From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: Yang Shi <shy828301@gmail.com>
Cc: hughd@google.com, ziy@nvidia.com,
kirill.shutemov@linux.intel.com, minchan@kernel.org,
naoya.horiguchi@nec.com, wangyugui@e16-tech.com,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [v4 PATCH 1/2] mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split
Date: Thu, 27 May 2021 13:52:14 +0300 [thread overview]
Message-ID: <20210527105214.jqbmyufsdtb5vdhm@box> (raw)
In-Reply-To: <20210526201239.3351-1-shy828301@gmail.com>
On Wed, May 26, 2021 at 01:12:38PM -0700, Yang Shi wrote:
> When debugging the bug reported by Wang Yugui [1], try_to_unmap() may
> fail, but the first VM_BUG_ON_PAGE() just checks page_mapcount() however
> it may miss the failure when head page is unmapped but other subpage is
> mapped. Then the second DEBUG_VM BUG() that check total mapcount would
> catch it. This may incur some confusion. And this is not a fatal issue,
> so consolidate the two DEBUG_VM checks into one VM_WARN_ON_ONCE_PAGE().
>
> [1] https://lore.kernel.org/linux-mm/20210412180659.B9E3.409509F4@e16-tech.com/
>
> Reviewed-by: Zi Yan <ziy@nvidia.com>
> Signed-off-by: Yang Shi <shy828301@gmail.com>
For both patches:
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
--
Kirill A. Shutemov
prev parent reply other threads:[~2021-05-27 10:52 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-26 20:12 Yang Shi
2021-05-26 20:12 ` [v4 PATCH 2/2] mm: rmap: make try_to_unmap() void function Yang Shi
2021-05-26 22:29 ` Minchan Kim
2021-05-26 23:03 ` Shakeel Butt
2021-05-26 22:02 ` [v4 PATCH 1/2] mm: thp: replace DEBUG_VM BUG with VM_WARN when unmap fails for split Hugh Dickins
2021-05-27 10:52 ` Kirill A. Shutemov [this message]
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