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