From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wanpeng Li Subject: Re: [PATCH] slub: Don't throw away partial remote slabs if there is no local memory Date: Tue, 7 Jan 2014 17:21:45 +0800 Message-ID: <44697.90796652$1389086557@news.gmane.org> References: <20140107132100.5b5ad198@kryten> <20140107074136.GA4011@lge.com> <52cbbf7b.2792420a.571c.ffffd476SMTPIN_ADDED_BROKEN@mx.google.com> <20140107091016.GA21965@lge.com> Reply-To: Wanpeng Li Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20140107091016.GA21965@lge.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linuxppc-dev-bounces+glppd-linuxppc64-dev=m.gmane.org@lists.ozlabs.org Sender: "Linuxppc-dev" To: Joonsoo Kim Cc: cl@linux-foundation.org, nacc@linux.vnet.ibm.com, penberg@kernel.org, linux-mm@kvack.org, paulus@samba.org, Anton Blanchard , mpm@selenic.com, linuxppc-dev@lists.ozlabs.org List-Id: linux-mm.kvack.org On Tue, Jan 07, 2014 at 06:10:16PM +0900, Joonsoo Kim wrote: >On Tue, Jan 07, 2014 at 04:48:40PM +0800, Wanpeng Li wrote: >> Hi Joonsoo, >> On Tue, Jan 07, 2014 at 04:41:36PM +0900, Joonsoo Kim wrote: >> >On Tue, Jan 07, 2014 at 01:21:00PM +1100, Anton Blanchard wrote: >> >> >> [...] >> >Hello, >> > >> >I think that we need more efforts to solve unbalanced node problem. >> > >> >With this patch, even if node of current cpu slab is not favorable to >> >unbalanced node, allocation would proceed and we would get the unintended memory. >> > >> >> We have a machine: >> >> [ 0.000000] Node 0 Memory: >> [ 0.000000] Node 4 Memory: 0x0-0x10000000 0x20000000-0x60000000 0x80000000-0xc0000000 >> [ 0.000000] Node 6 Memory: 0x10000000-0x20000000 0x60000000-0x80000000 >> [ 0.000000] Node 10 Memory: 0xc0000000-0x180000000 >> >> [ 0.041486] Node 0 CPUs: 0-19 >> [ 0.041490] Node 4 CPUs: >> [ 0.041492] Node 6 CPUs: >> [ 0.041495] Node 10 CPUs: >> >> The pages of current cpu slab should be allocated from fallback zones/nodes >> of the memoryless node in buddy system, how can not favorable happen? > >Hi, Wanpeng. > >IIRC, if we call kmem_cache_alloc_node() with certain node #, we try to >allocate the page in fallback zones/node of that node #. So fallback list isn't >related to fallback one of memoryless node #. Am I wrong? > Anton add node_spanned_pages(node) check, so current cpu slab mentioned above is against memoryless node. If I miss something? Regards, Wanpeng Li >Thanks. > >> >> >And there is one more problem. Even if we have some partial slabs on >> >compatible node, we would allocate new slab, because get_partial() cannot handle >> >this unbalance node case. >> > >> >To fix this correctly, how about following patch? >> > >> >> So I think we should fold both of your two patches to one. >> >> Regards, >> Wanpeng Li >> >> >Thanks. >> > >> >------------->8-------------------- >> >diff --git a/mm/slub.c b/mm/slub.c >> >index c3eb3d3..a1f6dfa 100644 >> >--- a/mm/slub.c >> >+++ b/mm/slub.c >> >@@ -1672,7 +1672,19 @@ static void *get_partial(struct kmem_cache *s, gfp_t flags, int node, >> > { >> > void *object; >> > int searchnode = (node == NUMA_NO_NODE) ? numa_node_id() : node; >> >+ struct zonelist *zonelist; >> >+ struct zoneref *z; >> >+ struct zone *zone; >> >+ enum zone_type high_zoneidx = gfp_zone(flags); >> > >> >+ if (!node_present_pages(searchnode)) { >> >+ zonelist = node_zonelist(searchnode, flags); >> >+ for_each_zone_zonelist(zone, z, zonelist, high_zoneidx) { >> >+ searchnode = zone_to_nid(zone); >> >+ if (node_present_pages(searchnode)) >> >+ break; >> >+ } >> >+ } >> > object = get_partial_node(s, get_node(s, searchnode), c, flags); >> > if (object || node != NUMA_NO_NODE) >> > return object; >> > >> >-- >> >To unsubscribe, send a message with 'unsubscribe linux-mm' in >> >the body to majordomo@kvack.org. For more info on Linux MM, >> >see: http://www.linux-mm.org/ . >> >Don't email: email@kvack.org >> >> -- >> To unsubscribe, send a message with 'unsubscribe linux-mm' in >> the body to majordomo@kvack.org. For more info on Linux MM, >> see: http://www.linux-mm.org/ . >> Don't email: email@kvack.org