From: Ingo Molnar <mingo@kernel.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Jerome Glisse <j.glisse@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Boaz Harrosh <boaz@plexistor.com>, Jan Kara <jack@suse.cz>,
Mike Snitzer <snitzer@redhat.com>, Neil Brown <neilb@suse.de>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Chris Mason <clm@fb.com>, Paul Mackerras <paulus@samba.org>,
"H. Peter Anvin" <hpa@zytor.com>, Christoph Hellwig <hch@lst.de>,
Alasdair Kergon <agk@redhat.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
Mel Gorman <mgorman@suse.de>,
Matthew Wilcox <willy@linux.intel.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Rik van Riel <riel@redhat.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Jens Axboe <axboe@kernel.dk>, Theodore Ts'o <tytso@mit.edu>,
"Martin K. Petersen" <martin.petersen@oracle.com>,
Julia Lawall <Julia.Lawall@lip6.fr>, Tejun Heo <tj@kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
paulmck@linux.vnet.ibm.com
Subject: Re: [PATCH v2 00/10] evacuate struct page from the block layer, introduce __pfn_t
Date: Fri, 8 May 2015 11:26:01 +0200 [thread overview]
Message-ID: <20150508092601.GA11002@gmail.com> (raw)
In-Reply-To: <20150508092044.GH889@ZenIV.linux.org.uk>
* Al Viro <viro@ZenIV.linux.org.uk> wrote:
> On Fri, May 08, 2015 at 07:37:59AM +0200, Ingo Molnar wrote:
>
> > So if code does iov_iter_get_pages_alloc() on a user address that
> > has a real struct page behind it - and some other code does a
> > regular get_user_pages() on it, we'll have two sets of struct page
> > descriptors, the 'real' one, and a fake allocated one, right?
>
> Huh? iov_iter_get_pages() is given an array of pointers to struct
> page, which it fills with what it finds. iov_iter_get_pages_alloc()
> *allocates* such an array, fills that with what it finds and gives
> the allocated array to caller.
>
> We are not allocating any struct page instances in either of those.
Ah, stupid me - thanks for the explanation!
Ingo
WARNING: multiple messages have this Message-ID (diff)
From: Ingo Molnar <mingo@kernel.org>
To: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Jerome Glisse <j.glisse@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Boaz Harrosh <boaz@plexistor.com>, Jan Kara <jack@suse.cz>,
Mike Snitzer <snitzer@redhat.com>, Neil Brown <neilb@suse.de>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
Chris Mason <clm@fb.com>, Paul Mackerras <paulus@samba.org>,
"H. Peter Anvin" <hpa@zytor.com>, Christoph Hellwig <hch@lst.de>,
Alasdair Kergon <agk@redhat.com>,
"linux-nvdimm@lists.01.org" <linux-nvdimm@ml01.01.org>,
Mel Gorman <mgorman@suse.de>,
Matthew Wilcox <willy@linux.intel.com>,
Ross Zwisler <ross.zwisler@linux.intel.com>,
Rik van Riel <riel@redhat.com>,
Martin Schwidefsky <schwidefsky@de.ibm.com>,
Jens Axboe <axboe@kernel.
Subject: Re: [PATCH v2 00/10] evacuate struct page from the block layer, introduce __pfn_t
Date: Fri, 8 May 2015 11:26:01 +0200 [thread overview]
Message-ID: <20150508092601.GA11002@gmail.com> (raw)
In-Reply-To: <20150508092044.GH889@ZenIV.linux.org.uk>
* Al Viro <viro@ZenIV.linux.org.uk> wrote:
> On Fri, May 08, 2015 at 07:37:59AM +0200, Ingo Molnar wrote:
>
> > So if code does iov_iter_get_pages_alloc() on a user address that
> > has a real struct page behind it - and some other code does a
> > regular get_user_pages() on it, we'll have two sets of struct page
> > descriptors, the 'real' one, and a fake allocated one, right?
>
> Huh? iov_iter_get_pages() is given an array of pointers to struct
> page, which it fills with what it finds. iov_iter_get_pages_alloc()
> *allocates* such an array, fills that with what it finds and gives
> the allocated array to caller.
>
> We are not allocating any struct page instances in either of those.
Ah, stupid me - thanks for the explanation!
Ingo
next prev parent reply other threads:[~2015-05-08 9:26 UTC|newest]
Thread overview: 180+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-05-06 20:04 [PATCH v2 00/10] evacuate struct page from the block layer, introduce __pfn_t Dan Williams
2015-05-06 20:04 ` Dan Williams
2015-05-06 20:04 ` [PATCH v2 01/10] arch: introduce __pfn_t for persistent memory i/o Dan Williams
2015-05-06 20:04 ` Dan Williams
2015-05-07 14:55 ` Stephen Rothwell
2015-05-07 14:55 ` Stephen Rothwell
2015-05-08 0:21 ` Dan Williams
2015-05-08 0:21 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 02/10] block: add helpers for accessing a bio_vec page Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-08 15:59 ` Dan Williams
2015-05-08 15:59 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 03/10] block: convert .bv_page to .bv_pfn bio_vec Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 04/10] dma-mapping: allow archs to optionally specify a ->map_pfn() operation Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 05/10] scatterlist: use sg_phys() Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 06/10] scatterlist: support "page-less" (__pfn_t only) entries Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 07/10] x86: support dma_map_pfn() Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 08/10] x86: support kmap_atomic_pfn_t() for persistent memory Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-06 20:20 ` [Linux-nvdimm] " Dan Williams
2015-05-06 20:20 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 09/10] dax: convert to __pfn_t Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-06 20:05 ` [PATCH v2 10/10] block: base support for pfn i/o Dan Williams
2015-05-06 20:05 ` Dan Williams
2015-05-06 20:50 ` [PATCH v2 00/10] evacuate struct page from the block layer, introduce __pfn_t Al Viro
2015-05-06 20:50 ` Al Viro
2015-05-06 22:10 ` Linus Torvalds
2015-05-06 22:10 ` Linus Torvalds
2015-05-06 22:10 ` Linus Torvalds
2015-05-06 23:47 ` Dan Williams
2015-05-06 23:47 ` Dan Williams
2015-05-06 23:47 ` Dan Williams
2015-05-07 0:19 ` Linus Torvalds
2015-05-07 0:19 ` Linus Torvalds
2015-05-07 0:19 ` Linus Torvalds
2015-05-07 2:36 ` Dan Williams
2015-05-07 2:36 ` Dan Williams
2015-05-07 2:36 ` Dan Williams
2015-05-07 9:02 ` Ingo Molnar
2015-05-07 9:02 ` Ingo Molnar
2015-05-07 9:02 ` Ingo Molnar
2015-05-07 14:42 ` Ingo Molnar
2015-05-07 14:42 ` Ingo Molnar
2015-05-07 14:42 ` Ingo Molnar
2015-05-07 15:52 ` Dan Williams
2015-05-07 15:52 ` Dan Williams
2015-05-07 15:52 ` Dan Williams
2015-05-07 17:52 ` Ingo Molnar
2015-05-07 17:52 ` Ingo Molnar
2015-05-07 17:52 ` Ingo Molnar
2015-05-07 15:00 ` Linus Torvalds
2015-05-07 15:00 ` Linus Torvalds
2015-05-07 15:00 ` Linus Torvalds
2015-05-07 15:40 ` Dan Williams
2015-05-07 15:40 ` Dan Williams
2015-05-07 15:40 ` Dan Williams
2015-05-07 15:58 ` Linus Torvalds
2015-05-07 15:58 ` Linus Torvalds
2015-05-07 15:58 ` Linus Torvalds
2015-05-07 16:03 ` Dan Williams
2015-05-07 16:03 ` Dan Williams
2015-05-07 16:03 ` Dan Williams
2015-05-07 17:36 ` Ingo Molnar
2015-05-07 17:36 ` Ingo Molnar
2015-05-07 17:36 ` Ingo Molnar
2015-05-07 17:42 ` Dan Williams
2015-05-07 17:42 ` Dan Williams
2015-05-07 17:42 ` Dan Williams
2015-05-07 17:56 ` Dave Hansen
2015-05-07 17:56 ` Dave Hansen
2015-05-07 17:56 ` Dave Hansen
2015-05-07 19:11 ` Ingo Molnar
2015-05-07 19:11 ` Ingo Molnar
2015-05-07 19:11 ` Ingo Molnar
2015-05-07 19:36 ` Jerome Glisse
2015-05-07 19:36 ` Jerome Glisse
2015-05-07 19:36 ` Jerome Glisse
2015-05-07 19:48 ` Ingo Molnar
2015-05-07 19:48 ` Ingo Molnar
2015-05-07 19:48 ` Ingo Molnar
2015-05-07 19:53 ` Ingo Molnar
2015-05-07 19:53 ` Ingo Molnar
2015-05-07 19:53 ` Ingo Molnar
2015-05-07 20:18 ` Jerome Glisse
2015-05-07 20:18 ` Jerome Glisse
2015-05-07 20:18 ` Jerome Glisse
2015-05-08 5:37 ` Ingo Molnar
2015-05-08 5:37 ` Ingo Molnar
2015-05-08 5:37 ` Ingo Molnar
2015-05-08 9:20 ` Al Viro
2015-05-08 9:20 ` Al Viro
2015-05-08 9:26 ` Ingo Molnar [this message]
2015-05-08 9:26 ` Ingo Molnar
2015-05-08 10:00 ` Al Viro
2015-05-08 10:00 ` Al Viro
2015-05-08 13:45 ` Rik van Riel
2015-05-08 13:45 ` Rik van Riel
2015-05-08 14:05 ` Ingo Molnar
2015-05-08 14:05 ` Ingo Molnar
2015-05-08 14:40 ` John Stoffel
2015-05-08 14:40 ` John Stoffel
2015-05-08 15:54 ` Linus Torvalds
2015-05-08 15:54 ` Linus Torvalds
2015-05-08 16:28 ` Al Viro
2015-05-08 16:28 ` Al Viro
2015-05-08 16:59 ` Rik van Riel
2015-05-08 16:59 ` Rik van Riel
2015-05-09 1:14 ` Linus Torvalds
2015-05-09 1:14 ` Linus Torvalds
2015-05-09 3:02 ` Rik van Riel
2015-05-09 3:02 ` Rik van Riel
2015-05-09 3:52 ` Linus Torvalds
2015-05-09 3:52 ` Linus Torvalds
2015-05-09 21:56 ` Dave Chinner
2015-05-09 21:56 ` Dave Chinner
2015-05-09 8:45 ` "Directly mapped persistent memory page cache" Ingo Molnar
2015-05-09 8:45 ` Ingo Molnar
2015-05-09 15:51 ` Eric W. Biederman
2015-05-09 15:51 ` Eric W. Biederman
2015-05-10 10:07 ` Ingo Molnar
2015-05-10 10:07 ` Ingo Molnar
2015-05-09 18:24 ` Dan Williams
2015-05-09 18:24 ` Dan Williams
2015-05-10 9:46 ` Ingo Molnar
2015-05-10 9:46 ` Ingo Molnar
2015-05-10 17:29 ` Dan Williams
2015-05-10 17:29 ` Dan Williams
2015-05-11 8:25 ` Dave Chinner
2015-05-11 8:25 ` Dave Chinner
2015-05-11 9:18 ` Ingo Molnar
2015-05-11 9:18 ` Ingo Molnar
2015-05-11 10:12 ` Zuckerman, Boris
2015-05-11 10:12 ` Zuckerman, Boris
2015-05-11 10:38 ` Ingo Molnar
2015-05-11 10:38 ` Ingo Molnar
2015-05-11 14:51 ` Jeff Moyer
2015-05-11 14:51 ` Jeff Moyer
2015-05-12 0:53 ` Dave Chinner
2015-05-12 0:53 ` Dave Chinner
2015-05-12 14:47 ` Jerome Glisse
2015-05-12 14:47 ` Jerome Glisse
2015-05-12 14:47 ` Jerome Glisse
2015-06-05 5:43 ` Dan Williams
2015-06-05 5:43 ` Dan Williams
2015-05-11 14:31 ` Matthew Wilcox
2015-05-11 14:31 ` Matthew Wilcox
2015-05-11 20:01 ` Jerome Glisse
2015-05-11 20:01 ` Jerome Glisse
2015-05-11 20:01 ` Jerome Glisse
2015-05-08 20:40 ` [PATCH v2 00/10] evacuate struct page from the block layer, introduce __pfn_t John Stoffel
2015-05-08 20:40 ` John Stoffel
2015-05-08 14:54 ` Rik van Riel
2015-05-08 14:54 ` Rik van Riel
2015-05-07 17:43 ` Linus Torvalds
2015-05-07 17:43 ` Linus Torvalds
2015-05-07 17:43 ` Linus Torvalds
2015-05-07 20:06 ` Dan Williams
2015-05-07 20:06 ` Dan Williams
2015-05-07 20:06 ` Dan Williams
2015-05-07 16:18 ` Christoph Hellwig
2015-05-07 16:18 ` Christoph Hellwig
2015-05-07 16:18 ` Christoph Hellwig
2015-05-07 16:41 ` Dan Williams
2015-05-07 16:41 ` Dan Williams
2015-05-07 16:41 ` Dan Williams
2015-05-07 18:40 ` Ingo Molnar
2015-05-07 18:40 ` Ingo Molnar
2015-05-07 18:40 ` Ingo Molnar
2015-05-07 19:44 ` Dan Williams
2015-05-07 19:44 ` Dan Williams
2015-05-07 19:44 ` Dan Williams
2015-05-07 17:30 ` Jerome Glisse
2015-05-07 17:30 ` Jerome Glisse
2015-05-07 17:30 ` Jerome Glisse
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