From: Abhradeep Chakraborty <chakrabortyabhradeep79@gmail.com>
Date: Thu, 30 Jun 2022 06:58:33 GMT
Subject: Re: [PATCH v2 4/6] pack-bitmap: prepare to read lookup table extension
Message-ID: <20220630065833.6333-1-chakrabortyabhradeep79@gmail.com>
In-Reply-To: <Yry0bKgayLB3GdsW@nand.local>


Taylor Blau <me@ttaylorr.com> wrote:

> That shouldn't be the case. When you have a chance, take a look at the
> alloc_nr macro, which shows how much memory we allocate at each
> step:
>
>     #define alloc_nr(x) (((x)+16)*3/2)
>
> Suppose we allocated 16 slots initially, so nr (the number of entries
> stored in the list) is 0 and alloc (the number of entries allocated) is
> 16. Then when we try to add the 17th item, we'll pass 16 to alloc_nr
> which will allocate 48 slots. Then 96, then 168, and so on.
>
> We only have to reallocate and copy the array when nr > alloc, which
> should be fairly infrequently, and happens less and less often the
> larger the array grows.

Ohh, I misunderstood the ALLOC_GROW function. Thanks!