From: Jan Kara Subject: Update readahead and max_sectors tunables References: bnc#548529 Patch-mainline: no Increase read_ahead_kb and max_sectors_kb to values from SLES10 SP3 to get back sequential IO performance if we are not compiling a -desktop kernel flavor. Signed-off-by: Jan Kara --- include/linux/blkdev.h | 4 ++++ include/linux/mm.h | 4 ++++ 2 files changed, 8 insertions(+) --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -1038,7 +1038,11 @@ extern int blk_verify_command(unsigned c enum blk_default_limits { BLK_MAX_SEGMENTS = 128, BLK_SAFE_MAX_SECTORS = 255, +#ifndef CONFIG_KERNEL_DESKTOP + BLK_DEF_MAX_SECTORS = 2048, +#else BLK_DEF_MAX_SECTORS = 1024, +#endif BLK_MAX_SEGMENT_SIZE = 65536, BLK_SEG_BOUNDARY_MASK = 0xFFFFFFFFUL, }; --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -1302,7 +1302,11 @@ int write_one_page(struct page *page, in void task_dirty_inc(struct task_struct *tsk); /* readahead.c */ +#ifndef CONFIG_KERNEL_DESKTOP +#define VM_MAX_READAHEAD 512 /* kbytes */ +#else #define VM_MAX_READAHEAD 128 /* kbytes */ +#endif #define VM_MIN_READAHEAD 16 /* kbytes (includes current page) */ int force_page_cache_readahead(struct address_space *mapping, struct file *filp,