From nobody Tue Feb 10 01:16:22 2026 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 8D4A4C0015E for ; Mon, 24 Jul 2023 13:50:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230460AbjGXNu1 (ORCPT ); Mon, 24 Jul 2023 09:50:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49520 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230330AbjGXNtw (ORCPT ); Mon, 24 Jul 2023 09:49:52 -0400 Received: from mail-wm1-x334.google.com (mail-wm1-x334.google.com [IPv6:2a00:1450:4864:20::334]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 556FB100 for ; Mon, 24 Jul 2023 06:46:50 -0700 (PDT) Received: by mail-wm1-x334.google.com with SMTP id 5b1f17b1804b1-3fbc244d307so41942555e9.1 for ; Mon, 24 Jul 2023 06:46:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1690206408; x=1690811208; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=2+5f3AgE150Mh6cYaW30LczJjyIbsUmp9ItlqNwo9Gs=; b=ikYTxmvNKkByuJlR0NutAuZwBS+HffntLHXBTOm8ABSvwCfWL2fKqLXT+iOY+era+y 0f+kQ2586uXX6d82nfLBSpOQr1gqnMFjKQ47G8ZLbVTI8NSLejjGc+kDPEvl1HVxnBUF jCpEFBNwQAA+XsldO7xDMXzVVhi5WukMODB/6kuUFR9VRoS+9pioBp657mkjAf4PNZ/i F4wa0/ndwm2yPUB7BijO2XndG4yNOsOBIbw8Z0pGdeoakBDEl8/5c+TqIcujNE6fR8ZQ FpFK7b0NO5bBOQMrm+8GlX2hKWNa2zqyvycuRIQfoA56RG/Cn9fc7U79QcopUi7lSSGW lQSg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1690206408; x=1690811208; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=2+5f3AgE150Mh6cYaW30LczJjyIbsUmp9ItlqNwo9Gs=; b=iMLyZHJf6jEXtbxwDDAos85BMzdy8NNfzcJ10mey5YSkwmYR8b7Jsj2xd2eaoU6scJ y5j3dyZeD0/a/kXOptt1NXnN38Y/SAyJUd+WcaD5L2rBTFz/mJv92AEoi+i/e0VZgxcz w09ZZyhueHjiblw0pRjr9hybFOKMoTy/MqFg5TNTkyHyqruwNLta33WCxy+KUh/iDL53 ag2dQQxHN0FuxcOAjjXtgez/AUT5CqkW6tpu1rnKkYU0fNVu5cKcM2Pe5Ym/6orXm3+T WbzbGO8+MDq4uezjOquvOZrjwcqqS9ek2Lm3dRw5FdlFJqG+YSSXICshGLp4BVf1CSyT MxPg== X-Gm-Message-State: ABy/qLbGeto0GKGPKAG5dsVAIgo3zjevd1AqopZ+fXRLYVhMJgLk8tqs h2PXpXyPYlnLf3FQ2YLFqdP3qw== X-Google-Smtp-Source: APBJJlG2oRr8ivYhrN6NtzN8nuU0+P+lfubBc/YogasGIn8tgMOZpf/GJE4V1pfPjhr20IzDbaEKIw== X-Received: by 2002:a1c:750a:0:b0:3fd:ad65:ea8b with SMTP id o10-20020a1c750a000000b003fdad65ea8bmr3233762wmc.12.1690206408483; Mon, 24 Jul 2023 06:46:48 -0700 (PDT) Received: from localhost.localdomain ([2a02:6b6a:b465:0:d7c4:7f46:8fed:f874]) by smtp.gmail.com with ESMTPSA id e19-20020a05600c219300b003fbe791a0e8sm10209354wme.0.2023.07.24.06.46.47 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 24 Jul 2023 06:46:48 -0700 (PDT) From: Usama Arif To: linux-mm@kvack.org, muchun.song@linux.dev, mike.kravetz@oracle.com, rppt@kernel.org Cc: linux-kernel@vger.kernel.org, fam.zheng@bytedance.com, liangma@liangbit.com, simon.evans@bytedance.com, punit.agrawal@bytedance.com, Usama Arif Subject: [RFC 1/4] mm/hugetlb: Skip prep of tail pages when HVO is enabled Date: Mon, 24 Jul 2023 14:46:41 +0100 Message-Id: <20230724134644.1299963-2-usama.arif@bytedance.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20230724134644.1299963-1-usama.arif@bytedance.com> References: <20230724134644.1299963-1-usama.arif@bytedance.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" When vmemmap is optimizable, it will free all the duplicated tail pages in hugetlb_vmemmap_optimize while preparing the new hugepage. Hence, there is no need to prepare them. For 1G x86 hugepages, it avoids preparing 262144 - 64 =3D 262080 struct pages per hugepage. Signed-off-by: Usama Arif --- mm/hugetlb.c | 30 +++++++++++++++++++++--------- mm/hugetlb_vmemmap.c | 2 +- mm/hugetlb_vmemmap.h | 1 + 3 files changed, 23 insertions(+), 10 deletions(-) diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 64a3239b6407..24352abbb9e5 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -1943,13 +1943,22 @@ static void prep_new_hugetlb_folio(struct hstate *h= , struct folio *folio, int ni } =20 static bool __prep_compound_gigantic_folio(struct folio *folio, - unsigned int order, bool demote) + unsigned int order, bool demote, + bool hugetlb_vmemmap_optimizable) { int i, j; int nr_pages =3D 1 << order; struct page *p; =20 __folio_clear_reserved(folio); + + /* + * No need to prep pages that will be freed later by hugetlb_vmemmap_opti= mize + * in prep_new_huge_page. Hence, reduce nr_pages to the pages that will b= e kept. + */ + if (hugetlb_vmemmap_optimizable) + nr_pages =3D HUGETLB_VMEMMAP_RESERVE_SIZE / sizeof(struct page); + for (i =3D 0; i < nr_pages; i++) { p =3D folio_page(folio, i); =20 @@ -2020,15 +2029,15 @@ static bool __prep_compound_gigantic_folio(struct f= olio *folio, } =20 static bool prep_compound_gigantic_folio(struct folio *folio, - unsigned int order) + unsigned int order, bool hugetlb_vmemmap_optimizable) { - return __prep_compound_gigantic_folio(folio, order, false); + return __prep_compound_gigantic_folio(folio, order, false, hugetlb_vmemma= p_optimizable); } =20 static bool prep_compound_gigantic_folio_for_demote(struct folio *folio, - unsigned int order) + unsigned int order, bool hugetlb_vmemmap_optimizable) { - return __prep_compound_gigantic_folio(folio, order, true); + return __prep_compound_gigantic_folio(folio, order, true, hugetlb_vmemmap= _optimizable); } =20 /* @@ -2185,7 +2194,8 @@ static struct folio *alloc_fresh_hugetlb_folio(struct= hstate *h, if (!folio) return NULL; if (hstate_is_gigantic(h)) { - if (!prep_compound_gigantic_folio(folio, huge_page_order(h))) { + if (!prep_compound_gigantic_folio(folio, huge_page_order(h), + vmemmap_should_optimize(h, &folio->page))) { /* * Rare failure to convert pages to compound page. * Free pages and try again - ONCE! @@ -3201,7 +3211,8 @@ static void __init gather_bootmem_prealloc(void) =20 VM_BUG_ON(!hstate_is_gigantic(h)); WARN_ON(folio_ref_count(folio) !=3D 1); - if (prep_compound_gigantic_folio(folio, huge_page_order(h))) { + if (prep_compound_gigantic_folio(folio, huge_page_order(h), + vmemmap_should_optimize(h, page))) { WARN_ON(folio_test_reserved(folio)); prep_new_hugetlb_folio(h, folio, folio_nid(folio)); free_huge_page(page); /* add to the hugepage allocator */ @@ -3624,8 +3635,9 @@ static int demote_free_hugetlb_folio(struct hstate *h= , struct folio *folio) subpage =3D folio_page(folio, i); inner_folio =3D page_folio(subpage); if (hstate_is_gigantic(target_hstate)) - prep_compound_gigantic_folio_for_demote(inner_folio, - target_hstate->order); + prep_compound_gigantic_folio_for_demote(folio, + target_hstate->order, + vmemmap_should_optimize(target_hstate, subpage)); else prep_compound_page(subpage, target_hstate->order); folio_change_private(inner_folio, NULL); diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index c2007ef5e9b0..b721e87de2b3 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -486,7 +486,7 @@ int hugetlb_vmemmap_restore(const struct hstate *h, str= uct page *head) } =20 /* Return true iff a HugeTLB whose vmemmap should and can be optimized. */ -static bool vmemmap_should_optimize(const struct hstate *h, const struct p= age *head) +bool vmemmap_should_optimize(const struct hstate *h, const struct page *he= ad) { if (!READ_ONCE(vmemmap_optimize_enabled)) return false; diff --git a/mm/hugetlb_vmemmap.h b/mm/hugetlb_vmemmap.h index 25bd0e002431..3525c514c061 100644 --- a/mm/hugetlb_vmemmap.h +++ b/mm/hugetlb_vmemmap.h @@ -57,4 +57,5 @@ static inline bool hugetlb_vmemmap_optimizable(const stru= ct hstate *h) { return hugetlb_vmemmap_optimizable_size(h) !=3D 0; } +bool vmemmap_should_optimize(const struct hstate *h, const struct page *he= ad); #endif /* _LINUX_HUGETLB_VMEMMAP_H */ --=20 2.25.1