From 4087a6e7fc773ba4eb217dfc196dfe1eee84b25d Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Wed, 10 Aug 2022 20:35:42 -0400 Subject: Read and write p->killed using atomics --- kernel/proc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/proc.c') diff --git a/kernel/proc.c b/kernel/proc.c index 2d0ffa1..221f0f8 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -422,7 +422,7 @@ wait(uint64 addr) } // No point waiting if we don't have any children. - if(!havekids || p->killed){ + if(!havekids || __sync_add_and_fetch(&p->killed, 0)){ release(&wait_lock); return -1; } @@ -588,7 +588,7 @@ kill(int pid) for(p = proc; p < &proc[NPROC]; p++){ acquire(&p->lock); if(p->pid == pid){ - p->killed = 1; + __sync_bool_compare_and_swap(&p->killed, 0, 1); if(p->state == SLEEPING){ // Wake process from sleep(). p->state = RUNNABLE; -- cgit v1.2.3 From 975f3b31d3fac2c271df3107263df6ae454a98be Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Thu, 11 Aug 2022 07:23:17 -0400 Subject: Clean up using killed() --- kernel/proc.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) (limited to 'kernel/proc.c') diff --git a/kernel/proc.c b/kernel/proc.c index 221f0f8..24680b6 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -422,7 +422,7 @@ wait(uint64 addr) } // No point waiting if we don't have any children. - if(!havekids || __sync_add_and_fetch(&p->killed, 0)){ + if(!havekids || killed(p)){ release(&wait_lock); return -1; } @@ -601,6 +601,12 @@ kill(int pid) return -1; } +int +killed(struct proc *p) +{ + return __sync_add_and_fetch(&p->killed, 0); +} + // Copy to either a user address, or kernel address, // depending on usr_dst. // Returns 0 on success, -1 on error. -- cgit v1.2.3 From 429c7b717edd4c23d3666327986052b9b6eb29eb Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Thu, 11 Aug 2022 08:42:52 -0400 Subject: Use atomic store_n and load_n --- kernel/proc.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'kernel/proc.c') diff --git a/kernel/proc.c b/kernel/proc.c index 24680b6..b4f8a80 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -588,7 +588,7 @@ kill(int pid) for(p = proc; p < &proc[NPROC]; p++){ acquire(&p->lock); if(p->pid == pid){ - __sync_bool_compare_and_swap(&p->killed, 0, 1); + __atomic_store_n(&p->killed, 1, __ATOMIC_SEQ_CST); if(p->state == SLEEPING){ // Wake process from sleep(). p->state = RUNNABLE; @@ -604,7 +604,7 @@ kill(int pid) int killed(struct proc *p) { - return __sync_add_and_fetch(&p->killed, 0); + return __atomic_load_n(&p->killed, __ATOMIC_SEQ_CST); } // Copy to either a user address, or kernel address, -- cgit v1.2.3 From 4f716c8550b406c3e4b3e0c21b986ef99bc06c40 Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Thu, 11 Aug 2022 14:22:00 -0400 Subject: Use p->lock to read p->killed --- kernel/proc.c | 17 +++++++++++++++-- 1 file changed, 15 insertions(+), 2 deletions(-) (limited to 'kernel/proc.c') diff --git a/kernel/proc.c b/kernel/proc.c index b4f8a80..5e37cb7 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -588,7 +588,7 @@ kill(int pid) for(p = proc; p < &proc[NPROC]; p++){ acquire(&p->lock); if(p->pid == pid){ - __atomic_store_n(&p->killed, 1, __ATOMIC_SEQ_CST); + p->killed = 1; if(p->state == SLEEPING){ // Wake process from sleep(). p->state = RUNNABLE; @@ -601,10 +601,23 @@ kill(int pid) return -1; } +void +setkilled(struct proc *p) +{ + acquire(&p->lock); + p->killed = 1; + release(&p->lock); +} + int killed(struct proc *p) { - return __atomic_load_n(&p->killed, __ATOMIC_SEQ_CST); + int k; + + acquire(&p->lock); + k = p->killed; + release(&p->lock); + return k; } // Copy to either a user address, or kernel address, -- cgit v1.2.3 From 1d4c437ea17e3254fe6138fd8dd181de413a43bf Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Wed, 17 Aug 2022 20:37:22 -0400 Subject: Use uint64 (thanks carlclone and Harry Porter) --- kernel/proc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/proc.c') diff --git a/kernel/proc.c b/kernel/proc.c index 580b3b6..3bb2618 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -259,7 +259,7 @@ userinit(void) int growproc(int n) { - uint sz; + uint64 sz; struct proc *p = myproc(); sz = p->sz; -- cgit v1.2.3 From 2f0b4d698bc48f4efb4b9fdca20f415ec765bf41 Mon Sep 17 00:00:00 2001 From: Frans Kaashoek Date: Mon, 22 Aug 2022 19:58:33 -0400 Subject: Use pp instead of np to be more consistent --- kernel/proc.c | 24 ++++++++++++------------ 1 file changed, 12 insertions(+), 12 deletions(-) (limited to 'kernel/proc.c') diff --git a/kernel/proc.c b/kernel/proc.c index 3bb2618..1ed3ee5 100644 --- a/kernel/proc.c +++ b/kernel/proc.c @@ -390,7 +390,7 @@ exit(int status) int wait(uint64 addr) { - struct proc *np; + struct proc *pp; int havekids, pid; struct proc *p = myproc(); @@ -399,27 +399,27 @@ wait(uint64 addr) for(;;){ // Scan through table looking for exited children. havekids = 0; - for(np = proc; np < &proc[NPROC]; np++){ - if(np->parent == p){ + for(pp = proc; pp < &proc[NPROC]; pp++){ + if(pp->parent == p){ // make sure the child isn't still in exit() or swtch(). - acquire(&np->lock); + acquire(&pp->lock); havekids = 1; - if(np->state == ZOMBIE){ + if(pp->state == ZOMBIE){ // Found one. - pid = np->pid; - if(addr != 0 && copyout(p->pagetable, addr, (char *)&np->xstate, - sizeof(np->xstate)) < 0) { - release(&np->lock); + pid = pp->pid; + if(addr != 0 && copyout(p->pagetable, addr, (char *)&pp->xstate, + sizeof(pp->xstate)) < 0) { + release(&pp->lock); release(&wait_lock); return -1; } - freeproc(np); - release(&np->lock); + freeproc(pp); + release(&pp->lock); release(&wait_lock); return pid; } - release(&np->lock); + release(&pp->lock); } } -- cgit v1.2.3