From: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
To: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, Mel Gorman <mgorman@suse.de>,
Michael Ellerman <mpe@ellerman.id.au>,
Sachin Sant <sachinp@linux.vnet.ibm.com>,
Michal Hocko <mhocko@kernel.org>,
Christopher Lameter <cl@linux.com>,
linuxppc-dev@lists.ozlabs.org,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Kirill Tkhai <ktkhai@virtuozzo.com>,
Bharata B Rao <bharata@linux.ibm.com>
Subject: Re: [PATCH 2/4] mm/slub: Use mem_node to allocate a new slab
Date: Tue, 17 Mar 2020 20:21:05 +0530 [thread overview]
Message-ID: <20200317145105.GA27520@linux.vnet.ibm.com> (raw)
In-Reply-To: <3d9629d4-4a6d-d2b5-28b7-58af497671c7@suse.cz>
* Vlastimil Babka <vbabka@suse.cz> [2020-03-17 14:53:26]:
> >> >
> >> > Mitigate this by allocating the new slab from the node_numa_mem.
> >>
> >> Are you sure this is really needed and the other 3 patches are not enough for
> >> the current SLUB code to work as needed? It seems you are changing the semantics
> >> here...
> >>
> >
> > The other 3 patches are not enough because we don't carry the searchnode
> > when the actual alloc_pages_node gets called.
> >
> > With only the 3 patches, we see the above Panic, its signature is slightly
> > different from what Sachin first reported and which I have carried in 1st
> > patch.
>
> Ah, I see. So that's the missing pgdat after your series [1] right?
Yes the pgdat would be missing after my cpuless, memoryless node patchset.
However..
>
> That sounds like an argument for Michal's suggestions that pgdats exist and have
> correctly populated zonelists for all possible nodes.
Only the first patch in this series would be affected by pgdat existing or
not. Even if the pgdat existed, the NODE_DATA[nid]->node_present_pages
would be 0. Right? So it would look at node_to_mem_node(). And since node 0 is
cpuless it would return 0. If we pass this node 0 (which is memoryless/cpuless) to
alloc_pages_node. Please note I am only setting node_numa_mem only
for offline nodes. However we could change this to set for all offline and
memoryless nodes.
> node_to_mem_node() could be just a shortcut for the first zone's node in the
> zonelist, so that fallback follows the topology.
>
> [1]
> https://lore.kernel.org/linuxppc-dev/20200311110237.5731-1-srikar@linux.vnet.ibm.com/t/#m76e5b4c4084380b1d4b193d5aa0359b987f2290e
>
--
Thanks and Regards
Srikar Dronamraju
next prev parent reply other threads:[~2020-03-17 14:51 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3381CD91-AB3D-4773-BA04-E7A072A63968@linux.vnet.ibm.com>
2020-03-17 13:17 ` [PATCH 0/4] Fix kmalloc_node on offline nodes Srikar Dronamraju
2020-03-17 13:17 ` [PATCH 1/4] mm: Check for node_online in node_present_pages Srikar Dronamraju
2020-03-17 13:37 ` Srikar Dronamraju
2020-03-17 13:17 ` [PATCH 2/4] mm/slub: Use mem_node to allocate a new slab Srikar Dronamraju
2020-03-17 13:34 ` Vlastimil Babka
2020-03-17 13:45 ` Srikar Dronamraju
2020-03-17 13:53 ` Vlastimil Babka
2020-03-17 14:51 ` Srikar Dronamraju [this message]
2020-03-17 15:29 ` Vlastimil Babka
2020-03-18 7:29 ` Srikar Dronamraju
2020-03-17 16:41 ` Srikar Dronamraju
2020-03-17 13:17 ` [PATCH 3/4] mm: Implement reset_numa_mem Srikar Dronamraju
2020-03-17 13:17 ` [PATCH 4/4] powerpc/numa: Set fallback nodes for offline nodes Srikar Dronamraju
2020-03-17 14:22 ` Bharata B Rao
2020-03-17 14:29 ` Srikar Dronamraju
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