From nobody Mon Sep 15 07:39:46 2025 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 1BCD7C46467 for ; Mon, 16 Jan 2023 06:31:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231845AbjAPGbs (ORCPT ); Mon, 16 Jan 2023 01:31:48 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57530 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231964AbjAPGbe (ORCPT ); Mon, 16 Jan 2023 01:31:34 -0500 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 4952DA271 for ; Sun, 15 Jan 2023 22:31:24 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1673850684; x=1705386684; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=owp2StX07FtXCpFgHDVBdQMId5O0fSuu5EeccMqJEM0=; b=Wm4J3j2ftVSSv5u7iglRlkvpzvZlVfz7JZ/QKb767dNJ2fznCbd1ELFT FVETVX21C3RNzWuLYHsJE0eyBQVrFHgP83AH8/Lu2Weo6wpo6ku5YZLzB OKrof6et4YBzVJahZ6pjB3Si6V00ggFnJjSMilhpcfiC7jRMVqoa2ipUO m/lYzjFUPxFKsBSyove62ROBQVv4Jz79xRbPfTpoCMkAVKKJK/sHfrvih JYEZAjGqeSfSrgVKocKiKgzyiGTDead5HeowQbkbk5vcbGF5uQOVyQBRe DQ8cbIuLgeE/JqzAnlnIbdMqgaPYWecIB1hTv86+ZwxvhKvvM5T/Wvu5g A==; X-IronPort-AV: E=McAfee;i="6500,9779,10591"; a="388892163" X-IronPort-AV: E=Sophos;i="5.97,220,1669104000"; d="scan'208";a="388892163" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jan 2023 22:31:23 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10591"; a="801286654" X-IronPort-AV: E=Sophos;i="5.97,220,1669104000"; d="scan'208";a="801286654" Received: from tiangeng-mobl.ccr.corp.intel.com (HELO yhuang6-mobl2.ccr.corp.intel.com) ([10.255.28.220]) by fmsmga001-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 15 Jan 2023 22:31:20 -0800 From: Huang Ying To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Huang Ying , Baolin Wang , Zi Yan , Yang Shi , Oscar Salvador , Matthew Wilcox , Bharata B Rao , Alistair Popple , haoxin , Minchan Kim Subject: [PATCH -v3 4/9] migrate_pages: split unmap_and_move() to _unmap() and _move() Date: Mon, 16 Jan 2023 14:30:52 +0800 Message-Id: <20230116063057.653862-5-ying.huang@intel.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20230116063057.653862-1-ying.huang@intel.com> References: <20230116063057.653862-1-ying.huang@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" This is a preparation patch to batch the folio unmapping and moving. In this patch, unmap_and_move() is split to migrate_folio_unmap() and migrate_folio_move(). So, we can batch _unmap() and _move() in different loops later. To pass some information between unmap and move, the original unused dst->mapping and dst->private are used. 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 --- include/linux/migrate.h | 1 + mm/migrate.c | 170 ++++++++++++++++++++++++++++++---------- 2 files changed, 130 insertions(+), 41 deletions(-) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 3ef77f52a4f0..7376074f2e1e 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -18,6 +18,7 @@ struct migration_target_control; * - zero on page migration success; */ #define MIGRATEPAGE_SUCCESS 0 +#define MIGRATEPAGE_UNMAP 1 =20 /** * struct movable_operations - Driver page migration diff --git a/mm/migrate.c b/mm/migrate.c index 9a667039c34c..0428449149f4 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1009,11 +1009,53 @@ static int move_to_new_folio(struct folio *dst, str= uct folio *src, return rc; } =20 -static int __unmap_and_move(struct folio *src, struct folio *dst, +/* + * To record some information during migration, we uses some unused + * fields (mapping and private) of struct folio of the newly allocated + * destination folio. This is safe because nobody is using them + * except us. + */ +static void __migrate_folio_record(struct folio *dst, + unsigned long page_was_mapped, + struct anon_vma *anon_vma) +{ + dst->mapping =3D (void *)anon_vma; + dst->private =3D (void *)page_was_mapped; +} + +static void __migrate_folio_extract(struct folio *dst, + int *page_was_mappedp, + struct anon_vma **anon_vmap) +{ + *anon_vmap =3D (void *)dst->mapping; + *page_was_mappedp =3D (unsigned long)dst->private; + dst->mapping =3D NULL; + dst->private =3D NULL; +} + +/* Cleanup src folio upon migration success */ +static void migrate_folio_done(struct folio *src, + enum migrate_reason reason) +{ + /* + * Compaction can migrate also non-LRU pages which are + * not accounted to NR_ISOLATED_*. They can be recognized + * as __PageMovable + */ + if (likely(!__folio_test_movable(src))) + mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + + folio_is_file_lru(src), -folio_nr_pages(src)); + + if (reason !=3D MR_MEMORY_FAILURE) + /* We release the page in page_handle_poison. */ + folio_put(src); +} + +static int __migrate_folio_unmap(struct folio *src, struct folio *dst, int force, enum migrate_mode mode) { int rc =3D -EAGAIN; - bool page_was_mapped =3D false; + int page_was_mapped =3D 0; struct anon_vma *anon_vma =3D NULL; bool is_lru =3D !__PageMovable(&src->page); =20 @@ -1089,8 +1131,8 @@ static int __unmap_and_move(struct folio *src, struct= folio *dst, goto out_unlock; =20 if (unlikely(!is_lru)) { - rc =3D move_to_new_folio(dst, src, mode); - goto out_unlock_both; + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return MIGRATEPAGE_UNMAP; } =20 /* @@ -1115,11 +1157,42 @@ static int __unmap_and_move(struct folio *src, stru= ct folio *dst, VM_BUG_ON_FOLIO(folio_test_anon(src) && !folio_test_ksm(src) && !anon_vma, src); try_to_migrate(src, 0); - page_was_mapped =3D true; + page_was_mapped =3D 1; } =20 - if (!folio_mapped(src)) - rc =3D move_to_new_folio(dst, src, mode); + if (!folio_mapped(src)) { + __migrate_folio_record(dst, page_was_mapped, anon_vma); + return MIGRATEPAGE_UNMAP; + } + + if (page_was_mapped) + remove_migration_ptes(src, src, false); + +out_unlock_both: + folio_unlock(dst); +out_unlock: + /* Drop an anon_vma reference if we took one */ + if (anon_vma) + put_anon_vma(anon_vma); + folio_unlock(src); +out: + + return rc; +} + +static int __migrate_folio_move(struct folio *src, struct folio *dst, + enum migrate_mode mode) +{ + int rc; + int page_was_mapped =3D 0; + struct anon_vma *anon_vma =3D NULL; + bool is_lru =3D !__PageMovable(&src->page); + + __migrate_folio_extract(dst, &page_was_mapped, &anon_vma); + + rc =3D move_to_new_folio(dst, src, mode); + if (unlikely(!is_lru)) + goto out_unlock_both; =20 /* * When successful, push dst to LRU immediately: so that if it @@ -1142,12 +1215,10 @@ static int __unmap_and_move(struct folio *src, stru= ct folio *dst, =20 out_unlock_both: folio_unlock(dst); -out_unlock: /* Drop an anon_vma reference if we took one */ if (anon_vma) put_anon_vma(anon_vma); folio_unlock(src); -out: /* * If migration is successful, decrease refcount of dst, * which will not free the page because new page owner increased @@ -1159,19 +1230,15 @@ static int __unmap_and_move(struct folio *src, stru= ct folio *dst, return rc; } =20 -/* - * Obtain the lock on folio, remove all ptes and migrate the folio - * to the newly allocated folio in dst. - */ -static int unmap_and_move(new_page_t get_new_page, - free_page_t put_new_page, - unsigned long private, struct folio *src, - int force, enum migrate_mode mode, - enum migrate_reason reason, - struct list_head *ret) +/* Obtain the lock on page, remove all ptes. */ +static int migrate_folio_unmap(new_page_t get_new_page, free_page_t put_ne= w_page, + unsigned long private, struct folio *src, + struct folio **dstp, int force, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) { struct folio *dst; - int rc =3D MIGRATEPAGE_SUCCESS; + int rc =3D MIGRATEPAGE_UNMAP; struct page *newpage =3D NULL; =20 if (!thp_migration_supported() && folio_test_transhuge(src)) @@ -1182,20 +1249,50 @@ static int unmap_and_move(new_page_t get_new_page, folio_clear_active(src); folio_clear_unevictable(src); /* free_pages_prepare() will clear PG_isolated. */ - goto out; + list_del(&src->lru); + migrate_folio_done(src, reason); + return MIGRATEPAGE_SUCCESS; } =20 newpage =3D get_new_page(&src->page, private); if (!newpage) return -ENOMEM; dst =3D page_folio(newpage); + *dstp =3D dst; =20 dst->private =3D NULL; - rc =3D __unmap_and_move(src, dst, force, mode); + rc =3D __migrate_folio_unmap(src, dst, force, mode); + if (rc =3D=3D MIGRATEPAGE_UNMAP) + return rc; + + /* + * A page that has not been migrated will have kept its + * references and be restored. + */ + /* restore the folio to right list. */ + if (rc !=3D -EAGAIN) + list_move_tail(&src->lru, ret); + + if (put_new_page) + put_new_page(&dst->page, private); + else + folio_put(dst); + + return rc; +} + +/* Migrate the folio to the newly allocated folio in dst. */ +static int migrate_folio_move(free_page_t put_new_page, unsigned long priv= ate, + struct folio *src, struct folio *dst, + enum migrate_mode mode, enum migrate_reason reason, + struct list_head *ret) +{ + int rc; + + rc =3D __migrate_folio_move(src, dst, mode); if (rc =3D=3D MIGRATEPAGE_SUCCESS) set_page_owner_migrate_reason(&dst->page, reason); =20 -out: if (rc !=3D -EAGAIN) { /* * A folio that has been migrated has all references @@ -1211,20 +1308,7 @@ static int unmap_and_move(new_page_t get_new_page, * we want to retry. */ if (rc =3D=3D MIGRATEPAGE_SUCCESS) { - /* - * Compaction can migrate also non-LRU folios which are - * not accounted to NR_ISOLATED_*. They can be recognized - * as __folio_test_movable - */ - if (likely(!__folio_test_movable(src))) - mod_node_page_state(folio_pgdat(src), NR_ISOLATED_ANON + - folio_is_file_lru(src), -folio_nr_pages(src)); - - if (reason !=3D MR_MEMORY_FAILURE) - /* - * We release the folio in page_handle_poison. - */ - folio_put(src); + migrate_folio_done(src, reason); } else { if (rc !=3D -EAGAIN) list_add_tail(&src->lru, ret); @@ -1516,7 +1600,7 @@ static int migrate_pages_batch(struct list_head *from= , new_page_t get_new_page, int pass =3D 0; bool is_large =3D false; bool is_thp =3D false; - struct folio *folio, *folio2; + struct folio *folio, *folio2, *dst =3D NULL; int rc, nr_pages; LIST_HEAD(split_folios); bool nosplit =3D (reason =3D=3D MR_NUMA_MISPLACED); @@ -1543,9 +1627,13 @@ static int migrate_pages_batch(struct list_head *fro= m, new_page_t get_new_page, =20 cond_resched(); =20 - rc =3D unmap_and_move(get_new_page, put_new_page, - private, folio, pass > 2, mode, - reason, ret_folios); + rc =3D migrate_folio_unmap(get_new_page, put_new_page, private, + folio, &dst, pass > 2, mode, + reason, ret_folios); + if (rc =3D=3D MIGRATEPAGE_UNMAP) + rc =3D migrate_folio_move(put_new_page, private, + folio, dst, mode, + reason, ret_folios); /* * The rules are: * Success: folio will be freed --=20 2.35.1