From nobody Fri Dec 19 17:35:47 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1EF8F1F3BB4 for ; Mon, 14 Apr 2025 22:25:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744669558; cv=none; b=S64CnYX/tLnIFYSsBt09s33Op2K/MLYQALy3Ug2s5sE5MXHSATi5WXbQcqIp0fsUyWXOBM4o0mo491JOtHM8MsJoSSXlw8nCZhsxakM0LKxyu6FfiqaZ+o21f0MFcjPkDmFGNn1/2PhOSLhuxVzvCybFyBVpz9QI4B8DkT6z2Kk= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744669558; c=relaxed/simple; bh=g9kdSNZmzjMow3T3hCtXuM8Ih81BoMLPCkHoErDGl2g=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=amnUHBX2Hg7533qHx0Sjm7N6XnOLXPeM99ktvA6qDw/M/fIf/okWrmiXsa9dSlSx73dJANw1t1JbpFS/EBhVR5T8TVcsEpfeqq416/hTCwNu9VZcak9QaVwbCz+MTyVBYT8x9qmhQWCcsrNuKvDYx/fkiwXk5mNtjoG5xc7U8ig= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=LtRpRs3N; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="LtRpRs3N" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744669556; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=FwpqttvBCnxGqGYUL3sPRwZ5zL6bMm0W6vYtJG5uftA=; b=LtRpRs3NFkfogAurgOVA4du2b7aMYhb5L7gXhOLqAd/wr33wv21NZHzvysuqGAvM9CA04l Wyw5uEPMvvXMtkga5Pa9T3abIirjfPtXOL+uERB7/AxRfTqyInJ3L++MmnzdeEpAR9wLTE m5xR+2Nl73NDbz0F3x/6YZgdIk5xM5w= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-154-__A_VGTmMayXFMB3zUZXyg-1; Mon, 14 Apr 2025 18:25:51 -0400 X-MC-Unique: __A_VGTmMayXFMB3zUZXyg-1 X-Mimecast-MFC-AGG-ID: __A_VGTmMayXFMB3zUZXyg_1744669540 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id CB0AA1809CA6; Mon, 14 Apr 2025 22:25:39 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.64.91]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id BD70C180B488; Mon, 14 Apr 2025 22:25:24 +0000 (UTC) From: Nico Pache To: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: akpm@linux-foundation.org, corbet@lwn.net, shuah@kernel.org, david@redhat.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, ryan.roberts@arm.com, willy@infradead.org, peterx@redhat.com, ioworker0@gmail.com, ziy@nvidia.com, wangkefeng.wang@huawei.com, dev.jain@arm.com, mhocko@suse.com, rientjes@google.com, hannes@cmpxchg.org, zokeefe@google.com, surenb@google.com, jglisse@google.com, cl@gentwo.org, jack@suse.cz, dave.hansen@linux.intel.com, will@kernel.org, tiwai@suse.de, catalin.marinas@arm.com, anshuman.khandual@arm.com, raquini@redhat.com, aarcange@redhat.com, kirill.shutemov@linux.intel.com, yang@os.amperecomputing.com, thomas.hellstrom@linux.intel.com, vishal.moola@gmail.com, sunnanyong@huawei.com, usamaarif642@gmail.com, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, rostedt@goodmis.org Subject: [PATCH v3 1/4] mm: defer THP insertion to khugepaged Date: Mon, 14 Apr 2025 16:24:53 -0600 Message-ID: <20250414222456.43212-2-npache@redhat.com> In-Reply-To: <20250414222456.43212-1-npache@redhat.com> References: <20250414222456.43212-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" setting /transparent_hugepages/enabled=3Dalways allows applications to benefit from THPs without having to madvise. However, the pf handler takes very few considerations to decide weather or not to actually use a THP. This can lead to a lot of wasted memory. khugepaged only operates on memory that was either allocated with enabled=3Dalways or MADV_HUGEPAGE. Introduce the ability to set enabled=3Ddefer, which will prevent THPs from being allocated by the page fault handler unless madvise is set, leaving it up to khugepaged to decide which allocations will collapse to a THP. This should allow applications to benefits from THPs, while curbing some of the memory waste. Co-developed-by: Rafael Aquini Signed-off-by: Rafael Aquini Signed-off-by: Nico Pache --- include/linux/huge_mm.h | 15 +++++++++++++-- mm/huge_memory.c | 31 +++++++++++++++++++++++++++---- 2 files changed, 40 insertions(+), 6 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index 95be9d266eff..b154bd11bd93 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -48,6 +48,7 @@ enum transparent_hugepage_flag { TRANSPARENT_HUGEPAGE_UNSUPPORTED, TRANSPARENT_HUGEPAGE_FLAG, TRANSPARENT_HUGEPAGE_REQ_MADV_FLAG, + TRANSPARENT_HUGEPAGE_DEFER_PF_INST_FLAG, TRANSPARENT_HUGEPAGE_DEFRAG_DIRECT_FLAG, TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_FLAG, TRANSPARENT_HUGEPAGE_DEFRAG_KSWAPD_OR_MADV_FLAG, @@ -186,6 +187,7 @@ static inline bool hugepage_global_enabled(void) { return transparent_hugepage_flags & ((1<; Mon, 14 Apr 2025 22:25:57 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.133.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744669559; cv=none; b=Y+L3fHJ18a5Y0Fp68ILo2JMxNZ+ABRgA+sNVC7aubFa7eRe4vCMRBfA8QoJX7lmUB/z9nxP6tk/YbmNuubnEsc50ZQvm08TSmZ9JVqmwcw+IkMQqEjtt5ilsegdV1WaTbCWK368NMcgsCAffEWMwzJ+VYVznOiRChfJCQSjQ1rE= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744669559; c=relaxed/simple; bh=VUqIXaC3Iywtn0+ijjtIpGttKQYKUOLmPnCvD6L0zao=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GL52Cq9DP23pjoBLAoWmeeN9uyGXUhf5ea9xsltXyqrFgL8a6SkAV02sdE+eXN34STnJtstTLTKzTWSbHtmdbDG/E8qbeXUUB3kLV+9h/mCGeFZHnmncfR4bPAKwmExEL6to0hSYK8/UalIUzzBeAQJuOlJsdQxou6tcAT81eQI= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=cxeHqMNC; arc=none smtp.client-ip=170.10.133.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="cxeHqMNC" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744669556; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CV9IGBx6ODvRJHViy9uocxS1JFT5Dwo7ktLvhKvEEnw=; b=cxeHqMNCcrFJOOunmJYDnJL4hEPk4VRUjAZU075SMj4gKa8EY8dmkc2qVakUG2S6A44eSX RaQcBogHkikw3WVEPFfKgILMHQg4cRC8fEK8yUDKPMAY6rDm042NfzBPdQHXv36AltnRe9 L0fbbyxxs8T3QdttQDAiFvtfQzEaAtM= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-10-qe0rroeyNIqL-m90P1mikQ-1; Mon, 14 Apr 2025 18:25:53 -0400 X-MC-Unique: qe0rroeyNIqL-m90P1mikQ-1 X-Mimecast-MFC-AGG-ID: qe0rroeyNIqL-m90P1mikQ_1744669549 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1EC0F1956087; Mon, 14 Apr 2025 22:25:49 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.64.91]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 29B63180B486; Mon, 14 Apr 2025 22:25:39 +0000 (UTC) From: Nico Pache To: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: akpm@linux-foundation.org, corbet@lwn.net, shuah@kernel.org, david@redhat.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, ryan.roberts@arm.com, willy@infradead.org, peterx@redhat.com, ioworker0@gmail.com, ziy@nvidia.com, wangkefeng.wang@huawei.com, dev.jain@arm.com, mhocko@suse.com, rientjes@google.com, hannes@cmpxchg.org, zokeefe@google.com, surenb@google.com, jglisse@google.com, cl@gentwo.org, jack@suse.cz, dave.hansen@linux.intel.com, will@kernel.org, tiwai@suse.de, catalin.marinas@arm.com, anshuman.khandual@arm.com, raquini@redhat.com, aarcange@redhat.com, kirill.shutemov@linux.intel.com, yang@os.amperecomputing.com, thomas.hellstrom@linux.intel.com, vishal.moola@gmail.com, sunnanyong@huawei.com, usamaarif642@gmail.com, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, rostedt@goodmis.org Subject: [PATCH v3 2/4] mm: document (m)THP defer usage Date: Mon, 14 Apr 2025 16:24:54 -0600 Message-ID: <20250414222456.43212-3-npache@redhat.com> In-Reply-To: <20250414222456.43212-1-npache@redhat.com> References: <20250414222456.43212-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" The new defer option for (m)THPs allows for a more conservative approach to (m)THPs. Document its usage in the transhuge admin-guide. Signed-off-by: Nico Pache --- Documentation/admin-guide/mm/transhuge.rst | 31 ++++++++++++++++------ 1 file changed, 23 insertions(+), 8 deletions(-) diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/adm= in-guide/mm/transhuge.rst index f0d4e78cedaa..d3f072bdd932 100644 --- a/Documentation/admin-guide/mm/transhuge.rst +++ b/Documentation/admin-guide/mm/transhuge.rst @@ -88,8 +88,9 @@ In certain cases when hugepages are enabled system wide, = application may end up allocating more memory resources. An application may mmap a large region but only touch 1 byte of it, in that case a 2M page might be allocated instead of a 4k page for no good. This is why it's -possible to disable hugepages system-wide and to only have them inside -MADV_HUGEPAGE madvise regions. +possible to disable hugepages system-wide, only have them inside +MADV_HUGEPAGE madvise regions, or defer them away from the page fault +handler to khugepaged. =20 Embedded systems should enable hugepages only inside madvise regions to eliminate any risk of wasting any precious byte of memory and to @@ -99,6 +100,15 @@ Applications that gets a lot of benefit from hugepages = and that don't risk to lose memory by using hugepages, should use madvise(MADV_HUGEPAGE) on their critical mmapped regions. =20 +Applications that would like to benefit from THPs but would still like a +more memory conservative approach can choose 'defer'. This avoids +inserting THPs at the page fault handler unless they are MADV_HUGEPAGE. +Khugepaged will then scan the mappings for potential collapses into (m)THP +pages. Admins using this the 'defer' setting should consider +tweaking khugepaged/max_ptes_none. The current default of 511 may +aggressively collapse your PTEs into PMDs. Lower this value to conserve +more memory (ie. max_ptes_none=3D64). + .. _thp_sysfs: =20 sysfs @@ -109,11 +119,14 @@ Global THP controls =20 Transparent Hugepage Support for anonymous memory can be entirely disabled (mostly for debugging purposes) or only enabled inside MADV_HUGEPAGE -regions (to avoid the risk of consuming more memory resources) or enabled -system wide. This can be achieved per-supported-THP-size with one of:: +regions (to avoid the risk of consuming more memory resources), defered to +khugepaged, or enabled system wide. + +This can be achieved per-supported-THP-size with one of:: =20 echo always >/sys/kernel/mm/transparent_hugepage/hugepages-kB/enabl= ed echo madvise >/sys/kernel/mm/transparent_hugepage/hugepages-kB/enab= led + echo defer >/sys/kernel/mm/transparent_hugepage/hugepages-kB/enabled echo never >/sys/kernel/mm/transparent_hugepage/hugepages-kB/enabled =20 where is the hugepage size being addressed, the available sizes @@ -136,6 +149,7 @@ The top-level setting (for use with "inherit") can be s= et by issuing one of the following commands:: =20 echo always >/sys/kernel/mm/transparent_hugepage/enabled + echo defer >/sys/kernel/mm/transparent_hugepage/enabled echo madvise >/sys/kernel/mm/transparent_hugepage/enabled echo never >/sys/kernel/mm/transparent_hugepage/enabled =20 @@ -281,7 +295,8 @@ of small pages into one large page:: A higher value leads to use additional memory for programs. A lower value leads to gain less thp performance. Value of max_ptes_none can waste cpu time very little, you can -ignore it. +ignore it. Consider lowering this value when using +``transparent_hugepage=3Ddefer`` =20 ``max_ptes_swap`` specifies how many pages can be brought in from swap when collapsing a group of pages into a transparent huge page:: @@ -306,14 +321,14 @@ Boot parameters =20 You can change the sysfs boot time default for the top-level "enabled" control by passing the parameter ``transparent_hugepage=3Dalways`` or -``transparent_hugepage=3Dmadvise`` or ``transparent_hugepage=3Dnever`` to = the -kernel command line. +``transparent_hugepage=3Dmadvise`` or ``transparent_hugepage=3Ddefer`` or +``transparent_hugepage=3Dnever`` to the kernel command line. =20 Alternatively, each supported anonymous THP size can be controlled by passing ``thp_anon=3D[KMG],[KMG]:;[KMG]-[KM= G]:``, where ```` is the THP size (must be a power of 2 of PAGE_SIZE and supported anonymous THP) and ```` is one of ``always``, ``madvise`= `, -``never`` or ``inherit``. +``defer``, ``never`` or ``inherit``. =20 For example, the following will set 16K, 32K, 64K THP to ``always``, set 128K, 512K to ``inherit``, set 256K to ``madvise`` and 1M, 2M --=20 2.48.1 From nobody Fri Dec 19 17:35:47 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id DE19F1F3BB4 for ; Mon, 14 Apr 2025 22:26:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744669569; cv=none; b=iWgF9MAenRB6/jkKc0QjkHelczWPqKy8XI+PfDv1IRHzE2D/rT3cbBrlerCH/Nj1ugxn292ie9/m9zbF287GKWM0SNMpvEUCVzG6yomNSivKxc5RgbxBSsketif8R2dcu6FwhGMfcsxK9pQPll+DInKejMH1xJmD/vEIBH7P/ns= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744669569; c=relaxed/simple; bh=4wUYKbOMyNvTXMN/uTNfEymawBrc7U7U73r2M7QOj8Y=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=QP36cxuEGeBBW1dfcYpaVggQrmzthT93tn7azn9/8ohmMxnmP99uFIFGu+ufou50vs6/de5wVUoxJNCoitY8eoeAfNwHWfNbZA+cI20c9X5SqzVRd+m1h1sHL/Hjk9AT5hetwRzucz3vF7OGkQ1XZ0bWCQk9yOEjHRGrxJFEDls= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=M2q+9Eop; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="M2q+9Eop" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744669566; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=msAh24K3udJPuo4uQvhJ2pQGaWpK+tApAzBqCKFUhws=; b=M2q+9EopNxmYB3k6QxFy6ehQEHZZY84RPL+navpaeylp41RZIhpRycxY7TxgeQKRrsfjCi trUS6bQDRXiXXx74FQITEAKu9Ibx3F2djF7Ba64gzwI9ge8mk69izefZ+ZVhgN/UUqMt8H c8XeVJCys4k/SiKwujMOOSj1iIW6UXk= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-689-7XVIjlpZMYCFtk_dDexsxw-1; Mon, 14 Apr 2025 18:26:02 -0400 X-MC-Unique: 7XVIjlpZMYCFtk_dDexsxw-1 X-Mimecast-MFC-AGG-ID: 7XVIjlpZMYCFtk_dDexsxw_1744669558 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 20A611956087; Mon, 14 Apr 2025 22:25:58 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.64.91]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 6E187180B487; Mon, 14 Apr 2025 22:25:49 +0000 (UTC) From: Nico Pache To: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: akpm@linux-foundation.org, corbet@lwn.net, shuah@kernel.org, david@redhat.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, ryan.roberts@arm.com, willy@infradead.org, peterx@redhat.com, ioworker0@gmail.com, ziy@nvidia.com, wangkefeng.wang@huawei.com, dev.jain@arm.com, mhocko@suse.com, rientjes@google.com, hannes@cmpxchg.org, zokeefe@google.com, surenb@google.com, jglisse@google.com, cl@gentwo.org, jack@suse.cz, dave.hansen@linux.intel.com, will@kernel.org, tiwai@suse.de, catalin.marinas@arm.com, anshuman.khandual@arm.com, raquini@redhat.com, aarcange@redhat.com, kirill.shutemov@linux.intel.com, yang@os.amperecomputing.com, thomas.hellstrom@linux.intel.com, vishal.moola@gmail.com, sunnanyong@huawei.com, usamaarif642@gmail.com, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, rostedt@goodmis.org Subject: [PATCH v3 3/4] khugepaged: add defer option to mTHP options Date: Mon, 14 Apr 2025 16:24:55 -0600 Message-ID: <20250414222456.43212-4-npache@redhat.com> In-Reply-To: <20250414222456.43212-1-npache@redhat.com> References: <20250414222456.43212-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" Now that we have defer to globally disable THPs at fault time, lets add a defer setting to the mTHP options. This will allow khugepaged to operate at that order, while avoiding it at PF time. Signed-off-by: Nico Pache --- include/linux/huge_mm.h | 5 +++++ mm/huge_memory.c | 38 +++++++++++++++++++++++++++++++++----- mm/khugepaged.c | 10 +++++----- 3 files changed, 43 insertions(+), 10 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index b154bd11bd93..fe6e8dd68100 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -96,6 +96,7 @@ extern struct kobj_attribute thpsize_shmem_enabled_attr; #define TVA_SMAPS (1 << 0) /* Will be used for procfs */ #define TVA_IN_PF (1 << 1) /* Page fault handler */ #define TVA_ENFORCE_SYSFS (1 << 2) /* Obey sysfs configuration */ +#define TVA_IN_KHUGEPAGE ((1 << 2) | (1 << 3)) /* Khugepaged defer support= */ =20 #define thp_vma_allowable_order(vma, vm_flags, tva_flags, order) \ (!!thp_vma_allowable_orders(vma, vm_flags, tva_flags, BIT(order))) @@ -182,6 +183,7 @@ extern unsigned long transparent_hugepage_flags; extern unsigned long huge_anon_orders_always; extern unsigned long huge_anon_orders_madvise; extern unsigned long huge_anon_orders_inherit; +extern unsigned long huge_anon_orders_defer; =20 static inline bool hugepage_global_enabled(void) { @@ -306,6 +308,9 @@ unsigned long thp_vma_allowable_orders(struct vm_area_s= truct *vma, /* Optimization to check if required orders are enabled early. */ if ((tva_flags & TVA_ENFORCE_SYSFS) && vma_is_anonymous(vma)) { unsigned long mask =3D READ_ONCE(huge_anon_orders_always); + + if ((tva_flags & TVA_IN_KHUGEPAGE) =3D=3D TVA_IN_KHUGEPAGE) + mask |=3D READ_ONCE(huge_anon_orders_defer); if (vm_flags & VM_HUGEPAGE) mask |=3D READ_ONCE(huge_anon_orders_madvise); if (hugepage_global_always() || hugepage_global_defer() || diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 4eee0001e0fa..30ea898d4ce6 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -81,6 +81,7 @@ unsigned long huge_zero_pfn __read_mostly =3D ~0UL; unsigned long huge_anon_orders_always __read_mostly; unsigned long huge_anon_orders_madvise __read_mostly; unsigned long huge_anon_orders_inherit __read_mostly; +unsigned long huge_anon_orders_defer __read_mostly; static bool anon_orders_configured __initdata; =20 static inline bool file_thp_enabled(struct vm_area_struct *vma) @@ -505,13 +506,15 @@ static ssize_t anon_enabled_show(struct kobject *kobj, const char *output; =20 if (test_bit(order, &huge_anon_orders_always)) - output =3D "[always] inherit madvise never"; + output =3D "[always] inherit madvise defer never"; else if (test_bit(order, &huge_anon_orders_inherit)) - output =3D "always [inherit] madvise never"; + output =3D "always [inherit] madvise defer never"; else if (test_bit(order, &huge_anon_orders_madvise)) - output =3D "always inherit [madvise] never"; + output =3D "always inherit [madvise] defer never"; + else if (test_bit(order, &huge_anon_orders_defer)) + output =3D "always inherit madvise [defer] never"; else - output =3D "always inherit madvise [never]"; + output =3D "always inherit madvise defer [never]"; =20 return sysfs_emit(buf, "%s\n", output); } @@ -527,25 +530,36 @@ static ssize_t anon_enabled_store(struct kobject *kob= j, spin_lock(&huge_anon_orders_lock); clear_bit(order, &huge_anon_orders_inherit); clear_bit(order, &huge_anon_orders_madvise); + clear_bit(order, &huge_anon_orders_defer); set_bit(order, &huge_anon_orders_always); spin_unlock(&huge_anon_orders_lock); } else if (sysfs_streq(buf, "inherit")) { spin_lock(&huge_anon_orders_lock); clear_bit(order, &huge_anon_orders_always); clear_bit(order, &huge_anon_orders_madvise); + clear_bit(order, &huge_anon_orders_defer); set_bit(order, &huge_anon_orders_inherit); spin_unlock(&huge_anon_orders_lock); } else if (sysfs_streq(buf, "madvise")) { spin_lock(&huge_anon_orders_lock); clear_bit(order, &huge_anon_orders_always); clear_bit(order, &huge_anon_orders_inherit); + clear_bit(order, &huge_anon_orders_defer); set_bit(order, &huge_anon_orders_madvise); spin_unlock(&huge_anon_orders_lock); + } else if (sysfs_streq(buf, "defer")) { + spin_lock(&huge_anon_orders_lock); + clear_bit(order, &huge_anon_orders_always); + clear_bit(order, &huge_anon_orders_inherit); + clear_bit(order, &huge_anon_orders_madvise); + set_bit(order, &huge_anon_orders_defer); + spin_unlock(&huge_anon_orders_lock); } else if (sysfs_streq(buf, "never")) { spin_lock(&huge_anon_orders_lock); clear_bit(order, &huge_anon_orders_always); clear_bit(order, &huge_anon_orders_inherit); clear_bit(order, &huge_anon_orders_madvise); + clear_bit(order, &huge_anon_orders_defer); spin_unlock(&huge_anon_orders_lock); } else ret =3D -EINVAL; @@ -1002,7 +1016,7 @@ static char str_dup[PAGE_SIZE] __initdata; static int __init setup_thp_anon(char *str) { char *token, *range, *policy, *subtoken; - unsigned long always, inherit, madvise; + unsigned long always, inherit, madvise, defer; char *start_size, *end_size; int start, end, nr; char *p; @@ -1014,6 +1028,8 @@ static int __init setup_thp_anon(char *str) always =3D huge_anon_orders_always; madvise =3D huge_anon_orders_madvise; inherit =3D huge_anon_orders_inherit; + defer =3D huge_anon_orders_defer; + p =3D str_dup; while ((token =3D strsep(&p, ";")) !=3D NULL) { range =3D strsep(&token, ":"); @@ -1053,18 +1069,28 @@ static int __init setup_thp_anon(char *str) bitmap_set(&always, start, nr); bitmap_clear(&inherit, start, nr); bitmap_clear(&madvise, start, nr); + bitmap_clear(&defer, start, nr); } else if (!strcmp(policy, "madvise")) { bitmap_set(&madvise, start, nr); bitmap_clear(&inherit, start, nr); bitmap_clear(&always, start, nr); + bitmap_clear(&defer, start, nr); } else if (!strcmp(policy, "inherit")) { bitmap_set(&inherit, start, nr); bitmap_clear(&madvise, start, nr); bitmap_clear(&always, start, nr); + bitmap_clear(&defer, start, nr); + } else if (!strcmp(policy, "defer")) { + bitmap_set(&defer, start, nr); + bitmap_clear(&madvise, start, nr); + bitmap_clear(&always, start, nr); + bitmap_clear(&inherit, start, nr); } else if (!strcmp(policy, "never")) { bitmap_clear(&inherit, start, nr); bitmap_clear(&madvise, start, nr); bitmap_clear(&always, start, nr); + bitmap_clear(&defer, start, nr); + } else { pr_err("invalid policy %s in thp_anon boot parameter\n", policy); goto err; @@ -1075,6 +1101,8 @@ static int __init setup_thp_anon(char *str) huge_anon_orders_always =3D always; huge_anon_orders_madvise =3D madvise; huge_anon_orders_inherit =3D inherit; + huge_anon_orders_defer =3D defer; + anon_orders_configured =3D true; return 1; =20 diff --git a/mm/khugepaged.c b/mm/khugepaged.c index d35abae76c93..1123a2225d6f 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -491,7 +491,7 @@ void khugepaged_enter_vma(struct vm_area_struct *vma, { if (!test_bit(MMF_VM_HUGEPAGE, &vma->vm_mm->flags) && hugepage_pmd_enabled()) { - if (thp_vma_allowable_order(vma, vm_flags, TVA_ENFORCE_SYSFS, + if (thp_vma_allowable_order(vma, vm_flags, TVA_IN_KHUGEPAGE, PMD_ORDER)) __khugepaged_enter(vma->vm_mm); } @@ -955,7 +955,7 @@ static int hugepage_vma_revalidate(struct mm_struct *mm= , unsigned long address, struct collapse_control *cc, int order) { struct vm_area_struct *vma; - unsigned long tva_flags =3D cc->is_khugepaged ? TVA_ENFORCE_SYSFS : 0; + unsigned long tva_flags =3D cc->is_khugepaged ? TVA_IN_KHUGEPAGE : 0; =20 if (unlikely(khugepaged_test_exit_or_disable(mm))) return SCAN_ANY_PROCESS; @@ -1430,7 +1430,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm, bool writable =3D false; int chunk_none_count =3D 0; int scaled_none =3D khugepaged_max_ptes_none >> (HPAGE_PMD_ORDER - KHUGEP= AGED_MIN_MTHP_ORDER); - unsigned long tva_flags =3D cc->is_khugepaged ? TVA_ENFORCE_SYSFS : 0; + unsigned long tva_flags =3D cc->is_khugepaged ? TVA_IN_KHUGEPAGE : 0; VM_BUG_ON(address & ~HPAGE_PMD_MASK); =20 result =3D find_pmd_or_thp_or_none(mm, address, &pmd); @@ -2550,7 +2550,7 @@ static int khugepaged_collapse_single_pmd(unsigned lo= ng addr, { int result =3D SCAN_FAIL; struct mm_struct *mm =3D vma->vm_mm; - unsigned long tva_flags =3D cc->is_khugepaged ? TVA_ENFORCE_SYSFS : 0; + unsigned long tva_flags =3D cc->is_khugepaged ? TVA_IN_KHUGEPAGE : 0; =20 if (thp_vma_allowable_order(vma, vma->vm_flags, tva_flags, PMD_ORDER)) { @@ -2635,7 +2635,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned = int pages, int *result, break; } if (!thp_vma_allowable_order(vma, vma->vm_flags, - TVA_ENFORCE_SYSFS, PMD_ORDER)) { + TVA_IN_KHUGEPAGE, PMD_ORDER)) { skip: progress++; continue; --=20 2.48.1 From nobody Fri Dec 19 17:35:47 2025 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 73A7A1F4CB8 for ; Mon, 14 Apr 2025 22:26:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744669578; cv=none; b=ayPIusfwbPbeaf9qpDkUOC5o4tvaJzELecdc3KFYIhrpXyto9m3zKkNc/83qYukTFepr2m4NeGrYEWTGXFZ2HuBbRKbRoFJzF+OttxvDq/yTR5/IuiHZbE2bb9YZ/vMClF3P1rQSvOWRC5Mv3a5Ft07QaKIuPCAXYl/x8thRSoo= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1744669578; c=relaxed/simple; bh=al6SKl71NAiNJnVYkq84dOJI0VdWszLtxLtJW6ZOVVk=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Dex9D0x6+MNwPxViTnW+JcyJtUcPH/dj6aTBuVTVKC3GOmIDWCbcb/QthSsSf6XNzqnk6BFEcT9oF6lFHqTKlaiV7BXXXA8qCkUzDAzVhnsRccNuDpWcn1wXoRuvDGztKyJGT5F/zW8Jkn9UiAB7xqOJtIpdaKDMUbBfSQd99oE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=SfMJ7q9Q; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="SfMJ7q9Q" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1744669575; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=7n76Fvpmfa8LN30y0qvCHdYcw71Um4Eimev9X0oBxqU=; b=SfMJ7q9Q/rLUtPUZoSRAo84etuWl+cZdhEgL9+f8FjUnV6GyumykKY+x2SR5r0Wvh9VvsX L+QLp7+1xtc/j8UqNBD8XO1YtyWYunsthKntzGDLRdNzbND2QdZm2W/FL7yP0yxdtIb2S0 vOPuxhDB9qMCx7ieqn7Uhvcd2aZ1gdA= Received: from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-447-XdkNGvy2OZa1MtxhAwhYsA-1; Mon, 14 Apr 2025 18:26:11 -0400 X-MC-Unique: XdkNGvy2OZa1MtxhAwhYsA-1 X-Mimecast-MFC-AGG-ID: XdkNGvy2OZa1MtxhAwhYsA_1744669567 Received: from mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.93]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 1D0AE1800262; Mon, 14 Apr 2025 22:26:07 +0000 (UTC) Received: from h1.redhat.com (unknown [10.22.64.91]) by mx-prod-int-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP id 6EB1B180B486; Mon, 14 Apr 2025 22:25:58 +0000 (UTC) From: Nico Pache To: linux-mm@kvack.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org Cc: akpm@linux-foundation.org, corbet@lwn.net, shuah@kernel.org, david@redhat.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, ryan.roberts@arm.com, willy@infradead.org, peterx@redhat.com, ioworker0@gmail.com, ziy@nvidia.com, wangkefeng.wang@huawei.com, dev.jain@arm.com, mhocko@suse.com, rientjes@google.com, hannes@cmpxchg.org, zokeefe@google.com, surenb@google.com, jglisse@google.com, cl@gentwo.org, jack@suse.cz, dave.hansen@linux.intel.com, will@kernel.org, tiwai@suse.de, catalin.marinas@arm.com, anshuman.khandual@arm.com, raquini@redhat.com, aarcange@redhat.com, kirill.shutemov@linux.intel.com, yang@os.amperecomputing.com, thomas.hellstrom@linux.intel.com, vishal.moola@gmail.com, sunnanyong@huawei.com, usamaarif642@gmail.com, mathieu.desnoyers@efficios.com, mhiramat@kernel.org, rostedt@goodmis.org Subject: [PATCH v3 4/4] selftests: mm: add defer to thp setting parser Date: Mon, 14 Apr 2025 16:24:56 -0600 Message-ID: <20250414222456.43212-5-npache@redhat.com> In-Reply-To: <20250414222456.43212-1-npache@redhat.com> References: <20250414222456.43212-1-npache@redhat.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.93 Content-Type: text/plain; charset="utf-8" add the defer setting to the selftests library for reading thp settings. Signed-off-by: Nico Pache --- tools/testing/selftests/mm/thp_settings.c | 1 + tools/testing/selftests/mm/thp_settings.h | 1 + 2 files changed, 2 insertions(+) diff --git a/tools/testing/selftests/mm/thp_settings.c b/tools/testing/self= tests/mm/thp_settings.c index ad872af1c81a..b2f9f62b302a 100644 --- a/tools/testing/selftests/mm/thp_settings.c +++ b/tools/testing/selftests/mm/thp_settings.c @@ -20,6 +20,7 @@ static const char * const thp_enabled_strings[] =3D { "always", "inherit", "madvise", + "defer", NULL }; =20 diff --git a/tools/testing/selftests/mm/thp_settings.h b/tools/testing/self= tests/mm/thp_settings.h index fc131d23d593..0d52e6d4f754 100644 --- a/tools/testing/selftests/mm/thp_settings.h +++ b/tools/testing/selftests/mm/thp_settings.h @@ -11,6 +11,7 @@ enum thp_enabled { THP_ALWAYS, THP_INHERIT, THP_MADVISE, + THP_DEFER, }; =20 enum thp_defrag { --=20 2.48.1