Messages in this thread | | | Date | Wed, 30 May 2012 02:14:38 +0200 | From | Andrea Arcangeli <> | Subject | Re: [PATCH 14/35] autonuma: knuma_migrated per NUMA node queues |
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Hi,
On Tue, May 29, 2012 at 03:51:08PM +0200, Peter Zijlstra wrote: > On Fri, 2012-05-25 at 19:02 +0200, Andrea Arcangeli wrote: > > > > diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h > > index 41aa49b..8e578e6 100644 > > --- a/include/linux/mmzone.h > > +++ b/include/linux/mmzone.h > > @@ -666,6 +666,12 @@ typedef struct pglist_data { > > struct task_struct *kswapd; > > int kswapd_max_order; > > enum zone_type classzone_idx; > > +#ifdef CONFIG_AUTONUMA > > + spinlock_t autonuma_lock; > > + struct list_head autonuma_migrate_head[MAX_NUMNODES]; > > + unsigned long autonuma_nr_migrate_pages; > > + wait_queue_head_t autonuma_knuma_migrated_wait; > > +#endif > > } pg_data_t; > > > > #define node_present_pages(nid) (NODE_DATA(nid)->node_present_pages) > > O(nr_nodes^2) data.. ISTR people rewriting a certain slab allocator to > get rid of that :-) > > Also, don't forget that MAX_NUMNODES is an unconditional 512 on distro > kernels, even when we only have 2. > > Now the total wasted space isn't too bad since its only 16 bytes, > totaling a whole 2M for a 256 node system. But still, something like > that wants at least a mention somewhere.
I fully agree, I prefer to fix it and I was fully aware about this. It's not a big deal so it got low priority to be fixed, but I intended to optimize this.
As long as num_possible_nodes() is initialized before the pgdat is allocated it shouldn't be difficult to optimize this moving struct list_head autonuma_migrate_head[0] at the end of the structure.
mm_autonuma and sched_autonuma initially also had MAX_NUMNODES arrays in them, then I converted to dynamic allocations to be optimal. We same needs to happen here.
Thanks, Andrea
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