* know what the actual RPC size is. If this needs to change, it makes more
* sense to tune the i_blkbits value for the file based on the OSTs it is
* striped over, rather than having a constant value for all files here. */
-#define RAS_INCREASE_STEP(inode) (1UL << inode->i_blkbits)
+
+/* RAS_INCREASE_STEP should be (1UL << (inode->i_blkbits - CFS_PAGE_SHIFT)).
+ * Temprarily set RAS_INCREASE_STEP to 1MB. After 4MB RPC is enabled
+ * by default, this should be adjusted corresponding with max_read_ahead_mb
+ * and max_read_ahead_per_file_mb otherwise the readahead budget can be used
+ * up quickly which will affect read performance siginificantly. See LU-2816 */
+#define RAS_INCREASE_STEP(inode) (ONE_MB_BRW_SIZE >> CFS_PAGE_SHIFT)
static inline int stride_io_mode(struct ll_readahead_state *ras)
{