[PATCH 00/16] [PATCH 00/15] 512K readahead size with thrashing safe readahead v3

From: Wu Fengguang
Date: Mon Mar 01 2010 - 00:38:22 EST


This enlarges the default readahead size from 128K to 512K.
To avoid possible regressions, also do
- scale down readahead size on small device and small memory
- thrashing safe context readahead
- add readahead tracing/stats support to help expose possible problems

Besides, the patchset also includes several algorithm updates:
- no start-of-file readahead after lseek
- faster radix_tree_next_hole()/radix_tree_prev_hole()
- pagecache context based mmap read-around

Changes since v2:
- add notes on readahead size
- limit read-around size for small memory system, but don't limit readahead size
- bug fix: allow context readahead async size grow to its full size
- bug fix: let radix_tree_lookup_leaf_node() handle the height=1 case

Changes since v1:
- update mmap read-around heuristics (Thanks to Nick Piggin)
- radix_tree_lookup_leaf_node() for the pagecache based mmap read-around
- use __print_symbolic() to show readahead pattern names
(Thanks to Steven Rostedt)
- scale down readahead size proportional to system memory
(Thanks to Matt Mackall)
- add readahead size kernel parameter (by Nikanth Karthikesan)
- add comments from Christian Ehrhardt

Changes since RFC:
- move the lenthy intro text to individual patch changelogs
- treat get_capacity()==0 as uninitilized value (Thanks to Vivek Goyal)
- increase readahead size limit for small devices (Thanks to Jens Axboe)
- add fio test results by Vivek Goyal

[PATCH 01/16] readahead: limit readahead size for small devices
[PATCH 02/16] readahead: retain inactive lru pages to be accessed soon
[PATCH 03/16] readahead: bump up the default readahead size
[PATCH 04/16] readahead: make default readahead size a kernel parameter
[PATCH 05/16] readahead: limit read-ahead size for small memory systems
[PATCH 06/16] readahead: add notes on readahead size
[PATCH 07/16] readahead: replace ra->mmap_miss with ra->ra_flags
[PATCH 08/16] readahead: thrashing safe context readahead
[PATCH 09/16] readahead: record readahead patterns
[PATCH 10/16] readahead: add tracing event
[PATCH 11/16] readahead: add /debug/readahead/stats
[PATCH 12/16] readahead: dont do start-of-file readahead after lseek()
[PATCH 13/16] radixtree: introduce radix_tree_lookup_leaf_node()
[PATCH 14/16] radixtree: speed up the search for hole
[PATCH 15/16] readahead: reduce MMAP_LOTSAMISS for mmap read-around
[PATCH 16/16] readahead: pagecache context based mmap read-around

Documentation/kernel-parameters.txt | 4
block/blk-core.c | 3
block/genhd.c | 24 +
fs/fuse/inode.c | 2
fs/read_write.c | 3
include/linux/fs.h | 64 +++
include/linux/mm.h | 8
include/linux/radix-tree.h | 2
include/trace/events/readahead.h | 78 ++++
lib/radix-tree.c | 104 ++++-
mm/Kconfig | 13
mm/filemap.c | 34 +
mm/readahead.c | 458 ++++++++++++++++++++++----
13 files changed, 688 insertions(+), 109 deletions(-)


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