diff mbox series

[1/3] doc: memcontrol: fix the obsolete content about force empty

Message ID 1546459533-36247-2-git-send-email-yang.shi@linux.alibaba.com (mailing list archive)
State New, archived
Headers show
Series [1/3] doc: memcontrol: fix the obsolete content about force empty | expand

Commit Message

Yang Shi Jan. 2, 2019, 8:05 p.m. UTC
We don't do page cache reparent anymore when offlining memcg, so update
force empty related content accordingly.

Cc: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>
---
 Documentation/cgroup-v1/memory.txt | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Shakeel Butt Jan. 2, 2019, 9:18 p.m. UTC | #1
On Wed, Jan 2, 2019 at 12:07 PM Yang Shi <yang.shi@linux.alibaba.com> wrote:
>
> We don't do page cache reparent anymore when offlining memcg, so update
> force empty related content accordingly.
>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>

Reviewed-by: Shakeel Butt <shakeelb@google.com>

> ---
>  Documentation/cgroup-v1/memory.txt | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
>
> diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt
> index 3682e99..8e2cb1d 100644
> --- a/Documentation/cgroup-v1/memory.txt
> +++ b/Documentation/cgroup-v1/memory.txt
> @@ -70,7 +70,7 @@ Brief summary of control files.
>   memory.soft_limit_in_bytes     # set/show soft limit of memory usage
>   memory.stat                    # show various statistics
>   memory.use_hierarchy           # set/show hierarchical account enabled
> - memory.force_empty             # trigger forced move charge to parent
> + memory.force_empty             # trigger forced page reclaim
>   memory.pressure_level          # set memory pressure notifications
>   memory.swappiness              # set/show swappiness parameter of vmscan
>                                  (See sysctl's vm.swappiness)
> @@ -459,8 +459,9 @@ About use_hierarchy, see Section 6.
>    the cgroup will be reclaimed and as many pages reclaimed as possible.
>
>    The typical use case for this interface is before calling rmdir().
> -  Because rmdir() moves all pages to parent, some out-of-use page caches can be
> -  moved to the parent. If you want to avoid that, force_empty will be useful.
> +  Though rmdir() offlines memcg, but the memcg may still stay there due to
> +  charged file caches. Some out-of-use page caches may keep charged until
> +  memory pressure happens. If you want to avoid that, force_empty will be useful.
>
>    Also, note that when memory.kmem.limit_in_bytes is set the charges due to
>    kernel pages will still be seen. This is not considered a failure and the
> --
> 1.8.3.1
>
Michal Hocko Jan. 3, 2019, 10:13 a.m. UTC | #2
On Thu 03-01-19 04:05:31, Yang Shi wrote:
> We don't do page cache reparent anymore when offlining memcg, so update
> force empty related content accordingly.
> 
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Johannes Weiner <hannes@cmpxchg.org>
> Signed-off-by: Yang Shi <yang.shi@linux.alibaba.com>

Thanks for the clean up.

Acked-by: Michal Hocko <mhocko@suse.com>

> ---
>  Documentation/cgroup-v1/memory.txt | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt
> index 3682e99..8e2cb1d 100644
> --- a/Documentation/cgroup-v1/memory.txt
> +++ b/Documentation/cgroup-v1/memory.txt
> @@ -70,7 +70,7 @@ Brief summary of control files.
>   memory.soft_limit_in_bytes	 # set/show soft limit of memory usage
>   memory.stat			 # show various statistics
>   memory.use_hierarchy		 # set/show hierarchical account enabled
> - memory.force_empty		 # trigger forced move charge to parent
> + memory.force_empty		 # trigger forced page reclaim
>   memory.pressure_level		 # set memory pressure notifications
>   memory.swappiness		 # set/show swappiness parameter of vmscan
>  				 (See sysctl's vm.swappiness)
> @@ -459,8 +459,9 @@ About use_hierarchy, see Section 6.
>    the cgroup will be reclaimed and as many pages reclaimed as possible.
>  
>    The typical use case for this interface is before calling rmdir().
> -  Because rmdir() moves all pages to parent, some out-of-use page caches can be
> -  moved to the parent. If you want to avoid that, force_empty will be useful.
> +  Though rmdir() offlines memcg, but the memcg may still stay there due to
> +  charged file caches. Some out-of-use page caches may keep charged until
> +  memory pressure happens. If you want to avoid that, force_empty will be useful.
>  
>    Also, note that when memory.kmem.limit_in_bytes is set the charges due to
>    kernel pages will still be seen. This is not considered a failure and the
> -- 
> 1.8.3.1
>
diff mbox series

Patch

diff --git a/Documentation/cgroup-v1/memory.txt b/Documentation/cgroup-v1/memory.txt
index 3682e99..8e2cb1d 100644
--- a/Documentation/cgroup-v1/memory.txt
+++ b/Documentation/cgroup-v1/memory.txt
@@ -70,7 +70,7 @@  Brief summary of control files.
  memory.soft_limit_in_bytes	 # set/show soft limit of memory usage
  memory.stat			 # show various statistics
  memory.use_hierarchy		 # set/show hierarchical account enabled
- memory.force_empty		 # trigger forced move charge to parent
+ memory.force_empty		 # trigger forced page reclaim
  memory.pressure_level		 # set memory pressure notifications
  memory.swappiness		 # set/show swappiness parameter of vmscan
 				 (See sysctl's vm.swappiness)
@@ -459,8 +459,9 @@  About use_hierarchy, see Section 6.
   the cgroup will be reclaimed and as many pages reclaimed as possible.
 
   The typical use case for this interface is before calling rmdir().
-  Because rmdir() moves all pages to parent, some out-of-use page caches can be
-  moved to the parent. If you want to avoid that, force_empty will be useful.
+  Though rmdir() offlines memcg, but the memcg may still stay there due to
+  charged file caches. Some out-of-use page caches may keep charged until
+  memory pressure happens. If you want to avoid that, force_empty will be useful.
 
   Also, note that when memory.kmem.limit_in_bytes is set the charges due to
   kernel pages will still be seen. This is not considered a failure and the