Sha Zhengju wrote:
Hi,
This is my second attempt to make memcg page stat lock simpler, the
first version: http://www.spinics.net/lists/linux-mm/msg50037.html.
In this version I investigate the potential race conditions among
page stat, move_account, charge, uncharge and try to prove it race
safe of my proposing lock scheme. The first patch is the basis of
the patchset, so if I've made some stupid mistake please do not
hesitate to point it out.
I have a provocational question. Who needs these numbers? I mean per-cgroup
nr_mapped and so on. It's too hard to maintain them carefully and I don't know
any clear usage for them. I have written several implementations of this stuff
for openvz kernel. But at the end I have decided to just remove it.
Do anybody knows really useful use cases for these nr_mapped counters?
In our kernel we have per-container nr_dirty and nr_writeback counters. Bit they are
implemented on top of radix-tree tags, and their owners are stored on inode/mapping.
So, this is completely different story.
I definitely have missed some discussions about these questions. Or not?
I hope it's a good time to return.
Change log:
v2<- v1:
* rewrite comments on race condition
* split orignal large patch to two parts
* change too heavy try_get_mem_cgroup_from_page() to rcu_read_lock
to hold memcg alive
Sha Zhengju (3):
memcg: rewrite the comment about race condition of page stat accounting
memcg: alter mem_cgroup_{update,inc,dec}_page_stat() args to memcg pointer
memcg: simplify lock of memcg page stat account
include/linux/memcontrol.h | 14 ++++++-------
mm/memcontrol.c | 16 ++++++---------
mm/rmap.c | 49 +++++++++++++++++++++++++++++++++-----------
3 files changed, 50 insertions(+), 29 deletions(-)
--
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>
--
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>