alloc_pages and struct page *

alloc_pages and struct page *

[Olivier Galibert]

If I get a struct page * from a call to alloc_pages with a non-zero
order, how do I get the struct page * of te following pages from the
same allocation in order to use them in calls to tcp_sendpage?

If there a documentation somewhere whcih would answer this kind of
questions?  Couldn't find anything pertinent in Documentation/*.

  OG.

Re: alloc_pages and struct page *

[Catalin Marinas]

Olivier Galibert <galibert@pobox.com> wrote:
> If I get a struct page * from a call to alloc_pages with a non-zero
> order, how do I get the struct page * of te following pages from the
> same allocation in order to use them in calls to tcp_sendpage?

page++;

The page structures are kept in an array, "mem_map" if
CONFIG_DISCONTIGMEM is not set or something like
"discontig_node_data[nid].node_mem_map" otherwise (this is true for
the ARM architecture, should be similar on the others). "alloc_pages"
allocates a contiguous range of pages from an array (and doesn't cross
a node boundary).

-- 
Catalin