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=-3.5 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS, URIBL_BLOCKED autolearn=ham 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 D89E5C43441 for ; Wed, 10 Oct 2018 16:56:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 910922077C for ; Wed, 10 Oct 2018 16:56:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="XtVbpkRo"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="HPRAe2pT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 910922077C Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726781AbeJKATn (ORCPT ); Wed, 10 Oct 2018 20:19:43 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:45146 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726515AbeJKATn (ORCPT ); Wed, 10 Oct 2018 20:19:43 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id 9A0EC600C1; Wed, 10 Oct 2018 16:56:42 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539190602; bh=rTGq1MPcA4dcO+RD/B2LbWZW48cyLy+nfDnbfxXA1ww=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=XtVbpkRoEHl7b9QaVc9wVwDg3x0fA8fpZofmWCTy4FtL/y1G/AEAxnFXBM4J1hXRR wtf4hkIP4T720sKwGEHleyOIJQcvjU8DdFAXVcGUExXqw+trjd9UafxKpzmvw7OcWA 8PHBOn0vItXcRnEG/aQ1l2q0VbwGJmYmTBTb/XDo= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id 70230600C1; Wed, 10 Oct 2018 16:56:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539190601; bh=rTGq1MPcA4dcO+RD/B2LbWZW48cyLy+nfDnbfxXA1ww=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=HPRAe2pTi4fIjuP6cbqZBujeqYkRZqLUtZOup/ouA+GCr8xukld3hRtmx29MpMfEb k4mQOCFTTKLAAVIRPNmHsnpoiq7nHG6PudXbXHfHr4T96ZKNvDHDZuouMCslCZLzLy 5Tu6EirhAnCYKXRI2vYyOha1R7NWub9G06jeUtA4= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Wed, 10 Oct 2018 22:26:41 +0530 From: Arun KS To: Vlastimil Babka Cc: kys@microsoft.com, haiyangz@microsoft.com, sthemmin@microsoft.com, boris.ostrovsky@oracle.com, jgross@suse.com, akpm@linux-foundation.org, dan.j.williams@intel.com, mhocko@suse.com, iamjoonsoo.kim@lge.com, gregkh@linuxfoundation.org, osalvador@suse.de, malat@debian.org, kirill.shutemov@linux.intel.com, jrdr.linux@gmail.com, yasu.isimatu@gmail.com, mgorman@techsingularity.net, aaron.lu@intel.com, devel@linuxdriverproject.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, xen-devel@lists.xenproject.org, vatsa@codeaurora.org, vinmenon@codeaurora.org, getarunks@gmail.com Subject: Re: [PATCH v5 1/2] memory_hotplug: Free pages as higher order In-Reply-To: <72215e75-6c7e-0aef-c06e-e3aba47cf806@suse.cz> References: <1538727006-5727-1-git-send-email-arunks@codeaurora.org> <72215e75-6c7e-0aef-c06e-e3aba47cf806@suse.cz> Message-ID: X-Sender: arunks@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2018-10-10 21:00, Vlastimil Babka wrote: > On 10/5/18 10:10 AM, Arun KS wrote: >> When free pages are done with higher order, time spend on >> coalescing pages by buddy allocator can be reduced. With >> section size of 256MB, hot add latency of a single section >> shows improvement from 50-60 ms to less than 1 ms, hence >> improving the hot add latency by 60%. Modify external >> providers of online callback to align with the change. >> >> Signed-off-by: Arun KS > > [...] > >> @@ -655,26 +655,44 @@ void __online_page_free(struct page *page) >> } >> EXPORT_SYMBOL_GPL(__online_page_free); >> >> -static void generic_online_page(struct page *page) >> +static int generic_online_page(struct page *page, unsigned int order) >> { >> - __online_page_set_limits(page); > > This is now not called anymore, although the xen/hv variants still do > it. The function seems empty these days, maybe remove it as a followup > cleanup? > >> - __online_page_increment_counters(page); >> - __online_page_free(page); >> + __free_pages_core(page, order); >> + totalram_pages += (1UL << order); >> +#ifdef CONFIG_HIGHMEM >> + if (PageHighMem(page)) >> + totalhigh_pages += (1UL << order); >> +#endif > > __online_page_increment_counters() would have used > adjust_managed_page_count() which would do the changes under > managed_page_count_lock. Are we safe without the lock? If yes, there > should perhaps be a comment explaining why. Looks unsafe without managed_page_count_lock. I think better have a similar implementation of free_boot_core() in memory_hotplug.c like we had in version 1 of patch. And use adjust_managed_page_count() instead of page_zone(page)->managed_pages += nr_pages; https://lore.kernel.org/patchwork/patch/989445/ -static void generic_online_page(struct page *page) +static int generic_online_page(struct page *page, unsigned int order) { - __online_page_set_limits(page); - __online_page_increment_counters(page); - __online_page_free(page); + unsigned long nr_pages = 1 << order; + struct page *p = page; + + for (loop = 0 ; loop < nr_pages ; loop++, p++) { + __ClearPageReserved(p); + set_page_count(p, 0); + } + + adjust_managed_page_count(page, nr_pages); + set_page_refcounted(page); + __free_pages(page, order); + + return 0; +} Regards, Arun