From: Vlastimil Babka <vbabka@suse.cz>
To: Minchan Kim <minchan@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Subject: Re: [PATCH v7 11/12] zsmalloc: page migration support
Date: Thu, 2 Jun 2016 13:44:45 +0200 [thread overview]
Message-ID: <8ebf6c9e-043d-0e70-7b6e-193771ead68d@suse.cz> (raw)
In-Reply-To: <20160602002519.GB1736@bbox>
On 06/02/2016 02:25 AM, Minchan Kim wrote:
> On Wed, Jun 01, 2016 at 04:09:26PM +0200, Vlastimil Babka wrote:
>> On 06/01/2016 01:21 AM, Minchan Kim wrote:
>>> + reset_page(page);
>>> + put_page(page);
>>> + page = newpage;
>>> +
>>> + ret = 0;
>>> +unpin_objects:
>>> + for (addr = s_addr + offset; addr < s_addr + pos;
>>> + addr += class->size) {
>>> + head = obj_to_head(page, addr);
>>> + if (head & OBJ_ALLOCATED_TAG) {
>>> + handle = head & ~OBJ_ALLOCATED_TAG;
>>> + if (!testpin_tag(handle))
>>> + BUG();
>>> + unpin_tag(handle);
>>> + }
>>> + }
>>> + kunmap_atomic(s_addr);
>>
>> The above seems suspicious to me. In the success case, page points to
>> newpage, but s_addr is still the original one?
>
> s_addr is virtual adress of old page by kmap_atomic so page pointer of
> new page doesn't matter.
Hmm, I see. The value (head address/handle) it reads from the old page
should be the same as the one in the newpage. And this value doesn't get
changed in the process. So it works, it's just subtle :)
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next prev parent reply other threads:[~2016-06-02 11:44 UTC|newest]
Thread overview: 49+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-31 23:21 [PATCH v7 00/12] Support non-lru page migration Minchan Kim
2016-05-31 23:21 ` [PATCH v7 01/12] mm: use put_page to free page instead of putback_lru_page Minchan Kim
2016-05-31 23:21 ` [PATCH v7 02/12] mm: migrate: support non-lru movable page migration Minchan Kim
2016-05-31 23:21 ` [PATCH v7 03/12] mm: balloon: use general non-lru movable page feature Minchan Kim
2016-05-31 23:21 ` [PATCH v7 04/12] zsmalloc: keep max_object in size_class Minchan Kim
2016-05-31 23:21 ` [PATCH v7 05/12] zsmalloc: use bit_spin_lock Minchan Kim
2016-05-31 23:21 ` [PATCH v7 06/12] zsmalloc: use accessor Minchan Kim
2016-05-31 23:21 ` [PATCH v7 07/12] zsmalloc: factor page chain functionality out Minchan Kim
2016-05-31 23:21 ` [PATCH v7 08/12] zsmalloc: introduce zspage structure Minchan Kim
2016-05-31 23:21 ` [PATCH v7 09/12] zsmalloc: separate free_zspage from putback_zspage Minchan Kim
2016-05-31 23:21 ` [PATCH v7 10/12] zsmalloc: use freeobj for index Minchan Kim
2016-05-31 23:21 ` [PATCH v7 11/12] zsmalloc: page migration support Minchan Kim
2016-06-01 14:09 ` Vlastimil Babka
2016-06-02 0:25 ` Minchan Kim
2016-06-02 11:44 ` Vlastimil Babka [this message]
2016-06-01 21:39 ` Andrew Morton
2016-06-02 0:15 ` Minchan Kim
[not found] ` <CGME20170119001317epcas1p188357c77e1f4ff08b6d3dcb76dedca06@epcas1p1.samsung.com>
2017-01-19 0:13 ` Chulmin Kim
2017-01-19 2:44 ` Minchan Kim
2017-01-19 3:39 ` Chulmin Kim
2017-01-19 6:21 ` Minchan Kim
2017-01-19 8:16 ` Chulmin Kim
2017-01-23 5:22 ` Minchan Kim
2017-01-23 5:30 ` Sergey Senozhatsky
2017-01-23 5:40 ` Minchan Kim
2017-01-25 4:06 ` Chulmin Kim
2017-01-25 4:25 ` Sergey Senozhatsky
2017-01-25 5:26 ` Minchan Kim
2017-01-26 17:04 ` Dan Streetman
2017-01-31 0:10 ` Minchan Kim
2017-01-31 13:09 ` Dan Streetman
2017-02-01 6:51 ` Minchan Kim
2017-02-01 19:38 ` Dan Streetman
2017-02-02 8:48 ` Minchan Kim
2016-05-31 23:21 ` [PATCH v7 12/12] zram: use __GFP_MOVABLE for memory allocation Minchan Kim
2016-06-01 21:41 ` [PATCH v7 00/12] Support non-lru page migration Andrew Morton
2016-06-01 22:40 ` Daniel Vetter
2016-06-02 0:36 ` Minchan Kim
2016-06-15 7:59 ` Sergey Senozhatsky
2016-06-15 23:12 ` Minchan Kim
2016-06-16 2:48 ` Sergey Senozhatsky
2016-06-16 2:58 ` Minchan Kim
2016-06-16 4:23 ` Sergey Senozhatsky
2016-06-16 4:47 ` Minchan Kim
2016-06-16 5:22 ` Sergey Senozhatsky
2016-06-16 6:47 ` Minchan Kim
2016-06-16 8:42 ` Sergey Senozhatsky
2016-06-16 10:09 ` Minchan Kim
2016-06-17 7:28 ` Joonsoo Kim
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