Home
Reading
Searching
Subscribe
Sponsors
Statistics
Posting
Contact
Spam
Lists
Links
About
Hosting
Filtering
Features Download
Marketing
Archives
FAQ
Blog
 
Gmane
From: Minchan Kim <minchan.kim <at> gmail.com>
Subject: [PATCH v2 00/10] Prevent LRU churning
Newsgroups: gmane.linux.kernel
Date: Sunday 29th May 2011 18:13:39 UTC (over 5 years ago)
Changelog since V1
 o Rebase on 2.6.39
 o change description slightly

There are some places to isolate and putback pages.
For example, compaction does it for getting contiguous page.
The problem is that if we isolate page in the middle of LRU and putback it
we lose LRU history as putback_lru_page inserts the page into head of LRU
list. 

LRU history is important parameter to select victim page in curre page
reclaim
when memory pressure is heavy. Unfortunately, if someone want to allocate
high-order page
and memory pressure is heavy, it would trigger compaction and we end up
lost LRU history.
It means we can evict working set pages and system latency would be high.

This patch is for solving the problem with two methods.

 * Anti-churning
   when we isolate page on LRU list, let's not isolate page we can't handle
 * De-churning
   when we putback page on LRU list in migration, let's insert new page
into old page's lru position.

[1,2,3/10] is just clean up.
[4,5,6/10] is related to Anti-churning. 
[7,8,9/10] is related to De-churning. 
[10/10] is adding to new tracepoints which is never for merge but just show
the effect.

I test and pass this series all[yes|no|mod|def]config.
And in my machine(1G DRAM, Intel Core 2 Duo), test scenario is following
as. 

1) Boot up
2) qemu ubuntu start up (1G mem)
3) Run many applications and switch attached script(which is made by Wu)

I think this is worst-case scenario since there are many contiguous pages
when machine boots up.
It means system memory isn't aging so that many pages are contiguous-LRU
order. It could make 
bad effect on inorder-lru but I solved the problem. Please see description
of [7/10].

Test result is following as. 
For compaction, it isolated about 20000 pages. Only 10 pages are put backed
with
out-of-order(ie, head of LRU) Others, about 19990 pages are put-backed with
in-order
(ie, position of old page while migration happens). It is eactly what I
want.

Welcome to any comment.

Minchan Kim (10):
  [1/10] Make clear description of isolate/putback functions
  [2/10] compaction: trivial clean up acct_isolated
  [3/10] Change int mode for isolate mode with enum ISOLATE_PAGE_MODE
  [4/10] Add additional isolation mode
  [5/10] compaction: make isolate_lru_page with filter aware
  [6/10] vmscan: make isolate_lru_page with filter aware
  [7/10] In order putback lru core
  [8/10] migration: make in-order-putback aware
  [9/10] compaction: make compaction use in-order putback
  [10/10] add tracepoints

 include/linux/memcontrol.h             |    5 +-
 include/linux/migrate.h                |   40 ++++
 include/linux/mm_types.h               |   16 ++-
 include/linux/swap.h                   |   18 ++-
 include/trace/events/inorder_putback.h |   79 +++++++
 include/trace/events/vmscan.h          |    8 +-
 mm/compaction.c                        |   47 ++--
 mm/internal.h                          |    2 +
 mm/memcontrol.c                        |    3 +-
 mm/migrate.c                           |  393
+++++++++++++++++++++++++++++++-
 mm/swap.c                              |    2 +-
 mm/vmscan.c                            |  115 ++++++++--
 12 files changed, 673 insertions(+), 55 deletions(-)
 create mode 100644 include/trace/events/inorder_putback.h

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to [email protected]  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:  email@kvack.org 
 
CD: 3ms