From: Vlastimil Babka <vbabka@suse.cz>
To: David Rientjes <rientjes@google.com>,
Andrew Morton <akpm@linux-foundation.org>
Cc: Mel Gorman <mgorman@techsingularity.net>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Michal Hocko <mhocko@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [patch for-4.11] mm, thp: fix setting of defer+madvise thp defrag mode
Date: Thu, 6 Apr 2017 12:26:16 +0200 [thread overview]
Message-ID: <5a543cb5-c356-71e9-4424-bfbbf66b4d11@suse.cz> (raw)
In-Reply-To: <alpine.DEB.2.10.1704051814420.137626@chino.kir.corp.google.com>
On 04/06/2017 03:17 AM, David Rientjes wrote:
> Setting thp defrag mode of "defer+madvise" actually sets "defer" in the
> kernel due to the name similarity and the out-of-order way the string is
> checked in defrag_store().
>
> Check the string in the correct order so that
> TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG is set appropriately for
> "defer+madvise".
>
> Fixes: 21440d7eb904 ("mm, thp: add new defer+madvise defrag option")
> Signed-off-by: David Rientjes <rientjes@google.com>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
> ---
> mm/huge_memory.c | 12 ++++++------
> 1 file changed, 6 insertions(+), 6 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -240,18 +240,18 @@ static ssize_t defrag_store(struct kobject *kobj,
> clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
> clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
> set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
> - } else if (!memcmp("defer", buf,
> - min(sizeof("defer")-1, count))) {
> - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
> - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
> - clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
> - set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
> } else if (!memcmp("defer+madvise", buf,
> min(sizeof("defer+madvise")-1, count))) {
> clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
> clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
> clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
> set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
> + } else if (!memcmp("defer", buf,
> + min(sizeof("defer")-1, count))) {
> + clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
> + clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, &transparent_hugepage_flags);
> + clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_REQ_MADV_FLAG, &transparent_hugepage_flags);
> + set_bit(TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, &transparent_hugepage_flags);
> } else if (!memcmp("madvise", buf,
> min(sizeof("madvise")-1, count))) {
> clear_bit(TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, &transparent_hugepage_flags);
>
--
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next prev parent reply other threads:[~2017-04-06 10:26 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-06 1:17 David Rientjes
2017-04-06 10:26 ` Vlastimil Babka [this message]
2017-04-06 13:39 ` Michal Hocko
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