Re: [PATCH] nvdimm: Add NVDIMM_NO_DEEPFLUSH flag to control btt data deepflush

dennis . wu Thu, 30 Jun 2022 21:38:09 -0700

Thank you Ira! Sorry for duplicating the patch.

The first patch is made on the kernel v5.17 and can't patch with thelatest Linux master and the second one is made with the Linux master.


On 7/1/22 06:32, Weiny, Ira wrote:

On Wed, Jun 29, 2022 at 09:58:01PM +0800, Dennis.Wu wrote:

Reason: we can have a global control of deepflush in the nfit module
by "no_deepflush" param. In the case of "no_deepflush=0", we still
need control data deepflush or not by the NVDIMM_NO_DEEPFLUSH flag.
In the BTT, the btt information block(btt_sb) will use deepflush.
Other like the data blocks(512B or 4KB),4 bytes btt_map and 16 bytes
bflog will not use the deepflush. so that, during the runtime, no
deepflush will be called in the BTT.

How: Add flag NVDIMM_NO_DEEPFLUSH which can use with NVDIMM_IO_ATOMIC
like NVDIMM_NO_DEEPFLUSH | NVDIMM_IO_ATOMIC.
"if (!(flags & NVDIMM_NO_DEEPFLUSH))", nvdimm_flush() will be called,
otherwise, the pmem_wmb() called to fense all previous write.

This looks like the same patch you sent earlier?  Did it change?  Is this a V2?

Ira

Signed-off-by: Dennis.Wu <[email protected]>
---
  drivers/nvdimm/btt.c   | 26 +++++++++++++++++---------
  drivers/nvdimm/claim.c |  9 +++++++--
  drivers/nvdimm/nd.h    |  4 ++++
  3 files changed, 28 insertions(+), 11 deletions(-)

diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c
index 9613e54c7a67..c71ba7a1edd0 100644
--- a/drivers/nvdimm/btt.c
+++ b/drivers/nvdimm/btt.c
@@ -70,6 +70,10 @@ static int btt_info_write(struct arena_info *arena, struct 
btt_sb *super)
        dev_WARN_ONCE(to_dev(arena), !IS_ALIGNED(arena->info2off, 512),
                "arena->info2off: %#llx is unaligned\n", arena->info2off);

+ /*

+        * btt_sb is critial information and need proper write
+        * nvdimm_flush will be called (deepflush)
+        */
        ret = arena_write_bytes(arena, arena->info2off, super,
                        sizeof(struct btt_sb), 0);
        if (ret)
@@ -384,7 +388,8 @@ static int btt_flog_write(struct arena_info *arena, u32 
lane, u32 sub,
  {
        int ret;

- ret = __btt_log_write(arena, lane, sub, ent, NVDIMM_IO_ATOMIC);

+       ret = __btt_log_write(arena, lane, sub, ent,
+               NVDIMM_IO_ATOMIC|NVDIMM_NO_DEEPFLUSH);
        if (ret)
                return ret;

@@ -429,7 +434,7 @@ static int btt_map_init(struct arena_info *arena)

                dev_WARN_ONCE(to_dev(arena), size < 512,
                        "chunk size: %#zx is unaligned\n", size);
                ret = arena_write_bytes(arena, arena->mapoff + offset, zerobuf,
-                               size, 0);
+                               size, NVDIMM_NO_DEEPFLUSH);
                if (ret)
                        goto free;

@@ -473,7 +478,7 @@ static int btt_log_init(struct arena_info *arena)

                dev_WARN_ONCE(to_dev(arena), size < 512,
                        "chunk size: %#zx is unaligned\n", size);
                ret = arena_write_bytes(arena, arena->logoff + offset, zerobuf,
-                               size, 0);
+                               size, NVDIMM_NO_DEEPFLUSH);
                if (ret)
                        goto free;

@@ -487,7 +492,7 @@ static int btt_log_init(struct arena_info *arena)

                ent.old_map = cpu_to_le32(arena->external_nlba + i);
                ent.new_map = cpu_to_le32(arena->external_nlba + i);
                ent.seq = cpu_to_le32(LOG_SEQ_INIT);
-               ret = __btt_log_write(arena, i, 0, &ent, 0);
+               ret = __btt_log_write(arena, i, 0, &ent, NVDIMM_NO_DEEPFLUSH);
                if (ret)
                        goto free;
        }
@@ -518,7 +523,7 @@ static int arena_clear_freelist_error(struct arena_info 
*arena, u32 lane)
                        unsigned long chunk = min(len, PAGE_SIZE);

ret = arena_write_bytes(arena, nsoff, zero_page,

-                               chunk, 0);
+                               chunk, NVDIMM_NO_DEEPFLUSH);
                        if (ret)
                                break;
                        len -= chunk;
@@ -592,7 +597,8 @@ static int btt_freelist_init(struct arena_info *arena)
                         * to complete the map write. So fix up the map.
                         */
                        ret = btt_map_write(arena, le32_to_cpu(log_new.lba),
-                                       le32_to_cpu(log_new.new_map), 0, 0, 0);
+                                       le32_to_cpu(log_new.new_map), 0, 0,
+                                       NVDIMM_NO_DEEPFLUSH);
                        if (ret)
                                return ret;
                }
@@ -1123,7 +1129,8 @@ static int btt_data_write(struct arena_info *arena, u32 
lba,
        u64 nsoff = to_namespace_offset(arena, lba);
        void *mem = kmap_atomic(page);

- ret = arena_write_bytes(arena, nsoff, mem + off, len, NVDIMM_IO_ATOMIC);

+       ret = arena_write_bytes(arena, nsoff, mem + off, len,
+               NVDIMM_IO_ATOMIC|NVDIMM_NO_DEEPFLUSH);
        kunmap_atomic(mem);

return ret;

@@ -1260,7 +1267,8 @@ static int btt_read_pg(struct btt *btt, struct 
bio_integrity_payload *bip,
                ret = btt_data_read(arena, page, off, postmap, cur_len);
                if (ret) {
                        /* Media error - set the e_flag */
-                       if (btt_map_write(arena, premap, postmap, 0, 1, 
NVDIMM_IO_ATOMIC))
+                       if (btt_map_write(arena, premap, postmap, 0, 1,
+                               NVDIMM_IO_ATOMIC|NVDIMM_NO_DEEPFLUSH))
                                dev_warn_ratelimited(to_dev(arena),
                                        "Error persistently tracking bad blocks at 
%#x\n",
                                        premap);
@@ -1393,7 +1401,7 @@ static int btt_write_pg(struct btt *btt, struct 
bio_integrity_payload *bip,
                        goto out_map;

ret = btt_map_write(arena, premap, new_postmap, 0, 0,

-                       NVDIMM_IO_ATOMIC);
+                       NVDIMM_IO_ATOMIC|NVDIMM_NO_DEEPFLUSH);
                if (ret)
                        goto out_map;

diff --git a/drivers/nvdimm/claim.c b/drivers/nvdimm/claim.c

index 030dbde6b088..c1fa3291c063 100644
--- a/drivers/nvdimm/claim.c
+++ b/drivers/nvdimm/claim.c
@@ -294,9 +294,14 @@ static int nsio_rw_bytes(struct nd_namespace_common *ndns,
        }

memcpy_flushcache(nsio->addr + offset, buf, size);

-       ret = nvdimm_flush(to_nd_region(ndns->dev.parent), NULL);
-       if (ret)
+       if (!(flags & NVDIMM_NO_DEEPFLUSH)) {
+               ret = nvdimm_flush(to_nd_region(ndns->dev.parent), NULL);
+               if (ret)
+                       rc = ret;
+       } else {
                rc = ret;
+               pmem_wmb();
+       }

return rc;

  }
diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h
index ec5219680092..a16e259a8cff 100644
--- a/drivers/nvdimm/nd.h
+++ b/drivers/nvdimm/nd.h
@@ -22,7 +22,11 @@ enum {
         */
        ND_MAX_LANES = 256,
        INT_LBASIZE_ALIGNMENT = 64,
+       /*
+        * NVDIMM_IO_ATOMIC | NVDIMM_NO_DEEPFLUSH is support.
+        */
        NVDIMM_IO_ATOMIC = 1,
+       NVDIMM_NO_DEEPFLUSH = 2,
  };

struct nvdimm_drvdata {

--
2.27.0

Re: [PATCH] nvdimm: Add NVDIMM_NO_DEEPFLUSH flag to control btt data deepflush

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