From: Michal Hocko <mhocko@suse.com>
To: Minchan Kim <minchan@kernel.org>
Cc: David Hildenbrand <david@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
joaodias@google.com
Subject: Re: [PATCH] mm: be more verbose for alloc_contig_range faliures
Date: Mon, 8 Mar 2021 13:49:11 +0100 [thread overview]
Message-ID: <YEYdR8azcawau9Rl@dhcp22.suse.cz> (raw)
In-Reply-To: <YEEle5xBAc7FUDNI@google.com>
On Thu 04-03-21 10:22:51, Minchan Kim wrote:
[...]
> How about this?
>
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 238d0fc232aa..489e557b9390 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -8481,7 +8481,8 @@ static inline void dump_migrate_failure_pages(struct list_head *page_list)
>
> /* [start, end) must belong to a single zone. */
> static int __alloc_contig_migrate_range(struct compact_control *cc,
> - unsigned long start, unsigned long end)
> + unsigned long start, unsigned long end,
> + bool nofail)
This sounds like a very bad idea to me. Your nofail definition might
differ from what we actually define as __GFP_NOFAIL but I do not think
this interface should ever promise anything that strong.
Sure movable, cma regions should effectively never fail but there will
never be any _guarantee_ for that.
Earlier in the discussion I have suggested dynamic debugging facility.
Documentation/admin-guide/dynamic-debug-howto.rst. Have you tried to
look into that direction?
> {
> /* This function is based on compact_zone() from compaction.c. */
> unsigned int nr_reclaimed;
> @@ -8522,7 +8523,8 @@ static int __alloc_contig_migrate_range(struct compact_control *cc,
> NULL, (unsigned long)&mtc, cc->mode, MR_CONTIG_RANGE);
> }
> if (ret < 0) {
> - dump_migrate_failure_pages(&cc->migratepages);
> + if (ret == -EBUSY && nofail)
> + dump_migrate_failure_pages(&cc->migratepages);
> putback_movable_pages(&cc->migratepages);
> return ret;
> }
> @@ -8610,7 +8612,9 @@ int alloc_contig_range(unsigned long start, unsigned long end,
> * allocated. So, if we fall through be sure to clear ret so that
> * -EBUSY is not accidentally used or returned to caller.
> */
> - ret = __alloc_contig_migrate_range(&cc, start, end);
> + ret = __alloc_contig_migrate_range(&cc, start, end,
> + migratetype == CMA ||
> + zone_idx(cc.zone) == ZONE_MOVABLE);
> if (ret && ret != -EBUSY)
> goto done;
> ret =0;
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2021-03-08 12:49 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-02-17 16:36 [PATCH] mm: be more verbose for alloc_contig_range faliures Minchan Kim
2021-02-17 16:51 ` David Hildenbrand
2021-02-17 17:26 ` Minchan Kim
2021-02-17 17:34 ` David Hildenbrand
2021-02-17 17:45 ` Minchan Kim
2021-02-18 8:56 ` Michal Hocko
2021-02-18 9:02 ` David Hildenbrand
2021-02-18 9:35 ` Michal Hocko
2021-02-18 9:43 ` David Hildenbrand
2021-02-18 9:59 ` Michal Hocko
2021-02-18 16:19 ` Minchan Kim
2021-02-18 16:26 ` David Hildenbrand
2021-02-18 16:47 ` Minchan Kim
2021-02-18 16:53 ` David Hildenbrand
2021-02-19 9:28 ` Michal Hocko
2021-02-19 9:30 ` David Hildenbrand
2021-02-19 10:02 ` Michal Hocko
2021-02-19 10:34 ` David Hildenbrand
2021-03-02 17:23 ` Minchan Kim
2021-03-04 16:01 ` Minchan Kim
2021-03-04 16:10 ` David Hildenbrand
2021-03-04 16:23 ` Minchan Kim
2021-03-04 16:28 ` David Hildenbrand
2021-03-04 17:11 ` Minchan Kim
2021-03-04 17:23 ` David Hildenbrand
2021-03-04 18:11 ` Minchan Kim
2021-03-04 18:22 ` Minchan Kim
2021-03-08 12:49 ` Michal Hocko [this message]
2021-03-08 13:22 ` David Hildenbrand
2021-03-08 14:11 ` Michal Hocko
2021-03-08 14:13 ` David Hildenbrand
2021-03-08 15:42 ` Michal Hocko
2021-03-08 15:58 ` Minchan Kim
2021-03-08 16:21 ` Michal Hocko
2021-03-08 17:01 ` Minchan Kim
2021-03-08 20:27 ` Minchan Kim
2021-02-18 16:10 ` Minchan Kim
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