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LU-14641 osd-ldiskfs: write commit declaring improvement
[fs/lustre-release.git] / lustre / osd-ldiskfs / osd_io.c
index 349e845..f8568c7 100644 (file)
@@ -1209,12 +1209,12 @@ cont_map:
                        GOTO(cleanup, rc);
                /*
                 * decay extent blocks if we could allocate
-                * good large(1M) extent.
+                * good large extent.
                 */
-               if (previous_total == 0 &&
-                   total >= OSD_DEFAULT_EXTENT_BYTES >> inode->i_blkbits)
+               if (total - previous_total >=
+                   osd_extent_bytes(osd) >> inode->i_blkbits)
                        osd_decay_extent_bytes(osd,
-                                              total << inode->i_blkbits);
+                               (total - previous_total) << inode->i_blkbits);
                /* look for next extent */
                fp = NULL;
                blocks += blocks_per_page * clen;
@@ -1355,6 +1355,7 @@ static int osd_is_mapped(struct dt_object *dt, __u64 offset,
        return cached_extent->mapped;
 }
 
+#define MAX_EXTENTS_PER_WRITE 100
 static int osd_declare_write_commit(const struct lu_env *env,
                                    struct dt_object *dt,
                                    struct niobuf_local *lnb, int npages,
@@ -1420,7 +1421,7 @@ static int osd_declare_write_commit(const struct lu_env *env,
                if (lnb[i].lnb_file_offset != extent.end || extent.end == 0) {
                        if (extent.end != 0)
                                extents += (extent.end - extent.start +
-                                       extent_bytes - 1) / extent_bytes;
+                                           extent_bytes - 1) / extent_bytes;
                        extent.start = lnb[i].lnb_file_offset;
                        extent.end = lnb[i].lnb_file_offset + lnb[i].lnb_len;
                } else {
@@ -1440,6 +1441,18 @@ static int osd_declare_write_commit(const struct lu_env *env,
 
        extents += (extent.end - extent.start +
                    extent_bytes - 1) / extent_bytes;
+       /**
+        * with system space usage growing up, mballoc codes won't
+        * try best to scan block group to align best free extent as
+        * we can. So extent bytes per extent could be decayed to a
+        * very small value, this could make us reserve too many credits.
+        * We could be more optimistic in the credit reservations, even
+        * in a case where the filesystem is nearly full, it is extremely
+        * unlikely that the worst case would ever be hit.
+        */
+       if (extents > MAX_EXTENTS_PER_WRITE)
+               extents = MAX_EXTENTS_PER_WRITE;
+
        /*
         * each extent can go into new leaf causing a split
         * 5 is max tree depth: inode + 4 index blocks
@@ -1482,6 +1495,11 @@ static int osd_declare_write_commit(const struct lu_env *env,
        else
                credits += extents;
 
+       CDEBUG(D_INODE,
+              "%s: inode #%lu extent_bytes %u extents %d credits %d\n",
+              osd_ino2name(inode), inode->i_ino, extent_bytes, extents,
+              credits);
+
 out_declare:
        osd_trans_declare_op(env, oh, OSD_OT_WRITE, credits);