From patchwork Fri Dec 15 22:03:50 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 10116557 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 EA7FD60327 for ; Fri, 15 Dec 2017 22:33:50 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id DBC2D292A5 for ; Fri, 15 Dec 2017 22:33:50 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id D07C9292A8; Fri, 15 Dec 2017 22:33:50 +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 21B07292A5 for ; Fri, 15 Dec 2017 22:33:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757248AbdLOWcd (ORCPT ); Fri, 15 Dec 2017 17:32:33 -0500 Received: from bombadil.infradead.org ([65.50.211.133]:45765 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756561AbdLOWFV (ORCPT ); Fri, 15 Dec 2017 17:05:21 -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=UsuFxRxWB3t7oup23G+BSg7747bppSFM53jBmIqXe0M=; b=J4zfobqgrHCyfcO7Q1SZQBFkn 9x2a7pefNN0MMCFuWTAoEndtlmfaU9rW7qlgH9GiINxGckIUqsLPZaOaVeFLauVPX0K4J+hME6UEZ IxBVX5Aqr9YMmZ9vT5kM8RlWUKd1wF2aRnemvEbPEHfGq2iLDFopR6qCIbIzZBARmn3kJsRojBStd 93Fal5F4R86LdNgSU2a6WKEZj1LLJya72k1IfUh2CctzD94Nx5ohvJ/P3obU7l5QFrpNBN5pST/km ant6I87BI43Ij8zIt9vTCv14IWi00xyJvpxbsVmqsg64QLQxPsgi5EBMFl3uSDwwIEKeT3z0Q+uRM ZYHmy3Vzw==; Received: from willy by bombadil.infradead.org with local (Exim 4.87 #1 (Red Hat Linux)) id 1ePy6G-00026I-4M; Fri, 15 Dec 2017 22:05:00 +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 18/78] xarray: Add xas_next and xas_prev Date: Fri, 15 Dec 2017 14:03:50 -0800 Message-Id: <20171215220450.7899-19-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 These two functions move the xas index by one position, and adjust the rest of the iterator state to match it. This is more efficient than calling xas_set() as it keeps the iterator at the leaves of the tree instead of walking the iterator from the root each time. Signed-off-by: Matthew Wilcox --- include/linux/xarray.h | 71 ++++++++++- lib/xarray.c | 74 ++++++++++++ tools/testing/radix-tree/xarray-test.c | 213 +++++++++++++++++++++++++++++++++ 3 files changed, 356 insertions(+), 2 deletions(-) diff --git a/include/linux/xarray.h b/include/linux/xarray.h index fea81383a301..2d889208b68d 100644 --- a/include/linux/xarray.h +++ b/include/linux/xarray.h @@ -640,6 +640,12 @@ static inline bool xas_not_node(struct xa_node *node) return ((unsigned long)node & 3) || !node; } +/* True if the node represents RESTART or an error */ +static inline bool xas_frozen(struct xa_node *node) +{ + return (unsigned long)node & 2; +} + /* True if the node represents head-of-tree, RESTART or BOUNDS */ static inline bool xas_top(struct xa_node *node) { @@ -758,8 +764,8 @@ static inline bool xa_iter_skip(const void *entry) } /* - * node->shift is always 0 for the inline iterators unless we're processing - * a multi-index entry. + * node->shift is always 0 for next_entry and next_tag unless we're processing + * a multi-index entry. It can be non-0 for next/prev, so it's not used there. */ #ifdef CONFIG_RADIX_TREE_MULTIORDER #define xa_node_shift(node) node->shift @@ -767,6 +773,67 @@ static inline bool xa_iter_skip(const void *entry) #define xa_node_shift(node) 0 #endif +void *__xas_next(struct xa_state *); +void *__xas_prev(struct xa_state *); + +/** + * xas_prev() - Move iterator to previous index. + * @xas: XArray operation state. + * + * If the @xas was in an error state, it will remain in an error state + * and this function will return %NULL. If the @xas has never been walked, + * it will have the effect of calling xas_load(). Otherwise one will be + * subtracted from the index and the state will be walked to the correct + * location in the array for the next operation. + * + * If the iterator was referencing index 0, this function wraps + * around to %ULONG_MAX. + * + * Return: The entry at the new index. This may be %NULL or an internal + * entry, although it should never be a node entry. + */ +static inline void *xas_prev(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + if (unlikely(xas_not_node(node) || node->shift || + xas->xa_offset == 0)) + return __xas_prev(xas); + + xas->xa_index--; + xas->xa_offset--; + return xa_entry(xas->xa, node, xas->xa_offset); +} + +/** + * xas_next() - Move state to next index. + * @xas: XArray operation state. + * + * If the @xas was in an error state, it will remain in an error state + * and this function will return %NULL. If the @xas has never been walked, + * it will have the effect of calling xas_load(). Otherwise one will be + * added to the index and the state will be walked to the correct + * location in the array for the next operation. + * + * If the iterator was referencing index %ULONG_MAX, this function wraps + * around to 0. + * + * Return: The entry at the new index. This may be %NULL or an internal + * entry, although it should never be a node entry. + */ +static inline void *xas_next(struct xa_state *xas) +{ + struct xa_node *node = xas->xa_node; + + if (unlikely(xas_not_node(node) || node->shift || + xas->xa_offset == XA_CHUNK_MASK)) + return __xas_next(xas); + + xas->xa_index++; + xas->xa_offset++; + return xa_entry(xas->xa, node, xas->xa_offset); +} + /** * xas_next_entry() - Advance iterator to next present entry. * @xas: XArray operation state. diff --git a/lib/xarray.c b/lib/xarray.c index a51fa1e1f74f..a4975aeedf6b 100644 --- a/lib/xarray.c +++ b/lib/xarray.c @@ -838,6 +838,80 @@ void xas_pause(struct xa_state *xas) } EXPORT_SYMBOL_GPL(xas_pause); +/* + * __xas_prev() - Find the previous entry in the XArray. + * @xas: XArray operation state. + * + * Helper function for xas_prev() which handles all the complex cases + * out of line. + */ +void *__xas_prev(struct xa_state *xas) +{ + void *entry; + + if (!xas_frozen(xas->xa_node)) + xas->xa_index--; + if (xas_not_node(xas->xa_node)) + return xas_load(xas); + + if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) + xas->xa_offset--; + + while (xas->xa_offset == 255) { + xas->xa_offset = xas->xa_node->offset - 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + return set_bounds(xas); + } + + for (;;) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + + xas->xa_node = xa_to_node(entry); + xas->xa_offset = get_offset(xas->xa_index, xas->xa_node); + } +} +EXPORT_SYMBOL_GPL(__xas_prev); + +/* + * __xas_next() - Find the next entry in the XArray. + * @xas: XArray operation state. + * + * Helper function for xas_next() which handles all the complex cases + * out of line. + */ +void *__xas_next(struct xa_state *xas) +{ + void *entry; + + if (!xas_frozen(xas->xa_node)) + xas->xa_index++; + if (xas_not_node(xas->xa_node)) + return xas_load(xas); + + if (xas->xa_offset != get_offset(xas->xa_index, xas->xa_node)) + xas->xa_offset++; + + while (xas->xa_offset == XA_CHUNK_SIZE) { + xas->xa_offset = xas->xa_node->offset + 1; + xas->xa_node = xa_parent(xas->xa, xas->xa_node); + if (!xas->xa_node) + return set_bounds(xas); + } + + for (;;) { + entry = xa_entry(xas->xa, xas->xa_node, xas->xa_offset); + if (!xa_is_node(entry)) + return entry; + + xas->xa_node = xa_to_node(entry); + xas->xa_offset = get_offset(xas->xa_index, xas->xa_node); + } +} +EXPORT_SYMBOL_GPL(__xas_next); + /** * xas_find() - Find the next present entry in the XArray. * @xas: XArray operation state. diff --git a/tools/testing/radix-tree/xarray-test.c b/tools/testing/radix-tree/xarray-test.c index 10de5d3d977a..43111786ebdd 100644 --- a/tools/testing/radix-tree/xarray-test.c +++ b/tools/testing/radix-tree/xarray-test.c @@ -92,6 +92,104 @@ void check_xas_error(struct xarray *xa) assert(xas.xa_node == XAS_BOUNDS); } +void check_xas_pause(struct xarray *xa) +{ + XA_STATE(xas, xa, 0); + void *entry; + unsigned int seen; + + xa_store(xa, 0, xa_mk_value(0), GFP_KERNEL); + xa_set_tag(xa, 0, XA_TAG_0); + + seen = 0; + rcu_read_lock(); + xas_for_each_tag(&xas, entry, ULONG_MAX, XA_TAG_0) { + if (!seen++) { + xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL); + xa_set_tag(xa, 1, XA_TAG_0); + } + } + rcu_read_unlock(); + /* We don't see an entry that was added after we started */ + assert(seen == 1); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + xas_for_each_tag(&xas, entry, ULONG_MAX, XA_TAG_0) { + if (!seen++) + xa_erase(xa, 1); + } + rcu_read_unlock(); + assert(seen == 1); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + xas_for_each(&xas, entry, ULONG_MAX) { + if (!seen++) + xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL); + } + rcu_read_unlock(); + assert(seen == 1); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + xas_for_each(&xas, entry, ULONG_MAX) { + if (!seen++) + xa_erase(xa, 1); + } + rcu_read_unlock(); + assert(seen == 1); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + for (entry = xas_load(&xas); entry; entry = xas_next(&xas)) { + if (!seen++) + xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL); + } + rcu_read_unlock(); + assert(seen == 2); + + seen = 0; + xas_set(&xas, 0); + rcu_read_lock(); + for (entry = xas_load(&xas); entry; entry = xas_next(&xas)) { + if (!seen++) + xa_erase(xa, 1); + } + rcu_read_unlock(); + assert(seen == 1); + + xa_store(xa, 1, xa_mk_value(1), GFP_KERNEL); + seen = 0; + xas_set(&xas, 0); + xas_for_each(&xas, entry, ULONG_MAX) { + if (!seen++) + xas_pause(&xas); + } + assert(seen == 2); + + seen = 0; + xas_set(&xas, 0); + for (entry = xas_load(&xas); entry; entry = xas_next(&xas)) { + if (!seen++) + xas_pause(&xas); + } + assert(seen == 2); + + seen = 0; + xas_set(&xas, 0); + xa_set_tag(xa, 1, XA_TAG_0); + xas_for_each_tag(&xas, entry, ULONG_MAX, XA_TAG_0) { + if (!seen++) + xas_pause(&xas); + } + assert(seen == 2); +} + void check_xas_retry(struct xarray *xa) { XA_STATE(xas, xa, 0); @@ -249,9 +347,108 @@ void check_xas_delete(struct xarray *xa) } } +void check_move_small(struct xarray *xa, unsigned long idx) +{ + XA_STATE(xas, xa, 0); + unsigned long i; + + xa_store(xa, 0, xa_mk_value(0), GFP_KERNEL); + xa_store(xa, idx, xa_mk_value(idx), GFP_KERNEL); + + for (i = 0; i < idx * 4; i++) { + void *entry = xas_next(&xas); + if (i <= idx) + assert(xas.xa_node != XAS_RESTART); + assert(xas.xa_index == i); + if (i == 0 || i == idx) + assert(entry == xa_mk_value(i)); + else + assert(entry == NULL); + } + xas_next(&xas); + assert(xas.xa_index == i); + + do { + void *entry = xas_prev(&xas); + i--; + if (i <= idx) + assert(xas.xa_node != XAS_RESTART); + assert(xas.xa_index == i); + if (i == 0 || i == idx) + assert(entry == xa_mk_value(i)); + else + assert(entry == NULL); + } while (i > 0); + + xas_set(&xas, ULONG_MAX); + assert(xas_next(&xas) == NULL); + assert(xas.xa_index == ULONG_MAX); + assert(xas_next(&xas) == xa_mk_value(0)); + assert(xas.xa_index == 0); + assert(xas_prev(&xas) == NULL); + assert(xas.xa_index == ULONG_MAX); +} + +void check_move(struct xarray *xa) +{ + XA_STATE(xas, xa, (1 << 16) - 1); + unsigned long i; + + for (i = 0; i < (1 << 16); i++) { + xa_store(xa, i, xa_mk_value(i), GFP_KERNEL); + } + + do { + void *entry = xas_prev(&xas); + i--; + assert(entry == xa_mk_value(i)); + assert(i == xas.xa_index); + } while (i != 0); + + assert(xas_prev(&xas) == NULL); + assert(xas.xa_index == ULONG_MAX); + + do { + void *entry = xas_next(&xas); + assert(entry == xa_mk_value(i)); + assert(i == xas.xa_index); + i++; + } while (i < (1 << 16)); + + for (i = (1 << 8); i < (1 << 15); i++) { + xa_erase(xa, i); + } + + i = xas.xa_index; + + do { + void *entry = xas_prev(&xas); + i--; + if ((i < (1 << 8)) || (i >= (1 << 15))) + assert(entry == xa_mk_value(i)); + else + assert(entry == NULL); + assert(i == xas.xa_index); + } while (i != 0); + + assert(xas_prev(&xas) == NULL); + assert(xas.xa_index == ULONG_MAX); + + do { + void *entry = xas_next(&xas); + if ((i < (1 << 8)) || (i >= (1 << 15))) + assert(entry == xa_mk_value(i)); + else + assert(entry == NULL); + assert(i == xas.xa_index); + i++; + } while (i < (1 << 16)); +} + void xarray_checks(void) { DEFINE_XARRAY(array); + unsigned long i; check_xa_err(&array); item_kill_tree(&array); @@ -265,6 +462,9 @@ void xarray_checks(void) check_xas_retry(&array); item_kill_tree(&array); + check_xas_pause(&array); + item_kill_tree(&array); + check_xa_load(&array); item_kill_tree(&array); @@ -279,6 +479,19 @@ void xarray_checks(void) check_xas_delete(&array); item_kill_tree(&array); + + for (i = 0; i < 16; i++) { + check_move_small(&array, 1UL << i); + item_kill_tree(&array); + } + + for (i = 2; i < 16; i++) { + check_move_small(&array, (1UL << i) - 1); + item_kill_tree(&array); + } + + check_move(&array); + item_kill_tree(&array); } int __weak main(void)