From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
linux-fsdevel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Hugh Dickins <hughd@google.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Yang Shi <yang.shi@linux.alibaba.com>,
Dave Chinner <dchinner@redhat.com>,
linux-kernel@vger.kernel.org, Jan Kara <jack@suse.cz>,
William Kucharski <william.kucharski@oracle.com>
Subject: [PATCH v3 03/12] mm/filemap: Add helper for finding pages
Date: Mon, 26 Oct 2020 04:13:59 +0000 [thread overview]
Message-ID: <20201026041408.25230-4-willy@infradead.org> (raw)
In-Reply-To: <20201026041408.25230-1-willy@infradead.org>
There is a lot of common code in find_get_entries(),
find_get_pages_range() and find_get_pages_range_tag(). Factor out
xas_find_get_entry() which simplifies all three functions.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
---
mm/filemap.c | 98 +++++++++++++++++++++++-----------------------------
1 file changed, 43 insertions(+), 55 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index edde5dc0d28f..00eaed59e797 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1856,6 +1856,43 @@ struct page *pagecache_get_page(struct address_space *mapping, pgoff_t index,
}
EXPORT_SYMBOL(pagecache_get_page);
+static inline struct page *xas_find_get_entry(struct xa_state *xas,
+ pgoff_t max, xa_mark_t mark)
+{
+ struct page *page;
+
+retry:
+ if (mark == XA_PRESENT)
+ page = xas_find(xas, max);
+ else
+ page = xas_find_marked(xas, max, mark);
+
+ if (xas_retry(xas, page))
+ goto retry;
+ /*
+ * A shadow entry of a recently evicted page, a swap
+ * entry from shmem/tmpfs or a DAX entry. Return it
+ * without attempting to raise page count.
+ */
+ if (!page || xa_is_value(page))
+ return page;
+
+ if (!page_cache_get_speculative(page))
+ goto reset;
+
+ /* Has the page moved or been split? */
+ if (unlikely(page != xas_reload(xas))) {
+ put_page(page);
+ goto reset;
+ }
+ VM_BUG_ON_PAGE(!thp_contains(page, xas->xa_index), page);
+
+ return page;
+reset:
+ xas_reset(xas);
+ goto retry;
+}
+
/**
* find_get_entries - gang pagecache lookup
* @mapping: The address_space to search
@@ -1895,42 +1932,21 @@ unsigned find_get_entries(struct address_space *mapping,
return 0;
rcu_read_lock();
- xas_for_each(&xas, page, ULONG_MAX) {
- if (xas_retry(&xas, page))
- continue;
- /*
- * A shadow entry of a recently evicted page, a swap
- * entry from shmem/tmpfs or a DAX entry. Return it
- * without attempting to raise page count.
- */
- if (xa_is_value(page))
- goto export;
-
- if (!page_cache_get_speculative(page))
- goto retry;
-
- /* Has the page moved or been split? */
- if (unlikely(page != xas_reload(&xas)))
- goto put_page;
-
+ while ((page = xas_find_get_entry(&xas, ULONG_MAX, XA_PRESENT))) {
/*
* Terminate early on finding a THP, to allow the caller to
* handle it all at once; but continue if this is hugetlbfs.
*/
- if (PageTransHuge(page) && !PageHuge(page)) {
+ if (!xa_is_value(page) && PageTransHuge(page) &&
+ !PageHuge(page)) {
page = find_subpage(page, xas.xa_index);
nr_entries = ret + 1;
}
-export:
+
indices[ret] = xas.xa_index;
entries[ret] = page;
if (++ret == nr_entries)
break;
- continue;
-put_page:
- put_page(page);
-retry:
- xas_reset(&xas);
}
rcu_read_unlock();
return ret;
@@ -1969,30 +1985,16 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
return 0;
rcu_read_lock();
- xas_for_each(&xas, page, end) {
- if (xas_retry(&xas, page))
- continue;
+ while ((page = xas_find_get_entry(&xas, end, XA_PRESENT))) {
/* Skip over shadow, swap and DAX entries */
if (xa_is_value(page))
continue;
- if (!page_cache_get_speculative(page))
- goto retry;
-
- /* Has the page moved or been split? */
- if (unlikely(page != xas_reload(&xas)))
- goto put_page;
-
pages[ret] = find_subpage(page, xas.xa_index);
if (++ret == nr_pages) {
*start = xas.xa_index + 1;
goto out;
}
- continue;
-put_page:
- put_page(page);
-retry:
- xas_reset(&xas);
}
/*
@@ -2091,9 +2093,7 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
return 0;
rcu_read_lock();
- xas_for_each_marked(&xas, page, end, tag) {
- if (xas_retry(&xas, page))
- continue;
+ while ((page = xas_find_get_entry(&xas, end, tag))) {
/*
* Shadow entries should never be tagged, but this iteration
* is lockless so there is a window for page reclaim to evict
@@ -2102,23 +2102,11 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index,
if (xa_is_value(page))
continue;
- if (!page_cache_get_speculative(page))
- goto retry;
-
- /* Has the page moved or been split? */
- if (unlikely(page != xas_reload(&xas)))
- goto put_page;
-
pages[ret] = page;
if (++ret == nr_pages) {
*index = page->index + thp_nr_pages(page);
goto out;
}
- continue;
-put_page:
- put_page(page);
-retry:
- xas_reset(&xas);
}
/*
--
2.28.0
next prev parent reply other threads:[~2020-10-26 4:41 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-26 4:13 [PATCH v3 00/12] Overhaul multi-page lookups for THP Matthew Wilcox (Oracle)
2020-10-26 4:13 ` [PATCH v3 01/12] mm: Make pagecache tagged lookups return only head pages Matthew Wilcox (Oracle)
2020-10-28 7:50 ` Mike Rapoport
2020-11-12 17:41 ` Matthew Wilcox
2020-11-12 19:11 ` Mike Rapoport
2020-10-26 4:13 ` [PATCH v3 02/12] mm/shmem: Use pagevec_lookup in shmem_unlock_mapping Matthew Wilcox (Oracle)
2020-10-26 4:13 ` Matthew Wilcox (Oracle) [this message]
2020-10-27 18:56 ` [PATCH v3 03/12] mm/filemap: Add helper for finding pages Christoph Hellwig
2020-11-12 14:25 ` Matthew Wilcox
2020-10-26 4:14 ` [PATCH v3 04/12] mm/filemap: Add mapping_seek_hole_data Matthew Wilcox (Oracle)
2020-10-26 10:48 ` Jan Kara
2020-10-26 12:17 ` Matthew Wilcox
2020-10-26 14:49 ` Jan Kara
2020-10-27 18:58 ` Christoph Hellwig
2020-10-27 20:04 ` Matthew Wilcox
2020-10-28 6:40 ` Christoph Hellwig
2020-10-26 4:14 ` [PATCH v3 05/12] mm: Add and use find_lock_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 06/12] mm: Add an 'end' parameter to find_get_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 07/12] mm: Add an 'end' parameter to pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 08/12] mm: Remove nr_entries parameter from pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 09/12] mm: Pass pvec directly to find_get_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 10/12] mm: Remove pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-10-26 4:14 ` [PATCH v3 11/12] mm/truncate,shmem: Handle truncates that split THPs Matthew Wilcox (Oracle)
2020-10-26 11:05 ` Jan Kara
2020-10-26 4:14 ` [PATCH v3 12/12] mm/filemap: Return only head pages from find_get_entries Matthew Wilcox (Oracle)
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