Implement vblock split write amp reduction algo

During a vblock split, we can save write amp by using mpool_mblock_punch() to FALLOC_FL_PUNCH_HOLE a portion of the mblock for both the left and right hand side destination mblocks. Signed-off-by: Tristan Partin <tpartin@micron.com> Co-authored-by: Nabeel Meeramohideen Mohamed <nmeeramohide@micron.com>
hse-project · Jan 19, 2023 · 4d35f54 · 4d35f54
1 parent d30305d
commit 4d35f54
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Showing 9 changed files with 326 additions and 102 deletions.
diff --git a/lib/cn/keep.c b/lib/cn/keep.c
@@ -93,7 +93,7 @@ kvset_keep_vblocks(
 
         for (uint32_t j = 0; j < cnt; ++j) {
             vbm->vbm_blkv[nv] = kvset_get_nth_vblock_id(kvset, j);
-            vbm->vbm_tot += kvset_get_nth_vblock_len(kvset, j);
+            vbm->vbm_tot += kvset_get_nth_vblock_wlen(kvset, j);
 
             if (j == vgmap_vbidx_out_end(kvset, kvg)) {
                 merr_t err;

diff --git a/lib/cn/kvset.c b/lib/cn/kvset.c
@@ -1773,11 +1773,19 @@ kvset_get_nth_vblock_id(struct kvset *ks, uint32_t index)
 }
 
 uint32_t
-kvset_get_nth_vblock_len(struct kvset *ks, uint32_t index)
+kvset_get_nth_vblock_wlen(struct kvset *ks, uint32_t index)
 {
     struct vblock_desc *vbd = lvx2vbd(ks, index);
 
-    return vbd ? vbd->vbd_len : 0;
+    return vbd ? vbd->vbd_wlen : 0;
+}
+
+uint32_t
+kvset_get_nth_vblock_alen(struct kvset *ks, uint32_t index)
+{
+    struct vblock_desc *vbd = lvx2vbd(ks, index);
+
+    return vbd ? vbd->vbd_alen : 0;
 }
 
 struct vblock_desc *
@@ -2297,7 +2305,7 @@ vr_start_read(
     /* update mblock properties */
     assert(lvx2vbd(ks, vbidx));
     vr->vr_mblk_dstart = lvx2vbd(ks, vbidx)->vbd_off;
-    vr->vr_mblk_dlen = lvx2vbd(ks, vbidx)->vbd_len;
+    vr->vr_mblk_dlen = lvx2vbd(ks, vbidx)->vbd_wlen;
     vr->vr_mbid = lvx2mbid(ks, vbidx);
 
     /* set io fields for async mblock read */
@@ -2708,7 +2716,7 @@ kvset_madvise_vblks(struct kvset *ks, int advice)
         for (j = 0; j < v->mbs_mblkc; j++) {
             struct vblock_desc *vbd = mbset_get_udata(v, j);
 
-            vbr_madvise_async(vbd, 0, vbd->vbd_len, advice, wq);
+            vbr_madvise_async(vbd, 0, vbd->vbd_wlen, advice, wq);
         }
     }
 }
@@ -2730,7 +2738,7 @@ kvset_madvise_capped(struct kvset *ks, int advice)
         for (uint j = 0; j < v->mbs_mblkc; j++) {
             struct vblock_desc *vbd = mbset_get_udata(v, j);
 
-            vbr_madvise_async(vbd, 0, min_t(uint, vbd->vbd_len, vra_len), advice, wq);
+            vbr_madvise_async(vbd, 0, min_t(uint, vbd->vbd_wlen, vra_len), advice, wq);
         }
     }
 }
@@ -2746,7 +2754,7 @@ kvset_madvise_vmaps(struct kvset *ks, int advice)
         for (uint j = 0; j < v->mbs_mblkc; j++) {
             struct vblock_desc *vbd = mbset_get_udata(v, j);
 
-            vbr_madvise(vbd, 0, vbd->vbd_len, advice);
+            vbr_madvise(vbd, 0, vbd->vbd_wlen, advice);
         }
     }
 }

diff --git a/lib/cn/kvset.h b/lib/cn/kvset.h
@@ -351,11 +351,18 @@ void
 kvset_set_rule(struct kvset *ks, enum cn_rule rule);
 
 /**
- * kvset_get_nth_vblock_len() - Get len of useful data in nth vblock
+ * Get len of useful written data in nth vblock
  */
 /* MTF_MOCK */
 uint32_t
-kvset_get_nth_vblock_len(struct kvset *km, uint32_t index);
+kvset_get_nth_vblock_wlen(struct kvset *km, uint32_t index);
+
+/**
+ * Get len of useful allocated data in nth vblock
+ */
+/* MTF_MOCK */
+uint32_t
+kvset_get_nth_vblock_alen(struct kvset *km, uint32_t index);
 
 /* MTF_MOCK */
 void