Bug 138549 – Remove BloomFilter size limit

• Status: RESOLVED
• Resolution: FIXED
• Component: Web Template Framework

[Antti Koivisto]

It works fine with sizes greater than 2^16.

[Antti Koivisto]

Created attachment 241261 [details]
patch

[Chris Dumez]

Comment on attachment 241261 [details]
patch

View in context: https://bugs.webkit.org/attachment.cgi?id=241261&action=review

> Source/WTF/wtf/BloomFilter.h:-40
> -    static_assert(keyBits <= 16, "BloomFilter key size must be less than or equal to 16!");

Shouldn't we make sure it is at least <= 32 so that 1 << keyBits below doesn't overflow?

I have looked carefully at the implementation but was this 16 value somehow corrected to the 16 value used in secondSlot() below?

[Chris Dumez]

(In reply to comment #2)
> Comment on attachment 241261 [details]
> patch
> 
> View in context:
> https://bugs.webkit.org/attachment.cgi?id=241261&action=review
> 
> > Source/WTF/wtf/BloomFilter.h:-40
> > -    static_assert(keyBits <= 16, "BloomFilter key size must be less than or equal to 16!");
> 
> Shouldn't we make sure it is at least <= 32 so that 1 << keyBits below
> doesn't overflow?
> 
> I have looked carefully at the implementation but was this 16 value somehow
> corrected to the 16 value used in secondSlot() below?

typo: s/corrected/connected

[Antti Koivisto]

I just removed the assert as it is unlikely anyone would try to create anything close to a 4GB filter.

I think we get sensible slot spread without any code changes. It is not entirely symmetric anymore, first slot uses the entire table while second is the lowest 2^16 slots. However there are only 16 unique bits per slot in the key anyway.

[Andreas Kling]

Comment on attachment 241261 [details]
patch

Sure, r=me

[Ahmad Saleem]

Landed - https://github.com/WebKit/WebKit/commit/c728c9b09cebb25ccf8b6d7906be1ccb334ac4e2

and didn't backed out. Marking "RESOLVED FIXED".