From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932732AbeAXJ1h (ORCPT ); Wed, 24 Jan 2018 04:27:37 -0500 Received: from pegase1.c-s.fr ([93.17.236.30]:26270 "EHLO pegase1.c-s.fr" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932534AbeAXJ1f (ORCPT ); Wed, 24 Jan 2018 04:27:35 -0500 Subject: Re: [PATCH v3 5/5] powerpc/mm: Fix growth direction for hugepages mmaps with slice To: "Aneesh Kumar K.V" , Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Scott Wood Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org References: <6920f6efe2dcdabf59350b2d31ee6bd4bdef57f4.1516783089.git.christophe.leroy@c-s.fr> <362a93307a09b521878c47a8999a39a228184293.1516783089.git.christophe.leroy@c-s.fr> From: Christophe LEROY Message-ID: Date: Wed, 24 Jan 2018 10:27:33 +0100 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.5.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: fr Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Le 24/01/2018 à 10:15, Aneesh Kumar K.V a écrit : > > > On 01/24/2018 02:32 PM, Christophe Leroy wrote: >> An application running with libhugetlbfs fails to allocate >> additional pages to HEAP due to the hugemap being done >> inconditionally as topdown mapping: >> >> mmap(0x10080000, 1572864, PROT_READ|PROT_WRITE, >> MAP_PRIVATE|MAP_ANONYMOUS|0x40000, -1, 0) = 0x73e80000 >> [...] >> mmap(0x74000000, 1048576, PROT_READ|PROT_WRITE, >> MAP_PRIVATE|MAP_ANONYMOUS|0x40000, -1, 0x180000) = 0x73d80000 >> munmap(0x73d80000, 1048576)             = 0 >> [...] >> mmap(0x74000000, 1572864, PROT_READ|PROT_WRITE, >> MAP_PRIVATE|MAP_ANONYMOUS|0x40000, -1, 0x180000) = 0x73d00000 >> munmap(0x73d00000, 1572864)             = 0 >> [...] >> mmap(0x74000000, 1572864, PROT_READ|PROT_WRITE, >> MAP_PRIVATE|MAP_ANONYMOUS|0x40000, -1, 0x180000) = 0x73d00000 >> munmap(0x73d00000, 1572864)             = 0 >> [...] >> >> As one can see from the above strace log, mmap() allocates further >> pages below the initial one because no space is available on top of it. >> >> This patch fixes it by requesting bottomup mapping as the non >> generic hugetlb_get_unmapped_area() does >> >> Fixes: d0f13e3c20b6f ("[POWERPC] Introduce address space "slices" ") >> Signed-off-by: Christophe Leroy >> --- >>   v3: Was a standalone patch before, but conflicts with this serie. >> >>   arch/powerpc/mm/hugetlbpage.c | 2 +- >>   1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/arch/powerpc/mm/hugetlbpage.c >> b/arch/powerpc/mm/hugetlbpage.c >> index 79e1378ee303..368ea6b248ad 100644 >> --- a/arch/powerpc/mm/hugetlbpage.c >> +++ b/arch/powerpc/mm/hugetlbpage.c >> @@ -558,7 +558,7 @@ unsigned long hugetlb_get_unmapped_area(struct >> file *file, unsigned long addr, >>           return radix__hugetlb_get_unmapped_area(file, addr, len, >>                                  pgoff, flags); >>   #endif >> -    return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1); >> +    return slice_get_unmapped_area(addr, len, flags, mmu_psize, 0); >>   } >>   #endif > > Why make this change also for PPC64? Can you do this #ifdef 8xx?.You can > ideally move hugetlb_get_unmapped_area to slice.h and then make this > much simpler for 8xxx? > Did you try with HUGETLB_MORECORE_HEAPBASE=0x11000000 on PPC64 as I suggested in my last email on this subject (22/01/2018 9:22) ? Before doing anything specific to the PPC32/8xx, I'd like to be sure the issue is definitly only on PPC32. Thanks, Christophe