[PATCH v2 3/5] swap: use direct I/O for SWP_FILE swap_readpage
From: Omar Sandoval <osandov@osandov.com>
Date: 2014-11-21 10:09:10
Also in:
linux-btrfs, linux-fsdevel, linux-nfs, lkml
Subsystem:
memory management, memory management - swap, the rest · Maintainers:
Andrew Morton, Chris Li, Kairui Song, Linus Torvalds
On Mon, Nov 17, 2014 at 07:48:17AM -0800, Christoph Hellwig wrote:
With the new iov_iter infrastructure that supprots direct I/O to kernel pages please get rid of the ->readpage hack first. I'm still utterly disapoined that this crap ever got merged.
Cc: Mel Gorman <mgorman@suse.de> Signed-off-by: Omar Sandoval <osandov@osandov.com> --- mm/page_io.c | 32 ++++++++++++++++++++++++++++---- 1 file changed, 28 insertions(+), 4 deletions(-)
diff --git a/mm/page_io.c b/mm/page_io.c
index 955db8b..10715e0 100644
--- a/mm/page_io.c
+++ b/mm/page_io.c@@ -283,8 +283,7 @@ int __swap_writepage(struct page *page, struct writeback_control *wbc, set_page_writeback(page); unlock_page(page); - ret = mapping->a_ops->direct_IO(ITER_BVEC | WRITE, - &kiocb, &from, + ret = mapping->a_ops->direct_IO(WRITE, &kiocb, &from, kiocb.ki_pos); if (ret == PAGE_SIZE) { count_vm_event(PSWPOUT);
@@ -348,12 +347,37 @@ int swap_readpage(struct page *page) } if (sis->flags & SWP_FILE) { + struct kiocb kiocb; struct file *swap_file = sis->swap_file; struct address_space *mapping = swap_file->f_mapping; + struct bio_vec bv = { + .bv_page = page, + .bv_len = PAGE_SIZE, + .bv_offset = 0, + }; + struct iov_iter to = { + .type = ITER_BVEC | READ, + .count = PAGE_SIZE, + .iov_offset = 0, + .nr_segs = 1, + }; + to.bvec = &bv; /* older gcc versions are broken */ + + init_sync_kiocb(&kiocb, swap_file); + kiocb.ki_pos = page_file_offset(page); + kiocb.ki_nbytes = PAGE_SIZE; - ret = mapping->a_ops->readpage(swap_file, page); - if (!ret) + ret = mapping->a_ops->direct_IO(READ, &kiocb, &to, + kiocb.ki_pos); + if (ret == PAGE_SIZE) { + SetPageUptodate(page); count_vm_event(PSWPIN); + ret = 0; + } else { + ClearPageUptodate(page); + SetPageError(page); + } + unlock_page(page); return ret; }
--
2.1.3
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