From: Wanpeng Li <liwanp@linux.vnet.ibm.com>
To: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Mel Gorman <mgorman@suse.de>, Rik van Riel <riel@redhat.com>,
Rafael Aquini <aquini@redhat.com>,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Christoph Lameter <cl@linux.com>, Joonsoo Kim <js1304@gmail.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Vlastimil Babka <vbabka@suse.cz>,
Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Subject: Re: [PATCH v2 2/7] mm/migrate: correct failure handling if !hugepage_migration_support()
Date: Tue, 10 Dec 2013 17:27:28 +0800 [thread overview]
Message-ID: <52a6de95.2590420a.170c.1019SMTPIN_ADDED_BROKEN@mx.google.com> (raw)
In-Reply-To: <20131210084507.GC24992@lge.com>
On Tue, Dec 10, 2013 at 05:45:07PM +0900, Joonsoo Kim wrote:
>On Tue, Dec 10, 2013 at 10:17:56AM +0800, Wanpeng Li wrote:
>> Hi Joonsoo,
>> On Mon, Dec 09, 2013 at 06:10:43PM +0900, Joonsoo Kim wrote:
>> >We should remove the page from the list if we fail without ENOSYS,
>> >since migrate_pages() consider error cases except -ENOMEM and -EAGAIN
>> >as permanent failure and it assumes that the page would be removed from
>> >the list. Without this patch, we could overcount number of failure.
>> >
>> >In addition, we should put back the new hugepage if
>> >!hugepage_migration_support(). If not, we would leak hugepage memory.
>> >
>> >Signed-off-by: Joonsoo Kim <iamjoonsoo.kim@lge.com>
>> >
>> >diff --git a/mm/migrate.c b/mm/migrate.c
>> >index c6ac87a..b1cfd01 100644
>> >--- a/mm/migrate.c
>> >+++ b/mm/migrate.c
>> >@@ -1011,7 +1011,7 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
>> > {
>> > int rc = 0;
>> > int *result = NULL;
>> >- struct page *new_hpage = get_new_page(hpage, private, &result);
>> >+ struct page *new_hpage;
>> > struct anon_vma *anon_vma = NULL;
>> >
>> > /*
>> >@@ -1021,9 +1021,12 @@ static int unmap_and_move_huge_page(new_page_t get_new_page,
>> > * tables or check whether the hugepage is pmd-based or not before
>> > * kicking migration.
>> > */
>> >- if (!hugepage_migration_support(page_hstate(hpage)))
>> >+ if (!hugepage_migration_support(page_hstate(hpage))) {
>> >+ putback_active_hugepage(hpage);
>> > return -ENOSYS;
>>
>> The memory hotplug(do_migrate_range) and hwpoison(soft_offline_huge_page) callsets both
>> will call putback_movable_pages/putback_active_hugepage for -ENOSYS case.
>
>Hello Wanpeng.
>
>Yes, those callsite handle error case, but error case handling should be done
>in unmap_and_move_huge_page(). It is mentioned on patch 1. If we defer to
>remove the pages from the list, nr_failed can be overcounted.
>
I see.
Reviewed-by: Wanpeng Li <liwanp@linux.vnet.ibm.com>
>Thanks.
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next prev parent reply other threads:[~2013-12-10 9:27 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-09 9:10 [PATCH v2 0/7] correct and clean-up migration related stuff Joonsoo Kim
2013-12-09 9:10 ` [PATCH v2 1/7] mm/migrate: add comment about permanent failure path Joonsoo Kim
2013-12-10 1:42 ` Wanpeng Li
2013-12-09 9:10 ` [PATCH v2 2/7] mm/migrate: correct failure handling if !hugepage_migration_support() Joonsoo Kim
2013-12-09 16:17 ` Christoph Lameter
2013-12-10 8:38 ` Joonsoo Kim
2013-12-10 2:17 ` Wanpeng Li
2013-12-10 8:45 ` Joonsoo Kim
2013-12-10 9:27 ` Wanpeng Li [this message]
2013-12-09 9:10 ` [PATCH v2 3/7] mm/mempolicy: correct putback method for isolate pages if failed Joonsoo Kim
2013-12-09 16:41 ` Rafael Aquini
2013-12-10 2:22 ` Wanpeng Li
2013-12-09 9:10 ` [PATCH v2 4/7] mm/migrate: remove putback_lru_pages, fix comment on putback_movable_pages Joonsoo Kim
2013-12-10 2:33 ` Wanpeng Li
2013-12-10 8:51 ` Joonsoo Kim
2013-12-10 9:00 ` Joonsoo Kim
2013-12-09 9:10 ` [PATCH v2 5/7] mm/compaction: respect ignore_skip_hint in update_pageblock_skip Joonsoo Kim
2013-12-10 2:50 ` Wanpeng Li
2013-12-09 9:10 ` [PATCH v2 6/7] mm/migrate: remove unused function, fail_migrate_page() Joonsoo Kim
2013-12-09 16:20 ` Christoph Lameter
2013-12-09 17:07 ` Naoya Horiguchi
2013-12-10 2:36 ` Wanpeng Li
2013-12-09 9:10 ` [PATCH v2 7/7] mm/migrate: remove result argument on page allocation function for migration Joonsoo Kim
2013-12-09 16:40 ` Christoph Lameter
2013-12-10 3:22 ` Wanpeng Li
2013-12-11 8:47 ` Joonsoo Kim
2013-12-11 16:00 ` Christoph Lameter
2013-12-12 0:07 ` Joonsoo Kim
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