Use 'unsigned int' instead of 'unsigned long' for the readahead indexes/sizes. This helps reduce memory consumption on 64bit CPU when a lot of files are opened. Note that the (smaller) 32bit index can support up to 16PB file. Which should be sufficient large at least for now. Signed-off-by: Fengguang Wu --- include/linux/fs.h | 10 +++++----- mm/filemap.c | 2 +- mm/readahead.c | 5 +++-- 3 files changed, 9 insertions(+), 8 deletions(-) --- linux-2.6.22-rc6-mm1.orig/include/linux/fs.h +++ linux-2.6.22-rc6-mm1/include/linux/fs.h @@ -771,16 +771,16 @@ struct fown_struct { * Track a single file's readahead state */ struct file_ra_state { - pgoff_t start; /* where readahead started */ - unsigned long size; /* # of readahead pages */ - unsigned long async_size; /* do asynchronous readahead when + unsigned int start; /* where readahead started */ + unsigned int size; /* # of readahead pages */ + unsigned int async_size; /* do asynchronous readahead when there are only # of pages ahead */ - unsigned long ra_pages; /* Maximum readahead window */ + unsigned int 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 long prev_index; /* Cache last read() position */ unsigned int prev_offset; /* Offset where last read() ended in a page */ + unsigned int prev_index; /* Cache last read() position */ }; /* --- linux-2.6.22-rc6-mm1.orig/mm/filemap.c +++ linux-2.6.22-rc6-mm1/mm/filemap.c @@ -840,7 +840,7 @@ static void shrink_readahead_size_eio(st if (count > 5) return; count++; - printk(KERN_WARNING "Reducing readahead size to %luK\n", + printk(KERN_WARNING "Reducing readahead size to %dK\n", ra->ra_pages << (PAGE_CACHE_SHIFT - 10)); } --- linux-2.6.22-rc6-mm1.orig/mm/readahead.c +++ linux-2.6.22-rc6-mm1/mm/readahead.c @@ -342,11 +342,12 @@ ondemand_readahead(struct address_space bool hit_readahead_marker, pgoff_t offset, unsigned long req_size) { - unsigned long max; /* max readahead pages */ + int max; /* max readahead pages */ int sequential; max = ra->ra_pages; - sequential = (offset - ra->prev_index <= 1UL) || (req_size > max); + sequential = ((unsigned int)offset - ra->prev_index <= 1UL) || + (req_size > max); /* * It's the expected callback offset, assume sequential access. -- - 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/