From: Qian Cai <cai@lca.pw>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: mgorman@techsingularity.net, vbabka@suse.cz, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [RESEND#2 PATCH] mm/compaction: fix an undefined behaviour
Date: Wed, 20 Mar 2019 18:12:40 -0400 [thread overview]
Message-ID: <a82bdba4-530a-95fd-8a05-5fd2fd67e4b4@lca.pw> (raw)
In-Reply-To: <20190320145826.9c647fe53bd999bbd2ee188d@linux-foundation.org>
On 3/20/19 5:58 PM, Andrew Morton wrote:
>> ---
>> mm/compaction.c | 4 +++-
>> 1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/mm/compaction.c b/mm/compaction.c
>> index e1a08fc92353..0d1156578114 100644
>> --- a/mm/compaction.c
>> +++ b/mm/compaction.c
>> @@ -1157,7 +1157,9 @@ static bool suitable_migration_target(struct compact_control *cc,
>> static inline unsigned int
>> freelist_scan_limit(struct compact_control *cc)
>> {
>> - return (COMPACT_CLUSTER_MAX >> cc->fast_search_fail) + 1;
>> + return (COMPACT_CLUSTER_MAX >>
>> + min((unsigned short)(BITS_PER_LONG - 1), cc->fast_search_fail))
>> + + 1;
>> }
>
> That's rather an eyesore. How about
>
> static inline unsigned int
> freelist_scan_limit(struct compact_control *cc)
> {
> unsigned short shift = BITS_PER_LONG - 1;
>
> return (COMPACT_CLUSTER_MAX >> min(shift, cc->fast_search_fail)) + 1;
> }
Agree. It looks better.
prev parent reply other threads:[~2019-03-20 22:12 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-03-20 20:33 Qian Cai
2019-03-20 21:58 ` Andrew Morton
2019-03-20 22:12 ` Qian Cai [this message]
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