On 17/05/2016 17:40, Thomas Monjalon wrote: > 2016-05-12 00:44, Jianfeng Tan: >> This patch adds an option, --huge-trybest, to use a recover mechanism to >> the case that there are not so many hugepages (declared in sysfs), which >> can be used. It relys on a mem access to fault-in hugepages, and if fails > relys -> relies > >> with SIGBUS, recover to previously saved stack environment with >> siglongjmp(). >> >> Besides, this solution fixes an issue when hugetlbfs is specified with an >> option of size. Currently DPDK does not respect the quota of a hugetblfs >> mount. It fails to init the EAL because it tries to map the number of free >> hugepages in the system rather than using the number specified in the quota >> for that mount. > It looks to be a bug. Why adding an option? > What is the benefit of the old behaviour, not using --try-best?
I do not see any benefit to the old behavior. Given that we need the signal handling for the cgroup use case, I would be inclined to use this method as the default instead of trying to figure out how many hugepages we have free, etc. Thoughts? Sergio >> +static sigjmp_buf jmpenv; >> + >> +static void sigbus_handler(int signo __rte_unused) >> +{ >> + siglongjmp(jmpenv, 1); >> +} >> + >> +/* Put setjmp into a wrap method to avoid compiling error. Any non-volatile, >> + * non-static local variable in the stack frame calling sigsetjmp might be >> + * clobbered by a call to longjmp. >> + */ >> +static int wrap_sigsetjmp(void) >> +{ >> + return sigsetjmp(jmpenv, 1); >> +} > Please add the word "huge" to these variables and functions. > >> +static struct sigaction action_old; >> +static int need_recover; >> + >> +static void >> +register_sigbus(void) >> +{ >> + sigset_t mask; >> + struct sigaction action; >> + >> + sigemptyset(&mask); >> + sigaddset(&mask, SIGBUS); >> + action.sa_flags = 0; >> + action.sa_mask = mask; >> + action.sa_handler = sigbus_handler; >> + >> + need_recover = !sigaction(SIGBUS, &action, &action_old); >> +} >> + >> +static void >> +recover_sigbus(void) >> +{ >> + if (need_recover) { >> + sigaction(SIGBUS, &action_old, NULL); >> + need_recover = 0; >> + } >> +} > Idem, Please add the word "huge". >