Commit 18b1de97 authored by Konrad Sztyber's avatar Konrad Sztyber Committed by Darek Stojaczyk
Browse files

lib/ftl: store metadata on non-volatile cache 



Send LBA along with the data block when mirroring writes to the
non-volatile cache. The metadata buffer is retrieved from the metadata
pool, so the maximum number of concurrent requests is limited to
nv_cache.max_request_cnt, while the number of blocks in a single request
is limited by nv_cache.max_requets_size.

Change-Id: If260302d16039183fb0fe073ef7419947532cfab
Signed-off-by: default avatarKonrad Sztyber <konrad.sztyber@intel.com>
Reviewed-on: https://review.gerrithub.io/c/spdk/spdk/+/458093


Reviewed-by: default avatarMateusz Kozlowski <mateusz.kozlowski@intel.com>
Reviewed-by: default avatarWojciech Malikowski <wojciech.malikowski@intel.com>
Reviewed-by: default avatarBen Walker <benjamin.walker@intel.com>
Reviewed-by: default avatarDarek Stojaczyk <dariusz.stojaczyk@intel.com>
Tested-by: default avatarSPDK CI Jenkins <sys_sgci@intel.com>
parent 11ff1f4a

lib/ftl/ftl_core.c

+32 −3
Original line number Diff line number Diff line
@@ -952,6 +952,7 @@ static uint64_t 
ftl_reserve_nv_cache(struct ftl_nv_cache *nv_cache, size_t *num_lbks)

{

	struct spdk_bdev *bdev = spdk_bdev_desc_get_bdev(nv_cache->bdev_desc);

	struct spdk_ftl_dev *dev = SPDK_CONTAINEROF(nv_cache, struct spdk_ftl_dev, nv_cache);

	uint64_t num_available, cache_size, cache_addr = FTL_LBA_INVALID;



	cache_size = spdk_bdev_get_num_blocks(bdev);
@@ -962,6 +963,8 @@ ftl_reserve_nv_cache(struct ftl_nv_cache *nv_cache, size_t *num_lbks) 
	}



	num_available = spdk_min(nv_cache->num_available, *num_lbks);

	num_available = spdk_min(num_available, dev->conf.nv_cache.max_request_cnt);



	if (spdk_unlikely(nv_cache->current_addr + num_available > cache_size)) {

		*num_lbks = cache_size - nv_cache->current_addr;

	} else {
@@ -998,6 +1001,7 @@ static void 
ftl_nv_cache_submit_cb(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg)

{

	struct ftl_io *io = cb_arg;

	struct ftl_nv_cache *nv_cache = &io->dev->nv_cache;



	if (spdk_unlikely(!success)) {

		SPDK_ERRLOG("Non-volatile cache write failed at %"PRIx64"\n", io->ppa.ppa);
@@ -1006,6 +1010,7 @@ ftl_nv_cache_submit_cb(struct spdk_bdev_io *bdev_io, bool success, void *cb_arg) 


	ftl_io_dec_req(io);

	if (ftl_io_done(io)) {

		spdk_mempool_put(nv_cache->md_pool, io->md);

		ftl_io_complete(io);

	}
@@ -1018,21 +1023,23 @@ ftl_submit_nv_cache(void *ctx) 
	struct ftl_io *io = ctx;

	struct spdk_ftl_dev *dev = io->dev;

	struct spdk_thread *thread;

	struct ftl_nv_cache *nv_cache = &dev->nv_cache;

	struct ftl_io_channel *ioch;

	int rc;



	ioch = spdk_io_channel_get_ctx(io->ioch);

	thread = spdk_io_channel_get_thread(io->ioch);



	rc = spdk_bdev_write_blocks(dev->nv_cache.bdev_desc, ioch->cache_ioch,

				    ftl_io_iovec_addr(io), io->ppa.ppa, io->lbk_cnt,

				    ftl_nv_cache_submit_cb, io);

	rc = spdk_bdev_write_blocks_with_md(nv_cache->bdev_desc, ioch->cache_ioch,

					    ftl_io_iovec_addr(io), io->md, io->ppa.ppa,

					    io->lbk_cnt, ftl_nv_cache_submit_cb, io);

	if (rc == -ENOMEM) {

		spdk_thread_send_msg(thread, ftl_submit_nv_cache, io);

		return;

	} else if (rc) {

		SPDK_ERRLOG("Write to persistent cache failed: %s (%"PRIu64", %"PRIu64")\n",

			    spdk_strerror(-rc), io->ppa.ppa, io->lbk_cnt);

		spdk_mempool_put(nv_cache->md_pool, io->md);

		io->status = -EIO;

		ftl_io_complete(io);

		return;
@@ -1042,6 +1049,19 @@ ftl_submit_nv_cache(void *ctx) 
	ftl_io_inc_req(io);

}



static void

ftl_nv_cache_fill_md(struct ftl_nv_cache *nv_cache, struct ftl_io *io)

{

	struct spdk_bdev *bdev = spdk_bdev_desc_get_bdev(nv_cache->bdev_desc);

	void *md_buf = io->md;

	size_t lbk_off;



	for (lbk_off = 0; lbk_off < io->lbk_cnt; ++lbk_off) {

		*(uint64_t *)md_buf = ftl_io_get_lba(io, lbk_off);

		md_buf = (char *)md_buf + spdk_bdev_get_md_size(bdev);

	}

}



static void

_ftl_write_nv_cache(void *ctx)

{
@@ -1061,9 +1081,17 @@ _ftl_write_nv_cache(void *ctx) 
			return;

		}



		child->md = spdk_mempool_get(dev->nv_cache.md_pool);

		if (spdk_unlikely(!child->md)) {

			ftl_io_free(child);

			spdk_thread_send_msg(thread, _ftl_write_nv_cache, io);

			break;

		}



		/* Reserve area on the write buffer cache */

		child->ppa.ppa = ftl_reserve_nv_cache(&dev->nv_cache, &num_lbks);

		if (child->ppa.ppa == FTL_LBA_INVALID) {

			spdk_mempool_put(dev->nv_cache.md_pool, child->md);

			ftl_io_free(child);

			spdk_thread_send_msg(thread, _ftl_write_nv_cache, io);

			break;
@@ -1074,6 +1102,7 @@ _ftl_write_nv_cache(void *ctx) 
			ftl_io_shrink_iovec(child, num_lbks);

		}



		ftl_nv_cache_fill_md(&dev->nv_cache, child);

		ftl_submit_nv_cache(child);

	}

lib/ftl/ftl_init.c

+12 −0
Original line number Diff line number Diff line
@@ -494,6 +494,18 @@ ftl_dev_init_nv_cache(struct spdk_ftl_dev *dev, struct spdk_bdev_desc *bdev_desc 
		return -1;

	}



	if (!spdk_bdev_is_md_separate(bdev)) {

		SPDK_ERRLOG("Bdev %s doesn't support separate metadata buffer IO\n",

			    spdk_bdev_get_name(bdev));

		return -1;

	}



	if (spdk_bdev_get_md_size(bdev) < sizeof(uint64_t)) {

		SPDK_ERRLOG("Bdev's %s metadata is too small (%"PRIu32")\n",

			    spdk_bdev_get_name(bdev), spdk_bdev_get_md_size(bdev));

		return -1;

	}



	/* The cache needs to be capable of storing at least two full bands. This requirement comes

	 * from the fact that cache works as a protection against power loss, so before the data

	 * inside the cache can be overwritten, the band it's stored on has to be closed.