From mboxrd@z Thu Jan 1 00:00:00 1970 From: Matthew Wilcox Subject: [PATCH v14 28/74] page cache; Convert find_get_pages_range_tag to XArray Date: Sat, 16 Jun 2018 19:00:06 -0700 Message-ID: <20180617020052.4759-29-willy@infradead.org> References: <20180617020052.4759-1-willy@infradead.org> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sourceforge.net; s=x; h=References:In-Reply-To:Message-Id:Date:Subject:Cc: To:From:Sender:Reply-To:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:List-Id:List-Help:List-Unsubscribe: List-Subscribe:List-Post:List-Owner:List-Archive; bh=gqfXkur72PH7I4OwP3gFuN/VelhPslyzABAv8sFERLY=; b=IQKTtVnVRo4ABHno0Q6F9aTziQ CfJ9wE906LjAlAyOKXcfbKBZZWmdTqTHHOvrBgtxQYYSjrO73SPPglGuWRnmR3XKUYxVhgloFn6el nd1tKGoLIxFKT+UP8TRR3WOHo15lwQaorEXpWo02mRW91Z6EqESdJ8ydXFQp1ncv65+s=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=sf.net; s=x ; h=References:In-Reply-To:Message-Id:Date:Subject:Cc:To:From:Sender:Reply-To :MIME-Version:Content-Type:Content-Transfer-Encoding:Content-ID: Content-Description:Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc :Resent-Message-ID:List-Id:List-Help:List-Unsubscribe:List-Subscribe: List-Post:List-Owner:List-Archive; bh=gqfXkur72PH7I4OwP3gFuN/VelhPslyzABAv8sFERLY=; b=XOajH4kzNu9J534Tp4ZByBnObd f7fUBSY4rt6bAqWLh1CUhsAX5MQZyDVKtU4yE9XPkQ8N8y4Q5IsWqS9w9HQ1ro+zUK9GCRiEp3at8 utXOop1fYOZGSlvUkBwhAsJsIc7x7wGilY/DlcHXsehdR2IMedoept/P+0Mh4HlCHj2o=; DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=References:In-Reply-To:Message-Id: Date:Subject:Cc:To:From:Sender:Reply-To:MIME-Version:Content-Type: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=gqfXkur72PH7I4OwP3gFuN/VelhPslyzABAv8sFERLY=; b=N4eJ/m/1odYXrpVpDWKP9mHAx V5k/MIG6m++e1+yf1i6Wap4ai0h2aTAwzT3yVGr0l8qjjX7vMRxpckgJyFt56oUPpIplHvUbXBytX czN/ZY6jfxsiFSX5Ce9NqAsCPRIbCyFkEopfs8NpvR8SRQzLw25ah5+hxCFoSsbhXGSrRVp9DBJnk yxKpxmkR27U7UT+U2c4u7kq9kefaoDxKR2wjq0KefjLrFI1igcvolGB1uzXDGz5qEESGb/IqpxtnD SXlyIbm9TCtKyvEscsj9W/z+NodFSszg13XEHJl9adI2VrmYV+PZ2VI1EKnk4QQGSc5R6Q8Dnr+Ki TA42+or4g==; In-Reply-To: <20180617020052.4759-1-willy@infradead.org> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: linux-f2fs-devel-bounces@lists.sourceforge.net To: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Cc: linux-nilfs@vger.kernel.org, Jan Kara , Jeff Layton , Jaegeuk Kim , Matthew Wilcox , linux-f2fs-devel@lists.sourceforge.net, Nicholas Piggin , Ryusuke Konishi , Lukas Czerner , Ross Zwisler , Christoph Hellwig , Goldwyn Rodrigues The 'end' parameter of the xas_for_each iterator avoids a useless iteration at the end of the range. Signed-off-by: Matthew Wilcox --- include/linux/pagemap.h | 4 +-- mm/filemap.c | 68 ++++++++++++++++------------------------- 2 files changed, 28 insertions(+), 44 deletions(-) diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h index 2f5d2d3ebaac..a6d635fefb01 100644 --- a/include/linux/pagemap.h +++ b/include/linux/pagemap.h @@ -363,10 +363,10 @@ 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_range_tag(struct address_space *mapping, pgoff_t *index, - pgoff_t end, int tag, unsigned int nr_pages, + pgoff_t end, xa_tag_t 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, + pgoff_t *index, xa_tag_t tag, unsigned int nr_pages, struct page **pages) { return find_get_pages_range_tag(mapping, index, (pgoff_t)-1, tag, diff --git a/mm/filemap.c b/mm/filemap.c index 8a69613fcdf3..83328635edaa 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1789,74 +1789,58 @@ EXPORT_SYMBOL(find_get_pages_contig); * @tag. We update @index to index the next page for the traversal. */ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, - pgoff_t end, int tag, unsigned int nr_pages, + pgoff_t end, xa_tag_t tag, unsigned int nr_pages, struct page **pages) { - struct radix_tree_iter iter; - void **slot; + XA_STATE(xas, &mapping->i_pages, *index); + struct page *page; unsigned ret = 0; if (unlikely(!nr_pages)) return 0; rcu_read_lock(); - radix_tree_for_each_tagged(slot, &mapping->i_pages, &iter, *index, tag) { - struct page *head, *page; - - if (iter.index > end) - break; -repeat: - page = radix_tree_deref_slot(slot); - if (unlikely(!page)) + xas_for_each_tagged(&xas, page, end, tag) { + struct page *head; + if (xas_retry(&xas, page)) continue; - - if (radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) { - slot = radix_tree_iter_retry(&iter); - continue; - } - /* - * A shadow entry of a recently evicted page. - * - * Those entries should never be tagged, but - * this tree walk is lockless and the tags are - * looked up in bulk, one radix tree node at a - * time, so there is a sizable window for page - * reclaim to evict a page we saw tagged. - * - * Skip over it. - */ + /* + * Shadow entries should never be tagged, but this iteration + * is lockless so there is a window for page reclaim to evict + * a page we saw tagged. Skip over it. + */ + if (xa_is_value(page)) continue; - } head = compound_head(page); if (!page_cache_get_speculative(head)) - goto repeat; + goto retry; /* The page was split under us? */ - if (compound_head(page) != head) { - put_page(head); - goto repeat; - } + if (compound_head(page) != head) + goto put_page; /* Has the page moved? */ - if (unlikely(page != *slot)) { - put_page(head); - goto repeat; - } + if (unlikely(page != xas_reload(&xas))) + goto put_page; pages[ret] = page; if (++ret == nr_pages) { - *index = pages[ret - 1]->index + 1; + *index = page->index + 1; goto out; } + continue; +put_page: + put_page(head); +retry: + xas_reset(&xas); } /* - * We come here when we got at @end. We take care to not overflow the + * We come here when we got to @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. + * iteration when there is a page at index -1 but that is already + * broken anyway. */ if (end == (pgoff_t)-1) *index = (pgoff_t)-1; -- 2.17.1 ------------------------------------------------------------------------------ Check out the vibrant tech community on one of the world's most engaging tech sites, Slashdot.org! http://sdm.link/slashdot