From patchwork Fri Dec 15 22:04:32 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 10116597 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 C638C60231 for ; Fri, 15 Dec 2017 22:35:53 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id B85F229F43 for ; Fri, 15 Dec 2017 22:35:53 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id AD4A22A153; Fri, 15 Dec 2017 22:35:53 +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 6D83A29F43 for ; Fri, 15 Dec 2017 22:35:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757110AbdLOWeO (ORCPT ); Fri, 15 Dec 2017 17:34:14 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:45721 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756401AbdLOWFU (ORCPT ); Fri, 15 Dec 2017 17:05:20 -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=Kq5DOaD8l/tl3fYpzCywVxco/HVIeqlyEFy7Ddl/UtI=; b=UDtxsYvWbkjdPN27VmGwLYVNH 5/VPnSJH3cT/v9H0Afu6yNUzfsBYnL905VDhF8Pe3KjLy2ogLv+u0MzTsnaP4yttPSxMn+bJBcWEW HTZRSKWNVi0mmwqkBT/+KCL9ajeB0J/nIf6vf2AJq3P6l1vaUPrQsd5zfnqVtp8c4y7coCTufIbre zQ7y3mfkJCkMGEW3CJN10ugak+xQzywCfRWvVO4XOFAJZ3q9bOjD39mOg/4fi0vlrKwP0dJarm/qE U/OP5G+GjyTNRaVOYzz9ttEs4vdwI8v2S8FKGKONJqg+5Xao+X04pH90ZRs1UNvjIWlp6tzreqdQ1 oGGrVLAMw==; Received: from willy by bombadil.infradead.org with local (Exim 4.87 #1 (Red Hat Linux)) id 1ePy6I-0002Ff-Ra; Fri, 15 Dec 2017 22:05:02 +0000 From: Matthew Wilcox To: linux-kernel@vger.kernel.org Cc: Matthew Wilcox , Ross Zwisler , David Howells , Shaohua Li , Jens Axboe , Rehas Sachdeva , Marc Zyngier , 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, linux-raid@vger.kernel.org Subject: [PATCH v5 60/78] dax: More XArray conversion Date: Fri, 15 Dec 2017 14:04:32 -0800 Message-Id: <20171215220450.7899-61-willy@infradead.org> X-Mailer: git-send-email 2.9.5 In-Reply-To: <20171215220450.7899-1-willy@infradead.org> References: <20171215220450.7899-1-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 This time, we want to convert get_unlocked_mapping_entry() to use the XArray. That has a ripple effect, causing us to change the waitqueues to hash on the address of the xarray rather than the address of the mapping (functionally equivalent), and create a lot of on-the-stack xa_state which are only used as a container for passing the xarray and the index down to deeper function calls. Also rename dax_wake_mapping_entry_waiter() to dax_wake_entry(). Signed-off-by: Matthew Wilcox --- fs/dax.c | 72 +++++++++++++++++++++++++++++----------------------------------- 1 file changed, 33 insertions(+), 39 deletions(-) diff --git a/fs/dax.c b/fs/dax.c index 46a4d83b1b46..2629ffa70575 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -120,7 +120,7 @@ static int dax_is_empty_entry(void *entry) * DAX radix tree locking */ struct exceptional_entry_key { - struct address_space *mapping; + struct xarray *xa; pgoff_t entry_start; }; @@ -129,9 +129,10 @@ struct wait_exceptional_entry_queue { struct exceptional_entry_key key; }; -static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, - pgoff_t index, void *entry, struct exceptional_entry_key *key) +static wait_queue_head_t *dax_entry_waitqueue(struct xa_state *xas, + void *entry, struct exceptional_entry_key *key) { + unsigned long index = xas->xa_index; unsigned long hash; /* @@ -142,10 +143,10 @@ static wait_queue_head_t *dax_entry_waitqueue(struct address_space *mapping, if (dax_is_pmd_entry(entry)) index &= ~PG_PMD_COLOUR; - key->mapping = mapping; + key->xa = xas->xa; key->entry_start = index; - hash = hash_long((unsigned long)mapping ^ index, DAX_WAIT_TABLE_BITS); + hash = hash_long((unsigned long)xas->xa ^ index, DAX_WAIT_TABLE_BITS); return wait_table + hash; } @@ -156,7 +157,7 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo struct wait_exceptional_entry_queue *ewait = container_of(wait, struct wait_exceptional_entry_queue, wait); - if (key->mapping != ewait->key.mapping || + if (key->xa != ewait->key.xa || key->entry_start != ewait->key.entry_start) return 0; return autoremove_wake_function(wait, mode, sync, NULL); @@ -167,13 +168,12 @@ static int wake_exceptional_entry_func(wait_queue_entry_t *wait, unsigned int mo * The important information it's conveying is whether the entry at * this index used to be a PMD entry. */ -static void dax_wake_mapping_entry_waiter(struct address_space *mapping, - pgoff_t index, void *entry, bool wake_all) +static void dax_wake_entry(struct xa_state *xas, void *entry, bool wake_all) { struct exceptional_entry_key key; wait_queue_head_t *wq; - wq = dax_entry_waitqueue(mapping, index, entry, &key); + wq = dax_entry_waitqueue(xas, entry, &key); /* * Checking for locked entry and prepare_to_wait_exclusive() happens @@ -205,10 +205,9 @@ static inline void *lock_slot(struct xa_state *xas) * * Must be called with xa_lock held. */ -static void *get_unlocked_mapping_entry(struct address_space *mapping, - pgoff_t index, void ***slotp) +static void *get_unlocked_mapping_entry(struct xa_state *xas) { - void *entry, **slot; + void *entry; struct wait_exceptional_entry_queue ewait; wait_queue_head_t *wq; @@ -216,22 +215,19 @@ static void *get_unlocked_mapping_entry(struct address_space *mapping, ewait.wait.func = wake_exceptional_entry_func; for (;;) { - entry = __radix_tree_lookup(&mapping->pages, index, NULL, - &slot); - if (!entry || - WARN_ON_ONCE(!xa_is_value(entry)) || !dax_locked(entry)) { - if (slotp) - *slotp = slot; + entry = xas_load(xas); + if (!entry || WARN_ON_ONCE(!xa_is_value(entry)) || + !dax_locked(entry)) return entry; - } - wq = dax_entry_waitqueue(mapping, index, entry, &ewait.key); + wq = dax_entry_waitqueue(xas, entry, &ewait.key); prepare_to_wait_exclusive(wq, &ewait.wait, TASK_UNINTERRUPTIBLE); - xa_unlock_irq(&mapping->pages); + xas_pause(xas); + xas_unlock_irq(xas); schedule(); finish_wait(wq, &ewait.wait); - xa_lock_irq(&mapping->pages); + xas_lock_irq(xas); } } @@ -251,7 +247,7 @@ static void dax_unlock_mapping_entry(struct address_space *mapping, xas_store(&xas, entry); /* Safe to not call xas_pause here -- we don't touch the array after */ xas_unlock_irq(&xas); - dax_wake_mapping_entry_waiter(mapping, index, entry, false); + dax_wake_entry(&xas, entry, false); } static void put_locked_mapping_entry(struct address_space *mapping, @@ -264,14 +260,13 @@ static void put_locked_mapping_entry(struct address_space *mapping, * Called when we are done with radix tree entry we looked up via * get_unlocked_mapping_entry() and which we didn't lock in the end. */ -static void put_unlocked_mapping_entry(struct address_space *mapping, - pgoff_t index, void *entry) +static void put_unlocked_mapping_entry(struct xa_state *xas, void *entry) { if (!entry) return; /* We have to wake up next waiter for the radix tree entry lock */ - dax_wake_mapping_entry_waiter(mapping, index, entry, false); + dax_wake_entry(xas, entry, false); } /* @@ -308,7 +303,7 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, restart: xa_lock_irq(&mapping->pages); - entry = get_unlocked_mapping_entry(mapping, index, &slot); + entry = get_unlocked_mapping_entry(&xas); if (WARN_ON_ONCE(entry && !xa_is_value(entry))) { entry = ERR_PTR(-EIO); @@ -318,8 +313,7 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, if (entry) { if (size_flag & DAX_PMD) { if (dax_is_pte_entry(entry)) { - put_unlocked_mapping_entry(mapping, index, - entry); + put_unlocked_mapping_entry(&xas, entry); entry = ERR_PTR(-EEXIST); goto out_unlock; } @@ -382,8 +376,7 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, if (pmd_downgrade) { radix_tree_delete(&mapping->pages, index); mapping->nrexceptional--; - dax_wake_mapping_entry_waiter(mapping, index, entry, - true); + dax_wake_entry(&xas, entry, true); } entry = dax_radix_locked_entry(0, size_flag | DAX_EMPTY); @@ -417,12 +410,13 @@ static void *grab_mapping_entry(struct address_space *mapping, pgoff_t index, static int __dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index, bool trunc) { + XA_STATE(xas, &mapping->pages, index); int ret = 0; void *entry; struct radix_tree_root *pages = &mapping->pages; xa_lock_irq(&mapping->pages); - entry = get_unlocked_mapping_entry(mapping, index, NULL); + entry = get_unlocked_mapping_entry(&xas); if (!entry || WARN_ON_ONCE(!xa_is_value(entry))) goto out; if (!trunc && @@ -433,7 +427,7 @@ static int __dax_invalidate_mapping_entry(struct address_space *mapping, mapping->nrexceptional--; ret = 1; out: - put_unlocked_mapping_entry(mapping, index, entry); + put_unlocked_mapping_entry(&xas, entry); xa_unlock_irq(&mapping->pages); return ret; } @@ -641,7 +635,7 @@ static int dax_writeback_one(struct block_device *bdev, { struct radix_tree_root *pages = &mapping->pages; XA_STATE(xas, pages, index); - void *entry2, **slot, *kaddr; + void *entry2, *kaddr; long ret = 0, id; sector_t sector; pgoff_t pgoff; @@ -656,7 +650,7 @@ static int dax_writeback_one(struct block_device *bdev, return -EIO; xa_lock_irq(&mapping->pages); - entry2 = get_unlocked_mapping_entry(mapping, index, &slot); + entry2 = get_unlocked_mapping_entry(&xas); /* Entry got punched out / reallocated? */ if (!entry2 || WARN_ON_ONCE(!xa_is_value(entry2))) goto put_unlocked; @@ -734,7 +728,7 @@ static int dax_writeback_one(struct block_device *bdev, return ret; put_unlocked: - put_unlocked_mapping_entry(mapping, index, entry2); + put_unlocked_mapping_entry(&xas, entry2); xa_unlock_irq(&mapping->pages); return ret; } @@ -1504,16 +1498,16 @@ static int dax_insert_pfn_mkwrite(struct vm_fault *vmf, struct address_space *mapping = vmf->vma->vm_file->f_mapping; pgoff_t index = vmf->pgoff; XA_STATE(xas, &mapping->pages, index); - void *entry, **slot; + void *entry; int vmf_ret, error; xa_lock_irq(&mapping->pages); - entry = get_unlocked_mapping_entry(mapping, index, &slot); + entry = get_unlocked_mapping_entry(&xas); /* Did we race with someone splitting entry or so? */ if (!entry || (pe_size == PE_SIZE_PTE && !dax_is_pte_entry(entry)) || (pe_size == PE_SIZE_PMD && !dax_is_pmd_entry(entry))) { - put_unlocked_mapping_entry(mapping, index, entry); + put_unlocked_mapping_entry(&xas, entry); xa_unlock_irq(&mapping->pages); trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, VM_FAULT_NOPAGE);