diff options
Diffstat (limited to 'mm/readahead.c')
| -rw-r--r-- | mm/readahead.c | 20 |
1 files changed, 19 insertions, 1 deletions
diff --git a/mm/readahead.c b/mm/readahead.c index ea650b8b02fb..95e3e71abb6b 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -128,6 +128,7 @@ #include <linux/blk-cgroup.h> #include <linux/fadvise.h> #include <linux/sched/mm.h> +#include <linux/fsnotify.h> #include "internal.h" @@ -549,6 +550,15 @@ void page_cache_sync_ra(struct readahead_control *ractl, pgoff_t prev_index, miss; /* + * If we have pre-content watches we need to disable readahead to make + * sure that we don't find 0 filled pages in cache that we never emitted + * events for. Filesystems supporting HSM must make sure to not call + * this function with ractl->file unset for files handled by HSM. + */ + if (ractl->file && unlikely(FMODE_FSNOTIFY_HSM(ractl->file->f_mode))) + return; + + /* * Even if readahead is disabled, issue this request as readahead * as we'll need it to satisfy the requested range. The forced * readahead will do the right thing and limit the read to just the @@ -626,6 +636,10 @@ void page_cache_async_ra(struct readahead_control *ractl, if (!ra->ra_pages) return; + /* See the comment in page_cache_sync_ra. */ + if (ractl->file && unlikely(FMODE_FSNOTIFY_HSM(ractl->file->f_mode))) + return; + /* * Same bit is used for PG_readahead and PG_reclaim. */ @@ -646,7 +660,11 @@ void page_cache_async_ra(struct readahead_control *ractl, 1UL << order); if (index == expected) { ra->start += ra->size; - ra->size = get_next_ra_size(ra, max_pages); + /* + * In the case of MADV_HUGEPAGE, the actual size might exceed + * the readahead window. + */ + ra->size = max(ra->size, get_next_ra_size(ra, max_pages)); ra->async_size = ra->size; goto readit; } |