Combine the file_ra_state members unsigned long prev_index unsigned int prev_offset into loff_t prev_pos It is more consistent and better supports huge files. Thanks to Peter for the nice proposal! Cc: Peter Zijlstra Cc: Christoph Lameter Signed-off-by: Fengguang Wu --- fs/ext3/dir.c | 2 +- fs/ext4/dir.c | 2 +- fs/splice.c | 2 +- include/linux/fs.h | 3 +-- mm/filemap.c | 11 ++++++----- mm/readahead.c | 15 ++++++++------- 6 files changed, 18 insertions(+), 17 deletions(-) --- linux-2.6.22-git15.orig/include/linux/fs.h +++ linux-2.6.22-git15/include/linux/fs.h @@ -704,8 +704,7 @@ struct file_ra_state { unsigned int ra_pages; /* Maximum readahead window */ int mmap_miss; /* Cache miss stat for mmap accesses */ - unsigned long prev_index; /* Cache last read() position */ - unsigned int prev_offset; /* Offset where last read() ended in a page */ + loff_t prev_pos; /* Cache last read() position */ }; /* --- linux-2.6.22-git15.orig/mm/filemap.c +++ linux-2.6.22-git15/mm/filemap.c @@ -879,8 +879,8 @@ void do_generic_mapping_read(struct addr cached_page = NULL; index = *ppos >> PAGE_CACHE_SHIFT; next_index = index; - prev_index = ra.prev_index; - prev_offset = ra.prev_offset; + prev_index = ra.prev_pos >> PAGE_CACHE_SHIFT; + prev_offset = ra.prev_pos & (PAGE_CACHE_SIZE-1); last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; offset = *ppos & ~PAGE_CACHE_MASK; @@ -966,7 +966,6 @@ page_ok: index += offset >> PAGE_CACHE_SHIFT; offset &= ~PAGE_CACHE_MASK; prev_offset = offset; - ra.prev_offset = offset; page_cache_release(page); if (ret == nr && desc->count) @@ -1056,7 +1055,9 @@ no_cached_page: out: *_ra = ra; - _ra->prev_index = prev_index; + _ra->prev_pos = prev_index; + _ra->prev_pos <<= PAGE_CACHE_SHIFT; + _ra->prev_pos |= prev_offset; *ppos = ((loff_t) index << PAGE_CACHE_SHIFT) + offset; if (cached_page) @@ -1415,7 +1416,7 @@ retry_find: * Found the page and have a reference on it. */ mark_page_accessed(page); - ra->prev_index = page->index; + ra->prev_pos = page->index << PAGE_CACHE_SHIFT; vmf->page = page; return ret | VM_FAULT_LOCKED; --- linux-2.6.22-git15.orig/mm/readahead.c +++ linux-2.6.22-git15/mm/readahead.c @@ -45,7 +45,7 @@ void file_ra_state_init(struct file_ra_state *ra, struct address_space *mapping) { ra->ra_pages = mapping->backing_dev_info->ra_pages; - ra->prev_index = -1; + ra->prev_pos = -1; } EXPORT_SYMBOL_GPL(file_ra_state_init); @@ -326,7 +326,7 @@ static unsigned long get_next_ra_size(st * indicator. The flag won't be set on already cached pages, to avoid the * readahead-for-nothing fuss, saving pointless page cache lookups. * - * prev_index tracks the last visited page in the _previous_ read request. + * prev_pos tracks the last visited byte in the _previous_ read request. * It should be maintained by the caller, and will be used for detecting * small random reads. Note that the readahead algorithm checks loosely * for sequential patterns. Hence interleaved reads might be served as @@ -350,11 +350,9 @@ ondemand_readahead(struct address_space bool hit_readahead_marker, pgoff_t offset, unsigned long req_size) { - int max; /* max readahead pages */ - int sequential; - - max = ra->ra_pages; - sequential = (offset - ra->prev_index <= 1UL) || (req_size > max); + int max = ra->ra_pages; /* max readahead pages */ + pgoff_t prev_offset; + int sequential; /* * It's the expected callback offset, assume sequential access. @@ -368,6 +366,9 @@ ondemand_readahead(struct address_space goto readit; } + prev_offset = ra->prev_pos >> PAGE_CACHE_SHIFT; + sequential = offset - prev_offset <= 1UL || req_size > max; + /* * Standalone, small read. * Read as is, and do not pollute the readahead state. --- linux-2.6.22-git15.orig/fs/ext3/dir.c +++ linux-2.6.22-git15/fs/ext3/dir.c @@ -143,7 +143,7 @@ static int ext3_readdir(struct file * fi sb->s_bdev->bd_inode->i_mapping, &filp->f_ra, filp, index, 1); - filp->f_ra.prev_index = index; + filp->f_ra.prev_pos = index << PAGE_CACHE_SHIFT; bh = ext3_bread(NULL, inode, blk, 0, &err); } --- linux-2.6.22-git15.orig/fs/ext4/dir.c +++ linux-2.6.22-git15/fs/ext4/dir.c @@ -142,7 +142,7 @@ static int ext4_readdir(struct file * fi sb->s_bdev->bd_inode->i_mapping, &filp->f_ra, filp, index, 1); - filp->f_ra.prev_index = index; + filp->f_ra.prev_pos = index << PAGE_CACHE_SHIFT; bh = ext4_bread(NULL, inode, blk, 0, &err); } --- linux-2.6.22-git15.orig/fs/splice.c +++ linux-2.6.22-git15/fs/splice.c @@ -447,7 +447,7 @@ fill_it: */ while (page_nr < nr_pages) page_cache_release(pages[page_nr++]); - in->f_ra.prev_index = index; + in->f_ra.prev_pos = index << PAGE_CACHE_SHIFT; if (spd.nr_pages) return splice_to_pipe(pipe, &spd); -- - 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/