Introduce a bit field ra->for_mmap for tagging mmap reads. The tag will be cleared immediate after submitting the IO. Acked-by: Jan Kara Signed-off-by: Wu Fengguang --- include/linux/fs.h | 1 + mm/filemap.c | 6 +++++- mm/readahead.c | 1 + 3 files changed, 7 insertions(+), 1 deletion(-) --- linux-next.orig/include/linux/fs.h 2012-01-25 15:57:50.000000000 +0800 +++ linux-next/include/linux/fs.h 2012-01-25 15:57:51.000000000 +0800 @@ -954,6 +954,7 @@ struct file_ra_state { unsigned int ra_pages; /* Maximum readahead window */ u16 mmap_miss; /* Cache miss stat for mmap accesses */ u8 pattern; /* one of RA_PATTERN_* */ + unsigned int for_mmap:1; /* readahead for mmap accesses */ loff_t prev_pos; /* Cache last read() position */ }; --- linux-next.orig/mm/filemap.c 2012-01-25 15:57:50.000000000 +0800 +++ linux-next/mm/filemap.c 2012-01-25 15:57:51.000000000 +0800 @@ -1578,6 +1578,7 @@ static void do_sync_mmap_readahead(struc return; if (VM_SequentialReadHint(vma)) { + ra->for_mmap = 1; page_cache_sync_readahead(mapping, ra, file, offset, ra->ra_pages); return; @@ -1597,6 +1598,7 @@ static void do_sync_mmap_readahead(struc /* * mmap read-around */ + ra->for_mmap = 1; ra->pattern = RA_PATTERN_MMAP_AROUND; ra_pages = max_sane_readahead(ra->ra_pages); ra->start = max_t(long, 0, offset - ra_pages / 2); @@ -1622,9 +1624,11 @@ static void do_async_mmap_readahead(stru return; if (ra->mmap_miss > 0) ra->mmap_miss--; - if (PageReadahead(page)) + if (PageReadahead(page)) { + ra->for_mmap = 1; page_cache_async_readahead(mapping, ra, file, page, offset, ra->ra_pages); + } } /** --- linux-next.orig/mm/readahead.c 2012-01-25 15:57:50.000000000 +0800 +++ linux-next/mm/readahead.c 2012-01-25 15:57:51.000000000 +0800 @@ -259,6 +259,7 @@ unsigned long ra_submit(struct file_ra_s actual = __do_page_cache_readahead(mapping, filp, ra->start, ra->size, ra->async_size); + ra->for_mmap = 0; return actual; } -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/