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From: David Teigland <teigland@redhat.com>
To: Heming Zhao <heming.zhao@suse.com>
Cc: Martin Wilck <mwilck@suse.de>,
	LVM general discussion and development <linux-lvm@redhat.com>
Subject: Re: [linux-lvm] system boot time regression when using lvm2-2.03.05
Date: Mon, 9 Sep 2019 09:09:56 -0500	[thread overview]
Message-ID: <20190909140956.GA31823@redhat.com> (raw)
In-Reply-To: <c1e8a6d2-d180-03c6-38ab-a402e813e99d@suse.com>

On Mon, Sep 09, 2019 at 11:42:17AM +0000, Heming Zhao wrote:
> Hello David,
> 
> You are right.  Without calling _online_pvscan_one(), the pv/vg/lv won't be actived.
> The activation jobs will be done by systemd calling lvm2-activation-*.services later.
> 
> Current code, the boot process is mainly blocked by:
> ```
> _pvscan_aa
>   vgchange_activate
>    _activate_lvs_in_vg
>     sync_local_dev_names
>      fs_unlock
>       dm_udev_wait <=== this point!
> ```

Thanks for debugging that.  With so many devices, one possibility that
comes to mind is this error you would probably have seen:
"Limit for the maximum number of semaphores reached"

> For fix this boot time regression, it looks lvm2 should have a config item in lvm2.conf
> i.e.: large_PV_boot_speedup.
> When this item is 1, pvcan won't call _online_pvscan_one, then let lvm2-activation*.service
> do the active jobs.
> Is it a workable solution?

We should look into fixing the udev problems.  I don't mind working around
udev when it won't do what we need; I'm not sure what the options are in
this case.

  reply	other threads:[~2019-09-09 14:09 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-29 13:52 [linux-lvm] system boot time regression when using lvm2-2.03.05 Heming Zhao
2019-08-29 14:37 ` David Teigland
2019-09-03  5:02   ` Heming Zhao
2019-09-03 15:17     ` David Teigland
2019-09-04  8:13       ` Heming Zhao
2019-09-05 12:35         ` Heming Zhao
2019-09-05 16:55           ` David Teigland
2019-09-06  4:31             ` Heming Zhao
2019-09-06  5:01               ` Heming Zhao
2019-09-06  6:51                 ` Martin Wilck
2019-09-06  8:46                   ` Heming Zhao
2019-09-06 14:15                     ` David Teigland
2019-09-06 14:26                     ` David Teigland
2019-09-06 14:03                   ` David Teigland
2019-09-09 11:42                     ` Heming Zhao
2019-09-09 14:09                       ` David Teigland [this message]
2019-09-10  8:01                         ` Martin Wilck
2019-09-10 15:20                           ` David Teigland
2019-09-10 20:38                             ` Zdenek Kabelac
2019-09-11  7:17                               ` Martin Wilck
2019-09-11  9:13                                 ` Zdenek Kabelac
2019-09-12 13:58                                   ` Martin Wilck

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