From: "Matthew Wilcox (Oracle)" <willy@infradead.org>
To: linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>,
akpm@linux-foundation.org, hughd@google.com, hch@lst.de,
hannes@cmpxchg.org, yang.shi@linux.alibaba.com,
dchinner@redhat.com, linux-kernel@vger.kernel.org,
Jan Kara <jack@suse.cz>,
William Kucharski <william.kucharski@oracle.com>
Subject: [PATCH v4 16/16] mm/filemap: Return only head pages from find_get_entries
Date: Thu, 12 Nov 2020 21:26:41 +0000 [thread overview]
Message-ID: <20201112212641.27837-17-willy@infradead.org> (raw)
In-Reply-To: <20201112212641.27837-1-willy@infradead.org>
All callers now expect head (and base) pages, and can handle multiple
head pages in a single batch, so make find_get_entries() behave that way.
Also take the opportunity to make it use the pagevec infrastructure
instead of open-coding how pvecs behave. This has the side-effect of
being able to append to a pagevec with existing contents, although we
don't make use of that functionality anywhere yet.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: William Kucharski <william.kucharski@oracle.com>
---
include/linux/pagemap.h | 2 --
mm/filemap.c | 36 ++++++++----------------------------
mm/internal.h | 2 ++
3 files changed, 10 insertions(+), 30 deletions(-)
diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h
index 46d4b1704770..65ef8db8eaab 100644
--- a/include/linux/pagemap.h
+++ b/include/linux/pagemap.h
@@ -448,8 +448,6 @@ static inline struct page *find_subpage(struct page *head, pgoff_t index)
return head + (index & (thp_nr_pages(head) - 1));
}
-unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
- pgoff_t end, struct pagevec *pvec, pgoff_t *indices);
unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start,
pgoff_t end, unsigned int nr_pages,
struct page **pages);
diff --git a/mm/filemap.c b/mm/filemap.c
index 479cbbadd93b..f8c294905e8d 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1878,49 +1878,29 @@ static inline struct page *find_get_entry(struct xa_state *xas, pgoff_t max,
* the mapping. The entries are placed in @pvec. find_get_entries()
* takes a reference on any actual pages it returns.
*
- * The search returns a group of mapping-contiguous page cache entries
- * with ascending indexes. There may be holes in the indices due to
- * not-present pages.
+ * The entries have ascending indexes. The indices may not be consecutive
+ * due to not-present entries or THPs.
*
* Any shadow entries of evicted pages, or swap entries from
* shmem/tmpfs, are included in the returned array.
*
- * If it finds a Transparent Huge Page, head or tail, find_get_entries()
- * stops at that page: the caller is likely to have a better way to handle
- * the compound page as a whole, and then skip its extent, than repeatedly
- * calling find_get_entries() to return all its tails.
- *
- * Return: the number of pages and shadow entries which were found.
+ * Return: The number of entries which were found.
*/
unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
pgoff_t end, struct pagevec *pvec, pgoff_t *indices)
{
XA_STATE(xas, &mapping->i_pages, start);
struct page *page;
- unsigned int ret = 0;
- unsigned nr_entries = PAGEVEC_SIZE;
rcu_read_lock();
while ((page = find_get_entry(&xas, end, 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 (!xa_is_value(page) && PageTransHuge(page) &&
- !PageHuge(page)) {
- page = find_subpage(page, xas.xa_index);
- nr_entries = ret + 1;
- }
-
- indices[ret] = xas.xa_index;
- pvec->pages[ret] = page;
- if (++ret == nr_entries)
+ indices[pvec->nr] = xas.xa_index;
+ if (!pagevec_add(pvec, page))
break;
}
rcu_read_unlock();
- pvec->nr = ret;
- return ret;
+ return pagevec_count(pvec);
}
/**
@@ -1939,8 +1919,8 @@ unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
* not returned.
*
* The entries have ascending indexes. The indices may not be consecutive
- * due to not-present entries, THP pages, pages which could not be locked
- * or pages under writeback.
+ * due to not-present entries, THPs, pages which could not be locked or
+ * pages under writeback.
*
* Return: The number of entries which were found.
*/
diff --git a/mm/internal.h b/mm/internal.h
index cb7487efa856..1f137a5d66bb 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -60,6 +60,8 @@ static inline void force_page_cache_readahead(struct address_space *mapping,
force_page_cache_ra(&ractl, &file->f_ra, nr_to_read);
}
+unsigned find_get_entries(struct address_space *mapping, pgoff_t start,
+ pgoff_t end, struct pagevec *pvec, pgoff_t *indices);
unsigned find_lock_entries(struct address_space *mapping, pgoff_t start,
pgoff_t end, struct pagevec *pvec, pgoff_t *indices);
--
2.28.0
next prev parent reply other threads:[~2020-11-12 21:27 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-12 21:26 [PATCH v4 00/16] Overhaul multi-page lookups for THP Matthew Wilcox (Oracle)
2020-11-12 21:26 ` [PATCH v4 01/16] mm: Make pagecache tagged lookups return only head pages Matthew Wilcox (Oracle)
2020-11-14 9:53 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 02/16] mm/shmem: Use pagevec_lookup in shmem_unlock_mapping Matthew Wilcox (Oracle)
2020-11-14 9:53 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 03/16] mm/swap: Optimise get_shadow_from_swap_cache Matthew Wilcox (Oracle)
2020-11-14 9:53 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 04/16] mm: Add FGP_ENTRY Matthew Wilcox (Oracle)
2020-11-14 10:00 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 05/16] mm/filemap: Rename find_get_entry to mapping_get_entry Matthew Wilcox (Oracle)
2020-11-14 10:01 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 06/16] mm/filemap: Add helper for finding pages Matthew Wilcox (Oracle)
2020-11-14 10:03 ` Christoph Hellwig
2020-11-14 15:15 ` Matthew Wilcox
2020-11-12 21:26 ` [PATCH v4 07/16] mm/filemap: Add mapping_seek_hole_data Matthew Wilcox (Oracle)
2020-11-14 10:04 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 08/16] iomap: Use mapping_seek_hole_data Matthew Wilcox (Oracle)
2020-11-14 10:06 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 09/16] mm: Add and use find_lock_entries Matthew Wilcox (Oracle)
2020-11-14 10:07 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 10/16] mm: Add an 'end' parameter to find_get_entries Matthew Wilcox (Oracle)
2020-11-14 10:08 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 11/16] mm: Add an 'end' parameter to pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-11-14 10:19 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 12/16] mm: Remove nr_entries parameter from pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-11-14 10:19 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 13/16] mm: Pass pvec directly to find_get_entries Matthew Wilcox (Oracle)
2020-11-14 10:21 ` Christoph Hellwig
2020-11-14 15:22 ` Matthew Wilcox
2020-11-12 21:26 ` [PATCH v4 14/16] mm: Remove pagevec_lookup_entries Matthew Wilcox (Oracle)
2020-11-14 10:22 ` Christoph Hellwig
2020-11-12 21:26 ` [PATCH v4 15/16] mm/truncate,shmem: Handle truncates that split THPs Matthew Wilcox (Oracle)
2020-11-12 21:26 ` Matthew Wilcox (Oracle) [this message]
2020-11-14 10:23 ` [PATCH v4 16/16] mm/filemap: Return only head pages from find_get_entries Christoph Hellwig
2020-11-16 10:34 ` [PATCH v4 00/16] Overhaul multi-page lookups for THP Hugh Dickins
2020-11-16 15:14 ` Matthew Wilcox
2020-11-16 21:27 ` Hugh Dickins
2020-11-17 15:39 ` Matthew Wilcox
2020-11-17 16:26 ` Hugh Dickins
2020-11-17 19:15 ` Matthew Wilcox
2020-11-17 23:43 ` Matthew Wilcox
2020-11-25 2:32 ` Matthew Wilcox
2020-11-25 2:50 ` Hugh Dickins
2020-11-25 2:56 ` Hugh Dickins
2020-11-25 23:08 ` Andrew Morton
2020-11-26 0:11 ` Hugh Dickins
2020-11-26 12:15 ` Matthew Wilcox
2020-11-26 19:24 ` Hugh Dickins
2020-11-26 20:07 ` Matthew Wilcox
2020-11-30 19:45 ` Hugh Dickins
2020-12-01 4:52 ` Hugh Dickins
[not found] ` <CGME20201203154604eucas1p200d001d25dd344a1dd1c7da34f35aad0@eucas1p2.samsung.com>
2020-12-03 15:46 ` Marek Szyprowski
[not found] ` <CGME20201203172725eucas1p2fddec1d269c55095859d490942b78b93@eucas1p2.samsung.com>
2020-12-03 17:27 ` Marek Szyprowski
2020-12-03 21:27 ` Qian Cai
2020-12-03 22:19 ` Hugh Dickins
2020-12-03 21:45 ` Hugh Dickins
2021-02-23 22:58 ` Andrew Morton
2021-02-23 23:27 ` Matthew Wilcox
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