From patchwork Sun Jun 19 13:38:51 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Muchun Song X-Patchwork-Id: 12886665 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]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2AD07C433EF for ; Sun, 19 Jun 2022 13:39:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 9E8158D0001; Sun, 19 Jun 2022 09:39:13 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 94A7A6B0083; Sun, 19 Jun 2022 09:39:13 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 775DF8D0001; Sun, 19 Jun 2022 09:39:13 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 61F206B0082 for ; Sun, 19 Jun 2022 09:39:13 -0400 (EDT) Received: from smtpin12.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id 3998860293 for ; Sun, 19 Jun 2022 13:39:13 +0000 (UTC) X-FDA: 79595091786.12.EF0679A Received: from mail-pg1-f176.google.com (mail-pg1-f176.google.com [209.85.215.176]) by imf06.hostedemail.com (Postfix) with ESMTP id D833318009B for ; Sun, 19 Jun 2022 13:39:12 +0000 (UTC) Received: by mail-pg1-f176.google.com with SMTP id 68so2598800pgb.10 for ; Sun, 19 Jun 2022 06:39:12 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20210112.gappssmtp.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=bbGK9Cq/QWBNj6gBb6mPcVvrSb8ReFvWjVflhIKzRWs=; b=rrTVVCLMAjnM1+iVJatswqIcAjrTDLivAhEksYylMzYTE62fDIBvFj8k8Z7h0BBUdT +WsGb6Hu/sGx6GK5ywjn6SAz3SakeLqEB2h73m/GumXE2U+lHyol1NIgak8/DmWPrs13 qTwjGL87wdjLTjMu6akWK1uB8FZ21Iw2xJj/nruXCvqc+DmWT/hrzVrge3HoFARRXqOv VB28FTF63Yjqok8tO2rAJ+i/fxFzt943jZSLY2wP2k9U4IBEhN7K8jLp6fWZUHJiCSPx OmUeeZIibVFk/jNb3UKf8hrtQxHFXw1om8GvdLrR8AkbjktTI/9wqEWlv/06hDHCAGs5 Quqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=bbGK9Cq/QWBNj6gBb6mPcVvrSb8ReFvWjVflhIKzRWs=; b=CFSx2PgCxR9zFIr0h3YTJne2gfzLJKvqBllrZpLq+boicNs+e9CLxk0uKahKoR2h8S AsbZ9fVgnIUF0V+yEPZfR/ZT/S0nlobPNE4r6oySYeJOqMbw2YFbcbtwopIE4MFT9jIZ EJP6ykSBD0AXf8AP4U9N9jy6kzT6WE0FZxIgrxM3D5J8YJoXGmBnHBFsNZ+cLUPpea3Y Qg2bTVx4QIe0LfgWP8wK/NQ45Q3XK/kfZwMsPA/kCE9EvSGTAeAAF9eI44xZGOepKBcK S5nZh/Ex416DJaUHFbdaUZhniZLDeReac6EYRDys3kqFDp45ICQ519fUWrH0DaLzVIUn 3c0Q== X-Gm-Message-State: AJIora+I3rMrqZqS/cJxb3iP7/0Qs/WpTeWa82j5zIApoOvfLIqhiMvV CZuF7oLPfK3aEiOS91ZLgqCtRw== X-Google-Smtp-Source: AGRyM1st/sgk1MrcQAH2Rp8wmGiSGnKtidFnDrDQccBM0dtJs6MhGnNGM51UuqornnzuEPbgq4Vomw== X-Received: by 2002:a63:9257:0:b0:40c:7b32:4734 with SMTP id s23-20020a639257000000b0040c7b324734mr6329043pgn.317.1655645951737; Sun, 19 Jun 2022 06:39:11 -0700 (PDT) Received: from FVFYT0MHHV2J.bytedance.net ([139.177.225.255]) by smtp.gmail.com with ESMTPSA id y23-20020a056a001c9700b0051b95c76752sm6990982pfw.153.2022.06.19.06.39.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 19 Jun 2022 06:39:11 -0700 (PDT) From: Muchun Song To: akpm@linux-foundation.org, corbet@lwn.net, david@redhat.com, mike.kravetz@oracle.com, osalvador@suse.de, paulmck@kernel.org Cc: linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com, smuchun@gmail.com, Muchun Song Subject: [PATCH v4 2/2] mm: memory_hotplug: make hugetlb_optimize_vmemmap compatible with memmap_on_memory Date: Sun, 19 Jun 2022 21:38:51 +0800 Message-Id: <20220619133851.68184-3-songmuchun@bytedance.com> X-Mailer: git-send-email 2.32.1 (Apple Git-133) In-Reply-To: <20220619133851.68184-1-songmuchun@bytedance.com> References: <20220619133851.68184-1-songmuchun@bytedance.com> MIME-Version: 1.0 ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1655645952; a=rsa-sha256; cv=none; b=0fyDYyAkKgzAiGwlqgVjrd6jiF/Lf918Lt7mARSqmJt6VcYxmg3rnjXB+01MRmRssBwcuz 4mo2O7hngprzlEZnxtytnadQSkiOjvjYpfr3TEXKBJre5ZYejM8TE717aEtcxcIjZwTuuQ aH3TFAGsq/8HKF4ffQI/zO9O7JX72Kg= ARC-Authentication-Results: i=1; imf06.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=rrTVVCLM; spf=pass (imf06.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.215.176 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1655645952; 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=bbGK9Cq/QWBNj6gBb6mPcVvrSb8ReFvWjVflhIKzRWs=; b=RhklT5z78J4AZc+AWf3eydSV/sAYZE99IQ22jE4ChvZsCblOf515/VjgCs3Trd4I7iw7Xv B3t1mme0+HaSSuvcEWVKrH47CobS3y7qwQF6pHDpHZpW4QFdz2NRwNZ9iPHI7p3Ic8U+BZ /Q1aUAGC/HOHoBxYf42gtkOVrKI12Lg= X-Stat-Signature: yprw6yk1ahdkqb7s9yubajhbdwcrh91a X-Rspamd-Queue-Id: D833318009B Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=bytedance-com.20210112.gappssmtp.com header.s=20210112 header.b=rrTVVCLM; spf=pass (imf06.hostedemail.com: domain of songmuchun@bytedance.com designates 209.85.215.176 as permitted sender) smtp.mailfrom=songmuchun@bytedance.com; dmarc=pass (policy=none) header.from=bytedance.com X-Rspamd-Server: rspam07 X-Rspam-User: X-HE-Tag: 1655645952-887444 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: For now, the feature of hugetlb_free_vmemmap is not compatible with the feature of memory_hotplug.memmap_on_memory, and hugetlb_free_vmemmap takes precedence over memory_hotplug.memmap_on_memory. However, someone wants to make memory_hotplug.memmap_on_memory takes precedence over hugetlb_free_vmemmap since memmap_on_memory makes it more likely to succeed memory hotplug in close-to-OOM situations. So the decision of making hugetlb_free_vmemmap take precedence is not wise and elegant. The proper approach is to have hugetlb_vmemmap.c do the check whether the section which the HugeTLB pages belong to can be optimized. If the section's vmemmap pages are allocated from the added memory block itself, hugetlb_free_vmemmap should refuse to optimize the vmemmap, otherwise, do the optimization. Then both kernel parameters are compatible. So this patch introduces VmemmapSelfHosted to mask any non-optimizable vmemmap pages. The hugetlb_vmemmap can use this flag to detect if a vmemmap page can be optimized. Signed-off-by: Muchun Song Co-developed-by: Oscar Salvador Signed-off-by: Oscar Salvador --- Documentation/admin-guide/kernel-parameters.txt | 22 +++++------ Documentation/admin-guide/sysctl/vm.rst | 5 +-- include/linux/memory_hotplug.h | 9 ----- include/linux/page-flags.h | 11 ++++++ mm/hugetlb_vmemmap.c | 52 +++++++++++++++++++++---- mm/memory_hotplug.c | 27 ++++++------- 6 files changed, 79 insertions(+), 47 deletions(-) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 8090130b544b..d740e2ed0e61 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1722,9 +1722,11 @@ Built with CONFIG_HUGETLB_PAGE_OPTIMIZE_VMEMMAP_DEFAULT_ON=y, the default is on. - This is not compatible with memory_hotplug.memmap_on_memory. - If both parameters are enabled, hugetlb_free_vmemmap takes - precedence over memory_hotplug.memmap_on_memory. + Note that the vmemmap pages may be allocated from the added + memory block itself when memory_hotplug.memmap_on_memory is + enabled, those vmemmap pages cannot be optimized even if this + feature is enabled. Other vmemmap pages not allocated from + the added memory block itself do not be affected. hung_task_panic= [KNL] Should the hung task detector generate panics. @@ -3069,10 +3071,12 @@ [KNL,X86,ARM] Boolean flag to enable this feature. Format: {on | off (default)} When enabled, runtime hotplugged memory will - allocate its internal metadata (struct pages) - from the hotadded memory which will allow to - hotadd a lot of memory without requiring - additional memory to do so. + allocate its internal metadata (struct pages, + those vmemmap pages cannot be optimized even + if hugetlb_free_vmemmap is enabled) from the + hotadded memory which will allow to hotadd a + lot of memory without requiring additional + memory to do so. This feature is disabled by default because it has some implication on large (e.g. GB) allocations in some configurations (e.g. small @@ -3082,10 +3086,6 @@ Note that even when enabled, there are a few cases where the feature is not effective. - This is not compatible with hugetlb_free_vmemmap. If - both parameters are enabled, hugetlb_free_vmemmap takes - precedence over memory_hotplug.memmap_on_memory. - memtest= [KNL,X86,ARM,M68K,PPC,RISCV] Enable memtest Format: default : 0 diff --git a/Documentation/admin-guide/sysctl/vm.rst b/Documentation/admin-guide/sysctl/vm.rst index 5c9aa171a0d3..d7374a1e8ac9 100644 --- a/Documentation/admin-guide/sysctl/vm.rst +++ b/Documentation/admin-guide/sysctl/vm.rst @@ -565,9 +565,8 @@ See Documentation/admin-guide/mm/hugetlbpage.rst hugetlb_optimize_vmemmap ======================== -This knob is not available when memory_hotplug.memmap_on_memory (kernel parameter) -is configured or the size of 'struct page' (a structure defined in -include/linux/mm_types.h) is not power of two (an unusual system config could +This knob is not available when the size of 'struct page' (a structure defined +in include/linux/mm_types.h) is not power of two (an unusual system config could result in this). Enable (set to 1) or disable (set to 0) the feature of optimizing vmemmap pages diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h index 20d7edf62a6a..e0b2209ab71c 100644 --- a/include/linux/memory_hotplug.h +++ b/include/linux/memory_hotplug.h @@ -351,13 +351,4 @@ void arch_remove_linear_mapping(u64 start, u64 size); extern bool mhp_supports_memmap_on_memory(unsigned long size); #endif /* CONFIG_MEMORY_HOTPLUG */ -#ifdef CONFIG_MHP_MEMMAP_ON_MEMORY -bool mhp_memmap_on_memory(void); -#else -static inline bool mhp_memmap_on_memory(void) -{ - return false; -} -#endif - #endif /* __LINUX_MEMORY_HOTPLUG_H */ diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index e66f7aa3191d..2aa5dcbfe468 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -193,6 +193,11 @@ enum pageflags { /* Only valid for buddy pages. Used to track pages that are reported */ PG_reported = PG_uptodate, + +#ifdef CONFIG_MEMORY_HOTPLUG + /* For self-hosted memmap pages */ + PG_vmemmap_self_hosted = PG_owner_priv_1, +#endif }; #define PAGEFLAGS_MASK ((1UL << NR_PAGEFLAGS) - 1) @@ -628,6 +633,12 @@ PAGEFLAG_FALSE(SkipKASanPoison, skip_kasan_poison) */ __PAGEFLAG(Reported, reported, PF_NO_COMPOUND) +#ifdef CONFIG_MEMORY_HOTPLUG +PAGEFLAG(VmemmapSelfHosted, vmemmap_self_hosted, PF_ANY) +#else +PAGEFLAG_FALSE(VmemmapSelfHosted, vmemmap_self_hosted) +#endif + /* * On an anonymous page mapped into a user virtual memory area, * page->mapping points to its anon_vma, not to a struct address_space; diff --git a/mm/hugetlb_vmemmap.c b/mm/hugetlb_vmemmap.c index 1089ea8a9c98..73bfbb47f6a4 100644 --- a/mm/hugetlb_vmemmap.c +++ b/mm/hugetlb_vmemmap.c @@ -10,7 +10,7 @@ */ #define pr_fmt(fmt) "HugeTLB: " fmt -#include +#include #include "hugetlb_vmemmap.h" /* @@ -97,18 +97,54 @@ int hugetlb_vmemmap_alloc(struct hstate *h, struct page *head) return ret; } +static unsigned int vmemmap_optimizable_pages(struct hstate *h, + struct page *head) +{ + if (READ_ONCE(vmemmap_optimize_mode) == VMEMMAP_OPTIMIZE_OFF) + return 0; + + if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG)) { + unsigned long pfn = page_to_pfn(head); + + /* + * Due to HugeTLB alignment requirements and the vmemmap pages + * being at the start of the hotplugged memory region in + * memory_hotplug.memmap_on_memory case. Checking the first + * vmemmap page's vmemmap if it is marked as VmemmapSelfHosted + * is sufficient. + * + * [ hotplugged memory ] + * [ section ][...][ section ] + * [ vmemmap ][ usable memory ] + * ^ | | | + * +---+ | | + * ^ | | + * +-------+ | + * ^ | + * +-------------------------------------------+ + * + * Hotplugged memory block never has non-present sections, while + * boot memory block can have one or more. So pfn_valid() is + * used to filter out the non-present section which also cannot + * be memmap_on_memory. + */ + pfn = ALIGN_DOWN(pfn, PHYS_PFN(memory_block_size_bytes())); + if (pfn_valid(pfn) && PageVmemmapSelfHosted(pfn_to_page(pfn))) + return 0; + } + + return hugetlb_optimize_vmemmap_pages(h); +} + void hugetlb_vmemmap_free(struct hstate *h, struct page *head) { unsigned long vmemmap_addr = (unsigned long)head; unsigned long vmemmap_end, vmemmap_reuse, vmemmap_pages; - vmemmap_pages = hugetlb_optimize_vmemmap_pages(h); + vmemmap_pages = vmemmap_optimizable_pages(h, head); if (!vmemmap_pages) return; - if (READ_ONCE(vmemmap_optimize_mode) == VMEMMAP_OPTIMIZE_OFF) - return; - static_branch_inc(&hugetlb_optimize_vmemmap_key); vmemmap_addr += RESERVE_VMEMMAP_SIZE; @@ -199,10 +235,10 @@ static struct ctl_table hugetlb_vmemmap_sysctls[] = { static __init int hugetlb_vmemmap_sysctls_init(void) { /* - * If "memory_hotplug.memmap_on_memory" is enabled or "struct page" - * crosses page boundaries, the vmemmap pages cannot be optimized. + * If "struct page" crosses page boundaries, the vmemmap pages cannot + * be optimized. */ - if (!mhp_memmap_on_memory() && is_power_of_2(sizeof(struct page))) + if (is_power_of_2(sizeof(struct page))) register_sysctl_init("vm", hugetlb_vmemmap_sysctls); return 0; diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c index 6662b86e9e64..3a59d4e97c03 100644 --- a/mm/memory_hotplug.c +++ b/mm/memory_hotplug.c @@ -43,30 +43,22 @@ #include "shuffle.h" #ifdef CONFIG_MHP_MEMMAP_ON_MEMORY -static int memmap_on_memory_set(const char *val, const struct kernel_param *kp) -{ - if (hugetlb_optimize_vmemmap_enabled()) - return 0; - return param_set_bool(val, kp); -} - -static const struct kernel_param_ops memmap_on_memory_ops = { - .flags = KERNEL_PARAM_OPS_FL_NOARG, - .set = memmap_on_memory_set, - .get = param_get_bool, -}; - /* * memory_hotplug.memmap_on_memory parameter */ static bool memmap_on_memory __ro_after_init; -module_param_cb(memmap_on_memory, &memmap_on_memory_ops, &memmap_on_memory, 0444); +module_param(memmap_on_memory, bool, 0444); MODULE_PARM_DESC(memmap_on_memory, "Enable memmap on memory for memory hotplug"); -bool mhp_memmap_on_memory(void) +static inline bool mhp_memmap_on_memory(void) { return memmap_on_memory; } +#else +static inline bool mhp_memmap_on_memory(void) +{ + return false; +} #endif enum { @@ -1035,7 +1027,7 @@ int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages, struct zone *zone) { unsigned long end_pfn = pfn + nr_pages; - int ret; + int ret, i; ret = kasan_add_zero_shadow(__va(PFN_PHYS(pfn)), PFN_PHYS(nr_pages)); if (ret) @@ -1043,6 +1035,9 @@ int mhp_init_memmap_on_memory(unsigned long pfn, unsigned long nr_pages, move_pfn_range_to_zone(zone, pfn, nr_pages, NULL, MIGRATE_UNMOVABLE); + for (i = 0; i < nr_pages; i++) + SetPageVmemmapSelfHosted(pfn_to_page(pfn + i)); + /* * It might be that the vmemmap_pages fully span sections. If that is * the case, mark those sections online here as otherwise they will be