From patchwork Mon Dec 4 10:20:21 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ryan Roberts X-Patchwork-Id: 13478088 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 85B77C10DC1 for ; Mon, 4 Dec 2023 10:21:07 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 283C16B0281; Mon, 4 Dec 2023 05:21:07 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 20C376B0282; Mon, 4 Dec 2023 05:21:07 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 05F456B0283; Mon, 4 Dec 2023 05:21:06 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id E05506B0281 for ; Mon, 4 Dec 2023 05:21:06 -0500 (EST) Received: from smtpin19.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay04.hostedemail.com (Postfix) with ESMTP id B92491A0158 for ; Mon, 4 Dec 2023 10:21:06 +0000 (UTC) X-FDA: 81528742932.19.5CF0978 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by imf14.hostedemail.com (Postfix) with ESMTP id 02610100014 for ; Mon, 4 Dec 2023 10:21:04 +0000 (UTC) Authentication-Results: imf14.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf14.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1701685265; 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; bh=M/StK3U56B8xrSAPv6sRmO6Le1sAWioQwp9awqHLLkY=; b=cQ9nXMjH4mFs2E0T3w39eSsefZKm+E/oKE1HU32t582RlHm5W+YBe199gHrmumE/VXh2XI cUdWkgVmlXl7ugm7TyB8hSBfvKYoMQ+P+hZo4LRwhScHNkqEGu5JmvzmSvCBDJyDt3qsVD OEsh1EBWyD96UDPj/SphSmwtXS8LzDw= ARC-Authentication-Results: i=1; imf14.hostedemail.com; dkim=none; dmarc=pass (policy=none) header.from=arm.com; spf=pass (imf14.hostedemail.com: domain of ryan.roberts@arm.com designates 217.140.110.172 as permitted sender) smtp.mailfrom=ryan.roberts@arm.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1701685265; a=rsa-sha256; cv=none; b=c0CARB2BoxCwEwv3ROZrZmClZHre8IC8WzXEpnutJGvR5yf0v7oQ/EgpyEdDxzRXvI2XoC PIlkP5gAfGsZcha8S+Pwty4BwsKS7OM6mP3Io1lY7HRLGQZkqKhYITV4ORCwmwaE9wY7MC eVpAVohysFWyU0wMT1+CNZinZefbVS4= Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 3365916A3; Mon, 4 Dec 2023 02:21:51 -0800 (PST) Received: from e125769.cambridge.arm.com (e125769.cambridge.arm.com [10.1.196.26]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1BD0B3F6C4; Mon, 4 Dec 2023 02:21:01 -0800 (PST) From: Ryan Roberts To: Andrew Morton , Matthew Wilcox , Yin Fengwei , David Hildenbrand , Yu Zhao , Catalin Marinas , Anshuman Khandual , Yang Shi , "Huang, Ying" , Zi Yan , Luis Chamberlain , Itaru Kitayama , "Kirill A. Shutemov" , John Hubbard , David Rientjes , Vlastimil Babka , Hugh Dickins , Kefeng Wang , Barry Song <21cnbao@gmail.com>, Alistair Popple Cc: Ryan Roberts , linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH v8 04/10] mm: thp: Support allocation of anonymous multi-size THP Date: Mon, 4 Dec 2023 10:20:21 +0000 Message-Id: <20231204102027.57185-5-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231204102027.57185-1-ryan.roberts@arm.com> References: <20231204102027.57185-1-ryan.roberts@arm.com> MIME-Version: 1.0 X-Rspamd-Queue-Id: 02610100014 X-Rspam-User: X-Rspamd-Server: rspam04 X-Stat-Signature: zu9ipq3aiqyrpsxkmfd7pwgo1r1enzf1 X-HE-Tag: 1701685264-80425 X-HE-Meta: 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 KocvIDmv WjOwEm7ENRJQ2zxzzxDmgXNTtKHlO0QTpqR74Lj2zTimAP0KbCdaqZPi7yf074SR5ko67fWr2l0d2BmezUCA+dPduDIy06o9c39TpsdvWRUAqd2Koxp1OMxwkE3esfKzwRumKlI+b7hM8ZT7ykoI6itKiJIcUpshlubOzE8S9tW7Ug7nV8TLmC28VB9KaruG1RJX2QfF4CXprdiGfLJ6ninbHTmCYm2Pn02S63jsYyyC0brI= 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: Introduce the logic to allow THP to be configured (through the new sysfs interface we just added) to allocate large folios to back anonymous memory, which are larger than the base page size but smaller than PMD-size. We call this new THP extension "multi-size THP" (mTHP). mTHP continues to be PTE-mapped, but in many cases can still provide similar benefits to traditional PMD-sized THP: Page faults are significantly reduced (by a factor of e.g. 4, 8, 16, etc. depending on the configured order), but latency spikes are much less prominent because the size of each page isn't as huge as the PMD-sized variant and there is less memory to clear in each page fault. The number of per-page operations (e.g. ref counting, rmap management, lru list management) are also significantly reduced since those ops now become per-folio. Some architectures also employ TLB compression mechanisms to squeeze more entries in when a set of PTEs are virtually and physically contiguous and approporiately aligned. In this case, TLB misses will occur less often. The new behaviour is disabled by default, but can be enabled at runtime by writing to /sys/kernel/mm/transparent_hugepage/hugepage-XXkb/enabled (see documentation in previous commit). The long term aim is to change the default to include suitable lower orders, but there are some risks around internal fragmentation that need to be better understood first. Signed-off-by: Ryan Roberts --- include/linux/huge_mm.h | 6 ++- mm/memory.c | 106 ++++++++++++++++++++++++++++++++++++---- 2 files changed, 101 insertions(+), 11 deletions(-) diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h index bd0eadd3befb..91a53b9835a4 100644 --- a/include/linux/huge_mm.h +++ b/include/linux/huge_mm.h @@ -68,9 +68,11 @@ extern struct kobj_attribute shmem_enabled_attr; #define HPAGE_PMD_NR (1<vma; + unsigned long orders; + int order; + + /* + * If uffd is active for the vma we need per-page fault fidelity to + * maintain the uffd semantics. + */ + if (userfaultfd_armed(vma)) + goto fallback; + + /* + * Get a list of all the (large) orders below PMD_ORDER that are enabled + * for this vma. Then filter out the orders that can't be allocated over + * the faulting address and still be fully contained in the vma. + */ + orders = thp_vma_allowable_orders(vma, vma->vm_flags, false, true, true, + BIT(PMD_ORDER) - 1); + orders = thp_vma_suitable_orders(vma, vmf->address, orders); + + if (!orders) + goto fallback; + + pte = pte_offset_map(vmf->pmd, vmf->address & PMD_MASK); + if (!pte) + return ERR_PTR(-EAGAIN); + + order = first_order(orders); + while (orders) { + addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order); + vmf->pte = pte + pte_index(addr); + if (pte_range_none(vmf->pte, 1 << order)) + break; + order = next_order(&orders, order); + } + + vmf->pte = NULL; + pte_unmap(pte); + + gfp = vma_thp_gfp_mask(vma); + + while (orders) { + addr = ALIGN_DOWN(vmf->address, PAGE_SIZE << order); + folio = vma_alloc_folio(gfp, order, vma, addr, true); + if (folio) { + clear_huge_page(&folio->page, addr, 1 << order); + return folio; + } + order = next_order(&orders, order); + } + +fallback: + return vma_alloc_zeroed_movable_folio(vma, vmf->address); +} +#else +#define alloc_anon_folio(vmf) \ + vma_alloc_zeroed_movable_folio((vmf)->vma, (vmf)->address) +#endif + /* * We enter with non-exclusive mmap_lock (to exclude vma changes, * but allow concurrent faults), and pte mapped but not yet locked. @@ -4132,6 +4210,9 @@ vm_fault_t do_swap_page(struct vm_fault *vmf) */ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) { + int i; + int nr_pages = 1; + unsigned long addr = vmf->address; bool uffd_wp = vmf_orig_pte_uffd_wp(vmf); struct vm_area_struct *vma = vmf->vma; struct folio *folio; @@ -4176,10 +4257,15 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) /* Allocate our own private page. */ if (unlikely(anon_vma_prepare(vma))) goto oom; - folio = vma_alloc_zeroed_movable_folio(vma, vmf->address); + folio = alloc_anon_folio(vmf); + if (IS_ERR(folio)) + return 0; if (!folio) goto oom; + nr_pages = folio_nr_pages(folio); + addr = ALIGN_DOWN(vmf->address, nr_pages * PAGE_SIZE); + if (mem_cgroup_charge(folio, vma->vm_mm, GFP_KERNEL)) goto oom_free_page; folio_throttle_swaprate(folio, GFP_KERNEL); @@ -4196,12 +4282,13 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) if (vma->vm_flags & VM_WRITE) entry = pte_mkwrite(pte_mkdirty(entry), vma); - vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, vmf->address, - &vmf->ptl); + vmf->pte = pte_offset_map_lock(vma->vm_mm, vmf->pmd, addr, &vmf->ptl); if (!vmf->pte) goto release; - if (vmf_pte_changed(vmf)) { - update_mmu_tlb(vma, vmf->address, vmf->pte); + if ((nr_pages == 1 && vmf_pte_changed(vmf)) || + (nr_pages > 1 && !pte_range_none(vmf->pte, nr_pages))) { + for (i = 0; i < nr_pages; i++) + update_mmu_tlb(vma, addr + PAGE_SIZE * i, vmf->pte + i); goto release; } @@ -4216,16 +4303,17 @@ static vm_fault_t do_anonymous_page(struct vm_fault *vmf) return handle_userfault(vmf, VM_UFFD_MISSING); } - inc_mm_counter(vma->vm_mm, MM_ANONPAGES); - folio_add_new_anon_rmap(folio, vma, vmf->address); + folio_ref_add(folio, nr_pages - 1); + add_mm_counter(vma->vm_mm, MM_ANONPAGES, nr_pages); + folio_add_new_anon_rmap(folio, vma, addr); folio_add_lru_vma(folio, vma); setpte: if (uffd_wp) entry = pte_mkuffd_wp(entry); - set_pte_at(vma->vm_mm, vmf->address, vmf->pte, entry); + set_ptes(vma->vm_mm, addr, vmf->pte, entry, nr_pages); /* No need to invalidate - it was non-present before */ - update_mmu_cache_range(vmf, vma, vmf->address, vmf->pte, 1); + update_mmu_cache_range(vmf, vma, addr, vmf->pte, nr_pages); unlock: if (vmf->pte) pte_unmap_unlock(vmf->pte, vmf->ptl);