From patchwork Tue Mar 6 19:24:03 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matthew Wilcox X-Patchwork-Id: 10262563 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 397FB602C8 for ; Tue, 6 Mar 2018 19:31:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 291722915D for ; Tue, 6 Mar 2018 19:31:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 1DF5D29161; Tue, 6 Mar 2018 19:31:14 +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=ham 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 A79882915D for ; Tue, 6 Mar 2018 19:31:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754086AbeCFTbK (ORCPT ); Tue, 6 Mar 2018 14:31:10 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:49310 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933307AbeCFTYl (ORCPT ); Tue, 6 Mar 2018 14:24:41 -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=vUPKR/5OptlQ4BngjrDJXGHNjkGi/TUPNgExS/XXlcQ=; b=g7nEOhEYUJyJ3W5sduHBv/erK kztWVXa3LfJcTYUqwPqCVvzoeXzRqCx86f5NCbdJHfRIULbkGbXt+EbqWOfpNskn9f9FJkFNLhrjp q7KsBdV/LYu/eGDAOkfBYdB4NL1y0zzW/vqLZl3ENdd7dzAx+pZZjy8Ukz5ga3TzMVWnooqqtLmAa ftDgizKsh5igIX2r676VXQvT2Wkv+Ws0G4Rp5sy5EvM6sgG0yHFd+cNL1yo+YgmgV9NlqoZEyTonr V6CUk7ha76+QhLPToIpSFsm0gMV9BUzfcQd+F1G3kGTNHP45EIoklRxkD+lDcDMun5MiGFR1h0/PC ngFd/ZGZA==; Received: from willy by bombadil.infradead.org with local (Exim 4.89 #1 (Red Hat Linux)) id 1etICW-0001fu-He; Tue, 06 Mar 2018 19:24:40 +0000 From: Matthew Wilcox To: Andrew Morton Cc: Matthew Wilcox , linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, Ryusuke Konishi , linux-nilfs@vger.kernel.org, linux-btrfs@vger.kernel.org Subject: [PATCH v8 53/63] memfd: Convert shmem_wait_for_pins to XArray Date: Tue, 6 Mar 2018 11:24:03 -0800 Message-Id: <20180306192413.5499-54-willy@infradead.org> X-Mailer: git-send-email 2.14.3 In-Reply-To: <20180306192413.5499-1-willy@infradead.org> References: <20180306192413.5499-1-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 As with shmem_tag_pins(), hold the lock around the entire loop instead of acquiring & dropping it for each entry we're going to untag. Signed-off-by: Matthew Wilcox --- mm/memfd.c | 61 +++++++++++++++++++++++++------------------------------------ 1 file changed, 25 insertions(+), 36 deletions(-) diff --git a/mm/memfd.c b/mm/memfd.c index 3b299d72df78..0e0835e63af2 100644 --- a/mm/memfd.c +++ b/mm/memfd.c @@ -64,9 +64,7 @@ static void shmem_tag_pins(struct address_space *mapping) */ static int shmem_wait_for_pins(struct address_space *mapping) { - struct radix_tree_iter iter; - void __rcu **slot; - pgoff_t start; + XA_STATE(xas, &mapping->i_pages, 0); struct page *page; int error, scan; @@ -74,7 +72,9 @@ static int shmem_wait_for_pins(struct address_space *mapping) error = 0; for (scan = 0; scan <= LAST_SCAN; scan++) { - if (!radix_tree_tagged(&mapping->i_pages, SHMEM_TAG_PINNED)) + unsigned int tagged = 0; + + if (!xas_tagged(&xas, SHMEM_TAG_PINNED)) break; if (!scan) @@ -82,45 +82,34 @@ static int shmem_wait_for_pins(struct address_space *mapping) else if (schedule_timeout_killable((HZ << scan) / 200)) scan = LAST_SCAN; - start = 0; - rcu_read_lock(); - radix_tree_for_each_tagged(slot, &mapping->i_pages, &iter, - start, SHMEM_TAG_PINNED) { - - page = radix_tree_deref_slot(slot); - if (radix_tree_exception(page)) { - if (radix_tree_deref_retry(page)) { - slot = radix_tree_iter_retry(&iter); - continue; - } - - page = NULL; - } - - if (page && - page_count(page) - page_mapcount(page) != 1) { - if (scan < LAST_SCAN) - goto continue_resched; - + xas_set(&xas, 0); + xas_lock_irq(&xas); + xas_for_each_tag(&xas, page, ULONG_MAX, SHMEM_TAG_PINNED) { + bool clear = true; + if (xa_is_value(page)) + continue; + if (page_count(page) - page_mapcount(page) != 1) { /* * On the last scan, we clean up all those tags * we inserted; but make a note that we still * found pages pinned. */ - error = -EBUSY; - } - - xa_lock_irq(&mapping->i_pages); - radix_tree_tag_clear(&mapping->i_pages, - iter.index, SHMEM_TAG_PINNED); - xa_unlock_irq(&mapping->i_pages); -continue_resched: - if (need_resched()) { - slot = radix_tree_iter_resume(slot, &iter); - cond_resched_rcu(); + if (scan == LAST_SCAN) + error = -EBUSY; + else + clear = false; } + if (clear) + xas_clear_tag(&xas, SHMEM_TAG_PINNED); + if (++tagged % XA_CHECK_SCHED) + continue; + + xas_pause(&xas); + xas_unlock_irq(&xas); + cond_resched(); + xas_lock_irq(&xas); } - rcu_read_unlock(); + xas_unlock_irq(&xas); } return error;