From: Michal Hocko <mhocko@kernel.org>
To: Shaohua Li <shli@fb.com>
Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Kernel-team@fb.com, minchan@kernel.org, hughd@google.com,
hannes@cmpxchg.org, riel@redhat.com, mgorman@techsingularity.net,
akpm@linux-foundation.org
Subject: Re: [PATCH V5 2/6] mm: don't assume anonymous pages have SwapBacked flag
Date: Mon, 27 Feb 2017 15:35:34 +0100 [thread overview]
Message-ID: <20170227143534.GE26504@dhcp22.suse.cz> (raw)
In-Reply-To: <3945232c0df3dd6c4ef001976f35a95f18dcb407.1487965799.git.shli@fb.com>
On Fri 24-02-17 13:31:45, Shaohua Li wrote:
> There are a few places the code assumes anonymous pages should have
> SwapBacked flag set. MADV_FREE pages are anonymous pages but we are
> going to add them to LRU_INACTIVE_FILE list and clear SwapBacked flag
> for them. The assumption doesn't hold any more, so fix them.
>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Hugh Dickins <hughd@google.com>
> Cc: Rik van Riel <riel@redhat.com>
> Cc: Mel Gorman <mgorman@techsingularity.net>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Acked-by: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Shaohua Li <shli@fb.com>
Looks good to me.
[...]
> index 96eb85c..c621088 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -1416,7 +1416,8 @@ static int try_to_unmap_one(struct page *page, struct vm_area_struct *vma,
> * Store the swap location in the pte.
> * See handle_pte_fault() ...
> */
> - VM_BUG_ON_PAGE(!PageSwapCache(page), page);
> + VM_BUG_ON_PAGE(!PageSwapCache(page) && PageSwapBacked(page),
> + page);
just this part makes me scratch my head. I really do not understand what
kind of problem it tries to prevent from, maybe I am missing something
obvoious...
>
> if (!PageDirty(page)) {
> /* It's a freeable page by MADV_FREE */
> --
> 2.9.3
>
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-02-27 14:35 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-24 21:31 [PATCH V5 0/6] mm: fix some MADV_FREE issues Shaohua Li
2017-02-24 21:31 ` [PATCH V5 1/6] mm: delete unnecessary TTU_* flags Shaohua Li
2017-02-27 13:48 ` Michal Hocko
2017-02-24 21:31 ` [PATCH V5 2/6] mm: don't assume anonymous pages have SwapBacked flag Shaohua Li
2017-02-27 6:48 ` Hillf Danton
2017-02-27 14:35 ` Michal Hocko [this message]
2017-02-27 16:10 ` Shaohua Li
2017-02-27 16:28 ` Michal Hocko
2017-02-24 21:31 ` [PATCH V5 3/6] mm: move MADV_FREE pages into LRU_INACTIVE_FILE list Shaohua Li
2017-02-27 6:28 ` Minchan Kim
2017-02-27 16:13 ` Shaohua Li
2017-02-27 16:30 ` Michal Hocko
2017-02-28 2:53 ` Minchan Kim
2017-02-27 14:53 ` Michal Hocko
2017-02-27 17:15 ` Johannes Weiner
2017-02-28 3:19 ` Hillf Danton
2017-02-24 21:31 ` [PATCH V5 4/6] mm: reclaim MADV_FREE pages Shaohua Li
2017-02-27 6:33 ` Minchan Kim
2017-02-27 16:19 ` Shaohua Li
2017-02-27 16:32 ` Michal Hocko
2017-02-28 5:02 ` Minchan Kim
2017-02-27 15:05 ` Michal Hocko
2017-02-27 17:21 ` Johannes Weiner
2017-02-28 3:21 ` Hillf Danton
2017-02-24 21:31 ` [PATCH V5 5/6] mm: enable MADV_FREE for swapless system Shaohua Li
2017-02-27 15:06 ` Michal Hocko
2017-02-28 3:22 ` Hillf Danton
2017-02-28 5:02 ` Minchan Kim
2017-02-24 21:31 ` [PATCH V5 6/6] proc: show MADV_FREE pages info in smaps Shaohua Li
2017-02-27 15:06 ` Michal Hocko
2017-02-28 3:23 ` Hillf Danton
2017-03-01 13:36 ` Michal Hocko
2017-03-01 17:37 ` Shaohua Li
2017-03-01 17:49 ` Michal Hocko
2017-03-01 18:18 ` Shaohua Li
2017-03-01 18:31 ` Johannes Weiner
2017-03-01 18:57 ` Michal Hocko
2017-03-02 7:39 ` Minchan Kim
2017-03-02 14:01 ` Johannes Weiner
2017-03-02 16:30 ` Michal Hocko
2017-03-04 0:10 ` Andrew Morton
2017-03-07 10:05 ` Michal Hocko
2017-03-07 22:43 ` Andrew Morton
2017-03-08 5:36 ` Minchan Kim
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