[PATCH] memcg remvoe redundant message at swapon

From: KAMEZAWA Hiroyuki
Date: Wed Mar 18 2009 - 20:46:18 EST


This is based on this thread http://marc.info/?l=linux-mm&m=123724233418715&w=2
against the mmotm.
=
From: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

It's pointed out that swap_cgroup's message at swapon() is nonsense.
Because
* It can be calculated very easily if all necessary information is
written in Kconfig.
* It's not necessary to annoying people at every swapon().

In other view, now, memory usage per swp_entry is reduced to 2bytes
from 8bytes(64bit) and I think it's reasonably small.

Reported-by: Hugh Dickins <hugh@xxxxxxxxxxx>
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
---
Index: mmotm-2.6.29-Mar11/mm/page_cgroup.c
===================================================================
--- mmotm-2.6.29-Mar11.orig/mm/page_cgroup.c
+++ mmotm-2.6.29-Mar11/mm/page_cgroup.c
@@ -426,13 +426,6 @@ int swap_cgroup_swapon(int type, unsigne
}
mutex_unlock(&swap_cgroup_mutex);

- printk(KERN_INFO
- "swap_cgroup: uses %ld bytes of vmalloc for pointer array space"
- " and %ld bytes to hold mem_cgroup information per swap ents\n",
- array_size, length * PAGE_SIZE);
- printk(KERN_INFO
- "swap_cgroup can be disabled by noswapaccount boot option.\n");
-
return 0;
nomem:
printk(KERN_INFO "couldn't allocate enough memory for swap_cgroup.\n");
Index: mmotm-2.6.29-Mar11/init/Kconfig
===================================================================
--- mmotm-2.6.29-Mar11.orig/init/Kconfig
+++ mmotm-2.6.29-Mar11/init/Kconfig
@@ -603,6 +603,8 @@ config CGROUP_MEM_RES_CTLR_SWAP
is disabled by boot option, this will be automatically disabled and
there will be no overhead from this. Even when you set this config=y,
if boot option "noswapaccount" is set, swap will not be accounted.
+ Now, memory usage of swap_cgroup is 2 bytes per entry. If swap page
+ size is 4096bytes, 512k per 1Gbytes of swap.

endif # CGROUPS


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