[PATCH v6 19/21] scripts/gdb: Add class to iterate over CPU masks

From: Jan Kiszka
Date: Mon Oct 28 2013 - 05:38:42 EST


Will be used first to count module references. It is optimized to read
the mask only once per stop.

Signed-off-by: Jan Kiszka <jan.kiszka@xxxxxxxxxxx>
---
scripts/gdb/linux/cpus.py | 54 +++++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 54 insertions(+)

diff --git a/scripts/gdb/linux/cpus.py b/scripts/gdb/linux/cpus.py
index b683da9..c1441f2 100644
--- a/scripts/gdb/linux/cpus.py
+++ b/scripts/gdb/linux/cpus.py
@@ -50,6 +50,60 @@ def per_cpu(var_ptr, cpu):
return pointer.cast(var_ptr.type).dereference()


+cpu_mask = {}
+
+
+def cpu_mask_invalidate(event):
+ global cpu_mask
+ cpu_mask = {}
+ gdb.events.stop.disconnect(cpu_mask_invalidate)
+ if hasattr(gdb.events, 'new_objfile'):
+ gdb.events.new_objfile.disconnect(cpu_mask_invalidate)
+
+
+class CpuList():
+ def __init__(self, mask_name):
+ global cpu_mask
+ self.mask = None
+ if mask_name in cpu_mask:
+ self.mask = cpu_mask[mask_name]
+ if self.mask is None:
+ self.mask = gdb.parse_and_eval(mask_name + ".bits")
+ if hasattr(gdb, 'events'):
+ cpu_mask[mask_name] = self.mask
+ gdb.events.stop.connect(cpu_mask_invalidate)
+ if hasattr(gdb.events, 'new_objfile'):
+ gdb.events.new_objfile.connect(cpu_mask_invalidate)
+ self.bits_per_entry = self.mask[0].type.sizeof * 8
+ self.num_entries = self.mask.type.sizeof * 8 / self.bits_per_entry
+ self.entry = -1
+ self.bits = 0
+
+ def __iter__(self):
+ return self
+
+ def next(self):
+ while self.bits == 0:
+ self.entry += 1
+ if self.entry == self.num_entries:
+ raise StopIteration
+ self.bits = self.mask[self.entry]
+ if self.bits != 0:
+ self.bit = 0
+ break
+
+ while self.bits & 1 == 0:
+ self.bits >>= 1
+ self.bit += 1
+
+ cpu = self.entry * self.bits_per_entry + self.bit
+
+ self.bits >>= 1
+ self.bit += 1
+
+ return cpu
+
+
class PerCpu(gdb.Function):
"""Return per-cpu variable.

--
1.8.1.1.298.ge7eed54

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