From: Dave Chinner <david@fromorbit.com>
To: Phillip Susi <phill@thesusis.net>
Cc: linux-fsdevel@vger.kernel.org
Subject: Re: Uneccesary flushes waking up suspended disks
Date: Mon, 11 Mar 2024 12:32:41 +1100 [thread overview]
Message-ID: <Ze5fOTojI+BhgXOW@dread.disaster.area> (raw)
In-Reply-To: <877cieqhaw.fsf@vps.thesusis.net>
On Thu, Mar 07, 2024 at 08:53:43AM -0500, Phillip Susi wrote:
> I have noticed that whenever you suspend to ram or shutdown the system,
> runtime pm suspended disks are woken up only to be spun right back down
> again. This is because the kernel syncs all filesystems, and they issue
> a cache flush. Since the disk is suspended however, there is nothing in
> the cache to flush, so this is wasteful.
>
> Should this be solved in the filesystems, or the block layer?
>
> I first started trying to fix this in ext4, but now I am thinking this
> is more of a generic issue that should be solved in the block layer. I
> am thinking that the block layer could keep a dirty flag that is set by
> any write request, and cleared by a flush, or when the disk is
> suspended. As long as the dirty flag is not set, any flush requests can
> just be discarded.
>
> Thoughts?
How do other filesystems behave? Is this a problem just on specific
filesystems?
-Dave.
--
Dave Chinner
david@fromorbit.com
next prev parent reply other threads:[~2024-03-11 1:32 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-07 13:53 Uneccesary flushes waking up suspended disks Phillip Susi
2024-03-07 15:37 ` Theodore Ts'o
2024-03-08 20:54 ` Phillip Susi
2024-03-09 17:37 ` Theodore Ts'o
2024-03-12 20:35 ` Phillip Susi
2024-03-11 1:32 ` Dave Chinner [this message]
2024-03-15 14:05 ` Phillip Susi
2024-03-16 4:38 ` Darrick J. Wong
2024-03-16 18:35 ` Phillip Susi
2024-03-17 22:45 ` Dave Chinner
2024-03-20 12:38 ` Phillip Susi
2024-03-20 21:58 ` Dave Chinner
2024-03-25 17:09 ` Phillip Susi
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