Re: [RFC] [PATCH 0/8] Inode diet v2

[Nick Piggin <nickpiggin@yahoo.com.au>]

Brian F. G. Bidulock wrote:
> Theodore,
> 
> On Wed, 21 Jun 2006, Theodore Tso wrote:
> 
> 
>>Unfortunately, since these structures are used by a large amount of
>>kernel code, some of the patches are quite involved, and/or will
>>require a lot of auditing and code review, for "only" 4 or 8 bytes at
>>a time (maybe more on 64-bit platforms).  However, since there are
>>many, many copies of struct inode all over the kernel, even a small
>>reduction in size can have a large beneficial result, and as the old
>>Chinese saying goes, a journey of thousand miles begins with a single
>>step....
> 
> 
> Can you grep inode_cache /proc/slabinfo to see whether you saved any
> memory at all?
> 
> You need to save 48 bytes per inode to fit one more into a slab with
> a 32 byte L1 cache slot; 120 bytes per inode, 64 byte L1 cache slot.

That would be interesting, but I don't think that is necessary. You
have different sizes of types and pages in different architectures
and configurations. Even if there were no immediate savings anywhere,
the inode diet still seems like a worthwhile investigation.

-- 
SUSE Labs, Novell Inc.
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