From: npiggin@kernel.dk
To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: [patch 00/35] my inode scaling series for review
Date: Tue, 19 Oct 2010 14:42:16 +1100 [thread overview]
Message-ID: <20101019034216.319085068@kernel.dk> (raw)
Here is my famously tardy inode scaling patch set, for review for merging.
Yes it is a lot of patches, but it is very well broken out. It is not
rocket science -- if you don't understand something please get me to add
comments.
Patches 1-13 incrementally take over inode_lock in small, conservative,
obvious (as possible) steps. Subsequent patches improve code and
performance.
The only significant changes made from the inode scaling work in the
vfs-scale tree are merging to mainline, taking review suggestions, changing
the patch set to be better split up and improving comments and changelogs.
This is compatible with the rest of the dcache scaling improvements in my
tree, including the store-free path walking (rcu-walk).
I don't think Dave Chinner's approach is the way to go for a number of
reasons.
* My locking design allows i_lock to lock the entire state of the icache
for a particular inode. Not so with Dave's, and he had to add code not
required with inode_lock synchronisation or my i_lock synchronisation.
I prefer being very conservative about making changes, especially before
inode_lock is lifted (which will be the end-point of bisection for any
locking breakage before it).
* As far as I can tell, I have addressed all Dave and Christoph's real
concerns. The disagreement about the i_lock locking model can easily be
solved if they post a couple of small incremental patches to the end of the
series, making i_lock locking less regular and no longer protecting icache
state of that given inode (like inode_lock was able to pre-patchset). I've
repeatedly disagreed with this approach, however.
* I have used RCU for inodes, and structured a lot of the locking around that.
RCU is required for store-free path walking, so it makes more sense IMO to
implement now rather than in a subsequent release (and reworking inode locking to take advantage of it). I have a design sketched for using slab RCU freeing, which is a little more complex, but it should be able to take care of any
real-workload regressions if we do discover them.
* I implement per-zone LRU lists and locking, which are desperately required
for reasonable NUMA performance, and are a first step towards proper mem
controller control of vfs caches (Google have a similar per-zone LRU patch
they need for their fakenuma based memory control, I believe).
* I implemented per-cpu locking for inode sb lists. The scalability and
single threaded performance of the full vfs-scale stack has been tested
quite well. Most of the vfs scales pretty linearly up to several hundreds
of sockets at least. I have counted cycles on various x86 and POWER
architectures to improve single threaded performance. It's an ongoing
process but there has been a lot of work done already there.
We want all these things ASAP, so it doesn't make sense to me to stage out
significant locking changes in the icache code over several releases. Just
get them out of the way now -- the series is bisectable and reviewable, so
I think it will reduce churn and headache for everyone to get it out of the
way now.
next reply other threads:[~2010-10-19 3:56 UTC|newest]
Thread overview: 70+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-19 3:42 npiggin [this message]
2010-10-19 3:42 ` [patch 01/35] bit_spinlock: add required includes npiggin
2010-10-19 3:42 ` [patch 02/35] kernel: add bl_list npiggin
2010-10-19 3:42 ` [patch 03/35] mm: implement per-zone shrinker npiggin
2010-10-19 4:49 ` KOSAKI Motohiro
2010-10-19 5:33 ` Nick Piggin
2010-10-19 5:40 ` KOSAKI Motohiro
2010-10-19 3:42 ` [patch 04/35] vfs: convert inode and dentry caches to " npiggin
2010-10-19 3:42 ` [patch 05/35] fs: icache lock s_inodes list npiggin
2010-10-19 3:42 ` [patch 06/35] fs: icache lock inode hash npiggin
2010-10-19 3:42 ` [patch 07/35] fs: icache lock i_state npiggin
2010-10-19 10:47 ` Miklos Szeredi
2010-10-19 17:06 ` Peter Zijlstra
2010-10-19 3:42 ` [patch 08/35] fs: icache lock i_count npiggin
2010-10-19 10:16 ` Boaz Harrosh
2010-10-20 2:14 ` Nick Piggin
2010-10-19 3:42 ` [patch 09/35] fs: icache lock lru/writeback lists npiggin
2010-10-19 3:42 ` [patch 10/35] fs: icache atomic inodes_stat npiggin
2010-10-19 3:42 ` [patch 11/35] fs: icache lock inode state npiggin
2010-10-19 3:42 ` [patch 12/35] fs: inode atomic last_ino, iunique lock npiggin
2010-10-19 3:42 ` [patch 13/35] fs: icache remove inode_lock npiggin
2010-10-19 3:42 ` [patch 14/35] fs: icache factor hash lock into functions npiggin
2010-10-19 3:42 ` [patch 15/35] fs: icache per-bucket inode hash locks npiggin
2010-10-19 3:42 ` [patch 16/35] fs: icache lazy inode lru npiggin
2010-10-19 3:42 ` [patch 17/35] fs: icache RCU free inodes npiggin
2010-10-19 3:42 ` [patch 18/35] fs: avoid inode RCU freeing for pseudo fs npiggin
2010-10-19 3:42 ` [patch 19/35] fs: icache remove redundant i_sb_list umount locking npiggin
2010-10-20 12:46 ` Al Viro
2010-10-20 13:03 ` Nick Piggin
2010-10-20 13:27 ` Al Viro
2010-10-19 3:42 ` [patch 20/35] fs: icache rcu walk for i_sb_list npiggin
2010-10-19 3:42 ` [patch 21/35] fs: icache per-cpu nr_inodes, non-atomic nr_unused counters npiggin
2010-10-19 3:42 ` [patch 22/35] fs: icache per-cpu last_ino allocator npiggin
2010-10-19 3:42 ` [patch 23/35] fs: icache use per-CPU lists and locks for sb inode lists npiggin
2010-10-19 15:33 ` Miklos Szeredi
2010-10-20 2:37 ` Nick Piggin
2010-10-19 3:42 ` [patch 24/35] fs: icache use RCU to avoid locking in hash lookups npiggin
2010-10-19 3:42 ` [patch 25/35] fs: icache reduce some locking overheads npiggin
2010-10-19 3:42 ` [patch 26/35] fs: icache alloc anonymous inode allocation npiggin
2010-10-19 15:50 ` Miklos Szeredi
2010-10-20 2:38 ` Nick Piggin
2010-10-19 16:33 ` Christoph Hellwig
2010-10-20 3:07 ` Nick Piggin
2010-10-19 3:42 ` [patch 27/35] fs: icache split IO and LRU lists npiggin
2010-10-19 16:12 ` Miklos Szeredi
2010-10-20 2:41 ` Nick Piggin
2010-10-19 3:42 ` [patch 28/35] fs: icache split writeback and lru locks npiggin
2010-10-19 3:42 ` [patch 29/35] fs: icache per-bdi writeback list locking npiggin
2010-10-19 3:42 ` [patch 30/35] fs: icache lazy LRU avoid LRU locking after IO operation npiggin
2010-10-19 3:42 ` [patch 31/35] fs: icache per-zone inode LRU npiggin
2010-10-19 12:38 ` Dave Chinner
2010-10-20 2:35 ` Nick Piggin
2010-10-20 3:12 ` Nick Piggin
2010-10-20 9:43 ` Dave Chinner
2010-10-20 10:02 ` Nick Piggin
2010-10-20 3:14 ` KOSAKI Motohiro
2010-10-20 3:20 ` Nick Piggin
2010-10-20 3:29 ` KOSAKI Motohiro
2010-10-20 10:19 ` Dave Chinner
2010-10-20 10:41 ` Nick Piggin
2010-10-19 3:42 ` [patch 32/35] fs: icache minimise I_FREEING latency npiggin
2010-10-19 3:42 ` [patch 33/35] fs: icache introduce inode_get/inode_get_ilock npiggin
2010-10-19 10:17 ` Boaz Harrosh
2010-10-20 2:17 ` Nick Piggin
2010-10-19 3:42 ` [patch 34/35] fs: inode rename i_count to i_refs npiggin
2010-10-19 3:42 ` [patch 35/35] fs: icache document more lock orders npiggin
2010-10-19 16:22 ` [patch 00/35] my inode scaling series for review Christoph Hellwig
2010-10-20 3:05 ` Nick Piggin
2010-10-20 13:14 ` Al Viro
2010-10-20 13:59 ` Nick Piggin
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