Oh, that makes sense. Though I wonder if you need to clear the caches at all when calling tbm_lossify(). Surely it never becomes un-lossified and plus, at least for lossy_page it would never be set to the current page anyway, it's either going to be set to InvalidBlockNumber, or some other previous page that
agree, fixed
was lossy. I also can't quite see the need to set page to NULL. Surely doing this would just mean we'd have to lookup the page again once tbm_lossify() is called if the next loop happened to be the same page? I think this would only be needed if the hash lookup was going to return a new instance of the page after we've lossified it, which from what I can tell won't happen.
Page could become an invalid pointer, because during tbm_mark_page_lossy() called from tbm_lossify() it could be freed.
I've also attached some benchmark results using your original table from up-thread. It seems that the caching if the page was seen as lossy is not much of a help in this test case. Did you find another one where you saw some better gains?
All what I found is about 0.5%... v3 contains your comments but it doesn't use
lossy_page cache.
--
Teodor Sigaev E-mail: teo...@sigaev.ru
WWW: http://www.sigaev.ru/
tbm_cachepage-2.3.patch.gz
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tbm_cachepage-3.patch.gz
Description: GNU Zip compressed data
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