Date: Fri, 10 Aug 2012 13:13:02 +0300 From: Konstantin Belousov <kostikbel@gmail.com> To: Jilles Tjoelker <jilles@stack.nl> Cc: freebsd-hackers@freebsd.org, davidxu@freebsd.org Subject: Re: system() using vfork() or posix_spawn() and libthr Message-ID: <20120810101302.GF2425@deviant.kiev.zoral.com.ua> In-Reply-To: <20120809110850.GA2425@deviant.kiev.zoral.com.ua> References: <20120730102408.GA19983@stack.nl> <20120730105303.GU2676@deviant.kiev.zoral.com.ua> <20120805215432.GA28704@stack.nl> <20120806082535.GI2676@deviant.kiev.zoral.com.ua> <20120809105648.GA79814@stack.nl> <20120809110850.GA2425@deviant.kiev.zoral.com.ua>
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--GLp9dJVi+aaipsRk Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Aug 09, 2012 at 02:08:50PM +0300, Konstantin Belousov wrote: > Third alternative, which seems to be even better, is to restore > single-threading of the parent for vfork(). I mean this patch. diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c index 6cb95cd..e59ee21 100644 --- a/sys/kern/kern_fork.c +++ b/sys/kern/kern_fork.c @@ -756,7 +756,7 @@ fork1(struct thread *td, int flags, int pages, struct p= roc **procp, struct thread *td2; struct vmspace *vm2; vm_ooffset_t mem_charged; - int error; + int error, single_threaded; static int curfail; static struct timeval lastfail; #ifdef PROCDESC @@ -815,6 +815,19 @@ fork1(struct thread *td, int flags, int pages, struct = proc **procp, } #endif =20 + if (((p1->p_flag & (P_HADTHREADS | P_SYSTEM)) =3D=3D P_HADTHREADS) && + (flags & RFPPWAIT) !=3D 0) { + PROC_LOCK(p1); + if (thread_single(SINGLE_BOUNDARY)) { + PROC_UNLOCK(p1); + error =3D ERESTART; + goto fail2; + } + PROC_UNLOCK(p1); + single_threaded =3D 1; + } else + single_threaded =3D 0; + mem_charged =3D 0; vm2 =3D NULL; if (pages =3D=3D 0) @@ -945,6 +958,12 @@ fail1: if (vm2 !=3D NULL) vmspace_free(vm2); uma_zfree(proc_zone, newproc); + if (single_threaded) { + PROC_LOCK(p1); + thread_single_end(); + PROC_UNLOCK(p1); + } +fail2: #ifdef PROCDESC if (((flags & RFPROCDESC) !=3D 0) && (fp_procdesc !=3D NULL)) { fdclose(td->td_proc->p_fd, fp_procdesc, *procdescp, td); diff --git a/tools/test/pthread_vfork/pthread_vfork_test.c b/tools/test/pth= read_vfork/pthread_vfork_test.c index e004727..88956c2 100644 --- a/tools/test/pthread_vfork/pthread_vfork_test.c +++ b/tools/test/pthread_vfork/pthread_vfork_test.c @@ -29,6 +29,8 @@ #include <sys/cdefs.h> __FBSDID("$FreeBSD$"); =20 +#include <sys/types.h> +#include <sys/wait.h> #include <err.h> #include <pthread.h> #include <signal.h> @@ -39,10 +41,11 @@ __FBSDID("$FreeBSD$"); =20 #define NUM_THREADS 100 =20 -void * -vfork_test(void *threadid) +static void * +vfork_test(void *threadid __unused) { - pid_t pid; + pid_t pid, wpid; + int status; =20 for (;;) { pid =3D vfork(); @@ -50,10 +53,20 @@ vfork_test(void *threadid) _exit(0); else if (pid =3D=3D -1) err(1, "Failed to vfork"); + else { + wpid =3D waitpid(pid, &status, 0); + if (wpid =3D=3D -1) + err(1, "waitpid"); + } } return (NULL); } =20 +static void +sighandler(int signo __unused) +{ +} + /* * This program invokes multiple threads and each thread calls * vfork() system call. @@ -63,19 +76,24 @@ main(void) { pthread_t threads[NUM_THREADS]; struct sigaction reapchildren; + sigset_t sigchld_mask; int rc, t; =20 memset(&reapchildren, 0, sizeof(reapchildren)); - reapchildren.sa_handler =3D SIG_IGN; - - /* Automatically reap zombies. */ + reapchildren.sa_handler =3D sighandler; if (sigaction(SIGCHLD, &reapchildren, NULL) =3D=3D -1) err(1, "Could not sigaction(SIGCHLD)"); =20 + sigemptyset(&sigchld_mask); + sigaddset(&sigchld_mask, SIGCHLD); + if (sigprocmask(SIG_BLOCK, &sigchld_mask, NULL) =3D=3D -1) + err(1, "sigprocmask"); + for (t =3D 0; t < NUM_THREADS; t++) { rc =3D pthread_create(&threads[t], NULL, vfork_test, (void *)t); if (rc) errc(1, rc, "pthread_create"); } + pause(); return (0); } --GLp9dJVi+aaipsRk Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (FreeBSD) iEYEARECAAYFAlAk3q4ACgkQC3+MBN1Mb4g29QCghHodkIf2zunuCoeJlrsux7QN fP8AoJ/taKj2h5VQAco2vg/NY90ZmyZW =c6ZU -----END PGP SIGNATURE----- --GLp9dJVi+aaipsRk--
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