From patchwork Wed Jan 17 20:20:48 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 10171751 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id EA5B160386 for ; Wed, 17 Jan 2018 21:06:30 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DA9AD23B23 for ; Wed, 17 Jan 2018 21:06:30 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id CEACE23B32; Wed, 17 Jan 2018 21:06:30 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.8 required=2.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,T_DKIM_INVALID autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 7377423B23 for ; Wed, 17 Jan 2018 21:06:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753545AbeAQVEo (ORCPT ); Wed, 17 Jan 2018 16:04:44 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:42313 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753551AbeAQUWf (ORCPT ); Wed, 17 Jan 2018 15:22:35 -0500 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=hKcEPe4kR3RayWYrXDL5OGhmbi/wyQbouxH8X/W8x0c=; b=cMdWvPZBeNgF/0dnsBvzTYEZc dY5o5MgYbIL6oQ1s0n99vuAtgyPS3QjhuiPYbi/TPErZiMmo5mEglshDKpQGDgYR3++NJXX25H2A6 t3woblmr+MEM/MhcnHnkNADwTQdYKmXcDTP60oyXM1N9HALW64cF5ujxsdTExyhRVWPNDioVMRUVO I6qIDu1n0k8rT+NldgVZzvbFxOjWvaZ5cbKCM+mfQQC+AG1e4xk8+MkivPjMw2vHezxoLldt253S0 Lp/ncb0in7ER0yPsxSixpQZPorUacSSqSDEt77te3rUAFhb5uhrExeCDNrTZw8tXrCf83foonih7x SGCqSdxiQ==; Received: from willy by bombadil.infradead.org with local (Exim 4.89 #1 (Red Hat Linux)) id 1ebuEE-0005mT-DS; Wed, 17 Jan 2018 20:22:34 +0000 From: Matthew Wilcox To: linux-kernel@vger.kernel.org Cc: Matthew Wilcox , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-nilfs@vger.kernel.org, linux-btrfs@vger.kernel.org, linux-xfs@vger.kernel.org, linux-usb@vger.kernel.org, Bjorn Andersson , Stefano Stabellini , iommu@lists.linux-foundation.org, linux-remoteproc@vger.kernel.org, linux-s390@vger.kernel.org, intel-gfx@lists.freedesktop.org, cgroups@vger.kernel.org, linux-sh@vger.kernel.org, David Howells Subject: [PATCH v6 24/99] page cache: Add and replace pages using the XArray Date: Wed, 17 Jan 2018 12:20:48 -0800 Message-Id: <20180117202203.19756-25-willy@infradead.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180117202203.19756-1-willy@infradead.org> References: <20180117202203.19756-1-willy@infradead.org> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Matthew Wilcox Use the XArray APIs to add and replace pages in the page cache. This removes two uses of the radix tree preload API and is significantly shorter code. Signed-off-by: Matthew Wilcox --- include/linux/swap.h | 8 ++- mm/filemap.c | 143 ++++++++++++++++++++++----------------------------- 2 files changed, 67 insertions(+), 84 deletions(-) diff --git a/include/linux/swap.h b/include/linux/swap.h index c2b8128799c1..394957963c4b 100644 --- a/include/linux/swap.h +++ b/include/linux/swap.h @@ -299,8 +299,12 @@ void *workingset_eviction(struct address_space *mapping, struct page *page); bool workingset_refault(void *shadow); void workingset_activation(struct page *page); -/* Do not use directly, use workingset_lookup_update */ -void workingset_update_node(struct radix_tree_node *node); +/* Only track the nodes of mappings with shadow entries */ +void workingset_update_node(struct xa_node *node); +#define mapping_set_update(xas, mapping) do { \ + if (!dax_mapping(mapping) && !shmem_mapping(mapping)) \ + xas_set_update(xas, workingset_update_node); \ +} while (0) /* Returns workingset_update_node() if the mapping has shadow entries. */ #define workingset_lookup_update(mapping) \ diff --git a/mm/filemap.c b/mm/filemap.c index f1b4480723dd..e6371b551de1 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -112,35 +112,6 @@ * ->tasklist_lock (memory_failure, collect_procs_ao) */ -static int page_cache_tree_insert(struct address_space *mapping, - struct page *page, void **shadowp) -{ - struct radix_tree_node *node; - void **slot; - int error; - - error = __radix_tree_create(&mapping->pages, page->index, 0, - &node, &slot); - if (error) - return error; - if (*slot) { - void *p; - - p = radix_tree_deref_slot_protected(slot, - &mapping->pages.xa_lock); - if (!xa_is_value(p)) - return -EEXIST; - - mapping->nrexceptional--; - if (shadowp) - *shadowp = p; - } - __radix_tree_replace(&mapping->pages, node, slot, page, - workingset_lookup_update(mapping)); - mapping->nrpages++; - return 0; -} - static void page_cache_tree_delete(struct address_space *mapping, struct page *page, void *shadow) { @@ -776,51 +747,44 @@ EXPORT_SYMBOL(file_write_and_wait_range); * locked. This function does not add the new page to the LRU, the * caller must do that. * - * The remove + add is atomic. The only way this function can fail is - * memory allocation failure. + * The remove + add is atomic. This function cannot fail. */ int replace_page_cache_page(struct page *old, struct page *new, gfp_t gfp_mask) { - int error; + struct address_space *mapping = old->mapping; + void (*freepage)(struct page *) = mapping->a_ops->freepage; + pgoff_t offset = old->index; + XA_STATE(xas, &mapping->pages, offset); + unsigned long flags; VM_BUG_ON_PAGE(!PageLocked(old), old); VM_BUG_ON_PAGE(!PageLocked(new), new); VM_BUG_ON_PAGE(new->mapping, new); - error = radix_tree_preload(gfp_mask & ~__GFP_HIGHMEM); - if (!error) { - struct address_space *mapping = old->mapping; - void (*freepage)(struct page *); - unsigned long flags; - - pgoff_t offset = old->index; - freepage = mapping->a_ops->freepage; - - get_page(new); - new->mapping = mapping; - new->index = offset; + get_page(new); + new->mapping = mapping; + new->index = offset; - xa_lock_irqsave(&mapping->pages, flags); - __delete_from_page_cache(old, NULL); - error = page_cache_tree_insert(mapping, new, NULL); - BUG_ON(error); + xas_lock_irqsave(&xas, flags); + xas_store(&xas, new); - /* - * hugetlb pages do not participate in page cache accounting. - */ - if (!PageHuge(new)) - __inc_node_page_state(new, NR_FILE_PAGES); - if (PageSwapBacked(new)) - __inc_node_page_state(new, NR_SHMEM); - xa_unlock_irqrestore(&mapping->pages, flags); - mem_cgroup_migrate(old, new); - radix_tree_preload_end(); - if (freepage) - freepage(old); - put_page(old); - } + old->mapping = NULL; + /* hugetlb pages do not participate in page cache accounting. */ + if (!PageHuge(old)) + __dec_node_page_state(new, NR_FILE_PAGES); + if (!PageHuge(new)) + __inc_node_page_state(new, NR_FILE_PAGES); + if (PageSwapBacked(old)) + __dec_node_page_state(new, NR_SHMEM); + if (PageSwapBacked(new)) + __inc_node_page_state(new, NR_SHMEM); + xas_unlock_irqrestore(&xas, flags); + mem_cgroup_migrate(old, new); + if (freepage) + freepage(old); + put_page(old); - return error; + return 0; } EXPORT_SYMBOL_GPL(replace_page_cache_page); @@ -829,12 +793,15 @@ static int __add_to_page_cache_locked(struct page *page, pgoff_t offset, gfp_t gfp_mask, void **shadowp) { + XA_STATE(xas, &mapping->pages, offset); int huge = PageHuge(page); struct mem_cgroup *memcg; int error; + void *old; VM_BUG_ON_PAGE(!PageLocked(page), page); VM_BUG_ON_PAGE(PageSwapBacked(page), page); + mapping_set_update(&xas, mapping); if (!huge) { error = mem_cgroup_try_charge(page, current->mm, @@ -843,39 +810,51 @@ static int __add_to_page_cache_locked(struct page *page, return error; } - error = radix_tree_maybe_preload(gfp_mask & ~__GFP_HIGHMEM); - if (error) { - if (!huge) - mem_cgroup_cancel_charge(page, memcg, false); - return error; - } - get_page(page); page->mapping = mapping; page->index = offset; - xa_lock_irq(&mapping->pages); - error = page_cache_tree_insert(mapping, page, shadowp); - radix_tree_preload_end(); - if (unlikely(error)) - goto err_insert; + do { + xas_lock_irq(&xas); + old = xas_create(&xas); + if (xas_error(&xas)) + goto unlock; + if (xa_is_value(old)) { + mapping->nrexceptional--; + if (shadowp) + *shadowp = old; + } else if (old) { + xas_set_err(&xas, -EEXIST); + goto unlock; + } + + xas_store(&xas, page); + mapping->nrpages++; + + /* + * hugetlb pages do not participate in + * page cache accounting. + */ + if (!huge) + __inc_node_page_state(page, NR_FILE_PAGES); +unlock: + xas_unlock_irq(&xas); + } while (xas_nomem(&xas, gfp_mask & ~__GFP_HIGHMEM)); + + if (xas_error(&xas)) + goto error; - /* hugetlb pages do not participate in page cache accounting. */ - if (!huge) - __inc_node_page_state(page, NR_FILE_PAGES); - xa_unlock_irq(&mapping->pages); if (!huge) mem_cgroup_commit_charge(page, memcg, false, false); trace_mm_filemap_add_to_page_cache(page); return 0; -err_insert: +error: page->mapping = NULL; /* Leave page->index set: truncation relies upon it */ - xa_unlock_irq(&mapping->pages); if (!huge) mem_cgroup_cancel_charge(page, memcg, false); put_page(page); - return error; + return xas_error(&xas); } /**