Re: Fix object re-hashing
- From
Linus Torvalds <torvalds@osdl.org>
- Date
- Feb 12, 2006, 19:39 UTC
- Message-ID
- <Pine.LNX.4.64.0602121137330.3691@g5.osdl.org>
- In-Reply-To
- <7vlkwg9ye0.fsf@assigned-by-dhcp.cox.net>
On Sun, 12 Feb 2006, Junio C Hamano wrote:
Show 11 quoted lines
> > > Btw, as it currently stands, I worry a tiny tiny bit about the > > > > obj_allocs = (obj_allocs < 32 ? 32 : 2 * obj_allocs) > > > > thing, because I think that second "32" needs to be a "64" to be really > > safe (ie guarantee that the new obj_allocs value is always at least twice > > the old one). > > obj_allocs starts out as 0 so the first value it gets is 32 when > you need to insert the first element.
Yes. The point being that the code is "conceptually wrong", not that it doesn't work in practice. If we somehow could get into the situation that we had a hash size of 31, resizing it to 32 would be incorrect.
Of course, if we just make it a rule that the hash size must always be a power-of-two (add a comment, and enforce the rule by changing the modulus into a bitwise "and"), then that issue too goes away.
Linus