From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8A22FC11F64 for ; Tue, 29 Jun 2021 02:35:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 76EF961D04 for ; Tue, 29 Jun 2021 02:35:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231851AbhF2Chz (ORCPT ); Mon, 28 Jun 2021 22:37:55 -0400 Received: from mail.kernel.org ([198.145.29.99]:58486 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231398AbhF2Chx (ORCPT ); Mon, 28 Jun 2021 22:37:53 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3560C61D02; Tue, 29 Jun 2021 02:35:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1624934126; bh=L9t32XMNt47V7wlIrVkPmXkeao2vVq7WlEa/w0wIFyw=; h=Date:From:To:Subject:In-Reply-To:From; b=mEVv8j1gYYyFV+0umGxQK3/+pviO6kIvhqGFaR1RdikcFJ6VCqhtmdXNKjOAfvcuL s+v9RkrsGPvWJ29tExsOHTNx2erj67yFqZpzL+LVm6fUk1ebdlcIHf6LxMLu2RZrX1 0ZV1NuVnHbh1NHFoSlHnCrkIwFRMdE6CU9Ea0DSQ= Date: Mon, 28 Jun 2021 19:35:25 -0700 From: Andrew Morton To: akpm@linux-foundation.org, alexanderduyck@fb.com, anshuman.khandual@arm.com, catalin.marinas@arm.com, david@redhat.com, gshan@redhat.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, mst@redhat.com, torvalds@linux-foundation.org, will@kernel.org Subject: [patch 041/192] virtio_balloon: specify page reporting order if needed Message-ID: <20210629023525.ututxfVsi%akpm@linux-foundation.org> In-Reply-To: <20210628193256.008961950a714730751c1423@linux-foundation.org> User-Agent: s-nail v14.8.16 Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org From: Gavin Shan Subject: virtio_balloon: specify page reporting order if needed The page reporting won't be triggered if the freeing page can't come up with a free area, whose size is equal or bigger than the threshold (page reporting order). The default page reporting order, equal to @pageblock_order, is too huge on some architectures to trigger page reporting. One example is ARM64 when 64KB base page size is used. PAGE_SIZE: 64KB pageblock_order: 13 (512MB) MAX_ORDER: 14 This specifies the page reporting order to 5 (2MB) for this specific case so that page reporting can be triggered. Link: https://lkml.kernel.org/r/20210625014710.42954-5-gshan@redhat.com Signed-off-by: Gavin Shan Reviewed-by: Alexander Duyck Cc: Michael S. Tsirkin Cc: David Hildenbrand Cc: Anshuman Khandual Cc: Catalin Marinas Cc: Will Deacon Signed-off-by: Andrew Morton --- drivers/virtio/virtio_balloon.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) --- a/drivers/virtio/virtio_balloon.c~virtio_balloon-specify-page-reporting-order-if-needed +++ a/drivers/virtio/virtio_balloon.c @@ -993,6 +993,23 @@ static int virtballoon_probe(struct virt goto out_unregister_oom; } + /* + * The default page reporting order is @pageblock_order, which + * corresponds to 512MB in size on ARM64 when 64KB base page + * size is used. The page reporting won't be triggered if the + * freeing page can't come up with a free area like that huge. + * So we specify the page reporting order to 5, corresponding + * to 2MB. It helps to avoid THP splitting if 4KB base page + * size is used by host. + * + * Ideally, the page reporting order is selected based on the + * host's base page size. However, it needs more work to report + * that value. The hard-coded order would be fine currently. + */ +#if defined(CONFIG_ARM64) && defined(CONFIG_ARM64_64K_PAGES) + vb->pr_dev_info.order = 5; +#endif + err = page_reporting_register(&vb->pr_dev_info); if (err) goto out_unregister_oom; _