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.
