Merge tag 'for-5.8/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm

Pull device mapper updates from Mike Snitzer:

 - The largest change for this cycle is the DM zoned target's metadata
   version 2 feature that adds support for pairing regular block devices
   with a zoned device to ease the performance impact associated with
   finite random zones of zoned device.

   The changes came in three batches: the first prepared for and then
   added the ability to pair a single regular block device, the second
   was a batch of fixes to improve zoned's reclaim heuristic, and the
   third removed the limitation of only adding a single additional
   regular block device to allow many devices.

   Testing has shown linear scaling as more devices are added.

 - Add new emulated block size (ebs) target that emulates a smaller
   logical_block_size than a block device supports

   The primary use-case is to emulate "512e" devices that have 512 byte
   logical_block_size and 4KB physical_block_size. This is useful to
   some legacy applications that otherwise wouldn't be able to be used
   on 4K devices because they depend on issuing IO in 512 byte
   granularity.

 - Add discard interfaces to DM bufio. First consumer of the interface
   is the dm-ebs target that makes heavy use of dm-bufio.

 - Fix DM crypt's block queue_limits stacking to not truncate
   logic_block_size.

 - Add Documentation for DM integrity's status line.

 - Switch DMDEBUG from a compile time config option to instead use
   dynamic debug via pr_debug.

 - Fix DM multipath target's hueristic for how it manages
   "queue_if_no_path" state internally.

   DM multipath now avoids disabling "queue_if_no_path" unless it is
   actually needed (e.g. in response to configure timeout or explicit
   "fail_if_no_path" message).

   This fixes reports of spurious -EIO being reported back to userspace
   application during fault tolerance testing with an NVMe backend.
   Added various dynamic DMDEBUG messages to assist with debugging
   queue_if_no_path in the future.

 - Add a new DM multipath "Historical Service Time" Path Selector.

 - Fix DM multipath's dm_blk_ioctl() to switch paths on IO error.

 - Improve DM writecache target performance by using explicit cache
   flushing for target's single-threaded usecase and a small cleanup to
   remove unnecessary test in persistent_memory_claim.

 - Other small cleanups in DM core, dm-persistent-data, and DM
   integrity.

* tag 'for-5.8/dm-changes' of git://git.kernel.org/pub/scm/linux/kernel/git/device-mapper/linux-dm: (62 commits)
  dm crypt: avoid truncating the logical block size
  dm mpath: add DM device name to Failing/Reinstating path log messages
  dm mpath: enhance queue_if_no_path debugging
  dm mpath: restrict queue_if_no_path state machine
  dm mpath: simplify __must_push_back
  dm zoned: check superblock location
  dm zoned: prefer full zones for reclaim
  dm zoned: select reclaim zone based on device index
  dm zoned: allocate zone by device index
  dm zoned: support arbitrary number of devices
  dm zoned: move random and sequential zones into struct dmz_dev
  dm zoned: per-device reclaim
  dm zoned: add metadata pointer to struct dmz_dev
  dm zoned: add device pointer to struct dm_zone
  dm zoned: allocate temporary superblock for tertiary devices
  dm zoned: convert to xarray
  dm zoned: add a 'reserved' zone flag
  dm zoned: improve logging messages for reclaim
  dm zoned: avoid unnecessary device recalulation for secondary superblock
  dm zoned: add debugging message for reading superblocks
  ...

1 files changed, 37 insertions, 5 deletions

diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c
index 613c171b1b6d..74f3c506f084 100644
--- a/drivers/md/dm-writecache.c
+++ b/drivers/md/dm-writecache.c
@@ -234,10 +234,6 @@ static int persistent_memory_claim(struct dm_writecache *wc)
 
 	wc->memory_vmapped = false;
 
-	if (!wc->ssd_dev->dax_dev) {
-		r = -EOPNOTSUPP;
-		goto err1;
-	}
 	s = wc->memory_map_size;
 	p = s >> PAGE_SHIFT;
 	if (!p) {
@@ -1143,6 +1139,42 @@ static int writecache_message(struct dm_target *ti, unsigned argc, char **argv,
 	return r;
 }
 
+static void memcpy_flushcache_optimized(void *dest, void *source, size_t size)
+{
+	/*
+	 * clflushopt performs better with block size 1024, 2048, 4096
+	 * non-temporal stores perform better with block size 512
+	 *
+	 * block size   512             1024            2048            4096
+	 * movnti       496 MB/s        642 MB/s        725 MB/s        744 MB/s
+	 * clflushopt   373 MB/s        688 MB/s        1.1 GB/s        1.2 GB/s
+	 *
+	 * We see that movnti performs better for 512-byte blocks, and
+	 * clflushopt performs better for 1024-byte and larger blocks. So, we
+	 * prefer clflushopt for sizes >= 768.
+	 *
+	 * NOTE: this happens to be the case now (with dm-writecache's single
+	 * threaded model) but re-evaluate this once memcpy_flushcache() is
+	 * enabled to use movdir64b which might invalidate this performance
+	 * advantage seen with cache-allocating-writes plus flushing.
+	 */
+#ifdef CONFIG_X86
+	if (static_cpu_has(X86_FEATURE_CLFLUSHOPT) &&
+	    likely(boot_cpu_data.x86_clflush_size == 64) &&
+	    likely(size >= 768)) {
+		do {
+			memcpy((void *)dest, (void *)source, 64);
+			clflushopt((void *)dest);
+			dest += 64;
+			source += 64;
+			size -= 64;
+		} while (size >= 64);
+		return;
+	}
+#endif
+	memcpy_flushcache(dest, source, size);
+}
+
 static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data)
 {
 	void *buf;
@@ -1168,7 +1200,7 @@ static void bio_copy_block(struct dm_writecache *wc, struct bio *bio, void *data
 			}
 		} else {
 			flush_dcache_page(bio_page(bio));
-			memcpy_flushcache(data, buf, size);
+			memcpy_flushcache_optimized(data, buf, size);
 		}
 
 		bvec_kunmap_irq(buf, &flags);