Re: [PATCH 1/3] xfs: fix per-cpu CIL structure aggregation racing with dying cpus

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

On Fri, Aug 25, 2023 at 09:53:04AM +1000, Dave Chinner wrote:
> On Thu, Aug 24, 2023 at 04:21:20PM -0700, Darrick J. Wong wrote:
> > @@ -554,6 +560,7 @@ xlog_cil_insert_items(
> >  	int			iovhdr_res = 0, split_res = 0, ctx_res = 0;
> >  	int			space_used;
> >  	int			order;
> > +	unsigned int		cpu_nr;
> >  	struct xlog_cil_pcp	*cilpcp;
> >  
> >  	ASSERT(tp);
> > @@ -577,7 +584,12 @@ xlog_cil_insert_items(
> >  	 * can't be scheduled away between split sample/update operations that
> >  	 * are done without outside locking to serialise them.
> >  	 */
> > -	cilpcp = get_cpu_ptr(cil->xc_pcp);
> > +	cpu_nr = get_cpu();
> > +	cilpcp = this_cpu_ptr(cil->xc_pcp);
> > +
> > +	/* Tell the future push that there was work added by this CPU. */
> > +	if (!cpumask_test_cpu(cpu_nr, &ctx->cil_pcpmask))
> > +		cpumask_test_and_set_cpu(cpu_nr, &ctx->cil_pcpmask);
> >  
> >  	/*
> >  	 * We need to take the CIL checkpoint unit reservation on the first
> 
> This code also needs the put_cpu_ptr(cil->xc_pcp) converted to
> put_cpu(), even though they end up doing exactly the same thing.
> 
> Other than that, it looks good. I'll pull this into my test trees
> and give it a run...

Ok, I'll look forward to seeing what happens. :)

--D

> Cheers,
> 
> Dave.
> -- 
> Dave Chinner
> david@fromorbit.com