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From: John Hubbard <jhubbard@nvidia.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Jan Kara <jack@suse.cz>, Dave Chinner <david@fromorbit.com>,
	Matthew Wilcox <willy@infradead.org>,
	Christopher Lameter <cl@linux.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Dan Williams <dan.j.williams@intel.com>,
	linux-mm@kvack.org, Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-rdma <linux-rdma@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH 4/6] mm: introduce page->dma_pinned_flags, _count
Date: Wed, 17 Oct 2018 17:03:03 -0700	[thread overview]
Message-ID: <2367ff26-809c-da94-a8f0-e921bdc4862a@nvidia.com> (raw)
In-Reply-To: <20181017110952.GN18839@dhcp22.suse.cz>

On 10/17/18 4:09 AM, Michal Hocko wrote:
> On Tue 16-10-18 18:48:23, John Hubbard wrote:
> [...]
>> It's hard to say exactly what the active/inactive/unevictable list should
>> be when DMA is done and put_user_page*() is called, because we don't know
>> if some device read, wrote, or ignored any of those pages. Although if 
>> put_user_pages_dirty() is called, that's an argument for "active", at least.
> 
> Any reason to not use putback_lru_page?

That does help with which LRU to use. I guess I'd still need to track whether
a page was on an LRU when get_user_pages() was called, because it seems
that that is not necessarily always the case. And putback_lru_page() definitely
wants to deal with a page that *was* previously on an LRU.

> 
> Please note I haven't really got through your patches to have a wider
> picture of the change so this is just hint for the LRU part of the
> issue.
> 

Understood, and the hints are much appreciated.

-- 
thanks,
John Hubbard
NVIDIA

WARNING: multiple messages have this Message-ID (diff)
From: John Hubbard <jhubbard@nvidia.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Jan Kara <jack@suse.cz>, Dave Chinner <david@fromorbit.com>,
	Matthew Wilcox <willy@infradead.org>,
	Christopher Lameter <cl@linux.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Dan Williams <dan.j.williams@intel.com>, <linux-mm@kvack.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	LKML <linux-kernel@vger.kernel.org>,
	linux-rdma <linux-rdma@vger.kernel.org>,
	<linux-fsdevel@vger.kernel.org>
Subject: Re: [PATCH 4/6] mm: introduce page->dma_pinned_flags, _count
Date: Wed, 17 Oct 2018 17:03:03 -0700	[thread overview]
Message-ID: <2367ff26-809c-da94-a8f0-e921bdc4862a@nvidia.com> (raw)
In-Reply-To: <20181017110952.GN18839@dhcp22.suse.cz>

On 10/17/18 4:09 AM, Michal Hocko wrote:
> On Tue 16-10-18 18:48:23, John Hubbard wrote:
> [...]
>> It's hard to say exactly what the active/inactive/unevictable list should
>> be when DMA is done and put_user_page*() is called, because we don't know
>> if some device read, wrote, or ignored any of those pages. Although if 
>> put_user_pages_dirty() is called, that's an argument for "active", at least.
> 
> Any reason to not use putback_lru_page?

That does help with which LRU to use. I guess I'd still need to track whether
a page was on an LRU when get_user_pages() was called, because it seems
that that is not necessarily always the case. And putback_lru_page() definitely
wants to deal with a page that *was* previously on an LRU.

> 
> Please note I haven't really got through your patches to have a wider
> picture of the change so this is just hint for the LRU part of the
> issue.
> 

Understood, and the hints are much appreciated.

-- 
thanks,
John Hubbard
NVIDIA

  reply	other threads:[~2018-10-18  0:03 UTC|newest]

Thread overview: 46+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-12  6:00 [PATCH 0/6] RFC: gup+dma: tracking dma-pinned pages john.hubbard
2018-10-12  6:00 ` [PATCH 1/6] mm: get_user_pages: consolidate error handling john.hubbard
2018-10-12  6:30   ` Balbir Singh
2018-10-12 22:45     ` John Hubbard
2018-10-12 22:45       ` John Hubbard
2018-10-12  6:00 ` [PATCH 2/6] mm: introduce put_user_page*(), placeholder versions john.hubbard
2018-10-12  7:35   ` Balbir Singh
2018-10-12 22:31     ` John Hubbard
2018-10-12 22:31       ` John Hubbard
2018-10-12  6:00 ` [PATCH 3/6] infiniband/mm: convert put_page() to put_user_page*() john.hubbard
2018-10-12  6:00 ` [PATCH 4/6] mm: introduce page->dma_pinned_flags, _count john.hubbard
2018-10-12 10:56   ` Balbir Singh
2018-10-13  0:15     ` John Hubbard
2018-10-13  0:15       ` John Hubbard
2018-10-24 11:00       ` Balbir Singh
2018-11-02 23:27         ` John Hubbard
2018-11-02 23:27           ` John Hubbard
2018-10-13  3:55   ` Dave Chinner
2018-10-13  7:34     ` John Hubbard
2018-10-13  7:34       ` John Hubbard
2018-10-13 16:47       ` Christoph Hellwig
2018-10-13 21:19         ` John Hubbard
2018-10-13 21:19           ` John Hubbard
2018-11-05  7:10         ` John Hubbard
2018-11-05  7:10           ` John Hubbard
2018-11-05  9:54           ` Jan Kara
2018-11-06  0:26             ` John Hubbard
2018-11-06  0:26               ` John Hubbard
2018-11-06  2:47               ` Dave Chinner
2018-11-06 11:00                 ` Jan Kara
2018-11-06 20:41                   ` Dave Chinner
2018-11-07  6:36                     ` John Hubbard
2018-11-07  6:36                       ` John Hubbard
2018-10-13 23:01       ` Dave Chinner
2018-10-16  8:51         ` Jan Kara
2018-10-17  1:48           ` John Hubbard
2018-10-17  1:48             ` John Hubbard
2018-10-17 11:09             ` Michal Hocko
2018-10-18  0:03               ` John Hubbard [this message]
2018-10-18  0:03                 ` John Hubbard
2018-10-19  8:11                 ` Michal Hocko
2018-10-12  6:00 ` [PATCH 5/6] mm: introduce zone_gup_lock, for dma-pinned pages john.hubbard
2018-10-12  6:00 ` [PATCH 6/6] mm: track gup pages with page->dma_pinned_* fields john.hubbard
2018-10-12 11:07   ` Balbir Singh
2018-10-13  0:33     ` John Hubbard
2018-10-13  0:33       ` John Hubbard

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