Messages in this thread | | | Date | Fri, 17 May 2013 11:17:08 -0700 | From | Zach Brown <> | Subject | Re: [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()) |
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> 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
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