From: Michal Hocko <mhocko@kernel.org>
To: Joonsoo Kim <js1304@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Linux Memory Management List <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
kernel-team@lge.com, Vlastimil Babka <vbabka@suse.cz>,
Christoph Hellwig <hch@infradead.org>,
Roman Gushchin <guro@fb.com>,
Mike Kravetz <mike.kravetz@oracle.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>
Subject: Re: [PATCH v3 4/8] mm/hugetlb: make hugetlb migration callback CMA aware
Date: Tue, 30 Jun 2020 08:42:56 +0200 [thread overview]
Message-ID: <20200630064256.GB2369@dhcp22.suse.cz> (raw)
In-Reply-To: <CAAmzW4PFEEs0FGe+XMHzRdXr0LpdF3TZZG2L3E+opRyZWDZ48A@mail.gmail.com>
On Tue 30-06-20 15:30:04, Joonsoo Kim wrote:
> 2020년 6월 29일 (월) 오후 4:55, Michal Hocko <mhocko@kernel.org>님이 작성:
[...]
> > diff --git a/mm/hugetlb.c b/mm/hugetlb.c
> > index 57ece74e3aae..c1595b1d36f3 100644
> > --- a/mm/hugetlb.c
> > +++ b/mm/hugetlb.c
> > @@ -1092,10 +1092,14 @@ static struct page *dequeue_huge_page_nodemask(struct hstate *h, gfp_t gfp_mask,
> > /* Movability of hugepages depends on migration support. */
> > static inline gfp_t htlb_alloc_mask(struct hstate *h)
> > {
> > + gfp_t gfp;
> > +
> > if (hugepage_movable_supported(h))
> > - return GFP_HIGHUSER_MOVABLE;
> > + gfp = GFP_HIGHUSER_MOVABLE;
> > else
> > - return GFP_HIGHUSER;
> > + gfp = GFP_HIGHUSER;
> > +
> > + return current_gfp_context(gfp);
> > }
> >
> > static struct page *dequeue_huge_page_vma(struct hstate *h,
> >
> > If we even fix this general issue for other allocations and allow a
> > better CMA exclusion then it would be implemented consistently for
> > everybody.
>
> Yes, I have reviewed the memalloc_nocma_{} APIs and found the better way
> for CMA exclusion. I will do it after this patch is finished.
>
> > Does this make more sense to you are we still not on the same page wrt
> > to the actual problem?
>
> Yes, but we have different opinions about it. As said above, I will make
> a patch for better CMA exclusion after this patchset. It will make
> code consistent.
> I'd really appreciate it if you wait until then.
As I've said I would _prefer_ simplicity over "correctness" if it is only
partial and hard to reason about from the userspace experience but this
is not something I would _insist_ on. If Mike as a maintainer of the
code is ok with that then I will not stand in the way.
But please note that a missing current_gfp_context inside
htlb_alloc_mask is a subtle bug. I do not think it matters right now but
with a growing use of scoped apis this might actually hit some day so I
believe we want to have it in place.
Thanks!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-06-30 6:43 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-06-23 6:13 [PATCH v3 0/8] clean-up the migration target allocation functions js1304
2020-06-23 6:13 ` [PATCH v3 1/8] mm/page_isolation: prefer the node of the source page js1304
2020-06-23 6:13 ` [PATCH v3 2/8] mm/migrate: move migration helper from .h to .c js1304
2020-06-23 6:13 ` [PATCH v3 3/8] mm/hugetlb: unify migration callbacks js1304
2020-06-24 21:18 ` Mike Kravetz
2020-06-25 11:26 ` Michal Hocko
2020-06-26 4:02 ` Joonsoo Kim
2020-07-02 16:13 ` Vlastimil Babka
2020-07-03 0:55 ` Joonsoo Kim
2020-06-23 6:13 ` [PATCH v3 4/8] mm/hugetlb: make hugetlb migration callback CMA aware js1304
2020-06-25 11:54 ` Michal Hocko
2020-06-26 4:49 ` Joonsoo Kim
2020-06-26 7:23 ` Michal Hocko
2020-06-29 6:27 ` Joonsoo Kim
2020-06-29 7:55 ` Michal Hocko
2020-06-30 6:30 ` Joonsoo Kim
2020-06-30 6:42 ` Michal Hocko [this message]
2020-06-30 7:22 ` Joonsoo Kim
2020-06-30 16:37 ` Mike Kravetz
2020-06-23 6:13 ` [PATCH v3 5/8] mm/migrate: make a standard migration target allocation function js1304
2020-06-25 12:05 ` Michal Hocko
2020-06-26 5:02 ` Joonsoo Kim
2020-06-26 7:33 ` Michal Hocko
2020-06-29 6:41 ` Joonsoo Kim
2020-06-29 8:03 ` Michal Hocko
2020-06-30 7:19 ` Joonsoo Kim
2020-07-03 15:25 ` Vlastimil Babka
2020-06-23 6:13 ` [PATCH v3 6/8] mm/gup: use a standard migration target allocation callback js1304
2020-06-25 12:08 ` Michal Hocko
2020-06-26 5:03 ` Joonsoo Kim
2020-07-03 15:56 ` Vlastimil Babka
2020-07-06 8:34 ` Joonsoo Kim
2020-06-23 6:13 ` [PATCH v3 7/8] mm/mempolicy: " js1304
2020-06-25 12:09 ` Michal Hocko
2020-07-03 15:59 ` Vlastimil Babka
2020-07-08 1:20 ` Qian Cai
2020-07-08 6:45 ` Michal Hocko
2020-10-08 3:21 ` Hugh Dickins
2020-10-08 17:29 ` Mike Kravetz
2020-10-09 5:50 ` Hugh Dickins
2020-10-09 17:42 ` Mike Kravetz
2020-10-09 22:23 ` Hugh Dickins
2020-10-10 0:25 ` Mike Kravetz
2020-06-23 6:13 ` [PATCH v3 8/8] mm/page_alloc: remove a wrapper for alloc_migration_target() js1304
2020-06-25 12:10 ` Michal Hocko
2020-07-03 16:18 ` Vlastimil Babka
2020-07-06 8:44 ` Joonsoo Kim
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