Re: [PATCH] pstore: change mutex locking to spin_locks

From: Don Zickus
Date: Fri Jul 22 2011 - 08:13:09 EST

On Fri, Jul 22, 2011 at 08:33:22AM +0800, Huang Ying wrote:
> On 07/22/2011 01:57 AM, Luck, Tony wrote:
> >>> Is it safe to call pstore_mkfile with IRQ disabled?
> >>>
> >>> pstore_mkfile -> d_alloc_name -> d_alloc -> kmem_cache_alloc(, GFP_KERNEL).
> >>
> >> Don't know. But would that mean we would have to put the pstore_mkfile
> >> on a workqueue then or something similar?
> >
> > That might be a good idea anyway. In the "oops" case we'd like the file
> > to appear in the pstore filesystem if the system stayed healthy despite
> > the oops[1]. There isn't any reason why the pstore entry must appear instantly.
> > Delaying the creation would avoid running into problems related to the
> > oops.
> For oops, it may be better to delay writing into something like
> workqueue. But for panic, I think we should write the record to backend
> (such as ERST) as soon as possible. So maybe it is better to write to
> backend as soon as possible and delay writing to pstore filesystem.

In the panic case do we care if the pstore fs is mounted (which leads us
to run pstore_mkfile)?

Actually it seems like most of the entry points into pstore_dumper would
not require the fs to create a new file. I think the exception is an

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