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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E4DBDCCD192 for ; Wed, 15 Oct 2025 14:18:18 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 35D288E003C; Wed, 15 Oct 2025 10:18:18 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 30D4E8E000A; Wed, 15 Oct 2025 10:18:18 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1FCDD8E003C; Wed, 15 Oct 2025 10:18:18 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id F408F8E000A for ; Wed, 15 Oct 2025 10:18:17 -0400 (EDT) Received: from smtpin08.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 92C6B1601B5 for ; Wed, 15 Oct 2025 14:18:17 +0000 (UTC) X-FDA: 84000553434.08.4189DF1 Received: from mail-pg1-f182.google.com (mail-pg1-f182.google.com [209.85.215.182]) by imf01.hostedemail.com (Postfix) with ESMTP id 9FCFB40017 for ; Wed, 15 Oct 2025 14:18:15 +0000 (UTC) Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=iZqrbFPj; spf=pass (imf01.hostedemail.com: domain of laoar.shao@gmail.com designates 209.85.215.182 as permitted sender) smtp.mailfrom=laoar.shao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1760537895; a=rsa-sha256; cv=none; b=7ysxdv/N2A96e8szdvfGKlZgLadjEH/va7GV0zZOr8drp1fpCttd0vXqi6jPVYopth54+C VFCX6/7tEt1tHspjDywGH/G0lyZUysvtvI5+ubFoTc2pNozH4LS48eh0VActc6Lx9Ot0nL vkJKcKaT6dp4DvKj3QLN4VQdoYKYxfs= ARC-Authentication-Results: i=1; imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20230601 header.b=iZqrbFPj; spf=pass (imf01.hostedemail.com: domain of laoar.shao@gmail.com designates 209.85.215.182 as permitted sender) smtp.mailfrom=laoar.shao@gmail.com; dmarc=pass (policy=none) header.from=gmail.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1760537895; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=1tfnp2VgNI7X5NDB06OaZAZrurrAWQnxjDDxodnKF9g=; b=QXQL90GJ7ghdfKAG9E9dasq0fnL2XIFOrHsgVlbIuauQ8sLA+dDrGMX6m5eQ5hBoAXxV5l bLDZWA2yyqkksYc3+Dciy69lJy2Xjlgd/6xZeTOQcIWVB+8vBhL1feZZ0YEU33IfccHWlA QRhAFDDLvpK1dCZK4J+Q0W6tk9YWY9Y= Received: by mail-pg1-f182.google.com with SMTP id 41be03b00d2f7-b58445361e8so876424a12.0 for ; Wed, 15 Oct 2025 07:18:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20230601; t=1760537894; x=1761142694; darn=kvack.org; 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=1tfnp2VgNI7X5NDB06OaZAZrurrAWQnxjDDxodnKF9g=; b=iZqrbFPjvudI4lp7h8GEpeDoW1vhU27MUzrPs2fI/Y7YfjMS/bni+V4zzdMK92bG3U W1MRalWqrX5Kwy6bA4viuTK9CUNGu183KDUWPgF9D1kp4wz5mZc9rFF4ILkfZaRfauCq Fzl8yNX/w5riNsKWLxsml01ZPPfyw+L6zNiqshD0vtybjta9QseskFmYCh631QTERncp tApMdz8fCE/VepfBKRa35wG2cZrnuMw+DtpZ3EHsxsB+FfoYHSP2hkJW3RG9Eq0KFtU/ 1rNG8/zKqsAhMnsuX5O+43dhWU7zYxEnDU9ZaE91PM9BiHTqMIhkiW/bglURdre+US8j uUXg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1760537894; x=1761142694; 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=1tfnp2VgNI7X5NDB06OaZAZrurrAWQnxjDDxodnKF9g=; b=CO+uH8nEMhIsixJm9IUIazs0ndRhHR8SwTHOgVrko5FGrA5YxM62eH8+RIcYSw0Lph GV21FiNoKdc3Lpmey2viH4wT5+dUIMGaGjMiriFZt5pvUFR1dunB3eQk7kvJetOroSmW QUZcmabf1XP/n9cBA9ICGVzfhsrJcsHwoTHpq15TIJByxLL3V/DGd7qDE0SzdZbArZOm g/xSiWBNDA0IarkxpOdbGc4Z5s3CdhQY7eLZPnQ0O1ogKDi6p5nzrkU6VCX5QomfyQBd ZlDgT7U99TMwY8m+MIsk+qt6foPIh62phaMm7T/IcYOMN1HE363655Qs8KtnYqcXPDYt 1jEQ== X-Forwarded-Encrypted: i=1; AJvYcCXqGWOIVhT7xJWRvEUvYdBlAgRC1eECwkn1OqRtdr30eHq8xjyNN04oXeIlVLjnGoJpdHORX7svNw==@kvack.org X-Gm-Message-State: AOJu0Yy5yp1qnHq1YmicJB3F8W5Jrp3WqulIlpWtb8DhFJWS8ip+mDai JsP5kG0X/beO1npIjmya855P3hY+PuaYun4jdrKYATcFm/ov5F2AfFnv X-Gm-Gg: ASbGncvVREyiFOJEtfLREbP+3PrwHxo+B7nXZXQg6DIMtHQx8VvHc7I1tTG5umhulO6 PueXDB4NAQwrT7RSgurZFD2A9iITpEFCKxFK/3kYZXuVZIe+f9HGY6hPLTDH3fJoELTX3UOWrbN 027MOWzsqk06EFW3Vb1F3R9eq4aMLaFP3kr6Smw4r9GFEwhaLPMQWkO85zBDReqDLVTeFRBvJIx egziOQ19wCUc6n8EbX/MNcD1Dt0A9i/Aa/jhF8E7JIhEuOlOyJRPaU6EwLE77QPs6O54IHus0Z8 Q6VpKCQADlHbOn/owx2r7cEQMD+iIz9X66efs9bwQuPTsUi+OC87tGgbnvntrw1K034leccJInb Ta2uRg2eUoEdQp/dEQlOjFz9fCT4NKzwRpd4EHC+a32AN4rXbvePDi+Ljjsa/ge0uXZjq2eSAeQ lEAV+WAkA6xo03CZ+H X-Google-Smtp-Source: AGHT+IGaH4Q7yuB3UefbX6fUnOF0Cq4qxYjfR/YqrSeLwExSFoNCC9hfKuz5SVL5H702WlYSyJC/fw== X-Received: by 2002:a17:902:ecc2:b0:281:fd60:807d with SMTP id d9443c01a7336-290919d5389mr3536805ad.2.1760537894159; Wed, 15 Oct 2025 07:18:14 -0700 (PDT) Received: from localhost.localdomain ([2409:891f:1b80:80c6:cd21:3ff9:2bca:36d1]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-29034f32d6fsm199561445ad.96.2025.10.15.07.18.04 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Wed, 15 Oct 2025 07:18:12 -0700 (PDT) From: Yafang Shao To: akpm@linux-foundation.org, david@redhat.com, ziy@nvidia.com, baolin.wang@linux.alibaba.com, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, npache@redhat.com, ryan.roberts@arm.com, dev.jain@arm.com, hannes@cmpxchg.org, usamaarif642@gmail.com, gutierrez.asier@huawei-partners.com, willy@infradead.org, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, ameryhung@gmail.com, rientjes@google.com, corbet@lwn.net, 21cnbao@gmail.com, shakeel.butt@linux.dev, tj@kernel.org, lance.yang@linux.dev, rdunlap@infradead.org Cc: bpf@vger.kernel.org, linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, Yafang Shao Subject: [RFC PATCH v10 mm-new 5/9] mm: thp: enable THP allocation exclusively through khugepaged Date: Wed, 15 Oct 2025 22:17:12 +0800 Message-Id: <20251015141716.887-6-laoar.shao@gmail.com> X-Mailer: git-send-email 2.37.1 (Apple Git-137.1) In-Reply-To: <20251015141716.887-1-laoar.shao@gmail.com> References: <20251015141716.887-1-laoar.shao@gmail.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Stat-Signature: jhb7cx1s57detzgh1rcag9qgpnm6w8oz X-Rspamd-Queue-Id: 9FCFB40017 X-Rspamd-Server: rspam09 X-HE-Tag: 1760537895-751913 X-HE-Meta: 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 vMw0qTU2 DOlPGs/bH18wO3sKnKep79nEhwxusnLmpYkbOMa4w173zKmfHyAofT8UMGV8TpxyyNKjGoSjkMBf/jBmuHWgiWu4Z3M6s6xByoQCAUBwt1n2S6GV/A1hlTCgX7x0Q5sKS2GucpBpINkY1+5/a6Mae8ZTDNDhHumlbS2GnDGsbQy1LNQKZJQyq8tCf5It2iivmFM4YU2AlapmGrtTekGdTwDdsei1fa9LxH+/ZhsxAaDc6NxAeNZWhJEqEwtjvJJ6CeDeHeexQVv38Q84O1MSDMmW0NhfcwtIePcvDoqJGpHSE3Qno9VtbNH6jTxu6JXMj/ktSYH3AL9tNDYWCUkcxNHC/LwUTRQ72Bf1+YfkqmFZQyKjriPgIqqNqq1KFNayTiC441O2MtWAXNJ781gxCo8gmG3IBRBRcaMs9qPlsGwZcB52276v05fL8kDByuKPEM8lpRCjpsXFP7OVR4NHOzWUI0HM/P0Psf9lGVs59VLiZgK8= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: khugepaged_enter_vma() ultimately invokes any attached BPF function with the TVA_KHUGEPAGED flag set when determining whether or not to enable khugepaged THP for a freshly faulted in VMA. Currently, on fault, we invoke this in do_huge_pmd_anonymous_page(), as invoked by create_huge_pmd() and only when we have already checked to see if an allowable TVA_PAGEFAULT order is specified. Since we might want to disallow THP on fault-in but allow it via khugepaged, we move things around so we always attempt to enter khugepaged upon fault. This change is safe because: - khugepaged operates at the MM level rather than per-VMA. The THP allocation might fail during page faults due to transient conditions (e.g., memory pressure), it is safe to add this MM to khugepaged for subsequent defragmentation. - If __thp_vma_allowable_orders(TVA_PAGEFAULT) returns 0, then __thp_vma_allowable_orders(TVA_KHUGEPAGED) will also return 0. While we could also extend prctl() to utilize this new policy, such a change would require a uAPI modification to PR_SET_THP_DISABLE. Signed-off-by: Yafang Shao Acked-by: Lance Yang Cc: Usama Arif --- mm/huge_memory.c | 1 - mm/memory.c | 13 ++++++++----- 2 files changed, 8 insertions(+), 6 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 08372dfcb41a..2b155a734c78 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1346,7 +1346,6 @@ vm_fault_t do_huge_pmd_anonymous_page(struct vm_fault *vmf) ret = vmf_anon_prepare(vmf); if (ret) return ret; - khugepaged_enter_vma(vma); if (!(vmf->flags & FAULT_FLAG_WRITE) && !mm_forbids_zeropage(vma->vm_mm) && diff --git a/mm/memory.c b/mm/memory.c index 58ea0f93f79e..64f91191ffff 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -6327,11 +6327,14 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, if (pud_trans_unstable(vmf.pud)) goto retry_pud; - if (pmd_none(*vmf.pmd) && - thp_vma_allowable_order(vma, TVA_PAGEFAULT, PMD_ORDER)) { - ret = create_huge_pmd(&vmf); - if (!(ret & VM_FAULT_FALLBACK)) - return ret; + if (pmd_none(*vmf.pmd)) { + if (vma_is_anonymous(vma)) + khugepaged_enter_vma(vma); + if (thp_vma_allowable_order(vma, TVA_PAGEFAULT, PMD_ORDER)) { + ret = create_huge_pmd(&vmf); + if (!(ret & VM_FAULT_FALLBACK)) + return ret; + } } else { vmf.orig_pmd = pmdp_get_lockless(vmf.pmd); -- 2.47.3