Commit 7e267a8c authored by Dan Williams's avatar Dan Williams
Browse files

libnvdimm, pmem: use REQ_FUA, REQ_FLUSH for nvdimm_flush() 



Given that nvdimm_flush() has higher overhead than wmb_pmem() (pointer
chasing through nd_region), and that we otherwise assume a platform has
ADR capability when flush hints are not present, move nvdimm_flush() to
REQ_FLUSH context.

Note that we still arrange for nvdimm_flush() to be called even in the
ADR case. We need at least once wmb() fence to push buffered writes in
the cpu out to the ADR protected domain.

Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 0c27af60

drivers/nvdimm/pmem.c

+12 −4
Original line number Diff line number Diff line
@@ -113,6 +113,11 @@ static int pmem_do_bvec(struct pmem_device *pmem, struct page *page, 
	return rc;

}



/* account for REQ_FLUSH rename, replace with REQ_PREFLUSH after v4.8-rc1 */

#ifndef REQ_FLUSH

#define REQ_FLUSH REQ_PREFLUSH

#endif



static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)

{

	int rc = 0;
@@ -121,6 +126,10 @@ static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio) 
	struct bio_vec bvec;

	struct bvec_iter iter;

	struct pmem_device *pmem = q->queuedata;

	struct nd_region *nd_region = to_region(pmem);



	if (bio->bi_rw & REQ_FLUSH)

		nvdimm_flush(nd_region);



	do_acct = nd_iostat_start(bio, &start);

	bio_for_each_segment(bvec, bio, iter) {
@@ -135,8 +144,8 @@ static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio) 
	if (do_acct)

		nd_iostat_end(bio, start);



	if (bio_data_dir(bio))

		nvdimm_flush(to_region(pmem));

	if (bio->bi_rw & REQ_FUA)

		nvdimm_flush(nd_region);



	bio_endio(bio);

	return BLK_QC_T_NONE;
@@ -149,8 +158,6 @@ static int pmem_rw_page(struct block_device *bdev, sector_t sector, 
	int rc;



	rc = pmem_do_bvec(pmem, page, PAGE_SIZE, 0, rw, sector);

	if (rw & WRITE)

		nvdimm_flush(to_region(pmem));



	/*

	 * The ->rw_page interface is subtle and tricky.  The core
@@ -279,6 +286,7 @@ static int pmem_attach_disk(struct device *dev, 
		return PTR_ERR(addr);

	pmem->virt_addr = (void __pmem *) addr;



	blk_queue_write_cache(q, true, true);

	blk_queue_make_request(q, pmem_make_request);

	blk_queue_physical_block_size(q, PAGE_SIZE);

	blk_queue_max_hw_sectors(q, UINT_MAX);

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