Re: [PATCH v4 0/3] ext4: increase mbcache scalability

From: Thavatchai Makphaibulchoke
Date: Sat Jan 25 2014 - 02:22:10 EST


On 01/24/2014 02:38 PM, Andi Kleen wrote:
> T Makphaibulchoke <tmac@xxxxxx> writes:
>
>> The patch consists of three parts.
>>
>> The first part changes the implementation of both the block and hash chains of
>> an mb_cache from list_head to hlist_bl_head and also introduces new members,
>> including a spinlock to mb_cache_entry, as required by the second part.
>
> spinlock per entry is usually overkill for larger hash tables.
>
> Can you use a second smaller lock table that just has locks and is
> indexed by a subset of the hash key. Most likely a very small
> table is good enough.
>
> Also I would be good to have some data on the additional memory consumption.
>
> -Andi
>

Thanks Andi for the comments. Will look into that.

Thanks,
Mak.

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