From 6e8aaedc1f3be2c9c7c3031499ad2b4bce05dfbc Mon Sep 17 00:00:00 2001 From: Kaz Kylheku Date: Fri, 20 Dec 2013 06:57:13 -0800 Subject: Fixing a bug and performance issue. Problem: we are using sigsetjmp but with a jmp_buf structure; it requires sigjmp_buf! Performance issue: sigsetjmp is a dog which makes system calls. Solution: let's roll our own cached version of sigprocmask which only calls the real sigprocmask when the mask changes. Then our extended_setjmp will just use regular setjmp, plus our own custom signal saving and restoring based on the cached version. * signal.c (sig_blocked_cache): New variable. (set_sig_handler): Use our sig_mask instead of sigprocmask. (mem_set_bits, mem_clr_bits): New static functions. (sig_mask): New function. * signal.h (extended_jmp_buf): New member, blocked. (extended_setjmp): save blocked signals by peeking into sig_blocked_cache, and restore using sig_mask. (sig_blocked_cache, sig_mask): Declared. --- signal.h | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) (limited to 'signal.h') diff --git a/signal.h b/signal.h index e2b794c1..8882c259 100644 --- a/signal.h +++ b/signal.h @@ -60,17 +60,23 @@ typedef struct { jmp_buf jb; sig_atomic_t se; + sigset_t blocked; int rv; } extended_jmp_buf; #define extended_setjmp(EJB) \ - (sigsetjmp((EJB).jb, 1) \ - ? (async_sig_enabled = (EJB).se, (EJB).rv) \ - : ((EJB).se = async_sig_enabled, 0)) + (setjmp((EJB).jb) \ + ? (async_sig_enabled = (EJB).se, \ + sig_mask(SIG_SETMASK, &(EJB).blocked, 0), \ + (EJB).rv) \ + : ((EJB).se = async_sig_enabled, \ + (EJB).blocked = sig_blocked_cache, 0)) #define extended_longjmp(EJB, ARG) \ ((EJB).rv = (ARG), longjmp((EJB).jb, 1)) +extern sigset_t sig_blocked_cache; + #else #define sig_save_enable do { @@ -98,3 +104,4 @@ void sig_init(void); val set_sig_handler(val signo, val lambda); val get_sig_handler(val signo); val sig_check(void); +int sig_mask(int how, const sigset_t *set, sigset_t *oldset); -- cgit v1.2.3