Re: [PATCH ] drivers/base: cacheinfo: remove warning in resume

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Hi Sumit,

I understand the warning we get but the patch is completely wrong.
One it removes the feature of adding/removing the cache devices
on cpu hotplug events. Have you tested your patch with simple cpu
hotplug and seen no change before and after this change ?

On 29/08/16 08:20, Sumit Gupta wrote:
CPU notifier is present for creating device
entries for child node "cache" under parent
node "cpu" as per DT.

Again DT is only on few architectures not on all(e.g. x86)

During resume from
suspend, while booting all non-boot CPU's,
this notifier for adding cache device gets
called before cpu device is added by
device_resume. Because of this warning message
of "parent should not be sleeping" comes during
resume.


Yes that's correct and needs to be fixed. I have seen this but haven't
spent much time to check in detail. It's harmless warning IMO.
See the comment in the code too:"This is a fib. But we'll allow new
children to be added below a resumed device, even if the device hasn't
been completed yet"

CPU devices are special and they have separate hotplug paths. So we need
to consider that for cpu devices and set is_prepared quite early.

Removing the notifier to explicitly add/remove
cache device as CPU and cache device get
added/removed anyway as part of normal suspend
resume sequence.
dpm_resume_end - > dpm_resume -> device_resume


Yes, but:
1. the caches objects are visible even when the cpu is offline
2. how is this handled for normal cpu-hotplug events ? This patch
   breaks the existing feature.

Signed-off-by: Sumit Gupta <sumitg@xxxxxxxxxx>
---
 drivers/base/cacheinfo.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/drivers/base/cacheinfo.c b/drivers/base/cacheinfo.c
index e9fd32e91668..17d9c051a16f 100644
--- a/drivers/base/cacheinfo.c
+++ b/drivers/base/cacheinfo.c
@@ -544,8 +544,6 @@ static int __init cacheinfo_sysfs_init(void)
 			goto out;
 		}
 	}
-	__hotcpu_notifier(cacheinfo_cpu_callback, 0);
-
 out:
 	cpu_notifier_register_done();
 	return rc;


--
Regards,
Sudeep
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