[-mm,05/13] block, THP: Make block_device_operations.rw_page support THP
diff mbox

Message ID 20170525064635.2832-6-ying.huang@intel.com
State New, archived
Headers show

Commit Message

Huang\, Ying May 25, 2017, 6:46 a.m. UTC
From: Huang Ying <ying.huang@intel.com>

The .rw_page in struct block_device_operations is used by the swap
subsystem to read/write the page contents from/into the corresponding
swap slot in the swap device.  To support the THP (Transparent Huge
Page) swap optimization, the .rw_page is enhanced to support to
read/write THP if possible.

Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@intel.com>
Cc: Vishal L Verma <vishal.l.verma@intel.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: linux-nvdimm@lists.01.org
---
 drivers/block/brd.c           |  6 +++++-
 drivers/block/zram/zram_drv.c |  2 ++
 drivers/nvdimm/btt.c          |  4 +++-
 drivers/nvdimm/pmem.c         | 42 +++++++++++++++++++++++++++++++-----------
 4 files changed, 41 insertions(+), 13 deletions(-)

Comments

Ross Zwisler June 2, 2017, 5:57 a.m. UTC | #1
On Thu, May 25, 2017 at 02:46:27PM +0800, Huang, Ying wrote:
> From: Huang Ying <ying.huang@intel.com>
> 
> The .rw_page in struct block_device_operations is used by the swap
> subsystem to read/write the page contents from/into the corresponding
> swap slot in the swap device.  To support the THP (Transparent Huge
> Page) swap optimization, the .rw_page is enhanced to support to
> read/write THP if possible.
> 
> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Cc: Minchan Kim <minchan@kernel.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Ross Zwisler <ross.zwisler@intel.com>
> Cc: Vishal L Verma <vishal.l.verma@intel.com>
> Cc: Jens Axboe <axboe@kernel.dk>
> Cc: linux-nvdimm@lists.01.org
> ---
>  drivers/block/brd.c           |  6 +++++-
>  drivers/block/zram/zram_drv.c |  2 ++
>  drivers/nvdimm/btt.c          |  4 +++-
>  drivers/nvdimm/pmem.c         | 42 +++++++++++++++++++++++++++++++-----------
>  4 files changed, 41 insertions(+), 13 deletions(-)

The changes in brd.c, zram_drv.c and pmem.c look good to me.  For those bits
you can add: 

Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>

I think we still want Vishal to make sure that the BTT changes are okay.  I
don't know that code well enough to know whether it's safe to throw 512 pages
at btt_[read|write]_pg().

Also, Ying, next time can you please CC me (and probably the linux-nvdimm
list) on the whole series?  It would give us more context on what the larger
change is, allow us to see the cover letter, allow us to test with all the
patches in the series, etc.  It's pretty easy for reviewers to skip over the
patches we don't care about or aren't in our area.

Thanks,
- Ross
Huang\, Ying June 5, 2017, 1 a.m. UTC | #2
Ross Zwisler <ross.zwisler@linux.intel.com> writes:

> On Thu, May 25, 2017 at 02:46:27PM +0800, Huang, Ying wrote:
>> From: Huang Ying <ying.huang@intel.com>
>> 
>> The .rw_page in struct block_device_operations is used by the swap
>> subsystem to read/write the page contents from/into the corresponding
>> swap slot in the swap device.  To support the THP (Transparent Huge
>> Page) swap optimization, the .rw_page is enhanced to support to
>> read/write THP if possible.
>> 
>> Signed-off-by: "Huang, Ying" <ying.huang@intel.com>
>> Cc: Johannes Weiner <hannes@cmpxchg.org>
>> Cc: Minchan Kim <minchan@kernel.org>
>> Cc: Dan Williams <dan.j.williams@intel.com>
>> Cc: Ross Zwisler <ross.zwisler@intel.com>
>> Cc: Vishal L Verma <vishal.l.verma@intel.com>
>> Cc: Jens Axboe <axboe@kernel.dk>
>> Cc: linux-nvdimm@lists.01.org
>> ---
>>  drivers/block/brd.c           |  6 +++++-
>>  drivers/block/zram/zram_drv.c |  2 ++
>>  drivers/nvdimm/btt.c          |  4 +++-
>>  drivers/nvdimm/pmem.c         | 42 +++++++++++++++++++++++++++++++-----------
>>  4 files changed, 41 insertions(+), 13 deletions(-)
>
> The changes in brd.c, zram_drv.c and pmem.c look good to me.  For those bits
> you can add: 
>
> Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>

Thanks!

> I think we still want Vishal to make sure that the BTT changes are okay.  I
> don't know that code well enough to know whether it's safe to throw 512 pages
> at btt_[read|write]_pg().
>
> Also, Ying, next time can you please CC me (and probably the linux-nvdimm
> list) on the whole series?  It would give us more context on what the larger
> change is, allow us to see the cover letter, allow us to test with all the
> patches in the series, etc.  It's pretty easy for reviewers to skip over the
> patches we don't care about or aren't in our area.

Sure.

Best Regards,
Huang, Ying

> Thanks,
> - Ross

Patch
diff mbox

diff --git a/drivers/block/brd.c b/drivers/block/brd.c
index 57b574f2f66a..4240d2a9dcf9 100644
--- a/drivers/block/brd.c
+++ b/drivers/block/brd.c
@@ -324,7 +324,11 @@  static int brd_rw_page(struct block_device *bdev, sector_t sector,
 		       struct page *page, bool is_write)
 {
 	struct brd_device *brd = bdev->bd_disk->private_data;
-	int err = brd_do_bvec(brd, page, PAGE_SIZE, 0, is_write, sector);
+	int err;
+
+	if (PageTransHuge(page))
+		return -ENOTSUPP;
+	err = brd_do_bvec(brd, page, PAGE_SIZE, 0, is_write, sector);
 	page_endio(page, is_write, err);
 	return err;
 }
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index 5f2a862d8e31..09b11286c927 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -1049,6 +1049,8 @@  static int zram_rw_page(struct block_device *bdev, sector_t sector,
 	struct zram *zram;
 	struct bio_vec bv;
 
+	if (PageTransHuge(page))
+		return -ENOTSUPP;
 	zram = bdev->bd_disk->private_data;
 
 	if (!valid_io_request(zram, sector, PAGE_SIZE)) {
diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 983718b8fd9b..46d4a0bd2ae6 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -1248,8 +1248,10 @@  static int btt_rw_page(struct block_device *bdev, sector_t sector,
 		struct page *page, bool is_write)
 {
 	struct btt *btt = bdev->bd_disk->private_data;
+	unsigned int len;
 
-	btt_do_bvec(btt, NULL, page, PAGE_SIZE, 0, is_write, sector);
+	len = hpage_nr_pages(page) * PAGE_SIZE;
+	btt_do_bvec(btt, NULL, page, len, 0, is_write, sector);
 	page_endio(page, is_write, 0);
 	return 0;
 }
diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
index c544d466ea51..e644115d56a7 100644
--- a/drivers/nvdimm/pmem.c
+++ b/drivers/nvdimm/pmem.c
@@ -78,22 +78,40 @@  static int pmem_clear_poison(struct pmem_device *pmem, phys_addr_t offset,
 static void write_pmem(void *pmem_addr, struct page *page,
 		unsigned int off, unsigned int len)
 {
-	void *mem = kmap_atomic(page);
-
-	memcpy_to_pmem(pmem_addr, mem + off, len);
-	kunmap_atomic(mem);
+	unsigned int chunk;
+	void *mem;
+
+	while (len) {
+		mem = kmap_atomic(page);
+		chunk = min_t(unsigned int, len, PAGE_SIZE);
+		memcpy_to_pmem(pmem_addr, mem + off, chunk);
+		kunmap_atomic(mem);
+		len -= chunk;
+		off = 0;
+		page++;
+		pmem_addr += PAGE_SIZE;
+	}
 }
 
 static int read_pmem(struct page *page, unsigned int off,
 		void *pmem_addr, unsigned int len)
 {
+	unsigned int chunk;
 	int rc;
-	void *mem = kmap_atomic(page);
-
-	rc = memcpy_mcsafe(mem + off, pmem_addr, len);
-	kunmap_atomic(mem);
-	if (rc)
-		return -EIO;
+	void *mem;
+
+	while (len) {
+		mem = kmap_atomic(page);
+		chunk = min_t(unsigned int, len, PAGE_SIZE);
+		rc = memcpy_mcsafe(mem + off, pmem_addr, chunk);
+		kunmap_atomic(mem);
+		if (rc)
+			return -EIO;
+		len -= chunk;
+		off = 0;
+		page++;
+		pmem_addr += PAGE_SIZE;
+	}
 	return 0;
 }
 
@@ -184,9 +202,11 @@  static int pmem_rw_page(struct block_device *bdev, sector_t sector,
 		       struct page *page, bool is_write)
 {
 	struct pmem_device *pmem = bdev->bd_queue->queuedata;
+	unsigned int len;
 	int rc;
 
-	rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, is_write, sector);
+	len = hpage_nr_pages(page) * PAGE_SIZE;
+	rc = pmem_do_bvec(pmem, page, len, 0, is_write, sector);
 
 	/*
 	 * The ->rw_page interface is subtle and tricky.  The core