On Wed, Jun 10, 2015 at 09:47:04AM +0200, Ingo Molnar wrote: > > * Mel Gorman <[email protected]> wrote: > > > --- a/include/linux/sched.h > > +++ b/include/linux/sched.h > > @@ -1289,6 +1289,18 @@ enum perf_event_task_context { > > perf_nr_task_contexts, > > }; > > > > +/* Track pages that require TLB flushes */ > > +struct tlbflush_unmap_batch { > > + /* > > + * Each bit set is a CPU that potentially has a TLB entry for one of > > + * the PFNs being flushed. See set_tlb_ubc_flush_pending(). > > + */ > > + struct cpumask cpumask; > > + > > + /* True if any bit in cpumask is set */ > > + bool flush_required; > > +}; > > + > > struct task_struct { > > volatile long state; /* -1 unrunnable, 0 runnable, >0 stopped */ > > void *stack; > > @@ -1648,6 +1660,10 @@ struct task_struct { > > unsigned long numa_pages_migrated; > > #endif /* CONFIG_NUMA_BALANCING */ > > > > +#ifdef CONFIG_ARCH_WANT_BATCHED_UNMAP_TLB_FLUSH > > + struct tlbflush_unmap_batch *tlb_ubc; > > +#endif > > Please embedd this constant size structure in task_struct directly so that > the > whole per task allocation overhead goes away: >
That puts a structure (72 bytes in the config I used) within the task struct even when it's not required. On a lightly loaded system direct reclaim will not be active and for some processes, it'll never be active. It's very wasteful. -- Mel Gorman SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
