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From devnull@lkml.org Tue May 14 14:45:20 2024 >From mailfetcher Wed Feb 8 12:36:31 2023 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on pi4 Authentication-Results: pi4.bmw12.nl; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: pi4.bmw12.nl; dkim=pass (Good 2048 bit rsa-sha256 signature) header.d=intel.com header.i=@intel.com header.a=rsa-sha256 Authentication-Results: pi4.bmw12.nl; spf=pass (sender SPF authorized) smtp.mailfrom=vger.kernel.org (client-ip=2620:137:e000::1:20; helo=out1.vger.email; envelope-from=linux-kernel-owner@vger.kernel.org; receiver=) Received: from secure.jasper.es [188.166.10.231] by 1dc7d414a5be with IMAP (fetchmail-6.3.26) for (single-drop); Wed, 08 Feb 2023 12:36:31 +0100 (CET) Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by pi4.bmw12.nl (Postfix) with ESMTP id 45E6F3F069 for ; Wed, 8 Feb 2023 12:36:28 +0100 (CET) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230073AbjBHLg0 (ORCPT ); Wed, 8 Feb 2023 06:36:26 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229539AbjBHLgX (ORCPT ); Wed, 8 Feb 2023 06: Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 60B3D2DE7A for ; Wed, 8 Feb 2023 03:36:22 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1675856182; x=1707392182; h=from:to:cc:subject:references:date:in-reply-to: message-id:mime-version; bh=8U1cq6u571MOpBdauFJ+N72lphdj+XDpLYcB04WZZqM=; b=QvZBmrlhW X-Ironport-AV: E=McAfee;i="6500,9779,10614"; a="415995799" X-Ironport-AV: E=Sophos;i="5.97,280,1669104000"; d="scan'208";a="415995799" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2023 03:36:03 -0800 X-Ironport-AV: E=McAfee;i="6500,9779,10614"; a="841149099" X-Ironport-AV: E=Sophos;i="5.97,280,1669104000"; d="scan'208";a="841149099" Received: from yhuang6-desk2.sh.intel.com (HELO yhuang6-desk2.ccr.corp.intel.com) ([10.238.208.55]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 Feb 2023 03:35:59 -0800 From: "Huang, Ying" To: haoxin Cc: Andrew Morton , , , Baolin Wang , Zi Yan , Yang Shi , Oscar Salvador <20230206063313.635011-3-ying.huang@intel.com> <840f6621-5a43-9cc2-6620-6d149ea712cd@linux.alibaba.com> Date: Wed, 08 Feb 2023 19:35:10 +0800 In-Reply-To: <840f6621-5a43-9cc2-6620-6d149ea712cd@linux.alibaba.com> (haoxin's message of "Wed, 8 Feb 2023 00:42:11 +0800") Message-Id: <874jrwgzkh.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 haoxin writes: > ( 2023/2/6 H2:33, Huang Ying S: >> This is a preparation patch to batch the folio unmapping and moving >> for the non-hugetlb folios. Based on that we can batch the TLB >> shootdown during the folio migration and make it possible to use some >> hardware accelerator for the folio copying. >> >> In this patch the hugetlb folios and non-hugetlb folios migration is >> separated in migrate_pages() to make it easy to change the non-hugetlb >> folios migration implementation. >> >> Signed-off-by: "Huang, Ying" >> Reviewed-by: Baolin Wang >> Cc: Zi Yan >> Cc: Yang Shi >> Cc: Oscar Salvador >> Cc: Matthew Wilcox >> Cc: Bharata B Rao >> Cc: Alistair Popple >> Cc: haoxin >> Cc: Minchan Kim >> Cc: Mike Kravetz >> Cc: Hyeonggon Yoo <42.hyeyoo@gmail.com> >> --- >> mm/migrate.c | 141 +++++++++++++++++++++++++++++++++++++++++++-------- >> 1 file changed, 119 insertions(+), 22 deletions(-) >> >> diff --git a/mm/migrate.c b/mm/migrate.c >> index ef388a9e4747..be7f37523463 100644 >> --- a/mm/migrate.c >> +++ b/mm/migrate.c >> @@ -1396,6 +1396,8 @@ static inline int try_split_folio(struct folio *folio, struct list_head *split_f >> return rc; >> } >> +#define NR_MAX_MIGRATE_PAGES_RETRY 10 >> + >> struct migrate_pages_stats { >> int nr_succeeded; /* Normal and large folios migrated successfully, in >> units of base pages */ >> @@ -1406,6 +1408,95 @@ struct migrate_pages_stats { >> int nr_thp_split; /* THP split before migrating */ >> }; >> +/* >> + * Returns the number of hugetlb folios that were not migrated, or an error code >> + * after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no hugetlb folios are movable >> + * any more because the list has become empty or no retryable hugetlb folios >> + * exist any more. It is caller's responsibility to call putback_movable_pages() >> + * only if ret != 0. >> + */ >> +static int migrate_hugetlbs(struct list_head *from, new_page_t get_new_page, >> + free_page_t put_new_page, unsigned long private, >> + enum migrate_mode mode, int reason, >> + struct migrate_pages_stats *stats, >> + struct list_head *ret_folios) >> +{ >> + int retry = 1; >> + int nr_failed = 0; >> + int nr_retry_pages = 0; >> + int pass = 0; >> + struct folio *folio, *folio2; >> + int rc, nr_pages; >> + >> + for (pass = 0; pass < NR_MAX_MIGRATE_PAGES_RETRY && retry; pass++) { >> + retry = 0; >> + nr_retry_pages = 0; >> + >> + list_for_each_entry_safe(folio, folio2, from, lru) { >> + if (!folio_test_hugetlb(folio)) >> + continue; >> + >> + nr_pages = folio_nr_pages(folio); >> + >> + cond_resched(); > Just curious, why put cond_resched() here, it makes > "nr_pages = folio_nr_pages(folio)" looks Separately with below > codes. This is the original behavior. Per my understanding, this can reduce the schedule latency of the page migration. >> + >> + rc = unmap_and_move_huge_page(get_new_page, >> + put_new_page, private, >> + &folio->page, pass > 2, mode, >> + reason, ret_folios); >> + /* >> + * The rules are: >> + * Success: hugetlb folio 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_folios list >> + */ >> + switch(rc) { >> + case -ENOSYS: >> + /* Hugetlb migration is unsupported */ >> + nr_failed++; >> + stats->nr_failed_pages += nr_pages; >> + list_move_tail(&folio->lru, ret_folios); >> + break; >> + case -ENOMEM: >> + /* >> + * When memory is low, don't bother to try to migrate >> + * other folios, just exit. >> + */ >> + stats->nr_failed_pages += nr_pages + nr_retry_pages; >> + return -ENOMEM; >> + case -EAGAIN: >> + retry++; >> + nr_retry_pages += nr_pages; >> + break; >> + case MIGRATEPAGE_SUCCESS: >> + stats->nr_succeeded += nr_pages; >> + break; >> + default: >> + /* >> + * Permanent failure (-EBUSY, etc.): >> + * unlike -EAGAIN case, the failed folio is >> + * removed from migration folio list and not >> + * retried in the next outer loop. >> + */ >> + nr_failed++; >> + stats->nr_failed_pages += nr_pages; >> + break; >> + } >> + } >> + } >> + /* >> + * nr_failed is number of hugetlb folios failed to be migrated. After >> + * NR_MAX_MIGRATE_PAGES_RETRY attempts, give up and count retried hugetlb >> + * folios as failed. >> + */ >> + nr_failed += retry; >> + stats->nr_failed_pages += nr_retry_pages; >> + >> + return nr_failed; >> +} >> + >> /* >> * migrate_pages - migrate the folios specified in a list, to the free folios >> * supplied as the target for the page migration >> @@ -1422,10 +1513,10 @@ struct migrate_pages_stats { >> * @ret_succeeded: Set to the number of folios migrated successfully if >> * the caller passes a non-NULL pointer. >> * >> - * The function returns after 10 attempts or if no folios are movable any more >> - * because the list has become empty or no retryable folios exist any more. >> - * It is caller's responsibility to call putback_movable_pages() to return folios >> - * to the LRU or free list only if ret != 0. >> + * The function returns after NR_MAX_MIGRATE_PAGES_RETRY attempts or if no folios >> + * are movable any more because the list has become empty or no retryable folios >> + * exist any more. It is caller's responsibility to call putback_movable_pages() >> + * only if ret != 0. >> * >> * Returns the number of {normal folio, large folio, hugetlb} that were not >> * migrated, or an error code. The number of large folio splits will be >> @@ -1439,7 +1530,7 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >> int retry = 1; >> int large_retry = 1; >> int thp_retry = 1; >> - int nr_failed = 0; >> + int nr_failed; >> int nr_retry_pages = 0; >> int nr_large_failed = 0; >> int pass = 0; >> @@ -1456,38 +1547,45 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >> trace_mm_migrate_pages_start(mode, reason); >> memset(&stats, 0, sizeof(stats)); >> + rc = migrate_hugetlbs(from, get_new_page, put_new_page, private, mode, reason, >> + &stats, &ret_folios); >> + if (rc < 0) >> + goto out; >> + nr_failed = rc; >> + >> split_folio_migration: >> - for (pass = 0; pass < 10 && (retry || large_retry); pass++) { >> + for (pass = 0; >> + pass < NR_MAX_MIGRATE_PAGES_RETRY && (retry || large_retry); >> + pass++) { >> retry = 0; >> large_retry = 0; >> thp_retry = 0; >> nr_retry_pages = 0; >> list_for_each_entry_safe(folio, folio2, from, lru) { >> + /* Retried hugetlb folios will be kept in list */ >> + if (folio_test_hugetlb(folio)) { >> + list_move_tail(&folio->lru, &ret_folios); >> + continue; >> + } >> + >> /* >> * Large folio statistics is based on the source large >> * folio. Capture required information that might get >> * lost during migration. >> */ >> - is_large = folio_test_large(folio) && !folio_test_hugetlb(folio); >> + is_large = folio_test_large(folio); >> is_thp = is_large && folio_test_pmd_mappable(folio); >> nr_pages = folio_nr_pages(folio); >> + >> cond_resched(); >> - if (folio_test_hugetlb(folio)) >> - rc = unmap_and_move_huge_page(get_new_page, >> - put_new_page, private, >> - &folio->page, pass > 2, mode, >> - reason, >> - &ret_folios); >> - else >> - rc = unmap_and_move(get_new_page, put_new_page, >> - private, folio, pass > 2, mode, >> - reason, &ret_folios); >> + rc = unmap_and_move(get_new_page, put_new_page, >> + private, folio, pass > 2, mode, >> + reason, &ret_folios); >> /* >> * The rules are: >> - * Success: non hugetlb folio will be freed, hugetlb >> - * folio will be put back >> + * Success: folio will be freed >> * -EAGAIN: stay on the from list >> * -ENOMEM: stay on the from list >> * -ENOSYS: stay on the from list >> @@ -1514,7 +1612,6 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >> stats.nr_thp_split += is_thp; >> break; >> } >> - /* Hugetlb migration is unsupported */ >> } else if (!no_split_folio_counting) { >> nr_failed++; >> } >> @@ -1608,8 +1705,8 @@ int migrate_pages(struct list_head *from, new_page_t get_new_page, >> */ >> if (!list_empty(&split_folios)) { >> /* >> - * Move non-migrated folios (after 10 retries) to ret_folios >> - * to avoid migrating them again. >> + * Move non-migrated folios (after NR_MAX_MIGRATE_PAGES_RETRY >> + * retries) to ret_folios to avoid migrating them again. >> */ >> list_splice_init(from, &ret_folios); >> list_splice_init(&split_folios, from); > Reviewed-by: Xin Hao Thanks! Best Regards, Huang, Ying