tuna: handle schedutils SystemError exceptions

Sometimes the refresh stopped due to threads disappearing and the schedutils
routines (get_affinity, set_affinity, etc) trowing SystemError exceptions,
handle them.

Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 81 insertions, 24 deletions

diff --git a/tuna-cmd.py b/tuna-cmd.py
index 2c4b566..8683867 100755
--- a/tuna-cmd.py
+++ b/tuna-cmd.py
@@ -86,7 +86,11 @@ def ps_show_header(has_ctxt_switch_info):
 		 "cmd")
 
 def ps_show_thread(pid, affect_children, ps, cpuinfo, irqs, nics, has_ctxt_switch_info):
-	affinity = schedutils.get_affinity(pid)
+	try:
+		affinity = schedutils.get_affinity(pid)
+	except SystemError: # (3, 'No such process')
+		return
+
 	if len(affinity) <= 4:
 		affinity = ",".join(str(a) for a in affinity)
 	else:
@@ -137,7 +141,10 @@ def ps_show(ps, affect_children, cpuinfo, irqs, threads, cpus,
 			continue
 		if not show_kthreads and iskth:
 			continue
-		affinity = schedutils.get_affinity(pid)
+		try:
+			affinity = schedutils.get_affinity(pid)
+		except SystemError: # (3, 'No such process')
+			continue
 		if cpus and not set(cpus).intersection(set(affinity)):
 			continue
 		ps_list.append(pid)
@@ -149,7 +156,7 @@ def ps_show(ps, affect_children, cpuinfo, irqs, threads, cpus,
 	for pid in ps_list:
 		ps_show_thread(pid, affect_children, ps, cpuinfo, irqs, nics, has_ctxt_switch_info)
 
-def ps(threads, cpus, show_uthreads, show_kthreads, affect_children):
+def do_ps(threads, cpus, show_uthreads, show_kthreads, affect_children):
 	ps = procfs.pidstats()
 	if affect_children:
 		ps.reload_threads()
@@ -215,7 +222,7 @@ def main():
 		elif o in ("-p", "--priority"):
 			tuna.threads_set_priority(threads, a, affect_children)
 		elif o in ("-P", "--show_threads"):
-			ps(threads, cpus, uthreads, kthreads, affect_children)
+			do_ps(threads, cpus, uthreads, kthreads, affect_children)
 		elif o in ("-m", "--move"):
 			if not cpus:
 				print "tuna: --move requires a cpu list!"
diff --git a/tuna/tuna.py b/tuna/tuna.py
index 6de6ec8..5cad29e 100755
--- a/tuna/tuna.py
+++ b/tuna/tuna.py
@@ -148,10 +148,16 @@ def move_threads_to_cpu(new_affinity, pid_list, set_affinity_warning = None):
 	ps = procfs.pidstats()
 	for pid in pid_list:
 		try:
-			curr_affinity = schedutils.get_affinity(pid)
-			if set(curr_affinity) != set(new_affinity):
-				schedutils.set_affinity(pid, new_affinity)
+			try:
 				curr_affinity = schedutils.get_affinity(pid)
+			except SystemError: # (3, 'No such process')
+				continue
+			if set(curr_affinity) != set(new_affinity):
+				try:
+					schedutils.set_affinity(pid, new_affinity)
+					curr_affinity = schedutils.get_affinity(pid)
+				except SystemError: # (3, 'No such process')
+					continue
 				if set(curr_affinity) == set(new_affinity):
 					changed = True
 				elif set_affinity_warning:
@@ -165,10 +171,16 @@ def move_threads_to_cpu(new_affinity, pid_list, set_affinity_warning = None):
 
 			threads = procfs.pidstats("/proc/%d/task" % pid)
 			for tid in threads.keys():
-				curr_affinity = schedutils.get_affinity(tid)
-				if set(curr_affinity) != set(new_affinity):
-					schedutils.set_affinity(tid, new_affinity)
+				try:
 					curr_affinity = schedutils.get_affinity(tid)
+				except SystemError: # (3, 'No such process')
+					continue
+				if set(curr_affinity) != set(new_affinity):
+					try:
+						schedutils.set_affinity(tid, new_affinity)
+						curr_affinity = schedutils.get_affinity(tid)
+					except SystemError: # (3, 'No such process')
+						continue
 					if set(curr_affinity) == set(new_affinity):
 						changed = True
 					elif set_affinity_warning:
@@ -195,11 +207,17 @@ def isolate_cpus(cpus, nr_cpus):
 	for pid in ps.keys():
 		if iskthread(pid):
 			continue
-		affinity = schedutils.get_affinity(pid)
+		try:
+			affinity = schedutils.get_affinity(pid)
+		except SystemError: # (3, 'No such process')
+			continue
 		if set(affinity).intersection(set(cpus)):
 			previous_pid_affinities[pid] = copy.copy(affinity)
 			affinity = affinity_remove_cpus(affinity, cpus, nr_cpus)
-			schedutils.set_affinity(pid, affinity)
+			try:
+				schedutils.set_affinity(pid, affinity)
+			except SystemError: # (3, 'No such process')
+				continue
 
 		if not ps[pid].has_key("threads"):
 			continue
@@ -207,11 +225,17 @@ def isolate_cpus(cpus, nr_cpus):
 		for tid in threads.keys():
 			if iskthread(tid):
 				continue
-			affinity = schedutils.get_affinity(tid)
+			try:
+				affinity = schedutils.get_affinity(tid)
+			except SystemError: # (3, 'No such process')
+				continue
 			if set(affinity).intersection(set(cpus)):
 				previous_pid_affinities[tid] = copy.copy(affinity)
 				affinity = affinity_remove_cpus(affinity, cpus, nr_cpus)
-				schedutils.set_affinity(tid, affinity)
+				try:
+					schedutils.set_affinity(tid, affinity)
+				except SystemError: # (3, 'No such process')
+					continue
 
 	del ps
 
@@ -239,11 +263,17 @@ def include_cpus(cpus, nr_cpus):
 	for pid in ps.keys():
 		if iskthread(pid):
 			continue
-		affinity = schedutils.get_affinity(pid)
+		try:
+			affinity = schedutils.get_affinity(pid)
+		except SystemError: # (3, 'No such process')
+			continue
 		if set(affinity).intersection(set(cpus)) != set(cpus):
 			previous_pid_affinities[pid] = copy.copy(affinity)
 			affinity = list(set(affinity + cpus))
-			schedutils.set_affinity(pid, affinity)
+			try:
+				schedutils.set_affinity(pid, affinity)
+			except SystemError: # (3, 'No such process')
+				continue
 
 		if not ps[pid].has_key("threads"):
 			continue
@@ -251,11 +281,17 @@ def include_cpus(cpus, nr_cpus):
 		for tid in threads.keys():
 			if iskthread(tid):
 				continue
-			affinity = schedutils.get_affinity(tid)
+			try:
+				affinity = schedutils.get_affinity(tid)
+			except SystemError: # (3, 'No such process')
+				continue
 			if set(affinity).intersection(set(cpus)) != set(cpus):
 				previous_pid_affinities[tid] = copy.copy(affinity)
 				affinity = list(set(affinity + cpus))
-				schedutils.set_affinity(tid, affinity)
+				try:
+					schedutils.set_affinity(tid, affinity)
+				except SystemError: # (3, 'No such process')
+					continue
 
 	del ps
 
@@ -298,7 +334,11 @@ def get_irq_affinity_text(irqs, irq):
 
 def thread_filtered(tid, cpus_filtered, show_kthreads, show_uthreads):
 	if cpus_filtered:
-		affinity = schedutils.get_affinity(tid)
+		try:
+			affinity = schedutils.get_affinity(tid)
+		except SystemError: # (3, 'No such process')
+			return False
+
 		if set(cpus_filtered + affinity) == set(cpus_filtered):
 			return True
 
@@ -357,8 +397,11 @@ def get_kthread_sched_tunings(proc = None):
 		if iskthread(pid):
 			name = proc[pid]["stat"]["comm"]
 			rtprio = int(proc[pid]["stat"]["rt_priority"])
-			policy = schedutils.get_scheduler(pid)
-			affinity = schedutils.get_affinity(pid)
+			try:
+				policy = schedutils.get_scheduler(pid)
+				affinity = schedutils.get_affinity(pid)
+			except SystemError: # (3, 'No such process')
+				continue
 			percpu = iskthread(pid) and \
 				 proc.is_bound_to_cpu(pid)
 			kthreads[name] = sched_tunings(name, pid, policy,
diff --git a/tuna/tuna_gui.py b/tuna/tuna_gui.py
index 48d7f6a..f012752 100644
--- a/tuna/tuna_gui.py
+++ b/tuna/tuna_gui.py
@@ -453,7 +453,11 @@ def thread_set_attributes(pid, threads, new_policy, new_prio, new_affinity, nr_c
 		else:
 			changed = True
 
-	curr_affinity = schedutils.get_affinity(pid)
+	try:
+		curr_affinity = schedutils.get_affinity(pid)
+	except SystemError: # (3, 'No such process')
+		return False
+
 	try:
 		new_affinity = [ int(a) for a in new_affinity.split(",") ]
 	except:
@@ -470,7 +474,10 @@ def thread_set_attributes(pid, threads, new_policy, new_prio, new_affinity, nr_c
 		except:
 			return invalid_affinity()
 
-		curr_affinity = schedutils.get_affinity(pid)
+		try:
+			curr_affinity = schedutils.get_affinity(pid)
+		except SystemError: # (3, 'No such process')
+			return False
 		if curr_affinity != new_affinity:
 			print "couldn't change pid %d from %s to %s!" % \
 			      ( pid, curr_affinity, new_affinity )
@@ -1077,11 +1084,11 @@ class procview:
 
 		try:
 			new_value[self.COL_POL] = schedutils.schedstr(schedutils.get_scheduler(tid))[6:]
+			thread_affinity_list = schedutils.get_affinity(tid)
 		except SystemError:
 			return True
 
 		new_value[self.COL_PID] = tid
-		thread_affinity_list = schedutils.get_affinity(tid)
 		new_value[self.COL_AFF] = tuna.list_to_cpustring(thread_affinity_list)
 		try:
 			new_value[self.COL_VOLCTXT] = int(thread_info["status"]["voluntary_ctxt_switches"])