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mm: implement find_get_pages_range_tag() 

Patch series "Ranged pagevec tagged lookup", v3.

In this series I provide a ranged variant of pagevec_lookup_tag() and
use it in places where it makes sense.  This series removes some common
code and it also has a potential for speeding up some operations
similarly as for pagevec_lookup_range() (but for now I can think of only
artificial cases where this happens).

This patch (of 16):

Implement a variant of find_get_pages_tag() that stops iterating at
given index.  Lots of users of this function (through pagevec_lookup())
actually want a range lookup and all of them are currently open-coding
this.

Also create corresponding pagevec_lookup_range_tag() function.

Link: http://lkml.kernel.org/r/20171009151359.31984-2-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
Reviewed-by: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Bob Peterson <rpeterso@redhat.com>
Cc: Chao Yu <yuchao0@huawei.com>
Cc: David Howells <dhowells@redhat.com>
Cc: David Sterba <dsterba@suse.com>
Cc: Ilya Dryomov <idryomov@gmail.com>
Cc: Jaegeuk Kim <jaegeuk@kernel.org>
Cc: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Cc: Steve French <sfrench@samba.org>
Cc: "Theodore Ts'o" <tytso@mit.edu>
Cc: "Yan, Zheng" <zyan@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Jan Kara 2017-11-15 17:34:33 -08:00 committed by Linus Torvalds
parent 6b4c54e378
commit 72b045aecd
4 changed files with 48 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

12
include/linux/pagemap.h
View File

@ -366,8 +366,16 @@ static inline unsigned find_get_pages(struct address_space *mapping,
}
unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t start,
unsigned int nr_pages, struct page **pages);
unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
int tag, unsigned int nr_pages, struct page **pages);
unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
pgoff_t end, int tag, unsigned int nr_pages,
struct page **pages);
static inline unsigned find_get_pages_tag(struct address_space *mapping,
pgoff_t *index, int tag, unsigned int nr_pages,
struct page **pages)
{
return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag,
nr_pages, pages);
}
unsigned find_get_entries_tag(struct address_space *mapping, pgoff_t start,
int tag, unsigned int nr_entries,
struct page **entries, pgoff_t *indices);

11
include/linux/pagevec.h
View File

@ -38,9 +38,16 @@ static inline unsigned pagevec_lookup(struct pagevec *pvec,
return pagevec_lookup_range(pvec, mapping, start, (pgoff_t)-1);
}
unsigned pagevec_lookup_tag(struct pagevec *pvec,
unsigned pagevec_lookup_range_tag(struct pagevec *pvec,
struct address_space *mapping, pgoff_t *index, pgoff_t end,
int tag, unsigned nr_pages);
static inline unsigned pagevec_lookup_tag(struct pagevec *pvec,
struct address_space *mapping, pgoff_t *index, int tag,
unsigned nr_pages);
unsigned nr_pages)
{
return pagevec_lookup_range_tag(pvec, mapping, index, (pgoff_t)-1, tag,
nr_pages);
}
static inline void pagevec_init(struct pagevec *pvec, int cold)
{

33
mm/filemap.c
View File

@ -1754,9 +1754,10 @@ repeat:
EXPORT_SYMBOL(find_get_pages_contig);
/**
* find_get_pages_tag - find and return pages that match @tag
* find_get_pages_range_tag - find and return pages in given range matching @tag
* @mapping: the address_space to search
* @index: the starting page index
* @end: The final page index (inclusive)
* @tag: the tag index
* @nr_pages: the maximum number of pages
* @pages: where the resulting pages are placed
@ -1764,8 +1765,9 @@ EXPORT_SYMBOL(find_get_pages_contig);
* Like find_get_pages, except we only return pages which are tagged with
* @tag. We update @index to index the next page for the traversal.
*/
unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
int tag, unsigned int nr_pages, struct page **pages)
unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
pgoff_t end, int tag, unsigned int nr_pages,
struct page **pages)
{
struct radix_tree_iter iter;
void **slot;
@ -1778,6 +1780,9 @@ unsigned find_get_pages_tag(struct address_space *mapping, pgoff_t *index,
radix_tree_for_each_tagged(slot, &mapping->page_tree,
&iter, *index, tag) {
struct page *head, *page;
if (iter.index > end)
break;
repeat:
page = radix_tree_deref_slot(slot);
if (unlikely(!page))
@ -1819,18 +1824,28 @@ repeat:
}
pages[ret] = page;
if (++ret == nr_pages)
break;
if (++ret == nr_pages) {
*index = pages[ret - 1]->index + 1;
goto out;
}
}
/*
* We come here when we got at @end. We take care to not overflow the
* index @index as it confuses some of the callers. This breaks the
* iteration when there is page at index -1 but that is already broken
* anyway.
*/
if (end == (pgoff_t)-1)
*index = (pgoff_t)-1;
else
*index = end + 1;
out:
rcu_read_unlock();
if (ret)
*index = pages[ret - 1]->index + 1;
return ret;
}
EXPORT_SYMBOL(find_get_pages_tag);
EXPORT_SYMBOL(find_get_pages_range_tag);
/**
* find_get_entries_tag - find and return entries that match @tag

9
mm/swap.c
View File

@ -986,14 +986,15 @@ unsigned pagevec_lookup_range(struct pagevec *pvec,
}
EXPORT_SYMBOL(pagevec_lookup_range);
unsigned pagevec_lookup_tag(struct pagevec *pvec, struct address_space *mapping,
pgoff_t *index, int tag, unsigned nr_pages)
unsigned pagevec_lookup_range_tag(struct pagevec *pvec,
struct address_space *mapping, pgoff_t *index, pgoff_t end,
int tag, unsigned nr_pages)
{
pvec->nr = find_get_pages_tag(mapping, index, tag,
pvec->nr = find_get_pages_range_tag(mapping, index, end, tag,
nr_pages, pvec->pages);
return pagevec_count(pvec);
}
EXPORT_SYMBOL(pagevec_lookup_tag);
EXPORT_SYMBOL(pagevec_lookup_range_tag);
/*
* Perform any setup for the swap system