[PATCH 14/23] thp, mm: naive support of thp in generic_perform_write
From: Kirill A. Shutemov <hidden>
Date: 2013-08-04 02:17:16
Also in:
linux-fsdevel, lkml
Subsystem:
memory management, page cache, the rest · Maintainers:
Andrew Morton, Matthew Wilcox, Jan Kara, Linus Torvalds
From: "Kirill A. Shutemov" <redacted> For now we still write/read at most PAGE_CACHE_SIZE bytes a time. This implementation doesn't cover address spaces with backing storage. Signed-off-by: Kirill A. Shutemov <redacted> --- mm/filemap.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index b17ebb9..066bbff 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c@@ -2382,6 +2382,7 @@ static ssize_t generic_perform_write(struct file *file, unsigned long bytes; /* Bytes to write to page */ size_t copied; /* Bytes copied from user */ void *fsdata; + int subpage_nr = 0; offset = (pos & (PAGE_CACHE_SIZE - 1)); bytes = min_t(unsigned long, PAGE_CACHE_SIZE - offset,
@@ -2411,8 +2412,14 @@ again: if (mapping_writably_mapped(mapping)) flush_dcache_page(page); + if (PageTransHuge(page)) { + off_t huge_offset = pos & ~HPAGE_PMD_MASK; + subpage_nr = huge_offset >> PAGE_CACHE_SHIFT; + } + pagefault_disable(); - copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); + copied = iov_iter_copy_from_user_atomic(page + subpage_nr, i, + offset, bytes); pagefault_enable(); flush_dcache_page(page);
--
1.8.3.2
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