lkml.org 
[lkml]   [2013]   [May]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [WiP]: aio support for migrating pages (Re: [PATCH V2 1/2] mm: hotplug: implement non-movable version of get_user_pages() called get_user_pages_non_movable())
> I ended up working on this a bit today, and managed to cobble together 
> something that somewhat works -- please see the patch below.

Just some quick observations:

> + ctx->ctx_file = anon_inode_getfile("[aio]", &aio_ctx_fops, ctx, O_RDWR);
> + if (IS_ERR(ctx->ctx_file)) {
> + ctx->ctx_file = NULL;
> + return -EAGAIN;
> + }

It's too bad that aio contexts will now be accounted against the filp
limits (get_empty_filp -> files_stat.max_files, etc).

> + for (i=0; i<nr_pages; i++) {
> + struct page *page;
> + void *ptr;
> + page = find_or_create_page(ctx->ctx_file->f_inode->i_mapping,
> + i, GFP_KERNEL);
> + if (!page) {
> + break;
> + }
> + ptr = kmap(page);
> + clear_page(ptr);
> + kunmap(page);
> + SetPageUptodate(page);
> + SetPageDirty(page);
> + unlock_page(page);
> + }

If they're GFP_KERNEL then you don't need to kmap them. But we probably
want to allocate with GFP_HIGHUSER and then use clear_user_highpage() to
zero them?

- z


\
 
 \ /
  Last update: 2013-05-17 21:01    [W:0.223 / U:0.120 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site