From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932797AbcGOMAj (ORCPT ); Fri, 15 Jul 2016 08:00:39 -0400 Received: from terminus.zytor.com ([198.137.202.10]:55744 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932565AbcGOMAf (ORCPT ); Fri, 15 Jul 2016 08:00:35 -0400 Date: Fri, 15 Jul 2016 04:59:17 -0700 From: tip-bot for Ingo Molnar Message-ID: Cc: bp@alien8.de, torvalds@linux-foundation.org, jpoimboe@redhat.com, dvlasenk@redhat.com, akpm@linux-foundation.org, brgerst@gmail.com, peterz@infradead.org, mingo@kernel.org, riel@redhat.com, hpa@zytor.com, tglx@linutronix.de, luto@kernel.org, linux-kernel@vger.kernel.org, luto@amacapital.net, oleg@redhat.com, Waiman.Long@hp.com Reply-To: jpoimboe@redhat.com, dvlasenk@redhat.com, akpm@linux-foundation.org, brgerst@gmail.com, bp@alien8.de, torvalds@linux-foundation.org, luto@amacapital.net, linux-kernel@vger.kernel.org, hpa@zytor.com, tglx@linutronix.de, luto@kernel.org, Waiman.Long@hp.com, oleg@redhat.com, peterz@infradead.org, riel@redhat.com, mingo@kernel.org In-Reply-To: <064ff6c7275734537f969e876f6cd0baa954d2cc.1468527351.git.luto@kernel.org> References: <064ff6c7275734537f969e876f6cd0baa954d2cc.1468527351.git.luto@kernel.org> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/mm] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Git-Commit-ID: af2cf278ef4f9289f88504c3e03cb12f76027575 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: af2cf278ef4f9289f88504c3e03cb12f76027575 Gitweb: http://git.kernel.org/tip/af2cf278ef4f9289f88504c3e03cb12f76027575 Author: Ingo Molnar AuthorDate: Thu, 14 Jul 2016 13:22:49 -0700 Committer: Ingo Molnar CommitDate: Fri, 15 Jul 2016 10:26:24 +0200 x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() So when memory hotplug removes a piece of physical memory from pagetable mappings, it also frees the underlying PGD entry. This complicates PGD management, so don't do this. We can keep the PGD mapped and the PUD table all clear - it's only a single 4K page per 512 GB of memory hotplugged. Signed-off-by: Ingo Molnar Signed-off-by: Andy Lutomirski Cc: Andrew Morton Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Brian Gerst Cc: Denys Vlasenko Cc: H. Peter Anvin Cc: Josh Poimboeuf Cc: Linus Torvalds Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Waiman Long Cc: linux-mm@kvack.org Link: http://lkml.kernel.org/r/064ff6c7275734537f969e876f6cd0baa954d2cc.1468527351.git.luto@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/mm/init_64.c | 27 --------------------------- 1 file changed, 27 deletions(-) diff --git a/arch/x86/mm/init_64.c b/arch/x86/mm/init_64.c index bb88fbc..e14f870 100644 --- a/arch/x86/mm/init_64.c +++ b/arch/x86/mm/init_64.c @@ -702,27 +702,6 @@ static void __meminit free_pmd_table(pmd_t *pmd_start, pud_t *pud) spin_unlock(&init_mm.page_table_lock); } -/* Return true if pgd is changed, otherwise return false. */ -static bool __meminit free_pud_table(pud_t *pud_start, pgd_t *pgd) -{ - pud_t *pud; - int i; - - for (i = 0; i < PTRS_PER_PUD; i++) { - pud = pud_start + i; - if (!pud_none(*pud)) - return false; - } - - /* free a pud table */ - free_pagetable(pgd_page(*pgd), 0); - spin_lock(&init_mm.page_table_lock); - pgd_clear(pgd); - spin_unlock(&init_mm.page_table_lock); - - return true; -} - static void __meminit remove_pte_table(pte_t *pte_start, unsigned long addr, unsigned long end, bool direct) @@ -913,7 +892,6 @@ remove_pagetable(unsigned long start, unsigned long end, bool direct) unsigned long addr; pgd_t *pgd; pud_t *pud; - bool pgd_changed = false; for (addr = start; addr < end; addr = next) { next = pgd_addr_end(addr, end); @@ -924,13 +902,8 @@ remove_pagetable(unsigned long start, unsigned long end, bool direct) pud = (pud_t *)pgd_page_vaddr(*pgd); remove_pud_table(pud, addr, next, direct); - if (free_pud_table(pud, pgd)) - pgd_changed = true; } - if (pgd_changed) - sync_global_pgds(start, end - 1, 1); - flush_tlb_all(); }