[RFC v8 08/10] tools/damon/record: Support physical memory monitoring

SeongJae Park
2020-08-31T10:50:47Z

This commit allows users to record the data accesses on physical memory
address space by passing 'paddr' as target to 'damo-record'. If the
init regions are given, the regions will be monitored. Else, it will
monitor biggest conitguous 'System RAM' region in '/proc/iomem' and
monitor the region.

Signed-off-by: SeongJae Park <sjpark@amazon.de>
---
tools/damon/_damon.py | 2 ++
tools/damon/record.py | 29 ++++++++++++++++++++++++++++-
2 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/tools/damon/_damon.py b/tools/damon/_damon.py
index a22ec3777c16..6ff278117e84 100644
--- a/tools/damon/_damon.py
+++ b/tools/damon/_damon.py
@@ -27,6 +27,8 @@ def set_target(tid, init_regions=[]):
if not os.path.exists(debugfs_init_regions):
return 0

+ if tid == 'paddr':
+ tid = 42
string = ' '.join(['%s %d %d' % (tid, r[0], r[1]) for r in init_regions])
return subprocess.call('echo "%s" > %s' % (string, debugfs_init_regions),
shell=True, executable='/bin/bash')
diff --git a/tools/damon/record.py b/tools/damon/record.py
index 11fd54001472..6fd0b59c73e0 100644
--- a/tools/damon/record.py
+++ b/tools/damon/record.py
@@ -101,6 +101,29 @@ def set_argparser(parser):
parser.add_argument('-o', '--out', metavar='<file path>', type=str,
default='damon.data', help='output file path')

+def default_paddr_region():
+ "Largest System RAM region becomes the default"
+ ret = []
+ with open('/proc/iomem', 'r') as f:
+ # example of the line: '100000000-42b201fff : System RAM'
+ for line in f:
+ fields = line.split(':')
+ if len(fields) != 2:
+ continue
+ name = fields[1].strip()
+ if name != 'System RAM':
+ continue
+ addrs = fields[0].split('-')
+ if len(addrs) != 2:
+ continue
+ start = int(addrs[0], 16)
+ end = int(addrs[1], 16)
+
+ sz_region = end - start
+ if not ret or sz_region > (ret[1] - ret[0]):
+ ret = [start, end]
+ return ret
+
def main(args=None):
global orig_attrs
if not args:
@@ -122,7 +145,11 @@ def main(args=None):
target = args.target

target_fields = target.split()
- if not subprocess.call('which %s &> /dev/null' % target_fields[0],
+ if target == 'paddr': # physical memory address space
+ if not init_regions:
+ init_regions = [default_paddr_region()]
+ do_record(target, False, init_regions, new_attrs, orig_attrs, pidfd)
+ elif not subprocess.call('which %s &> /dev/null' % target_fields[0],
shell=True, executable='/bin/bash'):
do_record(target, True, init_regions, new_attrs, orig_attrs, pidfd)
else:
--
2.17.1