diff options
| -rw-r--r-- | mm/readahead.c | 12 |
1 files changed, 10 insertions, 2 deletions
diff --git a/mm/readahead.c b/mm/readahead.c index 920aa20de891..f230b942cda2 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -381,6 +381,7 @@ ondemand_readahead(struct address_space *mapping, { struct backing_dev_info *bdi = inode_to_bdi(mapping->host); unsigned long max_pages = ra->ra_pages; + unsigned long add_pages; pgoff_t prev_offset; /* @@ -470,10 +471,17 @@ readit: * Will this read hit the readahead marker made by itself? * If so, trigger the readahead marker hit now, and merge * the resulted next readahead window into the current one. + * Take care of maximum IO pages as above. */ if (offset == ra->start && ra->size == ra->async_size) { - ra->async_size = get_next_ra_size(ra, max_pages); - ra->size += ra->async_size; + add_pages = get_next_ra_size(ra, max_pages); + if (ra->size + add_pages <= max_pages) { + ra->async_size = add_pages; + ra->size += add_pages; + } else { + ra->size = max_pages; + ra->async_size = max_pages >> 1; + } } return ra_submit(ra, mapping, filp); |