[PATCHv1, RFC 14/33] filemap: handle huge pages in do_generic_file_read()
From: Kirill A. Shutemov <hidden>
Date: 2016-07-26 00:35:16
Also in:
linux-block, linux-fsdevel, linux-mm, lkml
Subsystem:
memory management, page cache, the rest · Maintainers:
Andrew Morton, Matthew Wilcox, Linus Torvalds
Most of work happans on head page. Only when we need to do copy data to userspace we find relevant subpage. We are still limited by PAGE_SIZE per iteration. Lifting this limitation would require some more work. Signed-off-by: Kirill A. Shutemov <redacted> --- mm/filemap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index a3183e688718..566c7e6ca423 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c@@ -1819,6 +1819,7 @@ find_page: if (unlikely(page == NULL)) goto no_cached_page; } + page = compound_head(page); if (PageReadahead(page)) { page_cache_async_readahead(mapping, ra, filp, page,
@@ -1895,7 +1896,8 @@ page_ok: * now we can copy it to user space... */ - ret = copy_page_to_iter(page, offset, nr, iter); + ret = copy_page_to_iter(page + index - page->index, offset, + nr, iter); offset += ret; index += offset >> PAGE_SHIFT; offset &= ~PAGE_MASK;
@@ -2315,6 +2317,7 @@ page_not_uptodate: * because there really aren't any performance issues here * and we need to check for errors. */ + page = compound_head(page); ClearPageError(page); error = mapping->a_ops->readpage(file, page); if (!error) {
--
2.8.1
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