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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4607b38ce69sm20271651cf.90.2024.10.16.12.25.13 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Oct 2024 12:25:14 -0700 (PDT) From: Gregory Price To: x86@kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org Cc: dan.j.williams@intel.com, ira.weiny@intel.com, david@redhat.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, rafael@kernel.org, lenb@kernel.org, rppt@kernel.org, akpm@linux-foundation.org, alison.schofield@intel.com, Jonathan.Cameron@huawei.com, rrichter@amd.com, ytcoode@gmail.com, haibo1.xu@intel.com, dave.jiang@intel.com Subject: [PATCH v2 1/3] mm/memblock: implement memblock_advise_size_order and probe functions Date: Wed, 16 Oct 2024 15:24:43 -0400 Message-ID: <20241016192445.3118-2-gourry@gourry.net> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241016192445.3118-1-gourry@gourry.net> References: <20241016192445.3118-1-gourry@gourry.net> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hotplug memory sources may have opinions on what the memblock size should be - usually for alignment purposes. For example, CXL memory extents can be as small as 256MB with a matching physical alignment. Implement memblock_advise_size_order for use during early init, prior to allocator and smp init, for software to advise the system as to what the preferred block size should be. The probe function is meant for arch_init code to fetch this value once during memblock size calculation. Use of the advisement value is arch-specific, and no guarantee is made that it will be used. Calls to either function after probe results in -EBUSY to signal that advisement is ignored or that memblock_get_size_bytes should be used. Suggested-by: Ira Weiny Signed-off-by: Gregory Price --- include/linux/memblock.h | 2 ++ mm/memblock.c | 49 ++++++++++++++++++++++++++++++++++++++++ 2 files changed, 51 insertions(+) diff --git a/include/linux/memblock.h b/include/linux/memblock.h index fc4d75c6cec3..efb1f7cfbd58 100644 --- a/include/linux/memblock.h +++ b/include/linux/memblock.h @@ -111,6 +111,8 @@ static inline void memblock_discard(void) {} #endif void memblock_allow_resize(void); +int memblock_advise_size_order(int order); +int memblock_probe_size_order(void); int memblock_add_node(phys_addr_t base, phys_addr_t size, int nid, enum memblock_flags flags); int memblock_add(phys_addr_t base, phys_addr_t size); diff --git a/mm/memblock.c b/mm/memblock.c index 3b9dc2d89b8a..e0bdba011564 100644 --- a/mm/memblock.c +++ b/mm/memblock.c @@ -2009,6 +2009,55 @@ void __init memblock_allow_resize(void) memblock_can_resize = 1; } +/* + * @order: bit-order describing the preferred minimum block size + * + * Intended for use by early-boot software prior to smp and allocator init to + * advise the architecture what the minimum block size should be. Should only + * be called during arch init before allocator and smp init. + * + * This value can only decrease after it has been initially set, the intention + * is to identify the smallest supported alignment across all opinions. + * + * Use of this advisement value is arch-specific. + * + * Returns: 0 on success, -EINVAL if order is <=0, and -EBUSY if already probed + */ +static int memblock_sz_order; +#define MEMBLOCK_SZO_PROBED (-1) +int memblock_advise_size_order(int order) +{ + if (order <= 0) + return -EINVAL; + + if (memblock_sz_order == MEMBLOCK_SZO_PROBED) + return -EBUSY; + + if (memblock_sz_order) + memblock_sz_order = min(order, memblock_sz_order); + else + memblock_sz_order = order; + + return 0; +} + +/* + * memblock_probe_size_order is intended for arch init code to probe one time, + * for a suggested memory block size. After the first call, the result will + * always be -EBUSY. A late user should call memory_block_size_bytes instead to + * determine the actual block size in use. + * + * Should only be called during arch init prior to allocator and smp init. + * + * Returns: block size order, 0 if never set, or -EBUSY if previously probed. + */ +int memblock_probe_size_order(void) +{ + int rv = xchg(&memblock_sz_order, -1); + + return (rv == -1) ? -EBUSY : rv; +} + static int __init early_memblock(char *p) { if (p && strstr(p, "debug")) From patchwork Wed Oct 16 19:24:44 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Gregory Price X-Patchwork-Id: 13838794 Received: from mail-qt1-f169.google.com (mail-qt1-f169.google.com [209.85.160.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 37AFC215026 for ; Wed, 16 Oct 2024 19:25:17 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.160.169 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729106718; cv=none; b=C5M8w75sMb2SyDa/n4AWU8GMz+XPKC6GiGIecvJZWCLg7NnKL8/WQngQJ2ztMMovMaUPP+HpKlHKe4GP7a3GPdBourQxLWWoFmhgfy1jwgX/nKt/KK+2aqU959H/AmcH6w3UnvOy8HDI2eDa0lsiPipWD+Evtvc9janG5Xu94nc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729106718; c=relaxed/simple; bh=UFARBbqayRLFnWF98y3uEkaCwwYUXXMM3OzZ3HiPfXw=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=VAlUK3bKlf2eyI/vt+UCUIyp00gD+Vo+Prbv4uHAQol+xiWLNYTS6FxFeuJiqdskfb3tvG3dG9H9hHhXvGjm3Jg9/ZtcT7r/KbW8H59n07riPCW0P5uADLNqFQ5CR0/ZA0v5LPTrmoDgaAJwGGlK0PYZ7Tq/M82pIIfPOLbhtbE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net; spf=pass smtp.mailfrom=gourry.net; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b=Hk5bp7aR; arc=none smtp.client-ip=209.85.160.169 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=gourry.net Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gourry.net Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=gourry.net header.i=@gourry.net header.b="Hk5bp7aR" Received: by mail-qt1-f169.google.com with SMTP id d75a77b69052e-46045199e4dso1567781cf.3 for ; Wed, 16 Oct 2024 12:25:17 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gourry.net; s=google; t=1729106716; x=1729711516; darn=vger.kernel.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=KhSiZfD9mtqxRJdpC7TxMcZ82+QcCBZVMQrw8INyhYE=; b=Hk5bp7aR84sV4AFuoNdhLQKYRO1SAzKp65QOnd3latWq2n7RjMIOFxLRmQKJjo1AMM Ztkn2eRk1mra+G1ouMF1rJMJtntTMuIQbUduj++L1WCshVGa1INCz34oZaraXbZ6XuYo O3a6a6Bffj1J3ncunOU/gzIolYy/+CuXakCGqQvF0bBbUzpL0S44anj9f5LqkiXxdsbO SLdnw/TC81o/6M5XvZiFDjucVNYycfXv9Mf8Cx+IHg8JNh+svjM2Kly3+s1tiPmj5pow 1BHDHpRyZnXSp55iTNrx2kqHLNPCXdRrWF34pTVUC//6j4brkXdY3afOewwoQjOgomlB 9XzA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1729106716; x=1729711516; 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=KhSiZfD9mtqxRJdpC7TxMcZ82+QcCBZVMQrw8INyhYE=; b=wLKki7UqJi60+r1x409+iFND2eHPr88rezBPIi0JJgh3vNWuDCH5iKCNCFZbc71geB ShhLnbbsREaUwa8v/RXHQO9cDRn8fnc1/qs/t41OY9hT5ixEzky3A55wg8uc5IDFcQhv 7xzz4XwzMoIXeekmdW0c3pjR7hDP1tSEvaTIXqE+Exk+oun1N3QDYRXUo4788VuWFS7I EqfJaCBsnAR2BU+RGk2h/1vsksUWA8UyTMduuzq+1OcPjJ2puddTRgTfgysXpe8xvoJN 9VJ7T1bBrgZhXgCN4PaDgFKkMpUclQ8aXvVzsOh+kdglLfGXPba7RaNrxgs8tpOSsfv0 E51g== X-Forwarded-Encrypted: i=1; AJvYcCUsL2RH9n/9sMe5gpNYX5LAya+/2lzczxoi+baQtOPMgm25SJMz/dhrhOa4VHa2/vre5RzNF6ePdfGJ@vger.kernel.org X-Gm-Message-State: AOJu0Yx3Tszck+D7B0qAaIv+iJq6uZL9E+ERZjU/mpKdD16LGpY1rHzH UG1dz9CHpYWjZqyhbCBc3CQaRVR2BaK7m1DLfKVvtXCdP/v1SaJ/teiuxSVPL1o= X-Google-Smtp-Source: AGHT+IFAUHFf6NguMqIqPpOUU8ECxUJfxWjg38Snyk4DLApeDSEpJ+qoxL7DfuWK9Mow+ZcYMf8Ygg== X-Received: by 2002:a05:622a:244b:b0:45f:784:1b5a with SMTP id d75a77b69052e-46058444fa6mr282643391cf.25.1729106716169; Wed, 16 Oct 2024 12:25:16 -0700 (PDT) Received: from PC2K9PVX.TheFacebook.com (pool-173-79-56-208.washdc.fios.verizon.net. [173.79.56.208]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4607b38ce69sm20271651cf.90.2024.10.16.12.25.15 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Oct 2024 12:25:15 -0700 (PDT) From: Gregory Price To: x86@kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org Cc: dan.j.williams@intel.com, ira.weiny@intel.com, david@redhat.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, rafael@kernel.org, lenb@kernel.org, rppt@kernel.org, akpm@linux-foundation.org, alison.schofield@intel.com, Jonathan.Cameron@huawei.com, rrichter@amd.com, ytcoode@gmail.com, haibo1.xu@intel.com, dave.jiang@intel.com Subject: [PATCH v2 2/3] x86: probe memblock size advisement value during mm init Date: Wed, 16 Oct 2024 15:24:44 -0400 Message-ID: <20241016192445.3118-3-gourry@gourry.net> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241016192445.3118-1-gourry@gourry.net> References: <20241016192445.3118-1-gourry@gourry.net> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Systems with hotplug may provide an advisement value on what the memblock size should be. Probe this value when the rest of the configuration values are considered. The new heuristic is as follows 1) set_memory_block_size_order value if already set (cmdline param) 2) minimum block size if memory is less than large block limit 3) [new] hotplug advise: lesser of advise value or memory alignment 4) Max block size if system is bare-metal 5) Largest size that aligns to end of memory. Suggested-by: David Hildenbrand Signed-off-by: Gregory Price --- arch/x86/mm/init_64.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index ff253648706f..b72923b12d99 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -1439,6 +1439,7 @@ static unsigned long probe_memory_block_size(void) { unsigned long boot_mem_end = max_pfn << PAGE_SHIFT; unsigned long bz; + int order; /* If memory block size has been set, then use it */ bz = set_memory_block_size; @@ -1451,6 +1452,21 @@ static unsigned long probe_memory_block_size(void) goto done; } + /* Consider hotplug advisement value (if set) */ + order = memblock_probe_size_order(); + bz = order > 0 ? (1UL << order) : 0; + if (bz) { + /* Align down to max and up to min supported */ + bz = max(min(bz, MAX_BLOCK_SIZE), MIN_MEMORY_BLOCK_SIZE); + /* Use lesser of advisement and end of memory alignment */ + for (; bz > MIN_MEMORY_BLOCK_SIZE; bz >>= 1) { + if (IS_ALIGNED(boot_mem_end, bz)) + goto done; + } + /* Barring clean alignment, default to min block size */ + goto done; + } + /* * Use max block size to minimize overhead on bare metal, where * alignment for memory hotplug isn't a concern. 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[173.79.56.208]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-4607b38ce69sm20271651cf.90.2024.10.16.12.25.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 16 Oct 2024 12:25:17 -0700 (PDT) From: Gregory Price To: x86@kernel.org, linux-kernel@vger.kernel.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org Cc: dan.j.williams@intel.com, ira.weiny@intel.com, david@redhat.com, dave.hansen@linux.intel.com, luto@kernel.org, peterz@infradead.org, tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, hpa@zytor.com, rafael@kernel.org, lenb@kernel.org, rppt@kernel.org, akpm@linux-foundation.org, alison.schofield@intel.com, Jonathan.Cameron@huawei.com, rrichter@amd.com, ytcoode@gmail.com, haibo1.xu@intel.com, dave.jiang@intel.com Subject: [PATCH v2 3/3] acpi,srat: reduce memory block size if CFMWS has a smaller alignment Date: Wed, 16 Oct 2024 15:24:45 -0400 Message-ID: <20241016192445.3118-4-gourry@gourry.net> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20241016192445.3118-1-gourry@gourry.net> References: <20241016192445.3118-1-gourry@gourry.net> Precedence: bulk X-Mailing-List: linux-acpi@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 The CXL Fixed Memory Window allows for memory aligned down to the size of 256MB. However, by default on x86, memory blocks increase in size as total System RAM capacity increases. On x86, this caps out at 2G when 64GB of System RAM is reached. When the CFMWS regions are not aligned to memory block size, this results in lost capacity on either side of the alignment. Parse all CFMWS to detect the largest common denomenator among all regions, and advise memblock to reduce the block size accordingly. Suggested-by: Dan Williams Signed-off-by: Gregory Price --- drivers/acpi/numa/srat.c | 42 ++++++++++++++++++++++++++++++++++++++++ 1 file changed, 42 insertions(+) diff --git a/drivers/acpi/numa/srat.c b/drivers/acpi/numa/srat.c index 44f91f2c6c5d..5fc03a99570e 100644 --- a/drivers/acpi/numa/srat.c +++ b/drivers/acpi/numa/srat.c @@ -14,6 +14,7 @@ #include #include #include +#include #include #include #include @@ -333,6 +334,35 @@ acpi_parse_memory_affinity(union acpi_subtable_headers *header, return 0; } +/* + * CXL allows CFMW to be aligned along 256MB boundaries, but large memory + * systems default to larger alignments (2GB on x86). Misalignments can + * cause some capacity to become unreachable. Calculate the largest supported + * alignment for all CFMW to maximize the amount of mappable capacity. + */ +static int __init acpi_align_cfmws(union acpi_subtable_headers *header, + void *arg, const unsigned long table_end) +{ + struct acpi_cedt_cfmws *cfmws = (struct acpi_cedt_cfmws *)header; + u64 start = cfmws->base_hpa; + u64 size = cfmws->window_size; + unsigned long *fin_bz = arg; + unsigned long bz; + + for (bz = SZ_64T; bz >= SZ_256M; bz >>= 1) { + if (IS_ALIGNED(start, bz) && IS_ALIGNED(size, bz)) + break; + } + + /* Only adjust downward, we never want to increase block size */ + if (bz < *fin_bz && bz >= SZ_256M) + *fin_bz = bz; + else if (bz < SZ_256M) + pr_err("CFMWS: [BIOS BUG] base/size alignment violates spec\n"); + + return 0; +} + static int __init acpi_parse_cfmws(union acpi_subtable_headers *header, void *arg, const unsigned long table_end) { @@ -501,6 +531,7 @@ acpi_table_parse_srat(enum acpi_srat_type id, int __init acpi_numa_init(void) { int i, fake_pxm, cnt = 0; + unsigned long bz = SZ_64T; if (acpi_disabled) return -EINVAL; @@ -552,6 +583,17 @@ int __init acpi_numa_init(void) } last_real_pxm = fake_pxm; fake_pxm++; + + /* Calculate and set largest supported memory block size alignment */ + acpi_table_parse_cedt(ACPI_CEDT_TYPE_CFMWS, acpi_align_cfmws, &bz); + if (bz >= SZ_256M) { + if (memblock_advise_size_order(ffs(bz)-1) < 0) + pr_warn("CFMWS: memblock size advise failed\n"); + else + pr_info("CFMWS: memblock advised size(%ld)\n", bz); + } + + /* Then parse and fill the numa nodes with the described memory */ acpi_table_parse_cedt(ACPI_CEDT_TYPE_CFMWS, acpi_parse_cfmws, &fake_pxm);