On Thu, 2 Feb 2012 17:37:13 -0800 Ying Han <yinghan@xxxxxxxxxx> wrote: > In v3.3-rc1, the global LRU has been removed with commit > "mm: make per-memcg LRU lists exclusive". The patch fixes up the memcg docs. > > Signed-off-by: Ying Han <yinghan@xxxxxxxxxx> > --- > Documentation/cgroups/memory.txt | 25 ++++++++++++------------- > 1 files changed, 12 insertions(+), 13 deletions(-) > > diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt > index 4c95c00..847a2a4 100644 > --- a/Documentation/cgroups/memory.txt > +++ b/Documentation/cgroups/memory.txt > @@ -34,8 +34,7 @@ Current Status: linux-2.6.34-mmotm(development version of 2010/April) > > Features: > - accounting anonymous pages, file caches, swap caches usage and limiting them. > - - private LRU and reclaim routine. (system's global LRU and private LRU > - work independently from each other) > + - pages are linked to per-memcg LRU exclusively, and there is no global LRU. > - optionally, memory+swap usage can be accounted and limited. > - hierarchical accounting > - soft limit > @@ -154,7 +153,7 @@ updated. page_cgroup has its own LRU on cgroup. > 2.2.1 Accounting details > > All mapped anon pages (RSS) and cache pages (Page Cache) are accounted. > -Some pages which are never reclaimable and will not be on the global LRU > +Some pages which are never reclaimable and will not be on the LRU > are not accounted. We just account pages under usual VM management. > > RSS pages are accounted at page_fault unless they've already been accounted > @@ -209,19 +208,19 @@ In this case, setting memsw.limit_in_bytes=3G will prevent bad use of swap. > By using memsw limit, you can avoid system OOM which can be caused by swap > shortage. > > -* why 'memory+swap' rather than swap. > -The global LRU(kswapd) can swap out arbitrary pages. Swap-out means > -to move account from memory to swap...there is no change in usage of > -memory+swap. In other words, when we want to limit the usage of swap without > -affecting global LRU, memory+swap limit is better than just limiting swap from > -OS point of view. > - > * What happens when a cgroup hits memory.memsw.limit_in_bytes > When a cgroup hits memory.memsw.limit_in_bytes, it's useless to do swap-out > in this cgroup. Then, swap-out will not be done by cgroup routine and file > -caches are dropped. But as mentioned above, global LRU can do swapout memory > -from it for sanity of the system's memory management state. You can't forbid > -it by cgroup. > +caches are dropped. > + > +TODO: > +* use 'memory+swap' rather than swap was due to existence of global LRU. It can > +swap out arbitrary pages. Swap-out means to move account from memory to swap... > +there is no change in usage of memory+swap. In other words, when we want to > +limit the usage of swap without affecting global LRU, memory+swap limit is > +better than just limiting swap from OS point of view. However, the global LRU > +has been removed now and all pages are linked in private LRU. We might want to > +revisit this in the future. > Could you devide this memory+swap discussion to otehr patch ? Do you want to do memory locking by setting swap_limit=0 ? Thanks, -Kame -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>