From: Dan Williams <dan.j.williams@intel.com>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Linux MM" <linux-mm@kvack.org>,
"Jérôme Glisse" <jglisse@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Kirill Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH] mm, zone_device: replace {get, put}_zone_device_page() with a single reference
Date: Thu, 27 Apr 2017 09:38:29 -0700 [thread overview]
Message-ID: <CAPcyv4iFKb9VbwdjRwF4KLQ=2R6-=vYb6BbHQG6Kk-8QemC6WA@mail.gmail.com> (raw)
In-Reply-To: <d2b0159c-9227-3283-2a57-74e03d47a0cd@deltatee.com>
On Thu, Apr 27, 2017 at 9:33 AM, Logan Gunthorpe <logang@deltatee.com> wrote:
>
>
> On 27/04/17 10:14 AM, Dan Williams wrote:
>> You're overlooking that the page reference count 1 after
>> arch_add_memory(). So at the end of time we're just dropping the
>> arch_add_memory() reference to release the page and related
>> dev_pagemap.
>
> Thanks, that does actually make a lot more sense to me now. However,
> there still appears to be an asymmetry in that the pgmap->ref is
> incremented once and decremented once per page...
>
No, this hunk...
@@ -379,6 +374,7 @@ void *devm_memremap_pages(struct device *dev,
struct resource *res,
*/
list_del(&page->lru);
page->pgmap = pgmap;
+ percpu_ref_get(ref);
}
...is inside a for_each_device_pfn() loop.
WARNING: multiple messages have this Message-ID (diff)
From: Dan Williams <dan.j.williams@intel.com>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: "Andrew Morton" <akpm@linux-foundation.org>,
"Linux MM" <linux-mm@kvack.org>,
"Jérôme Glisse" <jglisse@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"Kirill Shutemov" <kirill.shutemov@linux.intel.com>
Subject: Re: [PATCH] mm, zone_device: replace {get, put}_zone_device_page() with a single reference
Date: Thu, 27 Apr 2017 09:38:29 -0700 [thread overview]
Message-ID: <CAPcyv4iFKb9VbwdjRwF4KLQ=2R6-=vYb6BbHQG6Kk-8QemC6WA@mail.gmail.com> (raw)
In-Reply-To: <d2b0159c-9227-3283-2a57-74e03d47a0cd@deltatee.com>
On Thu, Apr 27, 2017 at 9:33 AM, Logan Gunthorpe <logang@deltatee.com> wrote:
>
>
> On 27/04/17 10:14 AM, Dan Williams wrote:
>> You're overlooking that the page reference count 1 after
>> arch_add_memory(). So at the end of time we're just dropping the
>> arch_add_memory() reference to release the page and related
>> dev_pagemap.
>
> Thanks, that does actually make a lot more sense to me now. However,
> there still appears to be an asymmetry in that the pgmap->ref is
> incremented once and decremented once per page...
>
No, this hunk...
@@ -379,6 +374,7 @@ void *devm_memremap_pages(struct device *dev,
struct resource *res,
*/
list_del(&page->lru);
page->pgmap = pgmap;
+ percpu_ref_get(ref);
}
...is inside a for_each_device_pfn() loop.
--
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next prev parent reply other threads:[~2017-04-27 16:38 UTC|newest]
Thread overview: 91+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-04-20 21:46 [tip:x86/mm] x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation Dan Williams
2017-04-21 14:16 ` Kirill A. Shutemov
2017-04-21 19:30 ` Dan Williams
2017-04-23 9:52 ` [PATCH] Revert "x86/mm/gup: Switch GUP to the generic get_user_page_fast() implementation" Ingo Molnar
2017-04-23 23:31 ` get_zone_device_page() in get_page() and page_cache_get_speculative() Kirill A. Shutemov
2017-04-23 23:31 ` Kirill A. Shutemov
2017-04-24 17:23 ` Dan Williams
2017-04-24 17:23 ` Dan Williams
2017-04-24 17:30 ` Kirill A. Shutemov
2017-04-24 17:30 ` Kirill A. Shutemov
2017-04-24 17:47 ` Dan Williams
2017-04-24 17:47 ` Dan Williams
2017-04-24 18:01 ` Kirill A. Shutemov
2017-04-24 18:01 ` Kirill A. Shutemov
2017-04-24 18:25 ` Kirill A. Shutemov
2017-04-24 18:25 ` Kirill A. Shutemov
2017-04-24 18:41 ` Dan Williams
2017-04-24 18:41 ` Dan Williams
2017-04-25 13:19 ` Kirill A. Shutemov
2017-04-25 13:19 ` Kirill A. Shutemov
2017-04-25 16:44 ` Dan Williams
2017-04-25 16:44 ` Dan Williams
2017-04-27 0:55 ` [PATCH] mm, zone_device: replace {get, put}_zone_device_page() with a single reference Dan Williams
2017-04-27 0:55 ` Dan Williams
2017-04-27 8:33 ` Kirill A. Shutemov
2017-04-27 8:33 ` Kirill A. Shutemov
2017-04-28 6:39 ` Ingo Molnar
2017-04-28 6:39 ` Ingo Molnar
2017-04-28 8:14 ` [PATCH] mm, zone_device: Replace " Kirill A. Shutemov
2017-04-28 8:14 ` Kirill A. Shutemov
2017-04-28 17:23 ` [PATCH v2] mm, zone_device: replace " Dan Williams
2017-04-28 17:23 ` Dan Williams
2017-04-28 17:34 ` Jerome Glisse
2017-04-28 17:34 ` Jerome Glisse
2017-04-28 17:41 ` Dan Williams
2017-04-28 17:41 ` Dan Williams
2017-04-28 18:00 ` Jerome Glisse
2017-04-28 18:00 ` Jerome Glisse
2017-04-28 19:02 ` Dan Williams
2017-04-28 19:02 ` Dan Williams
2017-04-28 19:16 ` Jerome Glisse
2017-04-28 19:16 ` Jerome Glisse
2017-04-28 19:22 ` Dan Williams
2017-04-28 19:22 ` Dan Williams
2017-04-28 19:33 ` Jerome Glisse
2017-04-28 19:33 ` Jerome Glisse
2017-04-29 10:17 ` Kirill A. Shutemov
2017-04-29 10:17 ` Kirill A. Shutemov
2017-04-30 23:14 ` Jerome Glisse
2017-04-30 23:14 ` Jerome Glisse
2017-05-01 1:42 ` Dan Williams
2017-05-01 1:42 ` Dan Williams
2017-05-01 1:54 ` Jerome Glisse
2017-05-01 1:54 ` Jerome Glisse
2017-05-01 2:40 ` Dan Williams
2017-05-01 2:40 ` Dan Williams
2017-05-01 3:48 ` Logan Gunthorpe
2017-05-01 3:48 ` Logan Gunthorpe
2017-05-01 10:23 ` Kirill A. Shutemov
2017-05-01 10:23 ` Kirill A. Shutemov
2017-05-01 13:55 ` Jerome Glisse
2017-05-01 13:55 ` Jerome Glisse
2017-05-01 20:19 ` Dan Williams
2017-05-01 20:19 ` Dan Williams
2017-05-01 20:32 ` Jerome Glisse
2017-05-01 20:32 ` Jerome Glisse
2017-05-02 11:37 ` Kirill A. Shutemov
2017-05-02 11:37 ` Kirill A. Shutemov
2017-05-02 13:22 ` Jerome Glisse
2017-05-02 13:22 ` Jerome Glisse
2017-04-29 14:18 ` Ingo Molnar
2017-04-29 14:18 ` Ingo Molnar
2017-05-01 2:45 ` Dan Williams
2017-05-01 2:45 ` Dan Williams
2017-05-01 7:12 ` Ingo Molnar
2017-05-01 7:12 ` Ingo Molnar
2017-05-01 9:33 ` Kirill A. Shutemov
2017-05-01 9:33 ` Kirill A. Shutemov
2017-05-01 8:28 ` [tip:x86/mm] mm, zone_device: Replace {get, put}_zone_device_page() with a single reference to fix pmem crash tip-bot for Dan Williams
2017-04-27 16:11 ` [PATCH] mm, zone_device: replace {get, put}_zone_device_page() with a single reference Logan Gunthorpe
2017-04-27 16:11 ` Logan Gunthorpe
2017-04-27 16:14 ` Dan Williams
2017-04-27 16:14 ` Dan Williams
2017-04-27 16:33 ` Logan Gunthorpe
2017-04-27 16:33 ` Logan Gunthorpe
2017-04-27 16:38 ` Dan Williams [this message]
2017-04-27 16:38 ` Dan Williams
2017-04-27 16:45 ` Logan Gunthorpe
2017-04-27 16:45 ` Logan Gunthorpe
2017-04-27 16:46 ` Dan Williams
2017-04-27 16:46 ` Dan Williams
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