Re: [PATCH 12/13] MM: use AIO/DIO for reads from SWP_FS_OPS swap-space
From: Christoph Hellwig <hch@infradead.org>
Date: 2021-11-16 08:32:07
Also in:
linux-mm, linux-nfs, lkml
On Tue, Nov 16, 2021 at 01:44:04PM +1100, NeilBrown wrote:
When pages a read from SWP_FS_OPS swap-space, the reads are submitted as separate reads for each page. This is generally less efficient than larger reads. We can use the block-plugging infrastructure to delay submitting the read request until multiple contigious pages have been collected. This requires using ->direct_IO to submit the read (as ->readpages isn't suitable for swap).
Abusing the block code here seems little ugly. Also this won't compile if CONFIG_BLOCK is not set, will it? What is the problem with just batching up manually?
+ /* nofs needs as ->direct_IO may take the same mutex it takes for write */
Overly long line.