From: Dave Hansen <dave.hansen@intel.com>
To: Anshuman Khandual <khandual@linux.vnet.ibm.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: mhocko@suse.com, vbabka@suse.cz, mgorman@suse.de,
minchan@kernel.org, aneesh.kumar@linux.vnet.ibm.com,
bsingharora@gmail.com, srikar@linux.vnet.ibm.com,
haren@linux.vnet.ibm.com, jglisse@redhat.com,
dan.j.williams@intel.com
Subject: Re: [RFC V2 12/12] mm: Tag VMA with VM_CDM flag explicitly during mbind(MPOL_BIND)
Date: Tue, 7 Feb 2017 10:07:28 -0800 [thread overview]
Message-ID: <bfb7f080-6f0a-743f-654b-54f41443e44a@intel.com> (raw)
In-Reply-To: <e03e62e2-54fa-b0ce-0b58-5db7393f8e3c@linux.vnet.ibm.com>
On 01/30/2017 08:36 PM, Anshuman Khandual wrote:
> On 01/30/2017 11:24 PM, Dave Hansen wrote:
>> On 01/29/2017 07:35 PM, Anshuman Khandual wrote:
>>> + if ((new_pol->mode == MPOL_BIND)
>>> + && nodemask_has_cdm(new_pol->v.nodes))
>>> + set_vm_cdm(vma);
>> So, if you did:
>>
>> mbind(addr, PAGE_SIZE, MPOL_BIND, all_nodes, ...);
>> mbind(addr, PAGE_SIZE, MPOL_BIND, one_non_cdm_node, ...);
>>
>> You end up with a VMA that can never have KSM done on it, etc... Even
>> though there's no good reason for it. I guess /proc/$pid/smaps might be
>> able to help us figure out what was going on here, but that still seems
>> like an awful lot of damage.
>
> Agreed, this VMA should not remain tagged after the second call. It does
> not make sense. For this kind of scenarios we can re-evaluate the VMA
> tag every time the nodemask change is attempted. But if we are looking for
> some runtime re-evaluation then we need to steal some cycles are during
> general VMA processing opportunity points like merging and split to do
> the necessary re-evaluation. Should do we do these kind two kinds of
> re-evaluation to be more optimal ?
I'm still unconvinced that you *need* detection like this. Scanning big
VMAs is going to be really painful.
I thought I asked before but I can't find it in this thread. But, we
have explicit interfaces for disabling KSM and khugepaged. Why do we
need implicit ones like this in addition to those?
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next prev parent reply other threads:[~2017-02-07 18:07 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-30 3:35 [RFC V2 00/12] Define coherent device memory node Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 01/12] mm: Define coherent device memory (CDM) node Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 02/12] mm: Isolate HugeTLB allocations away from CDM nodes Anshuman Khandual
2017-01-30 17:19 ` Dave Hansen
2017-01-31 1:03 ` Anshuman Khandual
2017-01-31 1:37 ` Dave Hansen
2017-02-01 13:59 ` Anshuman Khandual
2017-02-01 19:01 ` Dave Hansen
2017-01-30 3:35 ` [RFC V2 03/12] mm: Change generic FALLBACK zonelist creation process Anshuman Khandual
2017-01-30 17:34 ` Dave Hansen
2017-01-31 1:36 ` Anshuman Khandual
2017-01-31 1:57 ` Dave Hansen
2017-01-31 7:25 ` John Hubbard
2017-01-31 18:04 ` Dave Hansen
2017-01-31 19:14 ` David Nellans
2017-02-01 6:56 ` Anshuman Khandual
2017-02-01 6:46 ` Anshuman Khandual
2017-02-01 6:40 ` Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 04/12] mm: Change mbind(MPOL_BIND) implementation for CDM nodes Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 05/12] cpuset: Add cpuset_inc() inside cpuset_init() Anshuman Khandual
2017-01-30 17:36 ` Dave Hansen
2017-01-30 20:30 ` Mel Gorman
2017-01-31 14:22 ` [RFC] cpuset: Enable changing of top_cpuset's mems_allowed nodemask Anshuman Khandual
2017-01-31 16:00 ` Mel Gorman
2017-02-01 7:31 ` Anshuman Khandual
2017-02-01 8:53 ` Michal Hocko
2017-02-01 9:18 ` Mel Gorman
2017-01-31 14:36 ` [RFC V2 05/12] cpuset: Add cpuset_inc() inside cpuset_init() Vlastimil Babka
2017-01-31 15:30 ` Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 06/12] mm: Exclude CDM nodes from task->mems_allowed and root cpuset Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 07/12] mm: Ignore cpuset enforcement when allocation flag has __GFP_THISNODE Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 08/12] mm: Add new VMA flag VM_CDM Anshuman Khandual
2017-01-30 18:52 ` Jerome Glisse
2017-01-31 4:22 ` Anshuman Khandual
2017-01-31 6:05 ` Jerome Glisse
2017-01-30 3:35 ` [RFC V2 09/12] mm: Exclude CDM marked VMAs from auto NUMA Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 10/12] mm: Ignore madvise(MADV_MERGEABLE) request for VM_CDM marked VMAs Anshuman Khandual
2017-01-30 3:35 ` [RFC V2 11/12] mm: Tag VMA with VM_CDM flag during page fault Anshuman Khandual
2017-01-30 17:51 ` Dave Hansen
2017-01-31 5:10 ` Anshuman Khandual
2017-01-31 17:54 ` Dave Hansen
2017-01-30 3:35 ` [RFC V2 12/12] mm: Tag VMA with VM_CDM flag explicitly during mbind(MPOL_BIND) Anshuman Khandual
2017-01-30 17:54 ` Dave Hansen
2017-01-31 4:36 ` Anshuman Khandual
2017-02-07 18:07 ` Dave Hansen [this message]
2017-02-08 14:13 ` Anshuman Khandual
2017-02-08 15:04 ` Jerome Glisse
2017-01-30 3:35 ` [DEBUG 13/21] powerpc/mm: Identify coherent device memory nodes during platform init Anshuman Khandual
2017-01-30 3:35 ` [DEBUG 14/21] powerpc/mm: Create numa nodes for hotplug memory Anshuman Khandual
2017-01-30 3:35 ` [DEBUG 15/21] powerpc/mm: Enable CONFIG_MOVABLE_NODE for PPC64 platform Anshuman Khandual
2017-01-30 3:35 ` [DEBUG 16/21] mm: Enable CONFIG_MOVABLE_NODE on powerpc Anshuman Khandual
2017-01-30 3:35 ` [DEBUG 17/21] mm: Export definition of 'zone_names' array through mmzone.h Anshuman Khandual
2017-01-30 3:35 ` [DEBUG 18/21] mm: Add debugfs interface to dump each node's zonelist information Anshuman Khandual
2017-01-30 3:36 ` [DEBUG 19/21] mm: Add migrate_virtual_range migration interface Anshuman Khandual
2017-01-30 3:36 ` [DEBUG 20/21] drivers: Add two drivers for coherent device memory tests Anshuman Khandual
2017-01-30 3:36 ` [DEBUG 21/21] selftests/powerpc: Add a script to perform random VMA migrations Anshuman Khandual
2017-01-31 5:48 ` [RFC V2 00/12] Define coherent device memory node Anshuman Khandual
2017-01-31 6:15 ` Jerome Glisse
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