Re: [PATCH v3 08/21] vmcore: copy non page-size aligned head and tail pages in 2nd kernel

From: Eric W. Biederman
Date: Tue Mar 19 2013 - 19:35:48 EST

Vivek Goyal <vgoyal@xxxxxxxxxx> writes:

> Are you saying that some parts of the vmcore file will support mmap() and
> others will not. If yes, how would a user know which parts of file are
> mappable and which are not.

I think I answered this in another email in my review but I will
reanswer here.

There is absolutely no need to copy pages. We can round up the mapping
to the nearest full page. Mmap already does that today for files so it
isn't even odd.

Which only leaves the headers and notes as potentially unmmapable. That
is more of a policy decision, and a decision on where we want to spend
memory. Rounding ELF notes to mutliples of PAGE_SIZE from a perspective
of memory usage seems pretty terrible taking memory usage up an order of

To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at
Please read the FAQ at