On Thu, Jan 14, 2021 at 10:35 AM Adhemerval Zanella wrote: > > > > On 31/10/2020 12:44, H.J. Lu via Libc-alpha wrote: > > Pass --list-tunables to ld.so to print tunables with min and max values. > > --- > > NEWS | 2 ++ > > elf/Makefile | 8 ++++++++ > > elf/dl-main.h | 2 +- > > elf/dl-tunables.c | 36 ++++++++++++++++++++++++++++++++++++ > > elf/dl-tunables.h | 2 ++ > > elf/dl-usage.c | 7 ++++++- > > elf/rtld.c | 23 +++++++++++++++++++++++ > > manual/tunables.texi | 37 +++++++++++++++++++++++++++++++++++++ > > 8 files changed, 115 insertions(+), 2 deletions(-) > > > > diff --git a/NEWS b/NEWS > > index 4307c4b1b0..a62e7307ef 100644 > > --- a/NEWS > > +++ b/NEWS > > @@ -9,6 +9,8 @@ Version 2.33 > > > > Major new features: > > > > +* Pass --list-tunables to ld.so to print tunable values. > > + > > Maybe use a similar sentence as for argv0: > > * The dynamic linker accepts the --list-tunables argument which prints > all the supported tunables. This option is disable is glibc is > configured with tunables disabled (--enable-tunables=no). Fixed. > > * The dynamic linker accepts the --argv0 argument and provides opportunity > > to change argv[0] string. > > > > diff --git a/elf/Makefile b/elf/Makefile > > index f10cc59e7c..86b282a32b 100644 > > --- a/elf/Makefile > > +++ b/elf/Makefile > > @@ -44,6 +44,10 @@ dl-routines += dl-tunables > > tunables-type = $(addprefix TUNABLES_FRONTEND_,$(have-tunables)) > > CPPFLAGS-dl-tunables.c += -DTUNABLES_FRONTEND=$(tunables-type) > > > > +ifeq (yesyes,$(build-shared)$(run-built-tests)) > > +tests-special += $(objpfx)list-tunables.out > > +endif > > + > > # Make sure that the compiler does not insert any library calls in tunables > > # code paths. > > Ok, it is enabled iff 'ifneq (no,$(have-tunables))'. > > > ifeq (yes,$(have-loop-to-function)) > > @@ -1812,3 +1816,7 @@ $(objpfx)argv0test.out: tst-rtld-argv0.sh $(objpfx)ld.so \ > > '$(test-wrapper-env)' '$(run_program_env)' \ > > '$(rpath-link)' 'test-argv0' > $@; \ > > $(evaluate-test) > > + > > +$(objpfx)list-tunables.out: $(objpfx)ld.so > > + $(objpfx)ld.so --list-tunables > $@; \ > > + $(evaluate-test) > > Maybe at least check for a tunable with a default value which be > equal to all architecture, like glibc.rtld.nns, glibc.malloc.perturb, etc? I added elf/tst-rtld-list-tunables.exp and elf/tst-rtld-list-tunables.sh to compare against rtld and malloc tunables. It passed on i686, x32 and x86-64. > > diff --git a/elf/dl-main.h b/elf/dl-main.h > > index b51256d3b4..f229867b8e 100644 > > --- a/elf/dl-main.h > > +++ b/elf/dl-main.h > > @@ -63,7 +63,7 @@ struct audit_list > > enum rtld_mode > > { > > rtld_mode_normal, rtld_mode_list, rtld_mode_verify, rtld_mode_trace, > > - rtld_mode_help, > > + rtld_mode_list_tunables, rtld_mode_help, > > }; > > > > /* Aggregated state information extracted from environment variables > > Ok. > > > diff --git a/elf/dl-tunables.c b/elf/dl-tunables.c > > index 2ba2844075..048601b704 100644 > > --- a/elf/dl-tunables.c > > +++ b/elf/dl-tunables.c > > @@ -398,6 +398,42 @@ __tunables_init (char **envp) > > } > > } > > > > +void > > +__tunables_print (void) > > +{ > > + for (int i = 0; i < sizeof (tunable_list) / sizeof (tunable_t); i++) > > Use array_length here. Fixed. > > + { > > + tunable_t *cur = &tunable_list[i]; > > Maybe use a const modifier here. Fixed. > > + _dl_printf ("%s: ", cur->name); > > + switch (cur->type.type_code) > > + { > > + case TUNABLE_TYPE_INT_32: > > + _dl_printf ("%d (min: %d, max: %d)\n", > > + (int) cur->val.numval, > > + (int) cur->type.min, > > + (int) cur->type.max); > > + break; > > + case TUNABLE_TYPE_UINT_64: > > + _dl_printf ("0x%lx (min: 0x%lx, max: 0x%lx)\n", > > + (long int) cur->val.numval, > > + (long int) cur->type.min, > > + (long int) cur->type.max); > > + break; > > + case TUNABLE_TYPE_SIZE_T: > > + _dl_printf ("0x%Zx (min: 0x%Zx, max: 0x%Zx)\n", > > + (size_t) cur->val.numval, > > + (size_t) cur->type.min, > > + (size_t) cur->type.max); > > + break; > > + case TUNABLE_TYPE_STRING: > > + _dl_printf ("%s\n", cur->val.strval ? cur->val.strval : ""); > > + break; > > + default: > > + __builtin_unreachable (); > > + } > > + } > > +} > > + > > Ok, it should be ok to use '%d' for signed and 'lx' for unsigned. > > > /* Set the tunable value. This is called by the module that the tunable exists > > in. */ > > void > > diff --git a/elf/dl-tunables.h b/elf/dl-tunables.h > > index 550b0cc7f4..4a0c90f3e0 100644 > > --- a/elf/dl-tunables.h > > +++ b/elf/dl-tunables.h > > @@ -69,9 +69,11 @@ typedef struct _tunable tunable_t; > > # include "dl-tunable-list.h" > > > > extern void __tunables_init (char **); > > +extern void __tunables_print (void); > > extern void __tunable_get_val (tunable_id_t, void *, tunable_callback_t); > > extern void __tunable_set_val (tunable_id_t, void *, void *, void *); > > rtld_hidden_proto (__tunables_init) > > +rtld_hidden_proto (__tunables_print) > > rtld_hidden_proto (__tunable_get_val) > > rtld_hidden_proto (__tunable_set_val) > > > > Ok. > > > diff --git a/elf/dl-usage.c b/elf/dl-usage.c > > index 796ad38b43..3ce19fb892 100644 > > --- a/elf/dl-usage.c > > +++ b/elf/dl-usage.c > > @@ -190,7 +190,12 @@ setting environment variables (which would be inherited by subprocesses).\n\ > > in LIST\n\ > > --audit LIST use objects named in LIST as auditors\n\ > > --preload LIST preload objects named in LIST\n\ > > - --argv0 STRING set argv[0] to STRING before running\n\ > > + --argv0 STRING set argv[0] to STRING before running\n" > > +#if HAVE_TUNABLES > > +"\ > > + --list-tunables list all tunables with minimum and maximum values\n" > > +#endif > > +"\ > > --help display this help and exit\n\ > > --version output version information and exit\n\ > > \n\ > > Ok. > > > diff --git a/elf/rtld.c b/elf/rtld.c > > index 5d117d0d2c..33993a6f8b 100644 > > --- a/elf/rtld.c > > +++ b/elf/rtld.c > > @@ -49,6 +49,10 @@ > > #include > > #include > > > > +#if HAVE_TUNABLES > > +# include > > +#endif > > + > > You can include this header regadless of HAVE_TUNABLES (it handles it > internally). Fixed. > > #include > > > > /* Only enables rtld profiling for architectures which provides non generic > > @@ -1248,6 +1252,16 @@ dl_main (const ElfW(Phdr) *phdr, > > _dl_argc -= 2; > > _dl_argv += 2; > > } > > +#if HAVE_TUNABLES > > + else if (! strcmp (_dl_argv[1], "--list-tunables")) > > + { > > + state.mode = rtld_mode_list_tunables; > > + > > + ++_dl_skip_args; > > + --_dl_argc; > > + ++_dl_argv; > > + } > > +#endif > > else if (strcmp (_dl_argv[1], "--help") == 0) > > { > > state.mode = rtld_mode_help; > > @@ -1268,6 +1282,15 @@ dl_main (const ElfW(Phdr) *phdr, > > else > > break; > > > > +#if HAVE_TUNABLES > > + if (__builtin_expect (state.mode, rtld_mode_normal) > > + == rtld_mode_list_tunables) > > Use > > if (__glibc_unlikely (state.mode == rtld_mode_list_tunables) Fixed. > > + { > > + __tunables_print (); > > + _exit (0); > > + } > > +#endif > > + > > /* If we have no further argument the program was called incorrectly. > > Grant the user some education. */ > > if (_dl_argc < 2) > > diff --git a/manual/tunables.texi b/manual/tunables.texi > > index d72d7a5ec0..924dac8876 100644 > > --- a/manual/tunables.texi > > +++ b/manual/tunables.texi > > @@ -28,6 +28,43 @@ Finally, the set of tunables available may vary between distributions as > > the tunables feature allows distributions to add their own tunables under > > their own namespace. > > > > +Passing @option{--list-tunables} to the dynamic loader to print all > > +tunables with minimum and maximum values: > > + > > +@example > > +$ /lib64/ld-linux-x86-64.so.2 --list-tunables > > +glibc.rtld.nns: 0x4 (min: 0x1, max: 0x10) > > +glibc.elision.skip_lock_after_retries: 3 (min: -2147483648, max: 2147483647) > > +glibc.malloc.trim_threshold: 0x0 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.malloc.perturb: 0 (min: 0, max: 255) > > +glibc.cpu.x86_shared_cache_size: 0x100000 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.elision.tries: 3 (min: -2147483648, max: 2147483647) > > +glibc.elision.enable: 0 (min: 0, max: 1) > > +glibc.cpu.x86_rep_movsb_threshold: 0x800 (min: 0x100, max: 0xffffffffffffffff) > > +glibc.malloc.mxfast: 0x0 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.elision.skip_lock_busy: 3 (min: -2147483648, max: 2147483647) > > +glibc.malloc.top_pad: 0x0 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.cpu.x86_rep_stosb_threshold: 0x800 (min: 0x1, max: 0xffffffffffffffff) > > +glibc.cpu.x86_non_temporal_threshold: 0xc0000 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.cpu.x86_shstk: > > Trailing whitespace. Fixed. > > +glibc.cpu.hwcap_mask: 0x6 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.malloc.mmap_max: 0 (min: -2147483648, max: 2147483647) > > +glibc.elision.skip_trylock_internal_abort: 3 (min: -2147483648, max: 2147483647) > > +glibc.malloc.tcache_unsorted_limit: 0x0 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.cpu.x86_ibt: > > Ditto. Fixed. > > +glibc.cpu.hwcaps: > > Ditto. Fixed. > > +glibc.elision.skip_lock_internal_abort: 3 (min: -2147483648, max: 2147483647) > > +glibc.malloc.arena_max: 0x0 (min: 0x1, max: 0xffffffffffffffff) > > +glibc.malloc.mmap_threshold: 0x0 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.cpu.x86_data_cache_size: 0x8000 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.malloc.tcache_count: 0x0 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.malloc.arena_test: 0x0 (min: 0x1, max: 0xffffffffffffffff) > > +glibc.pthread.mutex_spin_count: 100 (min: 0, max: 32767) > > +glibc.rtld.optional_static_tls: 0x200 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.malloc.tcache_max: 0x0 (min: 0x0, max: 0xffffffffffffffff) > > +glibc.malloc.check: 0 (min: 0, max: 3) > > +@end example > > + > > @menu > > * Tunable names:: The structure of a tunable name > > * Memory Allocation Tunables:: Tunables in the memory allocation subsystem > > Here is the updated patch. OK for master? Thanks. -- H.J.