From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753050AbaEBTEO (ORCPT ); Fri, 2 May 2014 15:04:14 -0400 Received: from mail-yh0-f52.google.com ([209.85.213.52]:54047 "EHLO mail-yh0-f52.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753015AbaEBTEM (ORCPT ); Fri, 2 May 2014 15:04:12 -0400 From: Dan Streetman To: Hugh Dickins , Andrew Morton , Mel Gorman Cc: Dan Streetman , Michal Hocko , Christian Ehrhardt , Rik van Riel , Weijie Yang , Johannes Weiner , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Paul Gortmaker , Steven Rostedt , Thomas Gleixner Subject: [PATCH 3/4] plist: add plist_rotate Date: Fri, 2 May 2014 15:02:29 -0400 Message-Id: <1399057350-16300-4-git-send-email-ddstreet@ieee.org> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1399057350-16300-1-git-send-email-ddstreet@ieee.org> References: <1397336454-13855-1-git-send-email-ddstreet@ieee.org> <1399057350-16300-1-git-send-email-ddstreet@ieee.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Add plist_rotate(), which moves the specified plist_node after all other same-priority plist_nodes in the list. This is needed by swap, which has a plist of swap_info_structs and needs to use each same-priority swap_info_struct equally. Also add plist_test_rotate() test function, for use by plist_test() to test plist_rotate() function. Signed-off-by: Dan Streetman Cc: Mel Gorman Cc: Paul Gortmaker Cc: Steven Rostedt Cc: Thomas Gleixner --- This patch is new to this patch set, and it's required by the next patch, which needs a way to move a plist entry to the end of all following same-priority entries. This is possible to do manually instead of adding a new plist function, but having a common plist function instead of code specific only to swap seems preferable. include/linux/plist.h | 2 ++ lib/plist.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++++ 2 files changed, 50 insertions(+) diff --git a/include/linux/plist.h b/include/linux/plist.h index c815491..06e6925 100644 --- a/include/linux/plist.h +++ b/include/linux/plist.h @@ -141,6 +141,8 @@ static inline void plist_node_init(struct plist_node *node, int prio) extern void plist_add(struct plist_node *node, struct plist_head *head); extern void plist_del(struct plist_node *node, struct plist_head *head); +extern void plist_rotate(struct plist_node *node, struct plist_head *head); + /** * plist_for_each - iterate over the plist * @pos: the type * to use as a loop counter diff --git a/lib/plist.c b/lib/plist.c index 1ebc95f..a8b54e5 100644 --- a/lib/plist.c +++ b/lib/plist.c @@ -134,6 +134,42 @@ void plist_del(struct plist_node *node, struct plist_head *head) plist_check_head(head); } +/** + * plist_rotate - Rotate @node to end of same-prio entries. + * + * @node: &struct plist_node pointer - entry to be moved + * @head: &struct plist_head pointer - list head + */ +void plist_rotate(struct plist_node *node, struct plist_head *head) +{ + struct plist_node *next; + struct list_head *next_node_list = &head->node_list; + + plist_check_head(head); + BUG_ON(plist_head_empty(head)); + BUG_ON(plist_node_empty(node)); + + if (node == plist_last(head)) + return; + + next = plist_next(node); + + if (node->prio != next->prio) + return; + + plist_del(node, head); + + plist_for_each_continue(next, head) { + if (node->prio != next->prio) { + next_node_list = &next->node_list; + break; + } + } + list_add_tail(&node->node_list, next_node_list); + + plist_check_head(head); +} + #ifdef CONFIG_DEBUG_PI_LIST #include #include @@ -170,6 +206,14 @@ static void __init plist_test_check(int nr_expect) BUG_ON(prio_pos->prio_list.next != &first->prio_list); } +static void __init plist_test_rotate(struct plist_node *node) +{ + plist_rotate(node, &test_head); + + if (node != plist_last(&test_head)) + BUG_ON(node->prio == plist_next(node)->prio); +} + static int __init plist_test(void) { int nr_expect = 0, i, loop; @@ -193,6 +237,10 @@ static int __init plist_test(void) nr_expect--; } plist_test_check(nr_expect); + if (!plist_node_empty(test_node + i)) { + plist_test_rotate(test_node + i); + plist_test_check(nr_expect); + } } for (i = 0; i < ARRAY_SIZE(test_node); i++) { -- 1.8.3.1