERCPU_VAR_CNT) {
- fprintf(stderr, "Reached the limit of per-CPU variables: %d\n",
- MAX_PERCPU_VAR_CNT);
- return -1;
+ if (encoder->percpu.var_cnt == encoder->percpu.allocated) {
+ struct var_info *new;
+
+ new = reallocarray_grow(encoder->percpu.vars,
+ &encoder->percpu.allocated,
+ sizeof(*encoder->percpu.vars));
+ if (!new) {
+ fprintf(stderr, "Failed to allocate memory for variables\n");
+ return -1;
+ }
+ encoder->percpu.vars = new;
}
encoder->percpu.vars[encoder->percpu.var_cnt].addr = addr;
encoder->percpu.vars[encoder->percpu.var_cnt].sz = size;
@@ -1720,6 +1737,9 @@ void btf_encoder__delete(struct btf_encoder *encoder)
encoder->functions.allocated = encoder->functions.cnt = 0;
free(encoder->functions.entries);
encoder->functions.entries = NULL;
+ encoder->percpu.allocated = encoder->percpu.var_cnt = 0;
+ free(encoder->percpu.vars);
+ encoder->percpu.vars = NULL;
free(encoder);
}
--
2.39.3
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH dwarves] btf_encoder: dynamically allocate the vars array for percpu variables
2024-03-01 12:41 [PATCH dwarves] btf_encoder: dynamically allocate the vars array for percpu variables Alan Maguire
@ 2024-03-01 15:24 ` Jiri Olsa
2024-03-01 21:46 ` Arnaldo Carvalho de Melo
0 siblings, 1 reply; 3+ messages in thread
From: Jiri Olsa @ 2024-03-01 15:24 UTC (permalink / raw)
To: Alan Maguire; +Cc: acme, dwarves, bpf, John Hubbard, Jiri Olsa
On Fri, Mar 01, 2024 at 12:41:06PM +0000, Alan Maguire wrote:
> Use consistent method across allocating function and per-cpu variable
> representations, based around (re)allocating the arrays based on demand.
> This avoids issues where the number of per-CPU variables exceeds the
> hardcoded limit.
>
> Reported-by: John Hubbard <jhubbard@nvidia.com>
> Suggested-by: Jiri Olsa <olsajiri@gmail.com>
> Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> Tested-by: John Hubbard <jhubbard@nvidia.com>
Acked/Tested-by: Jiri Olsa <jolsa@kernel.org>
thanks,
jirka
> ---
> btf_encoder.c | 38 +++++++++++++++++++++++++++++---------
> 1 file changed, 29 insertions(+), 9 deletions(-)
>
> diff --git a/btf_encoder.c b/btf_encoder.c
> index fd04008..a43d702 100644
> --- a/btf_encoder.c
> +++ b/btf_encoder.c
> @@ -50,8 +50,6 @@ struct elf_function {
> struct btf_encoder_state state;
> };
>
> -#define MAX_PERCPU_VAR_CNT 4096
> -
> struct var_info {
> uint64_t addr;
> const char *name;
> @@ -80,8 +78,9 @@ struct btf_encoder {
> is_rel;
> uint32_t array_index_id;
> struct {
> - struct var_info vars[MAX_PERCPU_VAR_CNT];
> + struct var_info *vars;
> int var_cnt;
> + int allocated;
> uint32_t shndx;
> uint64_t base_addr;
> uint64_t sec_sz;
> @@ -983,6 +982,16 @@ static int functions_cmp(const void *_a, const void *_b)
> #define max(x, y) ((x) < (y) ? (y) : (x))
> #endif
>
> +static void *reallocarray_grow(void *ptr, int *nmemb, size_t size)
> +{
> + int new_nmemb = max(1000, *nmemb * 3 / 2);
> + void *new = realloc(ptr, new_nmemb * size);
> +
> + if (new)
> + *nmemb = new_nmemb;
> + return new;
> +}
> +
> static int btf_encoder__collect_function(struct btf_encoder *encoder, GElf_Sym *sym)
> {
> struct elf_function *new;
> @@ -995,8 +1004,9 @@ static int btf_encoder__collect_function(struct btf_encoder *encoder, GElf_Sym *
> return 0;
>
> if (encoder->functions.cnt == encoder->functions.allocated) {
> - encoder->functions.allocated = max(1000, encoder->functions.allocated * 3 / 2);
> - new = realloc(encoder->functions.entries, encoder->functions.allocated * sizeof(*encoder->functions.entries));
> + new = reallocarray_grow(encoder->functions.entries,
> + &encoder->functions.allocated,
> + sizeof(*encoder->functions.entries));
> if (!new) {
> /*
> * The cleanup - delete_functions is called
> @@ -1439,10 +1449,17 @@ static int btf_encoder__collect_percpu_var(struct btf_encoder *encoder, GElf_Sym
> if (!encoder->is_rel)
> addr -= encoder->percpu.base_addr;
>
> - if (encoder->percpu.var_cnt == MAX_PERCPU_VAR_CNT) {
> - fprintf(stderr, "Reached the limit of per-CPU variables: %d\n",
> - MAX_PERCPU_VAR_CNT);
> - return -1;
> + if (encoder->percpu.var_cnt == encoder->percpu.allocated) {
> + struct var_info *new;
> +
> + new = reallocarray_grow(encoder->percpu.vars,
> + &encoder->percpu.allocated,
> + sizeof(*encoder->percpu.vars));
> + if (!new) {
> + fprintf(stderr, "Failed to allocate memory for variables\n");
> + return -1;
> + }
> + encoder->percpu.vars = new;
> }
> encoder->percpu.vars[encoder->percpu.var_cnt].addr = addr;
> encoder->percpu.vars[encoder->percpu.var_cnt].sz = size;
> @@ -1720,6 +1737,9 @@ void btf_encoder__delete(struct btf_encoder *encoder)
> encoder->functions.allocated = encoder->functions.cnt = 0;
> free(encoder->functions.entries);
> encoder->functions.entries = NULL;
> + encoder->percpu.allocated = encoder->percpu.var_cnt = 0;
> + free(encoder->percpu.vars);
> + encoder->percpu.vars = NULL;
>
> free(encoder);
> }
> --
> 2.39.3
>
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH dwarves] btf_encoder: dynamically allocate the vars array for percpu variables
2024-03-01 15:24 ` Jiri Olsa
@ 2024-03-01 21:46 ` Arnaldo Carvalho de Melo
0 siblings, 0 replies; 3+ messages in thread
From: Arnaldo Carvalho de Melo @ 2024-03-01 21:46 UTC (permalink / raw)
To: Jiri Olsa; +Cc: Alan Maguire, acme, dwarves, bpf, John Hubbard
On Fri, Mar 01, 2024 at 04:24:27PM +0100, Jiri Olsa wrote:
> On Fri, Mar 01, 2024 at 12:41:06PM +0000, Alan Maguire wrote:
> > Use consistent method across allocating function and per-cpu variable
> > representations, based around (re)allocating the arrays based on demand.
> > This avoids issues where the number of per-CPU variables exceeds the
> > hardcoded limit.
> >
> > Reported-by: John Hubbard <jhubbard@nvidia.com>
> > Suggested-by: Jiri Olsa <olsajiri@gmail.com>
> > Signed-off-by: Alan Maguire <alan.maguire@oracle.com>
> > Tested-by: John Hubbard <jhubbard@nvidia.com>
>
> Acked/Tested-by: Jiri Olsa <jolsa@kernel.org>
Applied, its pushed out to the repos on the next branch, tomorrow moves
to the master one.
Thanks!
- Arnaldo
^ permalink raw reply [flat|nested] 3+ messages in thread
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2024-03-01 12:41 [PATCH dwarves] btf_encoder: dynamically allocate the vars array for percpu variables Alan Maguire
2024-03-01 15:24 ` Jiri Olsa
2024-03-01 21:46 ` Arnaldo Carvalho de Melo
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