Re: [PATCH v3 03/16] index-helper: new daemon for caching index and related stuff

On Wed, Apr 13, 2016 at 1:05 AM, Junio C Hamano [off-list ref] wrote:

quoted

quoted

 - access is slow (unless cached, but we can't be sure)

We could solve this (and the other problem) with mlock.

Probably you meant madvise(2)?

For something of a size comparable to the index file held by
index-helper-daemon in-core, I'd expect we wouldn't page too
badly.

I had a look at linux implementation of madvise(MADV_WILLNEED). All it
does is force populating the entire memory region, which is good. But
I suspect when memory is under pressure, some pages may be reclaimed.
index files in monster repo case can go up to a few hundred megabytes,
chances of being reclaimed rise accordingly. But we can reconsider
mlock() later when/if real problems happen.
-- 
Duy