Re: [RFC PATCH v2] xfs: run blockgc on freeze to avoid iget stalls after reclaim

["Darrick J. Wong" <djwong@kernel.org>]

On Fri, Feb 02, 2024 at 02:41:56PM -0500, Brian Foster wrote:
> On Thu, Feb 01, 2024 at 12:16:03PM +1100, Dave Chinner wrote:
> > On Mon, Jan 29, 2024 at 10:02:16AM -0500, Brian Foster wrote:
> > > On Fri, Jan 26, 2024 at 10:46:12AM +1100, Dave Chinner wrote:
> > > > On Thu, Jan 25, 2024 at 07:46:55AM -0500, Brian Foster wrote:
> > > > > On Mon, Jan 22, 2024 at 02:23:44PM +1100, Dave Chinner wrote:
> > > > > > On Fri, Jan 19, 2024 at 02:36:45PM -0500, Brian Foster wrote:
> ...
> > Here's the fixes for the iget vs inactive vs freeze problems in the
> > upstream kernel:
> > 
> > https://lore.kernel.org/linux-xfs/20240201005217.1011010-1-david@fromorbit.com/T/#t
> > 
> > With that sorted, are there any other issues we know about that
> > running a blockgc scan during freeze might work around?
> > 
> 
> The primary motivation for the scan patch was the downstream/stable
> deadlock issue. The reason I posted it upstream is because when I
> considered the overall behavior change, I thought it uniformly
> beneficial to both contexts based on the (minor) benefits of the side
> effects of the scan. You don't need me to enumerate them, and none of
> them are uniquely important or worth overanalyzing.
> 
> The only real question that matters here is do you agree with the
> general reasoning for a blockgc scan during freeze, or shall I drop the
> patch?

I don't see any particular downside to flushing {block,inode}gc work
during a freeze, other than the loss of speculative preallocations
sounds painful.

Does Dave's patchset to recycle NEEDS_INACTIVE inodes eliminate the
stall problem?

--D

> Brian
> 
> > -Dave.
> > -- 
> > Dave Chinner
> > david@fromorbit.com
> > 
> 
>