Messages in this thread Patch in this message | | | From | "Kirill A. Shutemov" <> | Subject | [PATCHv6 15/22] thp, mm: naive support of thp in generic_perform_write | Date | Mon, 23 Sep 2013 15:05:43 +0300 |
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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 <kirill.shutemov@linux.intel.com> --- mm/filemap.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-)
diff --git a/mm/filemap.c b/mm/filemap.c index 410879a801..38d6856737 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -2384,12 +2384,14 @@ static ssize_t generic_perform_write(struct file *file, if (segment_eq(get_fs(), KERNEL_DS)) flags |= AOP_FLAG_UNINTERRUPTIBLE; + i_split_down_read(mapping->host); do { struct page *page; unsigned long offset; /* Offset into pagecache page */ 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, @@ -2419,8 +2421,14 @@ 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); @@ -2457,6 +2465,7 @@ again: } } while (iov_iter_count(i)); + i_split_up_read(mapping->host); return written ? written : status; } -- 1.8.4.rc3
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