ria->ria_start, ria->ria_end, ria->ria_stoff, ria->ria_length,\
ria->ria_pages)
-#define RAS_INCREASE_STEP PTLRPC_MAX_BRW_PAGES
+/* Limit this to the blocksize instead of PTLRPC_BRW_MAX_SIZE, since we don't
+ * 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. */
+
+/* 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)
{
RETURN(ret);
}
-static void ras_set_start(struct ll_readahead_state *ras, unsigned long index)
+static void ras_set_start(struct inode *inode, struct ll_readahead_state *ras,
+ unsigned long index)
{
- ras->ras_window_start = index & (~(RAS_INCREASE_STEP - 1));
+ ras->ras_window_start = index & (~(RAS_INCREASE_STEP(inode) - 1));
}
/* called with the ras_lock held or from places where it doesn't matter */
-static void ras_reset(struct ll_readahead_state *ras, unsigned long index)
+static void ras_reset(struct inode *inode, struct ll_readahead_state *ras,
+ unsigned long index)
{
- ras->ras_last_readpage = index;
- ras->ras_consecutive_requests = 0;
- ras->ras_consecutive_pages = 0;
- ras->ras_window_len = 0;
- ras_set_start(ras, index);
- ras->ras_next_readahead = max(ras->ras_window_start, index);
+ ras->ras_last_readpage = index;
+ ras->ras_consecutive_requests = 0;
+ ras->ras_consecutive_pages = 0;
+ ras->ras_window_len = 0;
+ ras_set_start(inode, ras, index);
+ ras->ras_next_readahead = max(ras->ras_window_start, index);
- RAS_CDEBUG(ras);
+ RAS_CDEBUG(ras);
}
/* called with the ras_lock held or from places where it doesn't matter */
void ll_readahead_init(struct inode *inode, struct ll_readahead_state *ras)
{
spin_lock_init(&ras->ras_lock);
- ras_reset(ras, 0);
+ ras_reset(inode, ras, 0);
ras->ras_requests = 0;
CFS_INIT_LIST_HEAD(&ras->ras_read_beads);
}
* Check whether the read request is in the stride window.
* If it is in the stride window, return 1, otherwise return 0.
*/
-static int index_in_stride_window(unsigned long index,
- struct ll_readahead_state *ras,
- struct inode *inode)
+static int index_in_stride_window(struct ll_readahead_state *ras,
+ unsigned long index)
{
- unsigned long stride_gap = index - ras->ras_last_readpage - 1;
+ unsigned long stride_gap;
- if (ras->ras_stride_length == 0 || ras->ras_stride_pages == 0 ||
- ras->ras_stride_pages == ras->ras_stride_length)
- return 0;
+ if (ras->ras_stride_length == 0 || ras->ras_stride_pages == 0 ||
+ ras->ras_stride_pages == ras->ras_stride_length)
+ return 0;
- /* If it is contiguous read */
- if (stride_gap == 0)
- return ras->ras_consecutive_pages + 1 <= ras->ras_stride_pages;
+ stride_gap = index - ras->ras_last_readpage - 1;
- /*Otherwise check the stride by itself */
- return (ras->ras_stride_length - ras->ras_stride_pages) == stride_gap &&
- ras->ras_consecutive_pages == ras->ras_stride_pages;
+ /* If it is contiguous read */
+ if (stride_gap == 0)
+ return ras->ras_consecutive_pages + 1 <= ras->ras_stride_pages;
+
+ /* Otherwise check the stride by itself */
+ return (ras->ras_stride_length - ras->ras_stride_pages) == stride_gap &&
+ ras->ras_consecutive_pages == ras->ras_stride_pages;
}
static void ras_update_stride_detector(struct ll_readahead_state *ras,
RAS_CDEBUG(ras);
}
-static void ras_increase_window(struct ll_readahead_state *ras,
- struct ll_ra_info *ra, struct inode *inode)
+static void ras_increase_window(struct inode *inode,
+ struct ll_readahead_state *ras,
+ struct ll_ra_info *ra)
{
- /* The stretch of ra-window should be aligned with max rpc_size
- * but current clio architecture does not support retrieve such
- * information from lower layer. FIXME later
- */
- if (stride_io_mode(ras))
- ras_stride_increase_window(ras, ra, RAS_INCREASE_STEP);
- else
- ras->ras_window_len = min(ras->ras_window_len +
- RAS_INCREASE_STEP,
- ra->ra_max_pages_per_file);
+ /* The stretch of ra-window should be aligned with max rpc_size
+ * but current clio architecture does not support retrieve such
+ * information from lower layer. FIXME later
+ */
+ if (stride_io_mode(ras))
+ ras_stride_increase_window(ras, ra, RAS_INCREASE_STEP(inode));
+ else
+ ras->ras_window_len = min(ras->ras_window_len +
+ RAS_INCREASE_STEP(inode),
+ ra->ra_max_pages_per_file);
}
void ras_update(struct ll_sb_info *sbi, struct inode *inode,
GOTO(out_unlock, 0);
}
}
- if (zero) {
- /* check whether it is in stride I/O mode*/
- if (!index_in_stride_window(index, ras, inode)) {
- if (ras->ras_consecutive_stride_requests == 0 &&
- ras->ras_request_index == 0) {
- ras_update_stride_detector(ras, index);
- ras->ras_consecutive_stride_requests ++;
- } else {
- ras_stride_reset(ras);
- }
- ras_reset(ras, index);
- ras->ras_consecutive_pages++;
- GOTO(out_unlock, 0);
- } else {
- ras->ras_consecutive_pages = 0;
- ras->ras_consecutive_requests = 0;
- if (++ras->ras_consecutive_stride_requests > 1)
- stride_detect = 1;
- RAS_CDEBUG(ras);
- }
- } else {
- if (ra_miss) {
- if (index_in_stride_window(index, ras, inode) &&
- stride_io_mode(ras)) {
- /*If stride-RA hit cache miss, the stride dector
- *will not be reset to avoid the overhead of
- *redetecting read-ahead mode */
- if (index != ras->ras_last_readpage + 1)
- ras->ras_consecutive_pages = 0;
- ras_reset(ras, index);
- RAS_CDEBUG(ras);
- } else {
- /* Reset both stride window and normal RA
- * window */
- ras_reset(ras, index);
- ras->ras_consecutive_pages++;
- ras_stride_reset(ras);
- GOTO(out_unlock, 0);
- }
- } else if (stride_io_mode(ras)) {
- /* If this is contiguous read but in stride I/O mode
- * currently, check whether stride step still is valid,
- * if invalid, it will reset the stride ra window*/
- if (!index_in_stride_window(index, ras, inode)) {
- /* Shrink stride read-ahead window to be zero */
- ras_stride_reset(ras);
- ras->ras_window_len = 0;
- ras->ras_next_readahead = index;
- }
- }
- }
- ras->ras_consecutive_pages++;
- ras->ras_last_readpage = index;
- ras_set_start(ras, index);
-
- if (stride_io_mode(ras))
- /* Since stride readahead is sentivite to the offset
- * of read-ahead, so we use original offset here,
- * instead of ras_window_start, which is 1M aligned*/
- ras->ras_next_readahead = max(index,
- ras->ras_next_readahead);
- else
- ras->ras_next_readahead = max(ras->ras_window_start,
- ras->ras_next_readahead);
- RAS_CDEBUG(ras);
+ if (zero) {
+ /* check whether it is in stride I/O mode*/
+ if (!index_in_stride_window(ras, index)) {
+ if (ras->ras_consecutive_stride_requests == 0 &&
+ ras->ras_request_index == 0) {
+ ras_update_stride_detector(ras, index);
+ ras->ras_consecutive_stride_requests++;
+ } else {
+ ras_stride_reset(ras);
+ }
+ ras_reset(inode, ras, index);
+ ras->ras_consecutive_pages++;
+ GOTO(out_unlock, 0);
+ } else {
+ ras->ras_consecutive_pages = 0;
+ ras->ras_consecutive_requests = 0;
+ if (++ras->ras_consecutive_stride_requests > 1)
+ stride_detect = 1;
+ RAS_CDEBUG(ras);
+ }
+ } else {
+ if (ra_miss) {
+ if (index_in_stride_window(ras, index) &&
+ stride_io_mode(ras)) {
+ /*If stride-RA hit cache miss, the stride dector
+ *will not be reset to avoid the overhead of
+ *redetecting read-ahead mode */
+ if (index != ras->ras_last_readpage + 1)
+ ras->ras_consecutive_pages = 0;
+ ras_reset(inode, ras, index);
+ RAS_CDEBUG(ras);
+ } else {
+ /* Reset both stride window and normal RA
+ * window */
+ ras_reset(inode, ras, index);
+ ras->ras_consecutive_pages++;
+ ras_stride_reset(ras);
+ GOTO(out_unlock, 0);
+ }
+ } else if (stride_io_mode(ras)) {
+ /* If this is contiguous read but in stride I/O mode
+ * currently, check whether stride step still is valid,
+ * if invalid, it will reset the stride ra window*/
+ if (!index_in_stride_window(ras, index)) {
+ /* Shrink stride read-ahead window to be zero */
+ ras_stride_reset(ras);
+ ras->ras_window_len = 0;
+ ras->ras_next_readahead = index;
+ }
+ }
+ }
+ ras->ras_consecutive_pages++;
+ ras->ras_last_readpage = index;
+ ras_set_start(inode, ras, index);
+
+ if (stride_io_mode(ras))
+ /* Since stride readahead is sentivite to the offset
+ * of read-ahead, so we use original offset here,
+ * instead of ras_window_start, which is RPC aligned */
+ ras->ras_next_readahead = max(index, ras->ras_next_readahead);
+ else
+ ras->ras_next_readahead = max(ras->ras_window_start,
+ ras->ras_next_readahead);
+ RAS_CDEBUG(ras);
- /* Trigger RA in the mmap case where ras_consecutive_requests
- * is not incremented and thus can't be used to trigger RA */
- if (!ras->ras_window_len && ras->ras_consecutive_pages == 4) {
- ras->ras_window_len = RAS_INCREASE_STEP;
- GOTO(out_unlock, 0);
- }
+ /* Trigger RA in the mmap case where ras_consecutive_requests
+ * is not incremented and thus can't be used to trigger RA */
+ if (!ras->ras_window_len && ras->ras_consecutive_pages == 4) {
+ ras->ras_window_len = RAS_INCREASE_STEP(inode);
+ GOTO(out_unlock, 0);
+ }
- /* Initially reset the stride window offset to next_readahead*/
- if (ras->ras_consecutive_stride_requests == 2 && stride_detect) {
- /**
- * Once stride IO mode is detected, next_readahead should be
- * reset to make sure next_readahead > stride offset
- */
- ras->ras_next_readahead = max(index, ras->ras_next_readahead);
- ras->ras_stride_offset = index;
- ras->ras_window_len = RAS_INCREASE_STEP;
- }
+ /* Initially reset the stride window offset to next_readahead*/
+ if (ras->ras_consecutive_stride_requests == 2 && stride_detect) {
+ /**
+ * Once stride IO mode is detected, next_readahead should be
+ * reset to make sure next_readahead > stride offset
+ */
+ ras->ras_next_readahead = max(index, ras->ras_next_readahead);
+ ras->ras_stride_offset = index;
+ ras->ras_window_len = RAS_INCREASE_STEP(inode);
+ }
- /* The initial ras_window_len is set to the request size. To avoid
- * uselessly reading and discarding pages for random IO the window is
- * only increased once per consecutive request received. */
- if ((ras->ras_consecutive_requests > 1 || stride_detect) &&
- !ras->ras_request_index)
- ras_increase_window(ras, ra, inode);
- EXIT;
+ /* The initial ras_window_len is set to the request size. To avoid
+ * uselessly reading and discarding pages for random IO the window is
+ * only increased once per consecutive request received. */
+ if ((ras->ras_consecutive_requests > 1 || stride_detect) &&
+ !ras->ras_request_index)
+ ras_increase_window(inode, ras, ra);
+ EXIT;
out_unlock:
RAS_CDEBUG(ras);
ras->ras_request_index++;
git://git.whamcloud.com / fs / lustre-release.git / blobdiff