From: Wei Yang <richard.weiyang@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Wei Yang <richard.weiyang@gmail.com>,
trivial@kernel.org, akpm@linux-foundation.org,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2 2/2] mm/memblock.c: check return value of memblock_reserve() in memblock_virt_alloc_internal()
Date: Tue, 20 Dec 2016 16:48:23 +0000 [thread overview]
Message-ID: <20161220164823.GB13224@vultr.guest> (raw)
In-Reply-To: <20161219152156.GC5175@dhcp22.suse.cz>
On Mon, Dec 19, 2016 at 04:21:57PM +0100, Michal Hocko wrote:
>On Sun 18-12-16 14:47:50, Wei Yang wrote:
>> memblock_reserve() may fail in case there is not enough regions.
>
>Have you seen this happenning in the real setups or this is a by-review
>driven change?
This is a by-review driven change.
>[...]
>> again:
>> alloc = memblock_find_in_range_node(size, align, min_addr, max_addr,
>> nid, flags);
>> - if (alloc)
>> + if (alloc && !memblock_reserve(alloc, size))
>> goto done;
>>
>> if (nid != NUMA_NO_NODE) {
>> alloc = memblock_find_in_range_node(size, align, min_addr,
>> max_addr, NUMA_NO_NODE,
>> flags);
>> - if (alloc)
>> + if (alloc && !memblock_reserve(alloc, size))
>> goto done;
>> }
>
>This doesn't look right. You can end up leaking the first allocated
>range.
>
Hmm... why?
If first memblock_reserve() succeed, it will jump to done, so that no 2nd
allocation.
If the second executes, it means the first allocation failed.
memblock_find_in_range_node() doesn't modify the memblock, it just tell you
there is a proper memory region available.
>>
>> @@ -1303,7 +1302,6 @@ static void * __init memblock_virt_alloc_internal(
>>
>> return NULL;
>> done:
>> - memblock_reserve(alloc, size);
>> ptr = phys_to_virt(alloc);
>> memset(ptr, 0, size);
>
>
>>
>> --
>> 2.5.0
>>
>> --
>> To unsubscribe, send a message with 'unsubscribe linux-mm' in
>> the body to majordomo@kvack.org. For more info on Linux MM,
>> see: http://www.linux-mm.org/ .
>> Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
>
>--
>Michal Hocko
>SUSE Labs
--
Wei Yang
Help you, Help me
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
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see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-12-20 16:48 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-18 14:47 [PATCH V2 0/2] mm/memblock.c: fix potential bug and code refine Wei Yang
2016-12-18 14:47 ` [PATCH V2 1/2] mm/memblock.c: trivial code refine in memblock_is_region_memory() Wei Yang
2016-12-19 15:15 ` Michal Hocko
2016-12-20 16:35 ` Wei Yang
2016-12-21 7:48 ` Michal Hocko
2016-12-21 12:43 ` Wei Yang
2016-12-21 12:48 ` Michal Hocko
2016-12-21 13:15 ` Wei Yang
2016-12-18 14:47 ` [PATCH V2 2/2] mm/memblock.c: check return value of memblock_reserve() in memblock_virt_alloc_internal() Wei Yang
2016-12-19 15:21 ` Michal Hocko
2016-12-20 16:48 ` Wei Yang [this message]
2016-12-21 7:51 ` Michal Hocko
2016-12-21 13:13 ` Wei Yang
2016-12-21 13:22 ` Michal Hocko
2016-12-21 14:39 ` Wei Yang
2016-12-21 14:52 ` Michal Hocko
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