Messages in this thread | | | Subject | Re: [PATCH 2/6] change alloc function in pcpu_alloc_pages | From | Minchan Kim <> | Date | Mon, 19 Apr 2010 00:54:39 +0900 |
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Hi, Christoph.
On Fri, 2010-04-16 at 11:07 -0500, Christoph Lameter wrote: > On Thu, 15 Apr 2010, Minchan Kim wrote: > > > I don't want to remove alloc_pages for UMA system. > > alloc_pages is the same as alloc_pages_any_node so why have it?
I don't want to force using '_node' postfix on UMA users. Maybe they don't care getting page from any node and event don't need to know about _NODE_.
> > > #define alloc_pages alloc_page_sexact_node > > > > What I want to remove is just alloc_pages_node. :) > > Why remove it? If you want to get rid of -1 handling then check all the
alloc_pages_node have multiple meaning as you said. So some of users misuses that API. I want to clear intention of user.
> callsites and make sure that they are not using -1.
Sure. I must do it before any progressing.
> > Also could you define a constant for -1? -1 may have various meanings. One > is the local node and the other is any node. The difference is if memory > policies are obeyed or not. Note that alloc_pages follows memory policies > whereas alloc_pages_node does not. > > Therefore > > alloc_pages() != alloc_pages_node( , -1) >
Yes, now it's totally different. On UMA, It's any node but on NUMA, local node.
My concern is following as.
alloc_pages_node means any node but it has nid argument. Why should user of alloc_pages who want to get page from any node pass nid argument? It's rather awkward.
Some of user misunderstood it and used alloc_pages_node instead of alloc_pages_exact_node although he already know exact _NID_. Of course, it's not a BUG since if nid >= 0 it works well.
But I want to remove such multiple meaning to clear intention of user.
-- Kind regards, Minchan Kim
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