lkml.org 
[lkml]   [2021]   [Sep]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Struct page proposal
On Mon, Sep 27, 2021 at 07:48:15PM +0200, Vlastimil Babka wrote:
> On 9/23/21 03:21, Kent Overstreet wrote:
> > So if we have this:
> >
> > struct page {
> > unsigned long allocator;
> > unsigned long allocatee;
> > };
> >
> > The allocator field would be used for either a pointer to slab/slub's state, if
> > it's a slab page, or if it's a buddy allocator page it'd encode the order of the
> > allocation - like compound order today, and probably whether or not the
> > (compound group of) pages is free.
>
> The "free page in buddy allocator" case will be interesting to implement.
> What the buddy allocator uses today is:
>
> - PageBuddy - determine if page is free; a page_type (part of mapcount
> field) today, could be a bit in "allocator" field that would have to be 0 in
> all other "page is allocated" contexts.
> - nid/zid - to prevent merging accross node/zone boundaries, now part of
> page flags
> - buddy order
> - a list_head (reusing the "lru") to hold the struct page on the appropriate
> free list, which has to be double-linked so page can be taken from the
> middle of the list instantly

That list_head is the problematic one. Why do we need to be able to take a page
from the middle of a freelist?

\
 
 \ /
  Last update: 2021-09-27 19:55    [W:0.304 / U:0.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site