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filemap: add filemap_get_folios_contig()

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Patch series "Convert to filemap_get_folios_contig()", v3.

This patch series replaces find_get_pages_contig() with
filemap_get_folios_contig().


This patch (of 7):

This function is meant to replace find_get_pages_contig().

Unlike find_get_pages_contig(), filemap_get_folios_contig() no longer
takes in a target number of pages to find - It returns up to 15 contiguous
folios.

To be more consistent with filemap_get_folios(),
filemap_get_folios_contig() now also updates the start index passed in,
and takes an end index.

Link: https://lkml.kernel.org/r/20220824004023.77310-1-vishal.moola@gmail.com
Link: https://lkml.kernel.org/r/20220824004023.77310-2-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Chris Mason <clm@fb.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Sterba <dsterb@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Vishal Moola (Oracle) 2022-08-23 17:40:17 -07:00 committed by Andrew Morton
parent 641608f362
commit 35b471467f
2 changed files with 75 additions and 0 deletions
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2
include/linux/pagemap.h
View File

@ -718,6 +718,8 @@ static inline struct page *find_subpage(struct page *head, pgoff_t index)
unsigned filemap_get_folios(struct address_space *mapping, pgoff_t *start,
pgoff_t end, struct folio_batch *fbatch);
unsigned filemap_get_folios_contig(struct address_space *mapping,
pgoff_t *start, pgoff_t end, struct folio_batch *fbatch);
unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
unsigned int nr_pages, struct page **pages);
unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,

73
mm/filemap.c
View File

@ -2196,6 +2196,79 @@ bool folio_more_pages(struct folio *folio, pgoff_t index, pgoff_t max)
return index < folio->index + folio_nr_pages(folio) - 1;
}
/**
* filemap_get_folios_contig - Get a batch of contiguous folios
* @mapping: The address_space to search
* @start: The starting page index
* @end: The final page index (inclusive)
* @fbatch: The batch to fill
*
* filemap_get_folios_contig() works exactly like filemap_get_folios(),
* except the returned folios are guaranteed to be contiguous. This may
* not return all contiguous folios if the batch gets filled up.
*
* Return: The number of folios found.
* Also update @start to be positioned for traversal of the next folio.
*/
unsigned filemap_get_folios_contig(struct address_space *mapping,
pgoff_t *start, pgoff_t end, struct folio_batch *fbatch)
{
XA_STATE(xas, &mapping->i_pages, *start);
unsigned long nr;
struct folio *folio;
rcu_read_lock();
for (folio = xas_load(&xas); folio && xas.xa_index <= end;
folio = xas_next(&xas)) {
if (xas_retry(&xas, folio))
continue;
/*
* If the entry has been swapped out, we can stop looking.
* No current caller is looking for DAX entries.
*/
if (xa_is_value(folio))
goto update_start;
if (!folio_try_get_rcu(folio))
goto retry;
if (unlikely(folio != xas_reload(&xas)))
goto put_folio;
if (!folio_batch_add(fbatch, folio)) {
nr = folio_nr_pages(folio);
if (folio_test_hugetlb(folio))
nr = 1;
*start = folio->index + nr;
goto out;
}
continue;
put_folio:
folio_put(folio);
retry:
xas_reset(&xas);
}
update_start:
nr = folio_batch_count(fbatch);
if (nr) {
folio = fbatch->folios[nr - 1];
if (folio_test_hugetlb(folio))
*start = folio->index + 1;
else
*start = folio->index + folio_nr_pages(folio);
}
out:
rcu_read_unlock();
return folio_batch_count(fbatch);
}
EXPORT_SYMBOL(filemap_get_folios_contig);
/**
* find_get_pages_contig - gang contiguous pagecache lookup
* @mapping: The address_space to search