From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e28smtp03.in.ibm.com (e28smtp03.in.ibm.com [122.248.162.3]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by ozlabs.org (Postfix) with ESMTPS id 9B1C32C00A1 for ; Sat, 15 Mar 2014 21:48:25 +1100 (EST) Received: from /spool/local by e28smtp03.in.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Sat, 15 Mar 2014 16:18:18 +0530 Received: from d28relay02.in.ibm.com (d28relay02.in.ibm.com [9.184.220.59]) by d28dlp01.in.ibm.com (Postfix) with ESMTP id 2342EE0045 for ; Sat, 15 Mar 2014 16:22:04 +0530 (IST) Received: from d28av05.in.ibm.com (d28av05.in.ibm.com [9.184.220.67]) by d28relay02.in.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id s2FAm5kG3604970 for ; Sat, 15 Mar 2014 16:18:05 +0530 Received: from d28av05.in.ibm.com (localhost [127.0.0.1]) by d28av05.in.ibm.com (8.14.4/8.14.4/NCO v10.0 AVout) with ESMTP id s2FAmEsH019417 for ; Sat, 15 Mar 2014 16:18:14 +0530 From: "Aneesh Kumar K.V" To: benh@kernel.crashing.org, paulus@samba.org, Rik van Riel Subject: [PATCH] powerpc/mm: Make sure a local_irq_disable prevent a parallel THP split Date: Sat, 15 Mar 2014 16:17:58 +0530 Message-Id: <1394880478-770-1-git-send-email-aneesh.kumar@linux.vnet.ibm.com> Cc: linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org, "Aneesh Kumar K.V" List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , From: "Aneesh Kumar K.V" We have generic code like the one in get_futex_key that assume that a local_irq_disable prevents a parallel THP split. Support that by adding a dummy smp call function after setting _PAGE_SPLITTING. Code paths like get_user_pages_fast still need to check for _PAGE_SPLITTING after disabling IRQ which indicate that a parallel THP splitting is ongoing. Now if they don't find _PAGE_SPLITTING set, then we can be sure that parallel split will now block in pmdp_splitting flush until we enables IRQ Signed-off-by: Aneesh Kumar K.V --- arch/powerpc/mm/pgtable_64.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/arch/powerpc/mm/pgtable_64.c b/arch/powerpc/mm/pgtable_64.c index 62bf5e8e78da..f6ce1f111f5b 100644 --- a/arch/powerpc/mm/pgtable_64.c +++ b/arch/powerpc/mm/pgtable_64.c @@ -647,6 +647,11 @@ void pmdp_splitting_flush(struct vm_area_struct *vma, if (old & _PAGE_HASHPTE) hpte_do_hugepage_flush(vma->vm_mm, address, pmdp); } + /* + * This ensures that generic code that rely on IRQ disabling + * to prevent a parallel THP split work as expected. + */ + kick_all_cpus_sync(); } /* -- 1.8.3.2