#!/usr/bin/env drgn## Copyright (C) 2024 Kemeng Shi <shikemeng@huaweicloud.com># Copyright (C) 2024 Huawei Inc desc = """This is a drgn script based on wq_monitor.py to monitor writeback info onbacking dev. For more info on drgn, visit https://github.com/osandov/drgn.   writeback(kB)     Amount of dirty pages are currently being written back to                    disk.   reclaimable(kB)   Amount of pages are currently reclaimable.   dirtied(kB)       Amount of pages have been dirtied.   wrttien(kB)       Amount of dirty pages have been written back to disk.   avg_wb(kBps)      Smoothly estimated write bandwidth of writing dirty pages                    back to disk.""" import signalimport reimport timeimport json import drgnfrom drgn.helpers.linux.list import list_for_each_entry import argparseparser = argparse.ArgumentParser(description=desc,                                 formatter_class=argparse.RawTextHelpFormatter)parser.add_argument('bdi', metavar='REGEX', nargs='*',                    help='Target backing device name patterns (all if empty)')parser.add_argument('-i', '--interval', metavar='SECS', type=float, default=1,                    help='Monitoring interval (0 to print once and exit)')parser.add_argument('-j', '--json', action='store_true',                    help='Output in json')parser.add_argument('-c', '--cgroup', action='store_true',                    help='show writeback of bdi in cgroup')args = parser.parse_args() bdi_list                = prog['bdi_list'] WB_RECLAIMABLE          = prog['WB_RECLAIMABLE']WB_WRITEBACK            = prog['WB_WRITEBACK']WB_DIRTIED              = prog['WB_DIRTIED']WB_WRITTEN              = prog['WB_WRITTEN']NR_WB_STAT_ITEMS        = prog['NR_WB_STAT_ITEMS'] PAGE_SHIFT              = prog['PAGE_SHIFT'] def K(x):    return x << (PAGE_SHIFT - 10) class Stats:    def dict(self, now):        return { 'timestamp'            : now,                 'name'                 : self.name,                 'writeback'            : self.stats[WB_WRITEBACK],                 'reclaimable'          : self.stats[WB_RECLAIMABLE],                 'dirtied'              : self.stats[WB_DIRTIED],                 'written'              : self.stats[WB_WRITTEN],                 'avg_wb'               : self.avg_bw, }     def table_header_str():        return f'{"":>16} {"writeback":>10} {"reclaimable":>12} ' \                f'{"dirtied":>9} {"written":>9} {"avg_bw":>9}'     def table_row_str(self):        out = f'{self.name[-16:]:16} ' \              f'{self.stats[WB_WRITEBACK]:10} ' \              f'{self.stats[WB_RECLAIMABLE]:12} ' \              f'{self.stats[WB_DIRTIED]:9} ' \              f'{self.stats[WB_WRITTEN]:9} ' \              f'{self.avg_bw:9} '        return out     def show_header():        if Stats.table_fmt:            print()            print(Stats.table_header_str())     def show_stats(self):        if Stats.table_fmt:            print(self.table_row_str())        else:            print(self.dict(Stats.now)) class WbStats(Stats):    def __init__(self, wb):        bdi_name = wb.bdi.dev_name.string_().decode()        # avoid to use bdi.wb.memcg_css which is only defined when        # CONFIG_CGROUP_WRITEBACK is enabled        if wb == wb.bdi.wb.address_of_():            ino = "1"        else:            ino = str(wb.memcg_css.cgroup.kn.id.value_())        self.name = bdi_name + '_' + ino         self.stats = [0] * NR_WB_STAT_ITEMS        for i in range(NR_WB_STAT_ITEMS):            if wb.stat[i].count >= 0:                self.stats[i] = int(K(wb.stat[i].count))            else:                self.stats[i] = 0         self.avg_bw = int(K(wb.avg_write_bandwidth)) class BdiStats(Stats):    def __init__(self, bdi):        self.name = bdi.dev_name.string_().decode()        self.stats = [0] * NR_WB_STAT_ITEMS        self.avg_bw = 0     def collectStats(self, wb_stats):        for i in range(NR_WB_STAT_ITEMS):            self.stats[i] += wb_stats.stats[i]         self.avg_bw += wb_stats.avg_bw exit_req = False def sigint_handler(signr, frame):    global exit_req    exit_req = True def main():    # handle args    Stats.table_fmt = not args.json    interval = args.interval    cgroup = args.cgroup     re_str = None    if args.bdi:        for r in args.bdi:            if re_str is None:                re_str = r            else:                re_str += '|' + r     filter_re = re.compile(re_str) if re_str else None     # monitoring loop    signal.signal(signal.SIGINT, sigint_handler)     while not exit_req:        Stats.now = time.time()         Stats.show_header()        for bdi in list_for_each_entry('struct backing_dev_info', bdi_list.address_of_(), 'bdi_list'):            bdi_stats = BdiStats(bdi)            if filter_re and not filter_re.search(bdi_stats.name):                continue             for wb in list_for_each_entry('struct bdi_writeback', bdi.wb_list.address_of_(), 'bdi_node'):                wb_stats = WbStats(wb)                bdi_stats.collectStats(wb_stats)                if cgroup:                    wb_stats.show_stats()             bdi_stats.show_stats()            if cgroup and Stats.table_fmt:                print()         if interval == 0:            break        time.sleep(interval) if __name__ == "__main__":    main()