问题
I want to reduce the kswapd timeout to increase the performance by use of fast devices like Flash, SSD as swapping devices.
回答1:
You can change the behavior of kswapd through 2 ways
Through Proc File System
From IBM Developerworks,
/proc/sys/vm/kswapd
Maximum number of pages the kernel tries to free at one time. If you want to increase bandwidth to/from swap, you will need to increase this number.
Minimum number of times the kernel tries to free a page on each swap.
The number of pages the kernel can write in one swap. This has the greatest impact on system performance. The larger the value, the more data can be swapped and the less time is spent disk seeking. However, a value that is too large will adversely affect system performance by flooding the request queue
Through Kernel Code
kswapd( void *p ) calls kswapd_try_to_sleep(). Here is where the kswapd daemon tries to sleep. Like this-
schedule_timeout(HZ/10) /* You need to modify here to change the timeout value */
Actually this is a very short time period for which it sleeps. After this short sleep, it checks if it was a premature sleep. If not, it goes fully to sleep ( no timeout here ) until explicitly woken up.
Tweaking the kernel code, building and testing it is no easy task. So I suggest you go the /proc filesystem way!
来源：https://stackoverflow.com/questions/9817737/how-to-change-the-linux-kernel-swap-daemon-kswapd-timeout