From patchwork Tue Sep 25 20:20:47 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Duyck X-Patchwork-Id: 10614787 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 5B7DE161F for ; Tue, 25 Sep 2018 20:21:15 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4BBBF2AD55 for ; Tue, 25 Sep 2018 20:21:15 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 3D0E92AD65; Tue, 25 Sep 2018 20:21:15 +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=-2.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_NONE autolearn=ham version=3.3.1 Received: from ml01.01.org (ml01.01.org [198.145.21.10]) (using TLSv1.2 with cipher DHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id B96C42AD55 for ; Tue, 25 Sep 2018 20:21:14 +0000 (UTC) Received: from [127.0.0.1] (localhost [IPv6:::1]) by ml01.01.org (Postfix) with ESMTP id AD54821A07A82; Tue, 25 Sep 2018 13:21:14 -0700 (PDT) X-Original-To: linux-nvdimm@lists.01.org Delivered-To: linux-nvdimm@lists.01.org Received-SPF: None (no SPF record) identity=mailfrom; client-ip=134.134.136.24; helo=mga09.intel.com; envelope-from=alexander.h.duyck@linux.intel.com; receiver=linux-nvdimm@lists.01.org Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id D64752114842B for ; Tue, 25 Sep 2018 13:21:12 -0700 (PDT) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 25 Sep 2018 13:21:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.54,303,1534834800"; d="scan'208";a="77230394" Received: from ahduyck-mobl.amr.corp.intel.com (HELO localhost.localdomain) ([10.7.198.152]) by orsmga006.jf.intel.com with ESMTP; 25 Sep 2018 13:20:47 -0700 Subject: [PATCH v5 3/4] mm: Create non-atomic version of SetPageReserved for init use From: Alexander Duyck To: linux-mm@kvack.org, akpm@linux-foundation.org, linux-kernel@vger.kernel.org, linux-nvdimm@lists.01.org Date: Tue, 25 Sep 2018 13:20:47 -0700 Message-ID: <20180925202018.3576.11607.stgit@localhost.localdomain> In-Reply-To: <20180925200551.3576.18755.stgit@localhost.localdomain> References: <20180925200551.3576.18755.stgit@localhost.localdomain> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-BeenThere: linux-nvdimm@lists.01.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "Linux-nvdimm developer list." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: pavel.tatashin@microsoft.com, mhocko@suse.com, dave.hansen@intel.com, jglisse@redhat.com, rppt@linux.vnet.ibm.com, mingo@kernel.org, kirill.shutemov@linux.intel.com Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" X-Virus-Scanned: ClamAV using ClamSMTP It doesn't make much sense to use the atomic SetPageReserved at init time when we are using memset to clear the memory and manipulating the page flags via simple "&=" and "|=" operations in __init_single_page. This patch adds a non-atomic version __SetPageReserved that can be used during page init and shows about a 10% improvement in initialization times on the systems I have available for testing. On those systems I saw initialization times drop from around 35 seconds to around 32 seconds to initialize a 3TB block of persistent memory. I believe the main advantage of this is that it allows for more compiler optimization as the __set_bit operation can be reordered whereas the atomic version cannot. I tried adding a bit of documentation based on commit ("mm, memory_hotplug: do not associate hotadded memory to zones until online"). Ideally the reserved flag should be set earlier since there is a brief window where the page is initialization via __init_single_page and we have not set the PG_Reserved flag. I'm leaving that for a future patch set as that will require a more significant refactor. Acked-by: Michal Hocko Reviewed-by: Pavel Tatashin Signed-off-by: Alexander Duyck --- v4: Added comment about __set_bit vs set_bit to the patch description v5: No change include/linux/page-flags.h | 1 + mm/page_alloc.c | 9 +++++++-- 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 934f91ef3f54..50ce1bddaf56 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -303,6 +303,7 @@ static inline void page_init_poison(struct page *page, size_t size) PAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) __CLEARPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) + __SETPAGEFLAG(Reserved, reserved, PF_NO_COMPOUND) PAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) __CLEARPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) __SETPAGEFLAG(SwapBacked, swapbacked, PF_NO_TAIL) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 511447ac02cf..926ad3083b28 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1238,7 +1238,12 @@ void __meminit reserve_bootmem_region(phys_addr_t start, phys_addr_t end) /* Avoid false-positive PageTail() */ INIT_LIST_HEAD(&page->lru); - SetPageReserved(page); + /* + * no need for atomic set_bit because the struct + * page is not visible yet so nobody should + * access it yet. + */ + __SetPageReserved(page); } } } @@ -5512,7 +5517,7 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone, page = pfn_to_page(pfn); __init_single_page(page, pfn, zone, nid); if (context == MEMMAP_HOTPLUG) - SetPageReserved(page); + __SetPageReserved(page); /* * Mark the block movable so that blocks are reserved for