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From:   chengming.zhou@linux.dev
To:     axboe@kernel.dk, tj@kernel.org
Cc:     linux-kernel@vger.kernel.org, zhouchengming@bytedance.com
Subject: [PATCH 1/3] iocost_monitor: fix kernel queue kobj changes
Date:   Fri,  4 Aug 2023 14:50:37 +0800
Message-ID: <20230804065039.8885-1-chengming.zhou@linux.dev>
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From: Chengming Zhou <zhouchengming@bytedance.com>

When I use iocost_monitor on nvme0n1, this error shows up:
"Could not find ioc for nvme0n1"

There is no kobj in struct queue in recent kernel, it seems that the commit
2bd85221a625 ("block: untangle request_queue refcounting from sysfs")
move the queue kobj to struct gendisk.

Fix it by using mq_kobj which is at the same level with queue kobj.

Signed-off-by: Chengming Zhou <zhouchengming@bytedance.com>
---
 tools/cgroup/iocost_monitor.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/cgroup/iocost_monitor.py b/tools/cgroup/iocost_monitor.py
index 0dbbc67400fc..7aa076cb559e 100644
--- a/tools/cgroup/iocost_monitor.py
+++ b/tools/cgroup/iocost_monitor.py
@@ -221,7 +221,7 @@ ioc = None
 for i, ptr in radix_tree_for_each(blkcg_root.blkg_tree.address_of_()):
     blkg = drgn.Object(prog, 'struct blkcg_gq', address=ptr)
     try:
-        if devname == blkg.q.kobj.parent.name.string_().decode('utf-8'):
+        if devname == blkg.q.mq_kobj.parent.name.string_().decode('utf-8'):
             q_id = blkg.q.id.value_()
             if blkg.pd[plid]:
                 root_iocg = container_of(blkg.pd[plid], 'struct ioc_gq', 'pd')
-- 
2.41.0