From: Rafael Aquini <aquini@redhat.com>
To: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Konstantin Khlebnikov <k.khlebnikov@samsung.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
linux-mm@kvack.org, Andrey Ryabinin <ryabinin.a.a@gmail.com>,
Sasha Levin <sasha.levin@oracle.com>
Subject: Re: [PATCH v2 2/6] mm/balloon_compaction: keep ballooned pages away from normal migration path
Date: Tue, 2 Sep 2014 08:31:34 -0400 [thread overview]
Message-ID: <20140902123133.GC14419@t510.redhat.com> (raw)
In-Reply-To: <20140830164113.29066.25879.stgit@zurg>
On Sat, Aug 30, 2014 at 08:41:13PM +0400, Konstantin Khlebnikov wrote:
> From: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
>
> Proper testing shows yet another problem in balloon migration: it works only
> once for each page. balloon_page_movable() check page flags and page_count.
> In __unmap_and_move page is locked, reference counter is elevated, so
> balloon_page_movable() _always_ fails here. As result in __unmap_and_move()
> migration goes to the normal migration path.
>
> Balloon ->migratepage() is so special, it returns MIGRATEPAGE_BALLOON_SUCCESS
> instead of MIGRATEPAGE_SUCCESS. After that in move_to_new_page() successfully
> migrated page got NULL into its mapping pointer and loses connectivity with
> balloon and ability for further migration.
>
> It's safe to use __is_movable_balloon_page here: page is isolated and pinned.
>
> Signed-off-by: Konstantin Khlebnikov <k.khlebnikov@samsung.com>
> Cc: stable <stable@vger.kernel.org> # v3.8
> ---
> include/linux/balloon_compaction.h | 5 +++++
> mm/migrate.c | 2 +-
> 2 files changed, 6 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/balloon_compaction.h b/include/linux/balloon_compaction.h
> index 53d482e..284fc1d 100644
> --- a/include/linux/balloon_compaction.h
> +++ b/include/linux/balloon_compaction.h
> @@ -258,6 +258,11 @@ static inline void balloon_page_delete(struct page *page)
> list_del(&page->lru);
> }
>
> +static inline bool __is_movable_balloon_page(struct page *page)
> +{
> + return false;
> +}
> +
> static inline bool balloon_page_movable(struct page *page)
> {
> return false;
> diff --git a/mm/migrate.c b/mm/migrate.c
> index 905b1aa..57c94f9 100644
> --- a/mm/migrate.c
> +++ b/mm/migrate.c
> @@ -873,7 +873,7 @@ static int __unmap_and_move(struct page *page, struct page *newpage,
> }
> }
>
> - if (unlikely(balloon_page_movable(page))) {
> + if (unlikely(__is_movable_balloon_page(page))) {
> /*
> * A ballooned page does not need any special attention from
> * physical to virtual reverse mapping procedures.
>
Acked-by: Rafael Aquini <aquini@redhat.com>
next prev parent reply other threads:[~2014-09-02 12:31 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-08-30 16:41 [PATCH v2 0/6] mm/balloon_compaction: fixes and cleanups Konstantin Khlebnikov
2014-08-30 16:41 ` [PATCH v2 1/6] mm/balloon_compaction: ignore anonymous pages Konstantin Khlebnikov
2014-09-02 12:29 ` Rafael Aquini
2014-08-30 16:41 ` [PATCH v2 2/6] mm/balloon_compaction: keep ballooned pages away from normal migration path Konstantin Khlebnikov
2014-09-02 12:31 ` Rafael Aquini [this message]
2014-08-30 16:41 ` [PATCH v2 3/6] mm/balloon_compaction: isolate balloon pages without lru_lock Konstantin Khlebnikov
2014-09-02 12:32 ` Rafael Aquini
2014-08-30 16:41 ` [PATCH v2 4/6] mm: introduce common page state for ballooned memory Konstantin Khlebnikov
2014-09-02 12:53 ` Rafael Aquini
2014-09-12 23:51 ` Andrew Morton
2014-09-13 5:26 ` Konstantin Khlebnikov
2014-09-13 5:42 ` Andrew Morton
2014-09-13 8:22 ` Konstantin Khlebnikov
2014-09-19 21:35 ` Andrew Morton
2014-09-20 5:25 ` Konstantin Khlebnikov
2014-09-20 6:23 ` Andrew Morton
2014-09-22 18:40 ` Konstantin Khlebnikov
2014-09-22 19:22 ` Rafael Aquini
2014-09-22 20:06 ` Konstantin Khlebnikov
2014-09-22 20:22 ` Rafael Aquini
2014-09-22 20:46 ` Konstantin Khlebnikov
2014-09-13 14:03 ` Sasha Levin
2014-08-30 16:41 ` [PATCH v2 5/6] mm/balloon_compaction: use common page ballooning Konstantin Khlebnikov
2014-09-02 12:57 ` Rafael Aquini
2014-09-12 23:57 ` Andrew Morton
2014-08-30 16:41 ` [PATCH v2 6/6] mm/balloon_compaction: general cleanup Konstantin Khlebnikov
2014-09-02 13:09 ` Rafael Aquini
2014-09-13 0:04 ` Andrew Morton
2014-09-13 0:06 ` Andrew Morton
2014-09-13 5:43 ` Konstantin Khlebnikov
2014-09-13 0:09 ` [PATCH v2 0/6] mm/balloon_compaction: fixes and cleanups Andrew Morton
2014-09-13 5:01 ` Konstantin Khlebnikov
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