Em Mon, Nov 02, 2020 at 10:29:22AM -0800, Hao Luo escreveu:
> This looks good to me. Thanks, Jiri.
>
> Acked-by: Hao Luo <haoluo@xxxxxxxxxx>
Thanks, applied, will wait for a v2 for the other.
> On Sat, Oct 31, 2020 at 3:31 PM Jiri Olsa <jolsa@xxxxxxxxxx> wrote:
> >
> > Moving find_all_percpu_vars under generic collect_symbols
> > function that walks over symbols and calls collect_percpu_var.
> >
> > We will add another collect function that needs to go through
> > all the symbols, so it's better we go through them just once.
> >
> > There's no functional change intended.
> >
> > Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
> > ---
> > btf_encoder.c | 124 +++++++++++++++++++++++++++-----------------------
> > 1 file changed, 67 insertions(+), 57 deletions(-)
> >
> > diff --git a/btf_encoder.c b/btf_encoder.c
> > index 4c92908beab2..1866bb16a8ba 100644
> > --- a/btf_encoder.c
> > +++ b/btf_encoder.c
> > @@ -250,75 +250,85 @@ static bool percpu_var_exists(uint64_t addr, uint32_t *sz, const char **name)
> > return true;
> > }
> >
> > -static int find_all_percpu_vars(struct btf_elf *btfe)
> > +static int collect_percpu_var(struct btf_elf *btfe, GElf_Sym *sym)
> > {
> > - uint32_t core_id;
> > - GElf_Sym sym;
> > + const char *sym_name;
> > + uint64_t addr;
> > + uint32_t size;
> >
> > - /* cache variables' addresses, preparing for searching in symtab. */
> > - percpu_var_cnt = 0;
> > + /* compare a symbol's shndx to determine if it's a percpu variable */
> > + if (elf_sym__section(sym) != btfe->percpu_shndx)
> > + return 0;
> > + if (elf_sym__type(sym) != STT_OBJECT)
> > + return 0;
> >
> > - /* search within symtab for percpu variables */
> > - elf_symtab__for_each_symbol(btfe->symtab, core_id, sym) {
> > - const char *sym_name;
> > - uint64_t addr;
> > - uint32_t size;
> > + addr = elf_sym__value(sym);
> > + /*
> > + * Store only those symbols that have allocated space in the percpu section.
> > + * This excludes the following three types of symbols:
> > + *
> > + * 1. __ADDRESSABLE(sym), which are forcely emitted as symbols.
> > + * 2. __UNIQUE_ID(prefix), which are introduced to generate unique ids.
> > + * 3. __exitcall(fn), functions which are labeled as exit calls.
> > + *
> > + * In addition, the variables defined using DEFINE_PERCPU_FIRST are
> > + * also not included, which currently includes:
> > + *
> > + * 1. fixed_percpu_data
> > + */
> > + if (!addr)
> > + return 0;
> >
> > - /* compare a symbol's shndx to determine if it's a percpu variable */
> > - if (elf_sym__section(&sym) != btfe->percpu_shndx)
> > - continue;
> > - if (elf_sym__type(&sym) != STT_OBJECT)
> > - continue;
> > + size = elf_sym__size(sym);
> > + if (!size)
> > + return 0; /* ignore zero-sized symbols */
> >
> > - addr = elf_sym__value(&sym);
> > - /*
> > - * Store only those symbols that have allocated space in the percpu section.
> > - * This excludes the following three types of symbols:
> > - *
> > - * 1. __ADDRESSABLE(sym), which are forcely emitted as symbols.
> > - * 2. __UNIQUE_ID(prefix), which are introduced to generate unique ids.
> > - * 3. __exitcall(fn), functions which are labeled as exit calls.
> > - *
> > - * In addition, the variables defined using DEFINE_PERCPU_FIRST are
> > - * also not included, which currently includes:
> > - *
> > - * 1. fixed_percpu_data
> > - */
> > - if (!addr)
> > - continue;
> > + sym_name = elf_sym__name(sym, btfe->symtab);
> > + if (!btf_name_valid(sym_name)) {
> > + dump_invalid_symbol("Found symbol of invalid name when encoding btf",
> > + sym_name, btf_elf__verbose, btf_elf__force);
> > + if (btf_elf__force)
> > + return 0;
> > + return -1;
> > + }
> >
> > - size = elf_sym__size(&sym);
> > - if (!size)
> > - continue; /* ignore zero-sized symbols */
> > + if (btf_elf__verbose)
> > + printf("Found per-CPU symbol '%s' at address 0x%lx\n", sym_name, addr);
> >
> > - sym_name = elf_sym__name(&sym, btfe->symtab);
> > - if (!btf_name_valid(sym_name)) {
> > - dump_invalid_symbol("Found symbol of invalid name when encoding btf",
> > - sym_name, btf_elf__verbose, btf_elf__force);
> > - if (btf_elf__force)
> > - continue;
> > - return -1;
> > - }
> > + if (percpu_var_cnt == MAX_PERCPU_VAR_CNT) {
> > + fprintf(stderr, "Reached the limit of per-CPU variables: %d\n",
> > + MAX_PERCPU_VAR_CNT);
> > + return -1;
> > + }
> > + percpu_vars[percpu_var_cnt].addr = addr;
> > + percpu_vars[percpu_var_cnt].sz = size;
> > + percpu_vars[percpu_var_cnt].name = sym_name;
> > + percpu_var_cnt++;
> >
> > - if (btf_elf__verbose)
> > - printf("Found per-CPU symbol '%s' at address 0x%lx\n", sym_name, addr);
> > + return 0;
> > +}
> > +
> > +static int collect_symbols(struct btf_elf *btfe, bool collect_percpu_vars)
> > +{
> > + uint32_t core_id;
> > + GElf_Sym sym;
> >
> > - if (percpu_var_cnt == MAX_PERCPU_VAR_CNT) {
> > - fprintf(stderr, "Reached the limit of per-CPU variables: %d\n",
> > - MAX_PERCPU_VAR_CNT);
> > + /* cache variables' addresses, preparing for searching in symtab. */
> > + percpu_var_cnt = 0;
> > +
> > + /* search within symtab for percpu variables */
> > + elf_symtab__for_each_symbol(btfe->symtab, core_id, sym) {
> > + if (collect_percpu_vars && collect_percpu_var(btfe, &sym))
> > return -1;
> > - }
> > - percpu_vars[percpu_var_cnt].addr = addr;
> > - percpu_vars[percpu_var_cnt].sz = size;
> > - percpu_vars[percpu_var_cnt].name = sym_name;
> > - percpu_var_cnt++;
> > }
> >
> > - if (percpu_var_cnt)
> > - qsort(percpu_vars, percpu_var_cnt, sizeof(percpu_vars[0]), percpu_var_cmp);
> > + if (collect_percpu_vars) {
> > + if (percpu_var_cnt)
> > + qsort(percpu_vars, percpu_var_cnt, sizeof(percpu_vars[0]), percpu_var_cmp);
> >
> > - if (btf_elf__verbose)
> > - printf("Found %d per-CPU variables!\n", percpu_var_cnt);
> > + if (btf_elf__verbose)
> > + printf("Found %d per-CPU variables!\n", percpu_var_cnt);
> > + }
> > return 0;
> > }
> >
> > @@ -347,7 +357,7 @@ int cu__encode_btf(struct cu *cu, int verbose, bool force,
> > if (!btfe)
> > return -1;
> >
> > - if (!skip_encoding_vars && find_all_percpu_vars(btfe))
> > + if (collect_symbols(btfe, !skip_encoding_vars))
> > goto out;
> >
> > has_index_type = false;
> > --
> > 2.26.2
> >
--
- Arnaldo
