On 3 September 2014 15:10, David Goulet <dgou...@efficios.com> wrote: > On 26 Aug (16:27:46), Umut Tezduyar Lindskog wrote: >> Instead of forking processes, load modules through libkmod. >> >> This adds a package dependency to kmod but can be disabled >> by --disable-kmod option in ./configure. > > First, thanks for this patch, this is really good to have! > > Adding a dependency on libkmod might needs a bit more discussion for > 2.6 which I'm quite open to that but I don't want to make the decision > alone. > > So could we for now simply use a "--enable-kmod" and by default disable > it? If we decide to depend on libkmod, should be quite easy to revert > back to --disable-kmod.
Actually, the default should be to use kmod if it is found, revert to modprobe otherwise. > Thanks! > David > >> >> The startup time has decreased by %36 on our embedded mips >> product. The measurement is done by cgroup cpu shares. >> --- >> configure.ac | 34 ++++++++++++++++++++++++ >> src/bin/lttng-sessiond/modprobe.c | 53 >> +++++++++++++++++++++++++++++++++++++ >> 2 files changed, 87 insertions(+) >> >> diff --git a/configure.ac b/configure.ac >> index a8e04f5..b36a95d 100644 >> --- a/configure.ac >> +++ b/configure.ac >> @@ -200,6 +200,32 @@ AC_CHECK_DECL([cmm_smp_mb__before_uatomic_or], [], >> [AC_MSG_ERROR([liburcu $liburcu_version or newer is needed])], >> [[#include <urcu.h>]] >> ) >> >> +# Check kmod library >> +AC_ARG_WITH(kmod-prefix, >> + AS_HELP_STRING([--with-kmod-prefix=PATH], >> + [Specify the installation prefix of the kmod library. >> + Headers must be in PATH/include; libraries in PATH/lib.]), >> + [ >> + CPPFLAGS="$CPPFLAGS -I${withval}/include" >> + LDFLAGS="$LDFLAGS -L${withval}/lib64 -L${withval}/lib" >> + ]) >> + >> +AC_ARG_ENABLE(kmod, >> + AS_HELP_STRING([--disable-kmod],[build without kmod support]), >> + kmod_support=$enableval, kmod_support=yes) >> + >> +AS_IF([test "x$kmod_support" = "xyes"], [ >> + AC_CHECK_LIB([kmod], [kmod_module_probe_insert_module], >> + [ >> + AC_DEFINE([HAVE_KMOD], [1], [has kmod support]) >> + LIBS="$LIBS -lkmod" >> + kmod_found=yes >> + ], >> + [AC_MSG_ERROR([Cannot find kmod >= 5. Use >> --with-kmod-prefix=PREFIX to specify its location, or specify --disable-kmod >> to build lttng-tools without kmod support.])] >> + ) >> +]) >> +AM_CONDITIONAL([HAVE_KMOD], [test "x$kmod_found" = xyes]) >> + >> AC_ARG_WITH(lttng-ust-prefix, >> AS_HELP_STRING([--with-lttng-ust-prefix=PATH], >> [Specify the installation prefix of the lttng-ust library. >> @@ -483,6 +509,14 @@ done >> AS_ECHO_N("Target architecture: ") >> AS_ECHO($target_arch) >> >> +# kmod enabled/disabled >> +AS_ECHO_N("kmod support: ") >> +AS_IF([test "x$kmod_support" = "xyes"],[ >> + AS_ECHO("Enabled") >> +],[ >> + AS_ECHO("Disabled") >> +]) >> + >> # LTTng-UST enabled/disabled >> AS_ECHO_N("Lttng-UST support: ") >> AS_IF([test "x$lttng_ust_support" = "xyes"],[ >> diff --git a/src/bin/lttng-sessiond/modprobe.c >> b/src/bin/lttng-sessiond/modprobe.c >> index 3cc67f0..40a2ee0 100644 >> --- a/src/bin/lttng-sessiond/modprobe.c >> +++ b/src/bin/lttng-sessiond/modprobe.c >> @@ -164,6 +164,58 @@ void modprobe_remove_lttng_all(void) >> modprobe_remove_lttng_control(); >> } >> >> +#if HAVE_KMOD >> +#include <libkmod.h> >> +static void log_kmod(void *data, int priority, const char *file, int line, >> + const char *fn, const char *format, va_list args) >> +{ >> + char *str; >> + if (vasprintf(&str, format, args) < 0) >> + return; >> + DBG("libkmod: %s", str); >> + free(str); >> +} >> +static int modprobe_lttng(struct kern_modules_param *modules, >> + int entries, int required) >> +{ >> + int ret = 0, i; >> + struct kmod_ctx *ctx; >> + >> + ctx = kmod_new(NULL, NULL); >> + if (!ctx) { >> + PERROR("Unable to create kmod library context"); >> + ret = -ENOMEM; >> + goto error; >> + } >> + >> + kmod_set_log_fn(ctx, log_kmod, NULL); >> + kmod_load_resources(ctx); >> + >> + for (i = 0; i < entries; i++) { >> + struct kmod_module *mod = NULL; >> + >> + ret = kmod_module_new_from_name(ctx, modules[i].name, &mod); >> + if (ret < 0) { >> + PERROR("Failed to create kmod module for %s", >> modules[i].name); >> + goto error; >> + } >> + >> + ret = kmod_module_probe_insert_module(mod, >> KMOD_PROBE_IGNORE_LOADED, NULL, NULL, NULL, NULL); >> + if (required && ret < 0) { >> + ERR("Unable to load module %s", modules[i].name); >> + } else { >> + DBG("Modprobe successfully %s", modules[i].name); >> + } >> + >> + kmod_module_unref(mod); >> + } >> + >> +error: >> + if (ctx) >> + kmod_unref(ctx); >> + return ret; >> +} >> +#else >> static int modprobe_lttng(struct kern_modules_param *modules, >> int entries, int required) >> { >> @@ -194,6 +246,7 @@ static int modprobe_lttng(struct kern_modules_param >> *modules, >> error: >> return ret; >> } >> +#endif >> >> /* >> * Load control kernel module(s). >> -- >> 1.7.10.4 >> >> >> _______________________________________________ >> lttng-dev mailing list >> lttng-dev@lists.lttng.org >> http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev > > _______________________________________________ > lttng-dev mailing list > lttng-dev@lists.lttng.org > http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev > _______________________________________________ lttng-dev mailing list lttng-dev@lists.lttng.org http://lists.lttng.org/cgi-bin/mailman/listinfo/lttng-dev