bug#22526: 25.0.90; Crash starting gnus

[Eli Zaretskii]

> From: Fabrice Popineau <fabrice.popineau@gmail.com>
> Date: Sun, 14 Feb 2016 22:41:43 +0100
> Cc: andrewjmoreton@gmail.com, 22526@debbugs.gnu.org
> 
> As vmmap shows it, the next region is unusable.
> The reserved region is 4k and the 60k after are lost.

But we only asked for 800 bytes, which could have been satisfied by
those 4KB that were reserved there, no?  So why dod the commit fail?

> I think it is worth to try that :
> 
> diff --git a/src/w32heap.c b/src/w32heap.c
> index 69706a3..db14357 100644
> --- a/src/w32heap.c
> +++ b/src/w32heap.c
> @@ -641,12 +641,12 @@ mmap_alloc (void **var, size_t nbytes)
> advance, and the buffer is enlarged several times as the data is
> decompressed on the fly. */
> if (nbytes < MAX_BUFFER_SIZE)
> - p = VirtualAlloc (NULL, (nbytes * 2), MEM_RESERVE, PAGE_READWRITE);
> + p = VirtualAlloc (NULL, ROUND_UP((nbytes * 2), get_allocation_unit()), 
> MEM_RESERVE,
> PAGE_READWRITE);
> 
> /* If it fails, or if the request is above 512MB, try with the
> requested size. */
> if (p == NULL)
> - p = VirtualAlloc (NULL, nbytes, MEM_RESERVE, PAGE_READWRITE);
> + p = VirtualAlloc (NULL, ROUND_UP(nbytes, get_allocation_unit()), 
> MEM_RESERVE,
> PAGE_READWRITE);
> 
> if (p != NULL)
> {
> 
> because running with it, vmmap shows now :
> 
> Images intégrées 1
> 
> and you see the 64k block is reserved, the first 4k are commited and the next 
> 60k are usable.
> Anyway, it is more correct with this patch than without it.

I agree.  I will commit something like that soon.