From patchwork Mon Dec 18 10:50:45 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ryan Roberts X-Patchwork-Id: 13496586 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 bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id C8AF4C46CCD for ; Mon, 18 Dec 2023 10:52:05 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-Id:Date:Subject:Cc:To:From:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=MQDj/Y2sffmtHme+Da6XiBX9QKyCMxz02Rc8m8Wf3d8=; b=wLq/gWwSJCueOw sJTKQiFUPg8w+ckwOopBbs0H0U+5SJ9z83prW+FN3O80TZb4WC5hxTvddm1YcBPsT2vPeagvztMTv pBGyZLrf/4bOKsGR8izVkrwkdVGmXZoaJysAb8wY2Gnrux1qyh5gUNw+UG2B92zb/W0bGBxMUAK0h ravGoQkc3KvovB4bjNVutvFSugeuli/f5iIR+5RbuRqTBcyDPZ4oF1Fgkl6MFVZv2wnBLJgnZ9MsB Q7GirX83OeaWuLMwxWtS8GksnmUEEPejMlNi97yLlwt+tuZMLu7KI9mLNCGxgOFIGt2cInxLvWXFX 5/vb4xowszFlb0mH8E7Q==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rFBDg-009u7t-1e; Mon, 18 Dec 2023 10:51:32 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.96 #2 (Red Hat Linux)) id 1rFBDY-009u4O-2J for linux-arm-kernel@lists.infradead.org; Mon, 18 Dec 2023 10:51:26 +0000 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 754E92F4; Mon, 18 Dec 2023 02:52:06 -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 9BE873F738; Mon, 18 Dec 2023 02:51:18 -0800 (PST) From: Ryan Roberts To: Catalin Marinas , Will Deacon , Ard Biesheuvel , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Andrew Morton , Anshuman Khandual , Matthew Wilcox , Yu Zhao , Mark Rutland , David Hildenbrand , Kefeng Wang , John Hubbard , Zi Yan , Barry Song <21cnbao@gmail.com>, Alistair Popple , Yang Shi Cc: Ryan Roberts , linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH v4 01/16] mm: thp: Batch-collapse PMD with set_ptes() Date: Mon, 18 Dec 2023 10:50:45 +0000 Message-Id: <20231218105100.172635-2-ryan.roberts@arm.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20231218105100.172635-1-ryan.roberts@arm.com> References: <20231218105100.172635-1-ryan.roberts@arm.com> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20231218_025124_849133_9DABA731 X-CRM114-Status: GOOD ( 14.27 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org Refactor __split_huge_pmd_locked() so that a present PMD can be collapsed to PTEs in a single batch using set_ptes(). It also provides a future opportunity to batch-add the folio to the rmap using David's new batched rmap APIs. This should improve performance a little bit, but the real motivation is to remove the need for the arm64 backend to have to fold the contpte entries. Instead, since the ptes are set as a batch, the contpte blocks can be initially set up pre-folded (once the arm64 contpte support is added in the next few patches). This leads to noticeable performance improvement during split. Signed-off-by: Ryan Roberts Acked-by: David Hildenbrand --- mm/huge_memory.c | 59 ++++++++++++++++++++++++++++-------------------- 1 file changed, 34 insertions(+), 25 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 6be1a380a298..fbf7e95ea983 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2535,15 +2535,16 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, pte = pte_offset_map(&_pmd, haddr); VM_BUG_ON(!pte); - for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { - pte_t entry; - /* - * Note that NUMA hinting access restrictions are not - * transferred to avoid any possibility of altering - * permissions across VMAs. - */ - if (freeze || pmd_migration) { + + /* + * Note that NUMA hinting access restrictions are not transferred to + * avoid any possibility of altering permissions across VMAs. + */ + if (freeze || pmd_migration) { + for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { + pte_t entry; swp_entry_t swp_entry; + if (write) swp_entry = make_writable_migration_entry( page_to_pfn(page + i)); @@ -2562,28 +2563,36 @@ static void __split_huge_pmd_locked(struct vm_area_struct *vma, pmd_t *pmd, entry = pte_swp_mksoft_dirty(entry); if (uffd_wp) entry = pte_swp_mkuffd_wp(entry); - } else { - entry = mk_pte(page + i, READ_ONCE(vma->vm_page_prot)); - if (write) - entry = pte_mkwrite(entry, vma); + + VM_WARN_ON(!pte_none(ptep_get(pte + i))); + set_pte_at(mm, addr, pte + i, entry); + } + } else { + pte_t entry; + + entry = mk_pte(page, READ_ONCE(vma->vm_page_prot)); + if (write) + entry = pte_mkwrite(entry, vma); + if (!young) + entry = pte_mkold(entry); + /* NOTE: this may set soft-dirty too on some archs */ + if (dirty) + entry = pte_mkdirty(entry); + if (soft_dirty) + entry = pte_mksoft_dirty(entry); + if (uffd_wp) + entry = pte_mkuffd_wp(entry); + + for (i = 0, addr = haddr; i < HPAGE_PMD_NR; i++, addr += PAGE_SIZE) { if (anon_exclusive) SetPageAnonExclusive(page + i); - if (!young) - entry = pte_mkold(entry); - /* NOTE: this may set soft-dirty too on some archs */ - if (dirty) - entry = pte_mkdirty(entry); - if (soft_dirty) - entry = pte_mksoft_dirty(entry); - if (uffd_wp) - entry = pte_mkuffd_wp(entry); page_add_anon_rmap(page + i, vma, addr, RMAP_NONE); + VM_WARN_ON(!pte_none(ptep_get(pte + i))); } - VM_BUG_ON(!pte_none(ptep_get(pte))); - set_pte_at(mm, addr, pte, entry); - pte++; + + set_ptes(mm, haddr, pte, entry, HPAGE_PMD_NR); } - pte_unmap(pte - 1); + pte_unmap(pte); if (!pmd_migration) page_remove_rmap(page, vma, true);