From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: Hillf Danton <dhillf@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
Michal Hocko <mhocko@suse.cz>,
"Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
Hugh Dickins <hughd@google.com>,
Davidlohr Bueso <davidlohr.bueso@hp.com>,
David Gibson <david@gibson.dropbear.id.au>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Wanpeng Li <liwanp@linux.vnet.ibm.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Subject: Re: [PATCH 01/18] mm, hugetlb: protect reserved pages when softofflining requests the pages
Date: Thu, 1 Aug 2013 15:07:45 +0900 [thread overview]
Message-ID: <20130801060745.GA5885@lge.com> (raw)
In-Reply-To: <CAJd=RBCj_wAHjv10FhhX+Fzx8p4ybeGykEfvqF=jZaok3s+j9w@mail.gmail.com>
On Wed, Jul 31, 2013 at 11:25:04PM +0800, Hillf Danton wrote:
> On Wed, Jul 31, 2013 at 2:37 PM, Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> > On Wed, Jul 31, 2013 at 02:21:38PM +0800, Hillf Danton wrote:
> >> On Wed, Jul 31, 2013 at 12:41 PM, Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> >> > On Wed, Jul 31, 2013 at 10:49:24AM +0800, Hillf Danton wrote:
> >> >> On Wed, Jul 31, 2013 at 10:27 AM, Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> >> >> > On Mon, Jul 29, 2013 at 03:24:46PM +0800, Hillf Danton wrote:
> >> >> >> On Mon, Jul 29, 2013 at 1:31 PM, Joonsoo Kim <iamjoonsoo.kim@lge.com> wrote:
> >> >> >> > alloc_huge_page_node() use dequeue_huge_page_node() without
> >> >> >> > any validation check, so it can steal reserved page unconditionally.
> >> >> >>
> >> >> >> Well, why is it illegal to use reserved page here?
> >> >> >
> >> >> > If we use reserved page here, other processes which are promised to use
> >> >> > enough hugepages cannot get enough hugepages and can die. This is
> >> >> > unexpected result to them.
> >> >> >
> >> >> But, how do you determine that a huge page is requested by a process
> >> >> that is not allowed to use reserved pages?
> >> >
> >> > Reserved page is just one for each address or file offset. If we need to
> >> > move this page, this means that it already use it's own reserved page, this
> >> > page is it. So we should not use other reserved page for moving this page.
> >> >
> >> Hm, how do you determine "this page" is not buddy?
> >
> > If this page comes from the buddy, it doesn't matter. It imply that
> > this mapping cannot use reserved page pool, because we always allocate
> > a page from reserved page pool first.
> >
> A buddy page also implies, if the mapping can use reserved pages, that no
> reserved page was available when requested. Now we can try reserved
> page again.
If the mapping can use reserved pages, reserved page is always allocated
earlier than the buddy. So the fact that there is the page implies that
reserved page is already allocated. Hm, do I miss something?
Thanks.
>
> --
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next prev parent reply other threads:[~2013-08-01 6:07 UTC|newest]
Thread overview: 67+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-07-29 5:31 [PATCH 00/18] mm, hugetlb: remove a hugetlb_instantiation_mutex Joonsoo Kim
2013-07-29 5:31 ` [PATCH 01/18] mm, hugetlb: protect reserved pages when softofflining requests the pages Joonsoo Kim
2013-07-29 7:24 ` Hillf Danton
2013-07-31 2:27 ` Joonsoo Kim
2013-07-31 2:49 ` Hillf Danton
2013-07-31 4:41 ` Joonsoo Kim
2013-07-31 6:21 ` Hillf Danton
2013-07-31 6:37 ` Joonsoo Kim
2013-07-31 15:25 ` Hillf Danton
2013-08-01 6:07 ` Joonsoo Kim [this message]
2013-08-01 16:17 ` Aneesh Kumar K.V
2013-08-04 5:10 ` Hillf Danton
2013-08-05 5:17 ` Aneesh Kumar K.V
2013-07-30 16:49 ` Aneesh Kumar K.V
2013-07-29 5:31 ` [PATCH 02/18] mm, hugetlb: change variable name reservations to resv Joonsoo Kim
2013-07-30 16:50 ` Aneesh Kumar K.V
2013-07-29 5:31 ` [PATCH 03/18] mm, hugetlb: unify region structure handling Joonsoo Kim
2013-07-30 17:27 ` Aneesh Kumar K.V
2013-07-31 2:36 ` Joonsoo Kim
2013-07-29 5:31 ` [PATCH 04/18] mm, hugetlb: region manipulation functions take resv_map rather list_head Joonsoo Kim
2013-07-29 5:31 ` [PATCH 05/18] mm, hugetlb: protect region tracking via newly introduced resv_map lock Joonsoo Kim
2013-07-29 8:58 ` Hillf Danton
2013-07-31 2:41 ` Joonsoo Kim
2013-07-29 18:53 ` Davidlohr Bueso
2013-07-31 2:43 ` Joonsoo Kim
2013-07-29 5:31 ` [PATCH 06/18] mm, hugetlb: remove vma_need_reservation() Joonsoo Kim
2013-07-29 17:52 ` Naoya Horiguchi
2013-07-31 4:53 ` Joonsoo Kim
2013-07-30 17:49 ` Aneesh Kumar K.V
2013-07-31 4:56 ` Joonsoo Kim
2013-07-29 5:31 ` [PATCH 07/18] mm, hugetlb: pass has_reserve to dequeue_huge_page_vma() Joonsoo Kim
2013-07-29 5:31 ` [PATCH 08/18] mm, hugetlb: do hugepage_subpool_get_pages() when avoid_reserve Joonsoo Kim
2013-07-29 18:05 ` Naoya Horiguchi
2013-07-31 5:02 ` Joonsoo Kim
2013-07-31 20:55 ` Naoya Horiguchi
2013-07-29 5:32 ` [PATCH 09/18] mm, hugetlb: unify has_reserve and avoid_reserve to use_reserve Joonsoo Kim
2013-07-29 5:32 ` [PATCH 10/18] mm, hugetlb: call vma_has_reserve() before entering alloc_huge_page() Joonsoo Kim
2013-07-29 18:27 ` Naoya Horiguchi
2013-07-31 5:06 ` Joonsoo Kim
2013-07-29 5:32 ` [PATCH 11/18] mm, hugetlb: move down outside_reserve check Joonsoo Kim
2013-07-29 18:39 ` Naoya Horiguchi
2013-07-31 5:08 ` Joonsoo Kim
2013-07-31 20:46 ` Naoya Horiguchi
2013-07-29 5:32 ` [PATCH 12/18] mm, hugetlb: remove a check for return value of alloc_huge_page() Joonsoo Kim
2013-07-29 5:32 ` [PATCH 13/18] mm, hugetlb: grab a page_table_lock after page_cache_release Joonsoo Kim
2013-07-29 18:50 ` Naoya Horiguchi
2013-07-29 5:32 ` [PATCH 14/18] mm, hugetlb: clean-up error handling in hugetlb_cow() Joonsoo Kim
2013-07-29 5:32 ` [PATCH 15/18] mm, hugetlb: move up anon_vma_prepare() Joonsoo Kim
2013-07-29 19:05 ` Naoya Horiguchi
2013-07-29 19:19 ` Naoya Horiguchi
2013-07-31 5:12 ` Joonsoo Kim
2013-07-31 16:43 ` Naoya Horiguchi
2013-07-29 5:32 ` [PATCH 16/18] mm, hugetlb: return a reserved page to a reserved pool if failed Joonsoo Kim
2013-07-29 20:19 ` Naoya Horiguchi
2013-07-31 5:21 ` Joonsoo Kim
2013-07-29 5:32 ` [PATCH 17/18] mm, hugetlb: retry if we fail to allocate a hugepage with use_reserve Joonsoo Kim
2013-07-29 7:28 ` David Gibson
2013-07-31 5:37 ` Joonsoo Kim
2013-08-03 10:43 ` David Gibson
2013-08-05 7:36 ` Joonsoo Kim
2013-08-07 0:18 ` Davidlohr Bueso
2013-08-07 1:03 ` David Gibson
2013-08-07 1:38 ` Davidlohr Bueso
2013-08-07 9:18 ` Joonsoo Kim
2013-08-09 0:02 ` David Gibson
2013-08-09 9:37 ` Joonsoo Kim
2013-07-29 5:32 ` [PATCH 18/18] mm, hugetlb: remove a hugetlb_instantiation_mutex Joonsoo Kim
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