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 X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,USER_AGENT_GIT autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3383AC47404 for ; Wed, 9 Oct 2019 08:21:49 +0000 (UTC) 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 mail.kernel.org (Postfix) with ESMTPS id F350021920 for ; Wed, 9 Oct 2019 08:21:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="gmLqxbEF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F350021920 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=arm.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:MIME-Version:Cc:List-Subscribe: List-Help:List-Post:List-Archive:List-Unsubscribe:List-Id:Message-Id:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To: References:List-Owner; bh=73sOZ+JU0NasGcaJP27zInFFXnFedtw7vmWJ5UC4u7c=; b=gmL qxbEF+sCslHVeix7MwCzs+sd/WEkbRyj69dlO8ljYGXmB1y1bmeHuMkkDm0jrfBRX4VO7XUHsr3YI Zdl8/mlonJildsMP9m670dWwg5Hel0CYhTv2r+alv98qXv8Y2PO46z0A6LkOv8IQnnQv2W9LOOjiu jqx43nTod+MuesXQnEXkFHZrjXeR9LPyKDUthuQQpd/apzwun0pLu+KWTT/e3MyJU93QIGQgpw8uI 7f4oje6p1mnDy4vha25ZkRHzNSp5GdluqWX4maKrz6K1pvla2LRqUOY6TP/ZvEyzU7XcVbBjs+TjQ MYz/mDyCnXed9q5vJ67H8TtfD9F6gEQ==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iI7EC-0000OK-GA; Wed, 09 Oct 2019 08:21:48 +0000 Received: from foss.arm.com ([217.140.110.172]) by bombadil.infradead.org with esmtp (Exim 4.92.2 #3 (Red Hat Linux)) id 1iI7E8-0000NC-C9 for linux-arm-kernel@lists.infradead.org; Wed, 09 Oct 2019 08:21:46 +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 49B4D337; Wed, 9 Oct 2019 01:21:41 -0700 (PDT) Received: from p8cg001049571a15.blr.arm.com (p8cg001049571a15.blr.arm.com [10.162.43.141]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 66BBB3F68E; Wed, 9 Oct 2019 01:21:34 -0700 (PDT) From: Anshuman Khandual To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, akpm@linux-foundation.org, catalin.marinas@arm.com, will@kernel.org Subject: [PATCH V9 0/2] arm64/mm: Enable memory hot remove Date: Wed, 9 Oct 2019 13:51:46 +0530 Message-Id: <1570609308-15697-1-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191009_012144_500872_D2BDEB9B X-CRM114-Status: GOOD ( 17.48 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: mark.rutland@arm.com, ira.weiny@intel.com, david@redhat.com, mgorman@techsingularity.net, steve.capper@arm.com, Robin.Murphy@arm.com, steven.price@arm.com, broonie@kernel.org, cai@lca.pw, ard.biesheuvel@arm.com, cpandya@codeaurora.org, arunks@codeaurora.org, dan.j.williams@intel.com, logang@deltatee.com, valentin.schneider@arm.com, suzuki.poulose@arm.com, osalvador@suse.de MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org This series enables memory hot remove on arm64 after fixing a possible arm64 platform specific kernel page table race condition. This series is based on linux-next (next-20191009). Concurrent vmalloc() and hot-remove conflict: As pointed out earlier on the v5 thread [2] there can be potential conflict between concurrent vmalloc() and memory hot-remove operation. The problem here is caused by inadequate locking in vmalloc() which protects installation of a page table page but not the walk or the leaf entry modification. Now free_empty_tables() and it's children functions take into account a maximum possible range on which it operates as a floor-ceiling boundary. This makes sure that no page table page is freed unless its fully within the maximum possible range as decided by the caller. Testing: Memory hot remove has been tested on arm64 for 4K, 16K, 64K page config options with all possible CONFIG_ARM64_VA_BITS and CONFIG_PGTABLE_LEVELS combinations. Changes in V9: - Dropped ACK tags from Steve and David as this series has changed since - Dropped WARN(!page) in free_hotplug_page_range() per Matthew Wilcox - Replaced pxx_page() with virt_to_page() in free_pxx_table() per Catalin - Dropped page and call virt_to_page() in free_hotplug_pgtable_page() - Replaced sparse_vmap with free_mapped per Catalin - Dropped ternary operators in all unmap_hotplug_pxx_range() per Catalin - Collapsed all free_pxx_table() into free_empty_pxx_table() per Catalin Changes in V8: (https://lkml.org/lkml/2019/9/23/22) - Dropped the first patch (memblock_[free|remove] reorder) from the series which is no longer needed for arm64 hot-remove enablement and was posted separately as (https://patchwork.kernel.org/patch/11146361/) - Dropped vmalloc-vmemmap detection and subsequent skipping of free_empty_tables() - Changed free_empty_[pxx]_tables() functions which now accepts a possible maximum floor-ceiling address range on which it operates. Also changed free_pxx_table() functions to check against required alignment as well as maximum floor-ceiling range as another prerequisite before freeing the page table page. - Dropped remove_pagetable(), instead call it's constituent functions directly Changes in V7: (https://lkml.org/lkml/2019/9/3/326) - vmalloc_vmemmap_overlap gets evaluated early during boot for a given config - free_empty_tables() gets conditionally called based on vmalloc_vmemmap_overlap Changes in V6: (https://lkml.org/lkml/2019/7/15/36) - Implemented most of the suggestions from Mark Rutland - Added in ptdump - remove_pagetable() now has two distinct passes over the kernel page table - First pass unmap_hotplug_range() removes leaf level entries at all level - Second pass free_empty_tables() removes empty page table pages - Kernel page table lock has been dropped completely - vmemmap_free() does not call freee_empty_tables() to avoid conflict with vmalloc() - All address range scanning are converted to do {} while() loop - Added 'unsigned long end' in __remove_pgd_mapping() - Callers need not provide starting pointer argument to free_[pte|pmd|pud]_table() - Drop the starting pointer argument from free_[pte|pmd|pud]_table() functions - Fetching pxxp[i] in free_[pte|pmd|pud]_table() is wrapped around in READ_ONCE() - free_[pte|pmd|pud]_table() now computes starting pointer inside the function - Fixed TLB handling while freeing huge page section mappings at PMD or PUD level - Added WARN_ON(!page) in free_hotplug_page_range() - Added WARN_ON(![pm|pud]_table(pud|pmd)) when there is no section mapping - [PATCH 1/3] mm/hotplug: Reorder memblock_[free|remove]() calls in try_remove_memory() - Request earlier for separate merger (https://patchwork.kernel.org/patch/10986599/) - s/__remove_memory/try_remove_memory in the subject line - s/arch_remove_memory/memblock_[free|remove] in the subject line - A small change in the commit message as re-order happens now for memblock remove functions not for arch_remove_memory() Changes in V5: (https://lkml.org/lkml/2019/5/29/218) - Have some agreement [1] over using memory_hotplug_lock for arm64 ptdump - Change 7ba36eccb3f8 ("arm64/mm: Inhibit huge-vmap with ptdump") already merged - Dropped the above patch from this series - Fixed indentation problem in arch_[add|remove]_memory() as per David - Collected all new Acked-by tags Changes in V4: (https://lkml.org/lkml/2019/5/20/19) - Implemented most of the suggestions from Mark Rutland - Interchanged patch [PATCH 2/4] <---> [PATCH 3/4] and updated commit message - Moved CONFIG_PGTABLE_LEVELS inside free_[pud|pmd]_table() - Used READ_ONCE() in missing instances while accessing page table entries - s/p???_present()/p???_none() for checking valid kernel page table entries - WARN_ON() when an entry is !p???_none() and !p???_present() at the same time - Updated memory hot-remove commit message with additional details as suggested - Rebased the series on 5.2-rc1 with hotplug changes from David and Michal Hocko - Collected all new Acked-by tags Changes in V3: (https://lkml.org/lkml/2019/5/14/197) - Implemented most of the suggestions from Mark Rutland for remove_pagetable() - Fixed applicable PGTABLE_LEVEL wrappers around pgtable page freeing functions - Replaced 'direct' with 'sparse_vmap' in remove_pagetable() with inverted polarity - Changed pointer names ('p' at end) and removed tmp from iterations - Perform intermediate TLB invalidation while clearing pgtable entries - Dropped flush_tlb_kernel_range() in remove_pagetable() - Added flush_tlb_kernel_range() in remove_pte_table() instead - Renamed page freeing functions for pgtable page and mapped pages - Used page range size instead of order while freeing mapped or pgtable pages - Removed all PageReserved() handling while freeing mapped or pgtable pages - Replaced XXX_index() with XXX_offset() while walking the kernel page table - Used READ_ONCE() while fetching individual pgtable entries - Taken overall init_mm.page_table_lock instead of just while changing an entry - Dropped previously added [pmd|pud]_index() which are not required anymore - Added a new patch to protect kernel page table race condition for ptdump - Added a new patch from Mark Rutland to prevent huge-vmap with ptdump Changes in V2: (https://lkml.org/lkml/2019/4/14/5) - Added all received review and ack tags - Split the series from ZONE_DEVICE enablement for better review - Moved memblock re-order patch to the front as per Robin Murphy - Updated commit message on memblock re-order patch per Michal Hocko - Dropped [pmd|pud]_large() definitions - Used existing [pmd|pud]_sect() instead of earlier [pmd|pud]_large() - Removed __meminit and __ref tags as per Oscar Salvador - Dropped unnecessary 'ret' init in arch_add_memory() per Robin Murphy - Skipped calling into pgtable_page_dtor() for linear mapping page table pages and updated all relevant functions Changes in V1: (https://lkml.org/lkml/2019/4/3/28) References: [1] https://lkml.org/lkml/2019/5/28/584 [2] https://lkml.org/lkml/2019/6/11/709 Anshuman Khandual (2): arm64/mm: Hold memory hotplug lock while walking for kernel page table dump arm64/mm: Enable memory hot remove arch/arm64/Kconfig | 3 + arch/arm64/include/asm/memory.h | 1 + arch/arm64/mm/mmu.c | 273 ++++++++++++++++++++++++++++++-- arch/arm64/mm/ptdump_debugfs.c | 4 + 4 files changed, 272 insertions(+), 9 deletions(-) -- 2.20.1 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel