Re: [PATCHv6 13/37] mm: make write_cache_pages() work on huge pages
From: Matthew Wilcox <willy@infradead.org>
Date: 2017-02-10 17:46:10
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On Thu, Jan 26, 2017 at 02:57:55PM +0300, Kirill A. Shutemov wrote:
We writeback whole huge page a time. Let's adjust iteration this way. Signed-off-by: Kirill A. Shutemov <redacted>
I think a lot of the complexity in this patch is from pagevec_lookup_tag giving you subpages rather than head pages...
quoted hunk ↗ jump to hunk
@@ -2268,7 +2273,8 @@ int write_cache_pages(struct address_space *mapping, * not be suitable for data integrity * writeout). */ - done_index = page->index + 1; + done_index = compound_head(page)->index + + hpage_nr_pages(page); done = 1; break; }
you'd still need this line, but it'd only be: done_index = page->index + (1 << compound_order(page)); I think we want: #define nr_pages(page) (1 << compound_order(page)) because we seem to be repeating that idiom quite a lot in these patches. done_index = page->index + nr_pages(page); Still doesn't quite fit on one line, but it's closer, and it's the ridiculous indentation in that function that's the real problem.