From: "Zi Yan" <zi.yan@cs.rutgers.edu>
To: David Rientjes <rientjes@google.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>,
Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Vlastimil Babka <vbabka@suse.cz>,
Andrea Argangeli <andrea@kernel.org>,
Stefan Priebe - Profihost AG <s.priebe@profihost.ag>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
Michal Hocko <mhocko@suse.com>
Subject: Re: [PATCH 2/2] mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask
Date: Thu, 04 Oct 2018 17:49:47 -0400 [thread overview]
Message-ID: <EA62D612-B537-435A-AF5B-96E49E878E0F@cs.rutgers.edu> (raw)
In-Reply-To: <alpine.DEB.2.21.1810041317010.16935@chino.kir.corp.google.com>
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On 4 Oct 2018, at 16:17, David Rientjes wrote:
> On Wed, 26 Sep 2018, Kirill A. Shutemov wrote:
>
>> On Tue, Sep 25, 2018 at 02:03:26PM +0200, Michal Hocko wrote:
>>> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
>>> index c3bc7e9c9a2a..c0bcede31930 100644
>>> --- a/mm/huge_memory.c
>>> +++ b/mm/huge_memory.c
>>> @@ -629,21 +629,40 @@ static vm_fault_t __do_huge_pmd_anonymous_page(struct vm_fault *vmf,
>>> * available
>>> * never: never stall for any thp allocation
>>> */
>>> -static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma)
>>> +static inline gfp_t alloc_hugepage_direct_gfpmask(struct vm_area_struct *vma, unsigned long addr)
>>> {
>>> const bool vma_madvised = !!(vma->vm_flags & VM_HUGEPAGE);
>>> + gfp_t this_node = 0;
>>> +
>>> +#ifdef CONFIG_NUMA
>>> + struct mempolicy *pol;
>>> + /*
>>> + * __GFP_THISNODE is used only when __GFP_DIRECT_RECLAIM is not
>>> + * specified, to express a general desire to stay on the current
>>> + * node for optimistic allocation attempts. If the defrag mode
>>> + * and/or madvise hint requires the direct reclaim then we prefer
>>> + * to fallback to other node rather than node reclaim because that
>>> + * can lead to excessive reclaim even though there is free memory
>>> + * on other nodes. We expect that NUMA preferences are specified
>>> + * by memory policies.
>>> + */
>>> + pol = get_vma_policy(vma, addr);
>>> + if (pol->mode != MPOL_BIND)
>>> + this_node = __GFP_THISNODE;
>>> + mpol_cond_put(pol);
>>> +#endif
>>
>> I'm not very good with NUMA policies. Could you explain in more details how
>> the code above is equivalent to the code below?
>>
>
> It breaks mbind() because new_page() is now using numa_node_id() to
> allocate migration targets for instead of using the mempolicy. I'm not
> sure that this patch was tested for mbind().
I do not see mbind() is broken. With both patches applied, I ran
"numactl -N 0 memhog -r1 4096m membind 1" and saw all pages are allocated
in Node 1 not Node 0, which is returned by numa_node_id().
From the source code, in alloc_pages_vma(), the nodemask is generated
from the memory policy (i.e. mbind in the case above), which only has
the nodes specified by mbind(). Then, __alloc_pages_nodemask() only uses
the zones from the nodemask. The numa_node_id() return value will be
ignored in the actual page allocation process if mbind policy is applied.
Let me know if I miss anything.
--
Best Regards
Yan Zi
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next prev parent reply other threads:[~2018-10-04 21:51 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 12:03 [PATCH 0/2] thp nodereclaim fixes Michal Hocko
2018-09-25 12:03 ` [PATCH 1/2] mm: thp: relax __GFP_THISNODE for MADV_HUGEPAGE mappings Michal Hocko
2018-09-25 12:20 ` Mel Gorman
2018-09-25 12:30 ` Michal Hocko
2018-10-04 20:16 ` David Rientjes
2018-10-04 21:10 ` Andrea Arcangeli
2018-10-04 23:05 ` David Rientjes
2018-10-06 3:19 ` Andrea Arcangeli
2018-10-05 7:38 ` Mel Gorman
2018-10-05 20:35 ` David Rientjes
2018-10-05 23:21 ` Andrea Arcangeli
2018-10-08 20:41 ` David Rientjes
2018-10-09 9:48 ` Mel Gorman
2018-10-09 12:27 ` Michal Hocko
2018-10-09 13:00 ` Mel Gorman
2018-10-09 14:25 ` Michal Hocko
2018-10-09 15:16 ` Mel Gorman
2018-10-09 23:03 ` Andrea Arcangeli
2018-10-10 21:19 ` David Rientjes
2018-10-15 22:30 ` David Rientjes
2018-10-15 22:44 ` Andrew Morton
2018-10-15 23:19 ` Andrea Arcangeli
2018-10-22 20:54 ` David Rientjes
2018-10-16 7:46 ` Mel Gorman
2018-10-16 22:37 ` Andrew Morton
2018-10-16 23:11 ` Andrea Arcangeli
2018-10-16 23:16 ` Andrew Morton
2018-10-17 7:08 ` Michal Hocko
2018-10-17 9:00 ` Mel Gorman
2018-10-22 21:04 ` David Rientjes
2018-10-23 1:27 ` Zi Yan
2018-10-28 21:45 ` David Rientjes
2018-10-23 7:57 ` Mel Gorman
2018-10-23 8:38 ` Mel Gorman
2018-10-15 22:57 ` Andrea Arcangeli
2018-10-22 20:45 ` David Rientjes
2018-10-09 22:17 ` David Rientjes
2018-10-09 22:51 ` Andrea Arcangeli
2018-10-10 7:54 ` Vlastimil Babka
2018-10-10 21:00 ` David Rientjes
2018-10-09 13:08 ` Vlastimil Babka
2018-10-09 22:21 ` Andrea Arcangeli
2018-10-29 5:17 ` Balbir Singh
2018-10-29 9:00 ` Michal Hocko
2018-10-29 9:42 ` Balbir Singh
2018-10-29 10:08 ` Michal Hocko
2018-10-29 10:56 ` Andrea Arcangeli
2018-09-25 12:03 ` [PATCH 2/2] mm, thp: consolidate THP gfp handling into alloc_hugepage_direct_gfpmask Michal Hocko
2018-09-26 13:30 ` Kirill A. Shutemov
2018-09-26 14:17 ` Michal Hocko
2018-09-26 14:22 ` Michal Hocko
2018-10-19 2:11 ` Andrew Morton
2018-10-19 8:06 ` Michal Hocko
2018-10-22 13:27 ` Vlastimil Babka
2018-10-24 23:17 ` Andrew Morton
2018-10-25 4:56 ` Vlastimil Babka
2018-10-25 16:14 ` Michal Hocko
2018-10-25 16:18 ` Andrew Morton
2018-10-25 16:45 ` Michal Hocko
2018-10-22 13:15 ` Vlastimil Babka
2018-10-22 13:30 ` Michal Hocko
2018-10-22 13:35 ` Vlastimil Babka
2018-10-22 13:46 ` Michal Hocko
2018-10-22 13:53 ` Vlastimil Babka
2018-10-04 20:17 ` David Rientjes
2018-10-04 21:49 ` Zi Yan [this message]
2018-10-09 12:36 ` Michal Hocko
2018-09-26 13:08 ` linux-mm@ archive on lore.kernel.org (Was: [PATCH 0/2] thp nodereclaim fixes) Kirill A. Shutemov
2018-09-26 13:14 ` Michal Hocko
2018-09-26 22:22 ` Andrew Morton
2018-09-26 23:08 ` Mel Gorman
2018-09-27 0:47 ` Konstantin Ryabitsev
2018-09-26 15:25 ` Konstantin Ryabitsev
2018-09-27 11:30 ` Kirill A. Shutemov
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