From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 3zFdFw3k6XzF0Zn for ; Tue, 9 Jan 2018 01:39:32 +1100 (AEDT) From: Christophe Leroy Subject: [PATCH] powerpc/mm: Fix growth direction for hugepages mmaps with slice To: Benjamin Herrenschmidt , Paul Mackerras , Michael Ellerman , Scott Wood Cc: linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Message-Id: <20180108143920.091256E955@localhost.localdomain> Date: Mon, 8 Jan 2018 15:39:19 +0100 (CET) List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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. This patch fixes it by taking into account MAP_GROWSDOWN flag. Fixes: d0f13e3c20b6f ("[POWERPC] Introduce address space "slices" ") Signed-off-by: Christophe Leroy --- arch/powerpc/mm/hugetlbpage.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/arch/powerpc/mm/hugetlbpage.c b/arch/powerpc/mm/hugetlbpage.c index 5c5873259127..76330a976f9e 100644 --- a/arch/powerpc/mm/hugetlbpage.c +++ b/arch/powerpc/mm/hugetlbpage.c @@ -558,7 +558,8 @@ 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, + flags & MAP_GROWSDOWN); } #endif -- 2.13.3