Atomically modify `nthreads' and move proc_free() out of KERNEL_LOCK().

ok jca@

diff --git a/sys/kern/kern_exit.c b/sys/kern/kern_exit.c
index a1d1456..fb61153 100644 (file)
--- a/sys/kern/kern_exit.c
+++ b/sys/kern/kern_exit.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_exit.c,v 1.231 2024/08/11 15:10:53 mvs Exp $     */
+/*     $OpenBSD: kern_exit.c,v 1.232 2024/08/16 16:19:03 mpi Exp $     */
 /*     $NetBSD: kern_exit.c,v 1.39 1996/04/22 01:38:25 christos Exp $  */
 
 /*
@@ -432,7 +432,7 @@ proc_free(struct proc *p)
 {
        crfree(p->p_ucred);
        pool_put(&proc_pool, p);
-       nthreads--;
+       atomic_dec_int(&nthreads);
 }
 
 /*
@@ -471,9 +471,7 @@ reaper(void *arg)
 
                if (p->p_flag & P_THREAD) {
                        /* Just a thread */
-                       KERNEL_LOCK();
                        proc_free(p);
-                       KERNEL_UNLOCK();
                } else {
                        struct process *pr = p->p_p;
 

diff --git a/sys/kern/kern_fork.c b/sys/kern/kern_fork.c
index e148c81..d0d465b 100644 (file)
--- a/sys/kern/kern_fork.c
+++ b/sys/kern/kern_fork.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: kern_fork.c,v 1.262 2024/08/11 15:10:53 mvs Exp $     */
+/*     $OpenBSD: kern_fork.c,v 1.263 2024/08/16 16:19:03 mpi Exp $     */
 /*     $NetBSD: kern_fork.c,v 1.29 1996/02/09 18:59:34 christos Exp $  */
 
 /*
@@ -65,7 +65,7 @@
 #include <machine/tcb.h>
 
 int    nprocesses = 1;         /* process 0 */
-int    nthreads = 1;           /* proc 0 */
+int    nthreads = 1;           /* [a] proc 0 */
 struct forkstat forkstat;
 
 void fork_return(void *);
@@ -307,6 +307,8 @@ struct timeval fork_tfmrate = { 10, 0 };
 int
 fork_check_maxthread(uid_t uid)
 {
+       int val;
+
        /*
         * Although process entries are dynamically created, we still keep
         * a global limit on the maximum number we will create. We reserve
@@ -316,14 +318,15 @@ fork_check_maxthread(uid_t uid)
         * the variable nthreads is the current number of procs, maxthread is
         * the limit.
         */
-       if ((nthreads >= maxthread - 5 && uid != 0) || nthreads >= maxthread) {
+       val = atomic_inc_int_nv(&nthreads);
+       if ((val > maxthread - 5 && uid != 0) || val > maxthread) {
                static struct timeval lasttfm;
 
                if (ratecheck(&lasttfm, &fork_tfmrate))
                        tablefull("thread");
+               atomic_dec_int(&nthreads);
                return EAGAIN;
        }
-       nthreads++;
 
        return 0;
 }
@@ -369,7 +372,7 @@ fork1(struct proc *curp, int flags, void (*func)(void *), void *arg,
 
                if (ratecheck(&lasttfm, &fork_tfmrate))
                        tablefull("process");
-               nthreads--;
+               atomic_dec_int(&nthreads);
                return EAGAIN;
        }
        nprocesses++;
@@ -382,7 +385,7 @@ fork1(struct proc *curp, int flags, void (*func)(void *), void *arg,
        if (uid != 0 && count > lim_cur(RLIMIT_NPROC)) {
                (void)chgproccnt(uid, -1);
                nprocesses--;
-               nthreads--;
+               atomic_dec_int(&nthreads);
                return EAGAIN;
        }
 
@@ -390,7 +393,7 @@ fork1(struct proc *curp, int flags, void (*func)(void *), void *arg,
        if (uaddr == 0) {
                (void)chgproccnt(uid, -1);
                nprocesses--;
-               nthreads--;
+               atomic_dec_int(&nthreads);
                return (ENOMEM);
        }
 
@@ -547,7 +550,7 @@ thread_fork(struct proc *curp, void *stack, void *tcb, pid_t *tidptr,
 
        uaddr = uvm_uarea_alloc();
        if (uaddr == 0) {
-               nthreads--;
+               atomic_dec_int(&nthreads);
                return ENOMEM;
        }