linux-kernel - Re: [RFC 5/5] pm: remove kernel thread freezing

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Message-ID: <1507079033.3075.3.camel@wdc.com>
Date:   Wed, 4 Oct 2017 01:03:54 +0000
From:   Bart Van Assche <Bart.VanAssche@....com>
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        "mcgrof@...nel.org" <mcgrof@...nel.org>
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Subject: Re: [RFC 5/5] pm: remove kernel thread freezing

On Wed, 2017-10-04 at 02:47 +0200, Luis R. Rodriguez wrote:
>   3) Lookup for kthreads which seem to generate IO -- address / review if
>      removal of the freezer API can be done somehow with a quescing. This
>      is currently for example being done on SCSI / md.
>  4) Only after all the above is done should we consider this patch or some
>     form of it.

After having given this more thought, I think we should omit these last two
steps. Modifying the md driver such that it does not submit I/O requests while
processes are frozen requires either to use the freezer API or to open-code it.
I think there is general agreement in the kernel community that open-coding a
single mechanism in multiple drivers is wrong. Does this mean that instead of
removing the freezer API we should keep it and review all its users instead?

Bart.