On Tue, Nov 04, 2014 at 05:36:39PM +0900, Kamezawa Hiroyuki wrote: > (2014/11/02 12:15), Johannes Weiner wrote: > > Memory cgroups used to have 5 per-page pointers. To allow users to > > disable that amount of overhead during runtime, those pointers were > > allocated in a separate array, with a translation layer between them > > and struct page. > > > > There is now only one page pointer remaining: the memcg pointer, that > > indicates which cgroup the page is associated with when charged. The > > complexity of runtime allocation and the runtime translation overhead > > is no longer justified to save that *potential* 0.19% of memory. With > > CONFIG_SLUB, page->mem_cgroup actually sits in the doubleword padding > > after the page->private member and doesn't even increase struct page, > > and then this patch actually saves space. Remaining users that care > > can still compile their kernels without CONFIG_MEMCG. > > > > text data bss dec hex filename > > 8828345 1725264 983040 11536649 b00909 vmlinux.old > > 8827425 1725264 966656 11519345 afc571 vmlinux.new > > > > Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> > > --- > > include/linux/memcontrol.h | 6 +- > > include/linux/mm_types.h | 5 + > > include/linux/mmzone.h | 12 -- > > include/linux/page_cgroup.h | 53 -------- > > init/main.c | 7 - > > mm/memcontrol.c | 124 +++++------------ > > mm/page_alloc.c | 2 - > > mm/page_cgroup.c | 319 -------------------------------------------- > > 8 files changed, 41 insertions(+), 487 deletions(-) > > > > Great! > Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx> Thank you! > BTW, init/Kconfig comments shouldn't be updated ? > (I'm sorry if it has been updated since your latest fix.) Good point. How about this? --- From: Johannes Weiner <hannes@xxxxxxxxxxx> Subject: [patch] mm: move page->mem_cgroup bad page handling into generic code fix Remove obsolete memory saving recommendations from the MEMCG Kconfig help text. Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx> --- init/Kconfig | 12 ------------ 1 file changed, 12 deletions(-) diff --git a/init/Kconfig b/init/Kconfig index 01b7f2a6abf7..d68d8b0780b3 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -983,18 +983,6 @@ config MEMCG Provides a memory resource controller that manages both anonymous memory and page cache. (See Documentation/cgroups/memory.txt) - Note that setting this option increases fixed memory overhead - associated with each page of memory in the system. By this, - 8(16)bytes/PAGE_SIZE on 32(64)bit system will be occupied by memory - usage tracking struct at boot. Total amount of this is printed out - at boot. - - Only enable when you're ok with these trade offs and really - sure you need the memory resource controller. Even when you enable - this, you can set "cgroup_disable=memory" at your boot option to - disable memory resource controller and you can avoid overheads. - (and lose benefits of memory resource controller) - config MEMCG_SWAP bool "Memory Resource Controller Swap Extension" depends on MEMCG && SWAP -- 2.1.3 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>