Gitweb: http://git.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commit;h=0835ab53eab5bbeebe1c135e92fb0c4d483dde17 Commit: 0835ab53eab5bbeebe1c135e92fb0c4d483dde17 Parent: 00d6296145c6b671a9886e380efc24f2731d856a Author: Andi Kleen <[EMAIL PROTECTED]> AuthorDate: Sat Feb 23 15:24:02 2008 -0800 Committer: Linus Torvalds <[EMAIL PROTECTED]> CommitDate: Sat Feb 23 17:12:16 2008 -0800
cgroup memory controller: document huge memory/cache overhead in Kconfig Document huge memory/cache overhead of memory controller in Kconfig I was a little surprised that 2.6.25-rc* increased struct page for the memory controller. At least on many x86-64 machines it will not fit into a single cache line now anymore and also costs considerable amounts of RAM. At earlier review I remembered asking for a external data structure for this. It's also quite unobvious that a innocent looking Kconfig option with a single line Kconfig description has such a negative effect. This patch attempts to document these disadvantages at least so that users configuring their kernel can make a informed decision. Signed-off-by: Andi Kleen <[EMAIL PROTECTED]> Cc: Balbir Singh <[EMAIL PROTECTED]> Acked-by: Paul Menage <[EMAIL PROTECTED]> Signed-off-by: Andrew Morton <[EMAIL PROTECTED]> Signed-off-by: Linus Torvalds <[EMAIL PROTECTED]> --- init/Kconfig | 8 ++++++++ 1 files changed, 8 insertions(+), 0 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index dcef8b5..f698a5a 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -394,6 +394,14 @@ config CGROUP_MEM_CONT Provides a memory controller that manages both page cache and RSS memory. + Note that setting this option increases fixed memory overhead + associated with each page of memory in the system by 4/8 bytes + and also increases cache misses because struct page on many 64bit + systems will not fit into a single cache line anymore. + + Only enable when you're ok with these trade offs and really + sure you need the memory controller. + config PROC_PID_CPUSET bool "Include legacy /proc/<pid>/cpuset file" depends on CPUSETS - To unsubscribe from this list: send the line "unsubscribe git-commits-head" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html