Re: [PATCH] process_{tree,blob}: Remove useless xstrdup calls

From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Apr 11, 2009, 19:58 UTC
Message-ID: <alpine.LFD.2.00.0904111255530.4583@localhost.localdomain>
In-Reply-To: <20090411194000.GB21300@atjola.homenet>

On Sat, 11 Apr 2009, Björn Steinbrink wrote:

Show 8 quoted lines

> 
> No, this is x86-64, 8 byte pointers. But the savings are trivially
> explained I think. The struct object_array things are 20 bytes here (per
> object overhead!), so that's about 5M * 20 = 100M. And the average name
> length for the objects was 19 bytes, which means about another 100M.
> Both, the object_array stuff as well as the path names, were allocated
> and never freed. Your patch removed the object_array stuff, and it made
> the memory allocations for the names temporary. Right?

Right.

My original one-liner patch just did the name freeing part, but it did so only at the _end_ (when actually calling show_object()), so it probably didn't help RSS very much - because you still had one point in time where you had all the names allocated. It probably helped packing (since it allocates more _afterwards_), but likely didn't make much of a difference for just 'git rev-list".

So that was the impetus for trying to just avoid the "keep all objects around on the 'object_array' thing" patch, and then cleaning up the show_object() call semantics.

		Linus