New: Slow bootup if mdev is chosen
https://bugs.busybox.net/show_bug.cgi?id=6596
Summary: Slow bootup if mdev is chosen
Product: buildroot
Version: 2013.08
Platform: Other
OS/Version: Linux
Status: NEW
Severity: minor
Priority: P5
Component: Other
AssignedTo: unassigned at buildroot.uclibc.org
ReportedBy: andreas.koop at zf.com
CC: buildroot at uclibc.org
Estimated Hours: 0.0
Created attachment 5090
--> https://bugs.busybox.net/attachment.cgi?id=5090
disable CONFIG_UEVENT_HELPER_PATH option
When I choose mdev my Nios II based board stalls for about two minutes during boot up. Then it proceeds again and boots normally. I've tracked the issue down. It's because buildroot sets CONFIG_UEVENT_HELPER_PATH to "/sbin/mdev" during kernel configuration. When I set it to an empty string Linux (3.10.0) boots up as usual again.
If you look at the kernel's own description of CONFIG_UEVENT_HELPER_PATH it states it shouldn't be used today anymore since it creates a high system load on bootup.
Mdev still works after it's startup script has been run. It writes "/sbin/mdev" to /proc/sys/kernel/hotplug which causes the kernel to inform mdev about new events.
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[Buildroot] [Bug 6596] Slow bootup if mdev is chosen
https://bugs.busybox.net/show_bug.cgi?id=6596
--- Comment #1 from Thomas De Schampheleire <[email protected]> 2013-10-24 08:19:22 UTC --- We have had a discussion about this topic in the past:
http://lists.busybox.net/pipermail/buildroot/2013-July/075148.html
I indeed have noticed the same slowdown, and our solution was the same (setting the UEVENT_HELPER to empty).
Given that the mentioned thread changed S10mdev to set mdev as helper after boot, I don't think we still need/want the in-kernel option.
Would you mind sending this change as a proper patch to the mailing list, including description and Signed-off-by? This would provide you with the necessary credit, and also facilitates discussion on the patch.
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[Buildroot] [Bug 6596] Slow bootup if mdev is chosen
In reply to bugzilla at busybox.nethttps://bugs.busybox.net/show_bug.cgi?id=6596
--- Comment #2 from Thomas De Schampheleire <[email protected]> 2014-02-07 08:43:41 UTC --- Patch sent to the mailing list, awaiting integration, after which this bug can
be closed...
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[Buildroot] [Bug 6596] Slow bootup if mdev is chosen
In reply to bugzilla at busybox.nethttps://bugs.busybox.net/show_bug.cgi?id=6596
Thomas De Schampheleire <[email protected]> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
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[Buildroot] [Bug 6596] Slow bootup if mdev is chosen
In reply to bugzilla at busybox.nethttps://bugs.busybox.net/show_bug.cgi?id=6596
Peter Korsgaard <[email protected]> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED--- Comment #3 from Peter Korsgaard <[email protected]> 2014-02-09 22:17:00 UTC --- Committed in git (05e2e35715d104e9dd67b4013d9b16a47b8eb3c0), thanks
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