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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B1CD4C6FA8B for ; Thu, 22 Sep 2022 06:23:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230021AbiIVGXB (ORCPT ); Thu, 22 Sep 2022 02:23:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229988AbiIVGW6 (ORCPT ); Thu, 22 Sep 2022 02:22:58 -0400 Received: from mga12.intel.com (mga12.intel.com [192.55.52.136]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B2D73A032D for ; Wed, 21 Sep 2022 23:22:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1663827777; x=1695363777; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=B2IMj1wxNxIezrIrTzyNldqwKTyK+xDNyJjvLLABEzE=; b=gNCpgVH73vDOTm8NvH1lEcnikECZsrTRnoM71n6j3Iklhc1FRheP97lL BdgSoasAlJ8VS/gSTU/Bk+4kCxffRWo4S6UhmwmcnJtqT1XKcq1Ovo8yE OJyayqF5L9qDc6PGrKYYz9qcS2XvrKsW55Cp0yjihEmVRNeDCb0E/gN0o zwq5pohb+o4kHbMBytKOdAxGIOUVFQs1z1ba6e/hUhjHm1WvjlyMlP0ck ZZig8Vlcp/uU1PxnphtqgW5Ti/96j9lma7WajM7gFasJzBoJvKt4IxFg5 HVRJc9eg6ss1VggNTp19ic4vvMgTc1U3EChpkPkKAccm/YPl/F9vWCY8x A==; X-IronPort-AV: E=McAfee;i="6500,9779,10477"; a="279933343" X-IronPort-AV: E=Sophos;i="5.93,335,1654585200"; d="scan'208";a="279933343" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga106.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Sep 2022 23:22:57 -0700 X-IronPort-AV: E=Sophos;i="5.93,335,1654585200"; d="scan'208";a="948467107" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Sep 2022 23:22:50 -0700 From: "Huang, Ying" To: Baolin Wang Cc: , , Andrew Morton , Zi Yan , Yang Shi , Oscar Salvador , Matthew Wilcox Subject: Re: [RFC 1/6] mm/migrate_pages: separate huge page and normal pages migration References: <20220921060616.73086-1-ying.huang@intel.com> <20220921060616.73086-2-ying.huang@intel.com> <0a41c051-7d7e-cb1b-8273-192252e74b94@linux.alibaba.com> Date: Thu, 22 Sep 2022 14:22:49 +0800 In-Reply-To: <0a41c051-7d7e-cb1b-8273-192252e74b94@linux.alibaba.com> (Baolin Wang's message of "Thu, 22 Sep 2022 14:03:55 +0800") Message-ID: <87pmfoj5c6.fsf@yhuang6-desk2.ccr.corp.intel.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=ascii Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Baolin Wang writes: > On 9/21/2022 2:06 PM, Huang Ying wrote: >> This is a preparation patch to batch the page unmapping and moving for >> the normal pages and THPs. Based on that we can batch the TLB >> shootdown during the page migration and make it possible to use some >> hardware accelerator for the page copying. >> In this patch the huge page (PageHuge()) and normal page and THP >> migration is separated in migrate_pages() to make it easy to change >> the normal page and THP migration implementation. >> Signed-off-by: "Huang, Ying" >> Cc: Zi Yan >> Cc: Yang Shi >> Cc: Baolin Wang >> Cc: Oscar Salvador >> Cc: Matthew Wilcox >> --- >> mm/migrate.c | 73 +++++++++++++++++++++++++++++++++++++++++++++------- >> 1 file changed, 64 insertions(+), 9 deletions(-) >> diff --git a/mm/migrate.c b/mm/migrate.c >> index 571d8c9fd5bc..117134f1c6dc 100644 >> --- a/mm/migrate.c >> +++ b/mm/migrate.c >> @@ -1414,6 +1414,66 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >> trace_mm_migrate_pages_start(mode, reason); >> + for (pass = 0; pass < 10 && retry; pass++) { >> + retry = 0; >> + >> + list_for_each_entry_safe(page, page2, from, lru) { >> + nr_subpages = compound_nr(page); >> + cond_resched(); >> + >> + if (!PageHuge(page)) >> + continue; >> + >> + rc = unmap_and_move_huge_page(get_new_page, >> + put_new_page, private, page, >> + pass > 2, mode, reason, >> + &ret_pages); >> + /* >> + * The rules are: >> + * Success: hugetlb page will be put back >> + * -EAGAIN: stay on the from list >> + * -ENOMEM: stay on the from list >> + * -ENOSYS: stay on the from list >> + * Other errno: put on ret_pages list then splice to >> + * from list >> + */ >> + switch(rc) { >> + case -ENOSYS: >> + /* Hugetlb migration is unsupported */ >> + nr_failed++; >> + nr_failed_pages += nr_subpages; >> + list_move_tail(&page->lru, &ret_pages); >> + break; >> + case -ENOMEM: >> + /* >> + * When memory is low, don't bother to try to migrate >> + * other pages, just exit. >> + */ >> + nr_failed++; >> + nr_failed_pages += nr_subpages + nr_retry_pages; >> + goto out; >> + case -EAGAIN: >> + retry++; >> + nr_retry_pages += nr_subpages; >> + break; >> + case MIGRATEPAGE_SUCCESS: >> + nr_succeeded += nr_subpages; >> + break; >> + default: >> + /* >> + * Permanent failure (-EBUSY, etc.): >> + * unlike -EAGAIN case, the failed page is >> + * removed from migration page list and not >> + * retried in the next outer loop. >> + */ >> + nr_failed++; >> + nr_failed_pages += nr_subpages; >> + break; >> + } >> + } >> + } >> + nr_failed += retry; > > Seems we should also record the nr_retry_pages? since the second loop > will reset the nr_retry_pages. > > nr_failed_pages += nr_retry_pages; Good catch! Will do that in the next version. > Besides, I also agree with Zi Yan's comment to simplify this larger > function. Yes. I think so too. Best Regards, Huang, Ying