diff options
| -rw-r--r-- | include/linux/fs.h | 4 | ||||
| -rw-r--r-- | mm/filemap.c | 7 | ||||
| -rw-r--r-- | mm/readahead.c | 30 |
3 files changed, 21 insertions, 20 deletions
diff --git a/include/linux/fs.h b/include/linux/fs.h index 0949e243b8b..55a74ffa7e3 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -696,13 +696,13 @@ struct file_ra_state { unsigned long size; unsigned long flags; /* ra flags RA_FLAG_xxx*/ unsigned long cache_hit; /* cache hit count*/ - unsigned long prev_page; /* Cache last read() position */ + unsigned long prev_index; /* Cache last read() position */ unsigned long ahead_start; /* Ahead window */ unsigned long ahead_size; unsigned long ra_pages; /* Maximum readahead window */ unsigned long mmap_hit; /* Cache hit stat for mmap accesses */ unsigned long mmap_miss; /* Cache miss stat for mmap accesses */ - unsigned int offset; /* Offset where last read() ended in a page */ + unsigned int prev_offset; /* Offset where last read() ended in a page */ }; #define RA_FLAG_MISS 0x01 /* a cache miss occured against this file */ #define RA_FLAG_INCACHE 0x02 /* file is already in cache */ diff --git a/mm/filemap.c b/mm/filemap.c index 07f5b77114a..5631d6b2a62 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -877,8 +877,8 @@ void do_generic_mapping_read(struct address_space *mapping, cached_page = NULL; index = *ppos >> PAGE_CACHE_SHIFT; next_index = index; - prev_index = ra.prev_page; - prev_offset = ra.offset; + prev_index = ra.prev_index; + prev_offset = ra.prev_offset; last_index = (*ppos + desc->count + PAGE_CACHE_SIZE-1) >> PAGE_CACHE_SHIFT; offset = *ppos & ~PAGE_CACHE_MASK; @@ -947,7 +947,8 @@ page_ok: offset += ret; index += offset >> PAGE_CACHE_SHIFT; offset &= ~PAGE_CACHE_MASK; - prev_offset = ra.offset = offset; + prev_offset = offset; + ra.prev_offset = offset; page_cache_release(page); if (ret == nr && desc->count) diff --git a/mm/readahead.c b/mm/readahead.c index 0a6fed9d365..9861e883fe5 100644 --- a/mm/readahead.c +++ b/mm/readahead.c @@ -37,7 +37,7 @@ 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_page = -1; + ra->prev_index = -1; } EXPORT_SYMBOL_GPL(file_ra_state_init); @@ -202,19 +202,19 @@ out: * size: Number of pages in that read * Together, these form the "current window". * Together, start and size represent the `readahead window'. - * prev_page: The page which the readahead algorithm most-recently inspected. + * prev_index: The page which the readahead algorithm most-recently inspected. * It is mainly used to detect sequential file reading. * If page_cache_readahead sees that it is again being called for * a page which it just looked at, it can return immediately without * making any state changes. - * offset: Offset in the prev_page where the last read ended - used for + * offset: Offset in the prev_index where the last read ended - used for * detection of sequential file reading. * ahead_start, * ahead_size: Together, these form the "ahead window". * ra_pages: The externally controlled max readahead for this fd. * * When readahead is in the off state (size == 0), readahead is disabled. - * In this state, prev_page is used to detect the resumption of sequential I/O. + * In this state, prev_index is used to detect the resumption of sequential I/O. * * The readahead code manages two windows - the "current" and the "ahead" * windows. The intent is that while the application is walking the pages @@ -417,7 +417,7 @@ static int make_ahead_window(struct address_space *mapping, struct file *filp, ra->ahead_size = get_next_ra_size(ra); ra->ahead_start = ra->start + ra->size; - block = force || (ra->prev_page >= ra->ahead_start); + block = force || (ra->prev_index >= ra->ahead_start); ret = blockable_page_cache_readahead(mapping, filp, ra->ahead_start, ra->ahead_size, ra, block); @@ -469,13 +469,13 @@ page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra, * We avoid doing extra work and bogusly perturbing the readahead * window expansion logic. */ - if (offset == ra->prev_page && --req_size) + if (offset == ra->prev_index && --req_size) ++offset; - /* Note that prev_page == -1 if it is a first read */ - sequential = (offset == ra->prev_page + 1); - ra->prev_page = offset; - ra->offset = 0; + /* Note that prev_index == -1 if it is a first read */ + sequential = (offset == ra->prev_index + 1); + ra->prev_index = offset; + ra->prev_offset = 0; max = get_max_readahead(ra); newsize = min(req_size, max); @@ -484,7 +484,7 @@ page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra, if (newsize == 0 || (ra->flags & RA_FLAG_INCACHE)) goto out; - ra->prev_page += newsize - 1; + ra->prev_index += newsize - 1; /* * Special case - first read at start of file. We'll assume it's @@ -540,18 +540,18 @@ page_cache_readahead(struct address_space *mapping, struct file_ra_state *ra, * we get called back on the first page of the ahead window which * will allow us to submit more IO. */ - if (ra->prev_page >= ra->ahead_start) { + if (ra->prev_index >= ra->ahead_start) { ra->start = ra->ahead_start; ra->size = ra->ahead_size; make_ahead_window(mapping, filp, ra, 0); recheck: - /* prev_page shouldn't overrun the ahead window */ - ra->prev_page = min(ra->prev_page, + /* prev_index shouldn't overrun the ahead window */ + ra->prev_index = min(ra->prev_index, ra->ahead_start + ra->ahead_size - 1); } out: - return ra->prev_page + 1; + return ra->prev_index + 1; } EXPORT_SYMBOL_GPL(page_cache_readahead); |