[PATCHv1, RFC 31/33] WIP: ext4: handle writeback with huge pages
From: Kirill A. Shutemov <hidden>
Date: 2016-07-26 00:35:33
Also in:
linux-ext4, linux-fsdevel, linux-mm, lkml
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
Modify mpage_map_and_submit_buffers() to do writeback with huge pages. This is somewhat unstable. I have hard time see full picture yet. More work is required. Not-yet-signed-off-by: Kirill A. Shutemov [off-list ref] --- fs/ext4/inode.c | 40 ++++++++++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 14 deletions(-)
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 2e22f62f007b..29133e4550fc 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c@@ -2088,16 +2088,16 @@ static int mpage_submit_page(struct mpage_da_data *mpd, struct page *page) loff_t size = i_size_read(mpd->inode); int err; - BUG_ON(page->index != mpd->first_page); - if (page->index == size >> PAGE_SHIFT) - len = size & ~PAGE_MASK; - else - len = PAGE_SIZE; + page = compound_head(page); + len = hpage_size(page); + if (page->index + hpage_nr_pages(page) - 1 == size >> PAGE_SHIFT) + len = size & ~hpage_mask(page); + clear_page_dirty_for_io(page); err = ext4_bio_write_page(&mpd->io_submit, page, len, mpd->wbc, false); if (!err) - mpd->wbc->nr_to_write--; - mpd->first_page++; + mpd->wbc->nr_to_write -= hpage_nr_pages(page); + mpd->first_page = round_up(mpd->first_page + 1, hpage_nr_pages(page)); return err; }
@@ -2245,12 +2245,16 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd) break; for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; + unsigned long diff; - if (page->index > end) + if (page_to_pgoff(page) > end) break; /* Up to 'end' pages must be contiguous */ - BUG_ON(page->index != start); + BUG_ON(page_to_pgoff(page) != start); + diff = (page - compound_head(page)) << bpp_bits; bh = head = page_buffers(page); + while (diff--) + bh = bh->b_this_page; do { if (lblk < mpd->map.m_lblk) continue;
@@ -2287,7 +2291,10 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd) * supports blocksize < pagesize as we will try to * convert potentially unmapped parts of inode. */ - mpd->io_submit.io_end->size += PAGE_SIZE; + if (PageTransCompound(page)) + mpd->io_submit.io_end->size += HPAGE_PMD_SIZE; + else + mpd->io_submit.io_end->size += PAGE_SIZE; /* Page fully mapped - let IO run! */ err = mpage_submit_page(mpd, page); if (err < 0) {
@@ -2295,6 +2302,10 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd) return err; } start++; + if (PageTransCompound(page)) { + start = round_up(start, HPAGE_PMD_NR); + break; + } } pagevec_release(&pvec); }
@@ -2534,7 +2545,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd) * mapping. However, page->index will not change * because we have a reference on the page. */ - if (page->index > end) + if (page_to_pgoff(page) > end) goto out; /*
@@ -2563,7 +2574,7 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd) if (!PageDirty(page) || (PageWriteback(page) && (mpd->wbc->sync_mode == WB_SYNC_NONE)) || - unlikely(page->mapping != mapping)) { + unlikely(page_mapping(page) != mapping)) { unlock_page(page); continue; }
@@ -2572,8 +2583,9 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd) BUG_ON(PageWriteback(page)); if (mpd->map.m_len == 0) - mpd->first_page = page->index; - mpd->next_page = page->index + 1; + mpd->first_page = page_to_pgoff(page); + mpd->next_page = round_up(mpd->first_page + 1, + hpage_nr_pages(compound_head(page))); /* Add all dirty buffers to mpd */ lblk = ((ext4_lblk_t)page->index) << (PAGE_SHIFT - blkbits);
--
2.8.1