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 CEBDDC43458 for ; Sun, 28 Jun 2026 19:02:01 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 7B13D6B0005; Sun, 28 Jun 2026 15:02:00 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 789716B0088; Sun, 28 Jun 2026 15:02:00 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 69F216B008A; Sun, 28 Jun 2026 15:02:00 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 3E92F6B0005 for ; Sun, 28 Jun 2026 15:02:00 -0400 (EDT) Received: from smtpin03.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id A259F1C33A9 for ; Sun, 28 Jun 2026 19:01:59 +0000 (UTC) X-FDA: 84930241158.03.CFCD310 Received: from mail-pf1-f202.google.com (mail-pf1-f202.google.com [209.85.210.202]) by imf14.hostedemail.com (Postfix) with ESMTP id 09C0110000A for ; Sun, 28 Jun 2026 19:01:57 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=P2t3Fc9Y; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf14.hostedemail.com: domain of 3pG9BagsKCOEVRXUDYSDQGDJRRJOH.FRPOLQXa-PPNYDFN.RUJ@flex--souravpanda.bounces.google.com designates 209.85.210.202 as permitted sender) smtp.mailfrom=3pG9BagsKCOEVRXUDYSDQGDJRRJOH.FRPOLQXa-PPNYDFN.RUJ@flex--souravpanda.bounces.google.com ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1782673318; b=M49X4ASdWPuUmm4AvYeVMVI5p/8Pm3S/IjqAXraik61p2n3sNQKMr/Jm8UuJVNKnOV/CF3 vQcAkFaY69/UYjFO8mDPFjqKSbPHSVQke1nqtbyFO5/ejBXyJ7qWFPvhZW7ttMWdT5VbeH NfpS13WiPKoVsCRhbRLOC1qhQg/b9nQ= ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1782673318; 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-type:content-transfer-encoding:in-reply-to: references:dkim-signature; bh=fHT/VH/FCGpteAy70lN8IuW/FU0GRl1Lj7eDs34tWTw=; b=o3Lmn1jXedtYDNWD0/8lwewAJ3XsxQ+ueHs4fNrkVk1hHJfnrZBsQw6/0L8mdKwLoCXKYn 8XQzrYFbxY2zewhcX2wbLKQYBSDRx7U8Lo7+XA+8jNEC9sZE2gkrIpPQJzrh+8gTyrwcPl qcWRFMKMzTdf0jh1qCn4BJfOHBzS0b8= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=pass header.d=google.com header.s=20251104 header.b=P2t3Fc9Y; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf14.hostedemail.com: domain of 3pG9BagsKCOEVRXUDYSDQGDJRRJOH.FRPOLQXa-PPNYDFN.RUJ@flex--souravpanda.bounces.google.com designates 209.85.210.202 as permitted sender) smtp.mailfrom=3pG9BagsKCOEVRXUDYSDQGDJRRJOH.FRPOLQXa-PPNYDFN.RUJ@flex--souravpanda.bounces.google.com Received: by mail-pf1-f202.google.com with SMTP id d2e1a72fcca58-8478423e020so352261b3a.0 for ; Sun, 28 Jun 2026 12:01:57 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1782673317; x=1783278117; darn=kvack.org; h=cc:to:from:subject:message-id:mime-version:date:from:to:cc:subject :date:message-id:reply-to; bh=fHT/VH/FCGpteAy70lN8IuW/FU0GRl1Lj7eDs34tWTw=; b=P2t3Fc9YY7I4KRw1ZtpThUTy+U9U08ZCHHC6CT4VDhiRRXDc/KTCnSWsnh16ONrg8n gAX1Zp9araufyZl4SvePH1FwarkVFrXjIpCyw2o8QgfDb94Fg+uht6kbWT7P9SOc82Z9 Vnm6FTanfMpX4RB2vYdKmBTp2hajao6mcZDS0z7mdhqidW3W3NrjAoaxGTDKoO7X6+e9 3Z8OIonHWCjx1pWDuCODtQeV2GWU5zj+RvceXR3QKanahv/senUqjYnIqcUR86X9sCrA gi5J+nMnX/hnhQaskfNxVq05Z/kLESBmgCmmGC3dzKG6/nJZPMDGbYQpqDzh7MzmplC/ b20Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1782673317; x=1783278117; h=cc:to:from:subject:message-id:mime-version:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=fHT/VH/FCGpteAy70lN8IuW/FU0GRl1Lj7eDs34tWTw=; b=tPksg8fBHQ5O9tyF2OowzeLbD/jUSM8zT0/cdwEG1cMxHWnKN+R2UeoRhkSlDGsz1W V8NdX0u2JYZW0izjECbg9jv6m6CLFMHIkDYYvP4oubwaQdW9JDKKcBZcAGi8F1WWDG7X uQjZypFP+2QuppEkiwRKlC89QcjKFuhIL9F4qP7qXYNOFCyBHwqOWDgb/5RRw8qD2pk0 1c14OJXL/a66t01/SFOciUwQGujs6BfuXF4Vsg8OvsWJTZ3XddojysNfpByOCwM8vOLR r7mL++hpNQkFnHm4tapzv5Buly88wOL/MHNu5eXkO9nVxUSU73MLQRFeDcu2wVUxh9G5 fSbg== X-Forwarded-Encrypted: i=1; AHgh+RqOt5MnZSt0qZzchRXN8oNazJGE80kiG6zXq8mPfgDhalc9zDkC+ZCUIFdBKQynbSAowOJA1ALzeA==@kvack.org X-Gm-Message-State: AOJu0YwC9VHRHkIdQ6cmMBwpXpBUkKObfK5JFknFvytJGhexNMDu5Ci6 sKExlfRFEpwe/rprZykPB7TRxgbm4fN/eMXFtbiOtwqRIjErNQIxiDdDM83JaPUyOzEuecTFtWC SgZtMVmFGKYSvNiG/HAaMHHVEyQ== X-Received: from pfbcj24.prod.google.com ([2002:a05:6a00:2998:b0:845:c378:7950]) (user=souravpanda job=prod-delivery.src-stubby-dispatcher) by 2002:a05:6a00:6c8e:b0:846:2f5b:c00 with SMTP id d2e1a72fcca58-8462f5b0d5fmr2493452b3a.54.1782673316699; Sun, 28 Jun 2026 12:01:56 -0700 (PDT) Date: Sun, 28 Jun 2026 19:01:55 +0000 Mime-Version: 1.0 X-Mailer: git-send-email 2.55.0.rc0.799.gd6f94ed593-goog Message-ID: <20260628190155.3655895-1-souravpanda@google.com> Subject: [PATCH v2] mm/hugetlb_cma: support percentage-based hugetlb_cma reservation From: Sourav Panda To: muchun.song@linux.dev, osalvador@suse.de, akpm@linux-foundation.org Cc: david@kernel.org, surenb@google.com, fvdl@google.com, gthelen@google.com, rientjes@google.com, souravpanda@google.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam08 X-Rspamd-Queue-Id: 09C0110000A X-Stat-Signature: t1xxqehutd933dcjhc6hdxs4sea3uduc X-HE-Tag: 1782673317-380323 X-HE-Meta: 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 0fR8I5Lk 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Currently, hugetlb_cma reservation only supports absolute sizes (e.g., hugetlb_cma=2G or hugetlb_cma=0:1G,1:1G). This can be restrictive in heterogeneous environments or when deploying common kernel command lines across machines with different memory capacities. Add support for percentage-based hugetlb_cma reservation (e.g., hugetlb_cma=20% or hugetlb_cma=0:20%,1:10%). The percentage is calculated against the total memory (for global settings) or against the node-specific memory (for node-specific settings) using memblock APIs during early boot. Signed-off-by: Sourav Panda Reported-by: kernel test robot Closes: https://lore.kernel.org/oe-kbuild-all/202606262023.IKUrn01I-lkp@intel.com/ --- Link: https://lore.kernel.org/linux-mm/20260625215900.2151690-1-souravpanda@google.com/ [v1] v2: - Use mul_u64_u32_div() instead of mult_frac() to avoid 64-bit division on 32-bit architectures (Reported by kernel test robot). - Fix physical memory size truncation on 32-bit PAE by using phys_addr_t in memblock_node_memory_size() (Sashiko). - Fix boot parameter override logic to respect standard last-one-wins precedence by clearing opposite values during parsing and clearing node-specific values when global values are parsed. .../admin-guide/kernel-parameters.txt | 7 +- mm/hugetlb_cma.c | 96 ++++++++++++++++++- 2 files changed, 97 insertions(+), 6 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 5a05b48d1684..846940ce2858 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -2064,8 +2064,11 @@ Kernel parameters hugetlb_cma= [HW,CMA,EARLY] The size of a CMA area used for allocation of gigantic hugepages. Or using node format, the size of a CMA area per node can be specified. - Format: nn[KMGTPE] or (node format) - :nn[KMGTPE][,:nn[KMGTPE]] + The size can be an absolute value (e.g., 2G) or a + percentage of the total memory or node memory (e.g., 20%). + Format: nn[KMGTPE] or nn% or (node format) + :nn[KMGTPE][,:nn[KMGTPE]] or + :nn%[,:nn%] Reserve a CMA area of given size and allocate gigantic hugepages using the CMA allocator. If enabled, the diff --git a/mm/hugetlb_cma.c b/mm/hugetlb_cma.c index 7693ccefd0c6..684ffa3537d2 100644 --- a/mm/hugetlb_cma.c +++ b/mm/hugetlb_cma.c @@ -9,6 +9,9 @@ #include #include +#include +#include +#include #include "internal.h" #include "hugetlb_cma.h" @@ -18,6 +21,28 @@ static unsigned long hugetlb_cma_size_in_node[MAX_NUMNODES] __initdata; static bool hugetlb_cma_only __ro_after_init; static unsigned long hugetlb_cma_size __ro_after_init; +static unsigned int hugetlb_cma_percent __initdata; +static unsigned int hugetlb_cma_percent_in_node[MAX_NUMNODES] __initdata; + +#ifdef CONFIG_NUMA +static phys_addr_t __init memblock_node_memory_size(int nid) +{ + struct memblock_region *reg; + phys_addr_t size = 0; + + for_each_mem_region(reg) { + if (reg->nid == nid) + size += reg->size; + } + return size; +} +#else +static phys_addr_t __init memblock_node_memory_size(int nid) +{ + return memblock_phys_mem_size(); +} +#endif + void hugetlb_cma_free_frozen_folio(struct folio *folio) { WARN_ON_ONCE(!cma_release_frozen(hugetlb_cma[folio_nid(folio)], @@ -100,14 +125,28 @@ static int __init cmdline_parse_hugetlb_cma(char *p) break; if (s[count] == ':') { + char *next; + if (tmp >= MAX_NUMNODES) break; nid = array_index_nospec(tmp, MAX_NUMNODES); s += count + 1; - tmp = memparse(s, &s); - hugetlb_cma_size_in_node[nid] = tmp; - hugetlb_cma_size += tmp; + tmp = memparse(s, &next); + if (*next == '%') { + if (tmp > 100) { + pr_warn("hugetlb_cma: invalid percentage %lu for node %d\n", + tmp, nid); + break; + } + hugetlb_cma_percent_in_node[nid] = tmp; + hugetlb_cma_size_in_node[nid] = 0; + s = next + 1; + } else { + hugetlb_cma_size_in_node[nid] = tmp; + hugetlb_cma_percent_in_node[nid] = 0; + s = next; + } /* * Skip the separator if have one, otherwise @@ -118,7 +157,28 @@ static int __init cmdline_parse_hugetlb_cma(char *p) else break; } else { - hugetlb_cma_size = memparse(p, &p); + char *next; + + tmp = memparse(p, &next); + if (*next == '%') { + if (tmp > 100) { + pr_warn("hugetlb_cma: invalid percentage %lu\n", tmp); + } else { + hugetlb_cma_percent = tmp; + hugetlb_cma_size = 0; + for (nid = 0; nid < MAX_NUMNODES; nid++) { + hugetlb_cma_size_in_node[nid] = 0; + hugetlb_cma_percent_in_node[nid] = 0; + } + } + } else { + hugetlb_cma_size = tmp; + hugetlb_cma_percent = 0; + for (nid = 0; nid < MAX_NUMNODES; nid++) { + hugetlb_cma_size_in_node[nid] = 0; + hugetlb_cma_percent_in_node[nid] = 0; + } + } break; } } @@ -144,8 +204,36 @@ void __init hugetlb_cma_reserve(void) { unsigned long size, reserved, per_node, order; bool node_specific_cma_alloc = false; + bool has_node_specific_param = false; int nid; + for (nid = 0; nid < MAX_NUMNODES; nid++) { + if (hugetlb_cma_size_in_node[nid] || hugetlb_cma_percent_in_node[nid]) { + has_node_specific_param = true; + break; + } + } + + if (has_node_specific_param) { + hugetlb_cma_size = 0; + for (nid = 0; nid < MAX_NUMNODES; nid++) { + if (hugetlb_cma_percent_in_node[nid]) { + phys_addr_t node_gfp_mem = memblock_node_memory_size(nid); + u64 s; + + s = mul_u64_u32_div((u64)node_gfp_mem, + hugetlb_cma_percent_in_node[nid], + 100); + + hugetlb_cma_size_in_node[nid] = s; + } + hugetlb_cma_size += hugetlb_cma_size_in_node[nid]; + } + } else if (hugetlb_cma_percent) { + hugetlb_cma_size = mul_u64_u32_div((u64)memblock_phys_mem_size(), + hugetlb_cma_percent, 100); + } + if (!hugetlb_cma_size) return; -- 2.55.0.rc0.799.gd6f94ed593-goog