lprocfs_counter_incr(sbi->ll_ra_stats, which);
}
+static inline bool ll_readahead_enabled(struct ll_sb_info *sbi)
+{
+ return sbi->ll_ra_info.ra_max_pages_per_file > 0 &&
+ sbi->ll_ra_info.ra_max_pages > 0;
+}
+
void ll_ra_stats_inc(struct inode *inode, enum ra_stat which)
{
struct ll_sb_info *sbi = ll_i2sbi(inode);
return start <= pos && pos <= end;
}
+enum ll_ra_page_hint {
+ MAYNEED = 0, /* this page possibly accessed soon */
+ WILLNEED /* this page is gurateed to be needed */
+};
+
/**
* Initiates read-ahead of a page with given index.
*
* \retval 0: page was added into \a queue for read ahead.
*/
static int ll_read_ahead_page(const struct lu_env *env, struct cl_io *io,
- struct cl_page_list *queue, pgoff_t index)
+ struct cl_page_list *queue, pgoff_t index,
+ enum ll_ra_page_hint hint)
{
struct cl_object *clob = io->ci_obj;
struct inode *inode = vvp_object_inode(clob);
- struct page *vmpage;
+ struct page *vmpage = NULL;
struct cl_page *page;
struct vvp_page *vpg;
enum ra_stat which = _NR_RA_STAT; /* keep gcc happy */
int rc = 0;
const char *msg = NULL;
+
ENTRY;
- vmpage = grab_cache_page_nowait(inode->i_mapping, index);
- if (vmpage == NULL) {
- which = RA_STAT_FAILED_GRAB_PAGE;
- msg = "g_c_p_n failed";
- GOTO(out, rc = -EBUSY);
+ switch (hint) {
+ case MAYNEED:
+ vmpage = grab_cache_page_nowait(inode->i_mapping, index);
+ if (vmpage == NULL) {
+ which = RA_STAT_FAILED_GRAB_PAGE;
+ msg = "g_c_p_n failed";
+ GOTO(out, rc = -EBUSY);
+ }
+ break;
+ case WILLNEED:
+ vmpage = find_or_create_page(inode->i_mapping, index,
+ GFP_NOFS);
+ if (vmpage == NULL)
+ GOTO(out, rc = -ENOMEM);
+ break;
+ default:
+ /* should not come here */
+ GOTO(out, rc = -EINVAL);
}
-
+
/* Check if vmpage was truncated or reclaimed */
if (vmpage->mapping != inode->i_mapping) {
which = RA_STAT_WRONG_GRAB_PAGE;
unlock_page(vmpage);
put_page(vmpage);
}
- if (msg != NULL) {
+ if (msg != NULL && hint == MAYNEED) {
ll_ra_stats_inc(inode, which);
CDEBUG(D_READA, "%s\n", msg);
static pgoff_t ras_align(struct ll_readahead_state *ras, pgoff_t index)
{
- return index - (index % ras->ras_rpc_pages);
+ unsigned opt_size = min(ras->ras_window_pages, ras->ras_rpc_pages);
+
+ if (opt_size == 0)
+ opt_size = 1;
+ return index - (index % opt_size);
}
/* Check whether the index is in the defined ra-window */
static unsigned long
ll_read_ahead_pages(const struct lu_env *env, struct cl_io *io,
struct cl_page_list *queue, struct ll_readahead_state *ras,
- struct ra_io_arg *ria, pgoff_t *ra_end)
+ struct ra_io_arg *ria, pgoff_t *ra_end, pgoff_t skip_index)
{
struct cl_read_ahead ra = { 0 };
/* busy page count is per stride */
for (page_idx = ria->ria_start_idx;
page_idx <= ria->ria_end_idx && ria->ria_reserved > 0;
page_idx++) {
+ if (skip_index && page_idx == skip_index)
+ continue;
if (ras_inside_ra_window(page_idx, ria)) {
if (ra.cra_end_idx == 0 || ra.cra_end_idx < page_idx) {
pgoff_t end_idx;
if (ras->ras_rpc_pages != ra.cra_rpc_pages &&
ra.cra_rpc_pages > 0)
ras->ras_rpc_pages = ra.cra_rpc_pages;
- /* trim it to align with optimal RPC size */
- end_idx = ras_align(ras, ria->ria_end_idx + 1);
- if (end_idx > 0 && !ria->ria_eof)
- ria->ria_end_idx = end_idx - 1;
+ if (!skip_index) {
+ /* trim it to align with optimal RPC size */
+ end_idx = ras_align(ras, ria->ria_end_idx + 1);
+ if (end_idx > 0 && !ria->ria_eof)
+ ria->ria_end_idx = end_idx - 1;
+ }
if (ria->ria_end_idx < ria->ria_end_idx_min)
ria->ria_end_idx = ria->ria_end_idx_min;
}
break;
/* If the page is inside the read-ahead window */
- rc = ll_read_ahead_page(env, io, queue, page_idx);
+ rc = ll_read_ahead_page(env, io, queue, page_idx,
+ MAYNEED);
if (rc < 0 && rc != -EBUSY)
break;
if (rc == -EBUSY) {
if (rc)
GOTO(out_put_env, rc);
- vvp_env_io(env)->vui_io_subtype = IO_NORMAL;
+ /* overwrite jobid inited in vvp_io_init() */
+ if (strncmp(ll_i2info(inode)->lli_jobid, work->lrw_jobid,
+ sizeof(work->lrw_jobid)))
+ memcpy(ll_i2info(inode)->lli_jobid, work->lrw_jobid,
+ sizeof(work->lrw_jobid));
+
vvp_env_io(env)->vui_fd = fd;
io->ci_state = CIS_LOCKED;
io->ci_async_readahead = true;
cl_2queue_init(queue);
rc = ll_read_ahead_pages(env, io, &queue->c2_qin, ras, ria,
- &ra_end_idx);
+ &ra_end_idx, 0);
if (ria->ria_reserved != 0)
ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved);
if (queue->c2_qin.pl_nr > 0) {
static int ll_readahead(const struct lu_env *env, struct cl_io *io,
struct cl_page_list *queue,
struct ll_readahead_state *ras, bool hit,
- struct file *file)
+ struct file *file, pgoff_t skip_index)
{
struct vvp_io *vio = vvp_env_io(env);
struct ll_thread_info *lti = ll_env_info(env);
if (ras->ras_window_pages > 0)
end_idx = ras->ras_window_start_idx + ras->ras_window_pages - 1;
+ if (skip_index)
+ end_idx = start_idx + ras->ras_window_pages - 1;
+
/* Enlarge the RA window to encompass the full read */
if (vio->vui_ra_valid &&
end_idx < vio->vui_ra_start_idx + vio->vui_ra_pages - 1)
vio->vui_ra_start_idx + vio->vui_ra_pages - 1;
pages_min = vio->vui_ra_start_idx + vio->vui_ra_pages -
ria->ria_start_idx;
+ /**
+ * For performance reason, exceeding @ra_max_pages
+ * are allowed, but this should be limited with RPC
+ * size in case a large block size read issued. Trim
+ * to RPC boundary.
+ */
+ pages_min = min(pages_min, ras->ras_rpc_pages -
+ (ria->ria_start_idx % ras->ras_rpc_pages));
}
+ /* don't over reserved for mmap range read */
+ if (skip_index)
+ pages_min = 0;
+
ria->ria_reserved = ll_ra_count_get(ll_i2sbi(inode), ria, pages,
pages_min);
if (ria->ria_reserved < pages)
atomic_read(&ll_i2sbi(inode)->ll_ra_info.ra_cur_pages),
ll_i2sbi(inode)->ll_ra_info.ra_max_pages);
- ret = ll_read_ahead_pages(env, io, queue, ras, ria, &ra_end_idx);
-
+ ret = ll_read_ahead_pages(env, io, queue, ras, ria, &ra_end_idx,
+ skip_index);
if (ria->ria_reserved != 0)
ll_ra_count_put(ll_i2sbi(inode), ria->ria_reserved);
RETURN(ret);
}
+static int ll_readpages(const struct lu_env *env, struct cl_io *io,
+ struct cl_page_list *queue,
+ pgoff_t start, pgoff_t end)
+{
+ int ret = 0;
+ __u64 kms;
+ pgoff_t page_idx;
+ int count = 0;
+
+ ENTRY;
+
+ ret = ll_readahead_file_kms(env, io, &kms);
+ if (ret != 0)
+ RETURN(ret);
+
+ if (kms == 0)
+ RETURN(0);
+
+ if (end != 0) {
+ unsigned long end_index;
+
+ end_index = (unsigned long)((kms - 1) >> PAGE_SHIFT);
+ if (end_index <= end)
+ end = end_index;
+ }
+
+ for (page_idx = start; page_idx <= end; page_idx++) {
+ ret= ll_read_ahead_page(env, io, queue, page_idx,
+ WILLNEED);
+ if (ret < 0)
+ break;
+ else if (ret == 0) /* ret 1 is already uptodate */
+ count++;
+ }
+
+ RETURN(count > 0 ? count : ret);
+}
+
static void ras_set_start(struct ll_readahead_state *ras, pgoff_t index)
{
ras->ras_window_start_idx = ras_align(ras, index);
ras_reset(ras, 0);
ras->ras_last_read_end_bytes = 0;
ras->ras_requests = 0;
+ ras->ras_range_min_start_idx = 0;
+ ras->ras_range_max_end_idx = 0;
+ ras->ras_range_requests = 0;
+ ras->ras_last_range_pages = 0;
}
/*
8UL << PAGE_SHIFT, 8UL << PAGE_SHIFT);
}
+static inline bool is_loose_mmap_read(struct ll_sb_info *sbi,
+ struct ll_readahead_state *ras,
+ unsigned long pos)
+{
+ unsigned long range_pages = sbi->ll_ra_info.ra_range_pages;
+
+ return pos_in_window(pos, ras->ras_last_read_end_bytes,
+ range_pages << PAGE_SHIFT,
+ range_pages << PAGE_SHIFT);
+}
+
+/**
+ * We have observed slow mmap read performances for some
+ * applications. The problem is if access pattern is neither
+ * sequential nor stride, but could be still adjacent in a
+ * small range and then seek a random position.
+ *
+ * So the pattern could be something like this:
+ *
+ * [1M data] [hole] [0.5M data] [hole] [0.7M data] [1M data]
+ *
+ *
+ * Every time an application reads mmap data, it may not only
+ * read a single 4KB page, but aslo a cluster of nearby pages in
+ * a range(e.g. 1MB) of the first page after a cache miss.
+ *
+ * The readahead engine is modified to track the range size of
+ * a cluster of mmap reads, so that after a seek and/or cache miss,
+ * the range size is used to efficiently prefetch multiple pages
+ * in a single RPC rather than many small RPCs.
+ */
+static void ras_detect_cluster_range(struct ll_readahead_state *ras,
+ struct ll_sb_info *sbi,
+ unsigned long pos, unsigned long count)
+{
+ pgoff_t last_pages, pages;
+ pgoff_t end_idx = (pos + count - 1) >> PAGE_SHIFT;
+
+ last_pages = ras->ras_range_max_end_idx -
+ ras->ras_range_min_start_idx + 1;
+ /* First time come here */
+ if (!ras->ras_range_max_end_idx)
+ goto out;
+
+ /* Random or Stride read */
+ if (!is_loose_mmap_read(sbi, ras, pos))
+ goto out;
+
+ ras->ras_range_requests++;
+ if (ras->ras_range_max_end_idx < end_idx)
+ ras->ras_range_max_end_idx = end_idx;
+
+ if (ras->ras_range_min_start_idx > (pos >> PAGE_SHIFT))
+ ras->ras_range_min_start_idx = pos >> PAGE_SHIFT;
+
+ /* Out of range, consider it as random or stride */
+ pages = ras->ras_range_max_end_idx -
+ ras->ras_range_min_start_idx + 1;
+ if (pages <= sbi->ll_ra_info.ra_range_pages)
+ return;
+out:
+ ras->ras_last_range_pages = last_pages;
+ ras->ras_range_requests = 0;
+ ras->ras_range_min_start_idx = pos >> PAGE_SHIFT;
+ ras->ras_range_max_end_idx = end_idx;
+}
+
static void ras_detect_read_pattern(struct ll_readahead_state *ras,
struct ll_sb_info *sbi,
loff_t pos, size_t count, bool mmap)
ras->ras_consecutive_bytes += count;
if (mmap) {
pgoff_t idx = ras->ras_consecutive_bytes >> PAGE_SHIFT;
+ unsigned long ra_range_pages =
+ max_t(unsigned long, RA_MIN_MMAP_RANGE_PAGES,
+ sbi->ll_ra_info.ra_range_pages);
- if ((idx >= 4 && (idx & 3UL) == 0) || stride_detect)
+ if ((idx >= ra_range_pages &&
+ idx % ra_range_pages == 0) || stride_detect)
ras->ras_need_increase_window = true;
} else if ((ras->ras_consecutive_requests > 1 || stride_detect)) {
ras->ras_need_increase_window = true;
*/
static void ras_update(struct ll_sb_info *sbi, struct inode *inode,
struct ll_readahead_state *ras, pgoff_t index,
- enum ras_update_flags flags)
+ enum ras_update_flags flags, struct cl_io *io)
{
struct ll_ra_info *ra = &sbi->ll_ra_info;
bool hit = flags & LL_RAS_HIT;
if (ras->ras_no_miss_check)
GOTO(out_unlock, 0);
- if (flags & LL_RAS_MMAP)
+ if (io && io->ci_rand_read)
+ GOTO(out_unlock, 0);
+
+ if (io && io->ci_seq_read) {
+ if (!hit) {
+ /* to avoid many small read RPC here */
+ ras->ras_window_pages = sbi->ll_ra_info.ra_range_pages;
+ ll_ra_stats_inc_sbi(sbi, RA_STAT_MMAP_RANGE_READ);
+ }
+ goto skip;
+ }
+
+ if (flags & LL_RAS_MMAP) {
+ unsigned long ra_pages;
+
+ ras_detect_cluster_range(ras, sbi, index << PAGE_SHIFT,
+ PAGE_SIZE);
ras_detect_read_pattern(ras, sbi, (loff_t)index << PAGE_SHIFT,
PAGE_SIZE, true);
+ /* we did not detect anything but we could prefetch */
+ if (!ras->ras_need_increase_window &&
+ ras->ras_window_pages <= sbi->ll_ra_info.ra_range_pages &&
+ ras->ras_range_requests >= 2) {
+ if (!hit) {
+ ra_pages = max_t(unsigned long,
+ RA_MIN_MMAP_RANGE_PAGES,
+ ras->ras_last_range_pages);
+ if (index < ra_pages / 2)
+ index = 0;
+ else
+ index -= ra_pages / 2;
+ ras->ras_window_pages = ra_pages;
+ ll_ra_stats_inc_sbi(sbi,
+ RA_STAT_MMAP_RANGE_READ);
+ } else {
+ ras->ras_window_pages = 0;
+ }
+ goto skip;
+ }
+ }
+
if (!hit && ras->ras_window_pages &&
index < ras->ras_next_readahead_idx &&
pos_in_window(index, ras->ras_window_start_idx, 0,
GOTO(out_unlock, 0);
}
}
+
+skip:
ras_set_start(ras, index);
if (stride_io_mode(ras)) {
{
struct inode *inode = vvp_object_inode(page->cp_obj);
struct ll_sb_info *sbi = ll_i2sbi(inode);
- struct ll_file_data *fd = file->private_data;
- struct ll_readahead_state *ras = &fd->fd_ras;
+ struct ll_file_data *fd = NULL;
+ struct ll_readahead_state *ras = NULL;
struct cl_2queue *queue = &io->ci_queue;
struct cl_sync_io *anchor = NULL;
struct vvp_page *vpg;
- int rc = 0;
+ int rc = 0, rc2 = 0;
bool uptodate;
+ pgoff_t io_start_index;
+ pgoff_t io_end_index;
ENTRY;
+ if (file) {
+ fd = file->private_data;
+ ras = &fd->fd_ras;
+ }
+
vpg = cl2vvp_page(cl_object_page_slice(page->cp_obj, page));
uptodate = vpg->vpg_defer_uptodate;
- if (sbi->ll_ra_info.ra_max_pages_per_file > 0 &&
- sbi->ll_ra_info.ra_max_pages > 0 &&
- !vpg->vpg_ra_updated) {
+ if (ll_readahead_enabled(sbi) && !vpg->vpg_ra_updated && ras) {
struct vvp_io *vio = vvp_env_io(env);
enum ras_update_flags flags = 0;
flags |= LL_RAS_HIT;
if (!vio->vui_ra_valid)
flags |= LL_RAS_MMAP;
- ras_update(sbi, inode, ras, vvp_index(vpg), flags);
+ ras_update(sbi, inode, ras, vvp_index(vpg), flags, io);
}
cl_2queue_init(queue);
cl_2queue_add(queue, page);
}
- if (sbi->ll_ra_info.ra_max_pages_per_file > 0 &&
- sbi->ll_ra_info.ra_max_pages > 0) {
- int rc2;
+ io_start_index = cl_index(io->ci_obj, io->u.ci_rw.crw_pos);
+ io_end_index = cl_index(io->ci_obj, io->u.ci_rw.crw_pos +
+ io->u.ci_rw.crw_count - 1);
+ if (ll_readahead_enabled(sbi) && ras && !io->ci_rand_read) {
+ pgoff_t skip_index = 0;
+ if (ras->ras_next_readahead_idx < vvp_index(vpg))
+ skip_index = vvp_index(vpg);
rc2 = ll_readahead(env, io, &queue->c2_qin, ras,
- uptodate, file);
- CDEBUG(D_READA, DFID "%d pages read ahead at %lu\n",
+ uptodate, file, skip_index);
+ CDEBUG(D_READA, DFID " %d pages read ahead at %lu\n",
+ PFID(ll_inode2fid(inode)), rc2, vvp_index(vpg));
+ } else if (vvp_index(vpg) == io_start_index &&
+ io_end_index - io_start_index > 0) {
+ rc2 = ll_readpages(env, io, &queue->c2_qin, io_start_index + 1,
+ io_end_index);
+ CDEBUG(D_READA, DFID " %d pages read at %lu\n",
PFID(ll_inode2fid(inode)), rc2, vvp_index(vpg));
}
ras->ras_next_readahead_idx = end_idx + 1;
ras->ras_async_last_readpage_idx = start_idx;
spin_unlock(&ras->ras_lock);
+ memcpy(lrw->lrw_jobid, ll_i2info(inode)->lli_jobid,
+ sizeof(lrw->lrw_jobid));
ll_readahead_work_add(inode, lrw);
} else {
return -ENOMEM;
unsigned long fast_read_pages =
max(RA_REMAIN_WINDOW_MIN, ras->ras_rpc_pages);
loff_t skip_pages;
+ loff_t stride_bytes = ras->ras_stride_bytes;
- if (stride_io_mode(ras)) {
+ if (stride_io_mode(ras) && stride_bytes) {
skip_pages = (ras->ras_stride_length +
- ras->ras_stride_bytes - 1) / ras->ras_stride_bytes;
+ ras->ras_stride_bytes - 1) / stride_bytes;
skip_pages *= fast_read_pages;
} else {
skip_pages = fast_read_pages;
/* For fast read, it updates read ahead state only
* if the page is hit in cache because non cache page
* case will be handled by slow read later. */
- ras_update(sbi, inode, ras, vvp_index(vpg), flags);
+ ras_update(sbi, inode, ras, vvp_index(vpg), flags, io);
/* avoid duplicate ras_update() call */
vpg->vpg_ra_updated = 1;
*/
if (file->f_flags & O_DIRECT &&
lcc && lcc->lcc_type == LCC_RW &&
- !io->ci_ignore_lockless) {
+ !io->ci_dio_lock) {
unlock_page(vmpage);
- io->ci_ignore_lockless = 1;
+ io->ci_dio_lock = 1;
io->ci_need_restart = 1;
RETURN(-ENOLCK);
}
git://git.whamcloud.com / fs / lustre-release.git / blobdiff