2022-10-17 20:28:19

by Vishal Moola

Subject: [PATCH v3 03/23] filemap: Convert __filemap_fdatawait_range() to use filemap_get_folios_tag()

Converted function to use folios. This is in preparation for the removal
of find_get_pages_range_tag().

Signed-off-by: Vishal Moola (Oracle) <[email protected]>
---
mm/filemap.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/mm/filemap.c b/mm/filemap.c
index aa6e90ab0551..d78d62a7e44a 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -503,28 +503,30 @@ static void __filemap_fdatawait_range(struct address_space *mapping,
{
pgoff_t index = start_byte >> PAGE_SHIFT;
pgoff_t end = end_byte >> PAGE_SHIFT;
- struct pagevec pvec;
- int nr_pages;
+ struct folio_batch fbatch;
+ unsigned nr_folios;

if (end_byte < start_byte)
return;

- pagevec_init(&pvec);
+ folio_batch_init(&fbatch);
+
while (index <= end) {
unsigned i;

- nr_pages = pagevec_lookup_range_tag(&pvec, mapping, &index,
- end, PAGECACHE_TAG_WRITEBACK);
- if (!nr_pages)
+ nr_folios = filemap_get_folios_tag(mapping, &index, end,
+ PAGECACHE_TAG_WRITEBACK, &fbatch);
+
+ if (!nr_folios)
break;

- for (i = 0; i < nr_pages; i++) {
- struct page *page = pvec.pages[i];
+ for (i = 0; i < nr_folios; i++) {
+ struct folio *folio = fbatch.folios[i];

- wait_on_page_writeback(page);
- ClearPageError(page);
+ folio_wait_writeback(folio);
+ folio_clear_error(folio);
}
- pagevec_release(&pvec);
+ folio_batch_release(&fbatch);
cond_resched();
}
}
--
2.36.1

2022-10-24 22:00:23

by Matthew Wilcox

Subject: Re: [PATCH v3 03/23] filemap: Convert __filemap_fdatawait_range() to use filemap_get_folios_tag()

On Mon, Oct 17, 2022 at 01:24:31PM -0700, Vishal Moola (Oracle) wrote:
> Converted function to use folios. This is in preparation for the removal
> of find_get_pages_range_tag().

Yes, it is, but this patch also has some nice advantages of its own:

- Removes a call to wait_on_page_writeback(), which removes a call
to compound_head()
- Removes a call to ClearPageError(), which removes another call
to compound_head()
- Removes a call to pagevec_release(), which will eventually
remove a third call to compound_head() (it doesn't today, but
one day ...)

So you can definitely say that it removes 50 bytes of text and two
calls to compound_head(). And that way, this patch justifies its
existance by itself ;-)

> Signed-off-by: Vishal Moola (Oracle) <[email protected]>

Reviewed-by: Matthew Wilcox (Oracle) <[email protected]>