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Date: Sat, 16 Jun 2018 19:00:33 -0700 From: Matthew Wilcox <willy@...radead.org> To: linux-mm@...ck.org, linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org Cc: Matthew Wilcox <willy@...radead.org>, Jan Kara <jack@...e.cz>, Jeff Layton <jlayton@...hat.com>, Lukas Czerner <lczerner@...hat.com>, Ross Zwisler <ross.zwisler@...ux.intel.com>, Christoph Hellwig <hch@....de>, Goldwyn Rodrigues <rgoldwyn@...e.com>, Nicholas Piggin <npiggin@...il.com>, Ryusuke Konishi <konishi.ryusuke@....ntt.co.jp>, linux-nilfs@...r.kernel.org, Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <yuchao0@...wei.com>, linux-f2fs-devel@...ts.sourceforge.net Subject: [PATCH v14 55/74] memfd: Convert memfd_tag_pins to XArray Switch to a batch-processing model like memfd_wait_for_pins() and use the xa_state previously set up by memfd_wait_for_pins(). Signed-off-by: Matthew Wilcox <willy@...radead.org> Reviewed-by: Mike Kravetz <mike.kravetz@...cle.com> --- mm/memfd.c | 44 ++++++++++++++++++-------------------------- 1 file changed, 18 insertions(+), 26 deletions(-) diff --git a/mm/memfd.c b/mm/memfd.c index e7d6be725b7a..636de8d5c7c3 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -28,37 +28,29 @@ #define MEMFD_TAG_PINNED PAGECACHE_TAG_TOWRITE #define LAST_SCAN 4 /* about 150ms max */ -static void memfd_tag_pins(struct address_space *mapping) +static void memfd_tag_pins(struct xa_state *xas) { - struct radix_tree_iter iter; - void __rcu **slot; - pgoff_t start; struct page *page; + unsigned int tagged = 0; lru_add_drain(); - start = 0; - rcu_read_lock(); - - radix_tree_for_each_slot(slot, &mapping->i_pages, &iter, start) { - page = radix_tree_deref_slot(slot); - if (!page || radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) { - slot = radix_tree_iter_retry(&iter); - continue; - } - } else if (page_count(page) - page_mapcount(page) > 1) { - xa_lock_irq(&mapping->i_pages); - radix_tree_tag_set(&mapping->i_pages, iter.index, - MEMFD_TAG_PINNED); - xa_unlock_irq(&mapping->i_pages); - } - if (need_resched()) { - slot = radix_tree_iter_resume(slot, &iter); - cond_resched_rcu(); - } + xas_lock_irq(xas); + xas_for_each(xas, page, ULONG_MAX) { + if (xa_is_value(page)) + continue; + if (page_count(page) - page_mapcount(page) > 1) + xas_set_tag(xas, MEMFD_TAG_PINNED); + + if (++tagged % XA_CHECK_SCHED) + continue; + + xas_pause(xas); + xas_unlock_irq(xas); + cond_resched(); + xas_lock_irq(xas); } - rcu_read_unlock(); + xas_unlock_irq(xas); } /* @@ -76,7 +68,7 @@ static int memfd_wait_for_pins(struct address_space *mapping) struct page *page; int error, scan; - memfd_tag_pins(mapping); + memfd_tag_pins(&xas); error = 0; for (scan = 0; scan <= LAST_SCAN; scan++) { -- 2.17.1
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