From: Wu Fengguang Make the kconfig option READAHEAD_SMOOTH_AGING depend on READAHEAD_ALLOW_OVERHEADS, and turned off by default. Signed-off-by: Wu Fengguang Signed-off-by: Andrew Morton --- mm/Kconfig | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-) diff -puN mm/Kconfig~readahead-state-based-method-aging-accounting-readahead-kconfig-option-readahead_smooth_aging mm/Kconfig --- a/mm/Kconfig~readahead-state-based-method-aging-accounting-readahead-kconfig-option-readahead_smooth_aging +++ a/mm/Kconfig @@ -216,6 +216,14 @@ config DEBUG_READAHEAD Say N for production servers. config READAHEAD_SMOOTH_AGING - def_bool n if NUMA - default y if !NUMA - depends on ADAPTIVE_READAHEAD + bool "Fine grained readahead aging" + default n + depends on READAHEAD_ALLOW_OVERHEADS && !NUMA + help + Enable fine grained, mooth accounting of readahead aging. + + It can help servers which meet the following two conditions: + - have large number of concurrent readers + - have the danger of readahead thrashing(i.e. memory tight) + + This feature is only available on non-NUMA systems. _