From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-x234.google.com (mail-pa0-x234.google.com [IPv6:2607:f8b0:400e:c03::234]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 1A26E1A0908 for ; Sun, 10 Jan 2016 11:55:05 +1100 (AEDT) Received: by mail-pa0-x234.google.com with SMTP id cy9so302320388pac.0 for ; Sat, 09 Jan 2016 16:55:05 -0800 (PST) Date: Sat, 9 Jan 2016 16:54:59 -0800 (PST) From: Hugh Dickins To: Laurent Dufour cc: Andrew Morton , Michael Ellerman , "Aneesh Kumar K.V" , Cyrill Gorcunov , Martin Schwidefsky , linuxppc-dev@lists.ozlabs.org, linux-mm@kvack.org Subject: [PATCH next] powerpc/mm: fix _PAGE_SWP_SOFT_DIRTY breaking swapoff Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Swapoff after swapping hangs on the G5, when CONFIG_CHECKPOINT_RESTORE=y but CONFIG_MEM_SOFT_DIRTY is not set. That's because the non-zero _PAGE_SWP_SOFT_DIRTY bit, added by CONFIG_HAVE_ARCH_SOFT_DIRTY=y, is not discounted when CONFIG_MEM_SOFT_DIRTY is not set: so swap ptes cannot be recognized. (I suspect that the peculiar dependence of HAVE_ARCH_SOFT_DIRTY on CHECKPOINT_RESTORE in arch/powerpc/Kconfig comes from an incomplete attempt to solve this problem.) It's true that the relationship between CONFIG_HAVE_ARCH_SOFT_DIRTY and and CONFIG_MEM_SOFT_DIRTY is too confusing, and it's true that swapoff should be made more robust; but nevertheless, fix up the powerpc ifdefs as x86_64 and s390 (which met the same problem) have them, defining the bits as 0 if CONFIG_MEM_SOFT_DIRTY is not set. Signed-off-by: Hugh Dickins --- arch/powerpc/include/asm/book3s/64/hash.h | 5 +++++ arch/powerpc/include/asm/book3s/64/pgtable.h | 9 ++++++--- 2 files changed, 11 insertions(+), 3 deletions(-) --- 4.4-next/arch/powerpc/include/asm/book3s/64/hash.h 2016-01-06 11:54:01.377508976 -0800 +++ linux/arch/powerpc/include/asm/book3s/64/hash.h 2016-01-09 13:54:24.410893347 -0800 @@ -33,7 +33,12 @@ #define _PAGE_F_GIX_SHIFT 12 #define _PAGE_F_SECOND 0x08000 /* Whether to use secondary hash or not */ #define _PAGE_SPECIAL 0x10000 /* software: special page */ + +#ifdef CONFIG_MEM_SOFT_DIRTY #define _PAGE_SOFT_DIRTY 0x20000 /* software: software dirty tracking */ +#else +#define _PAGE_SOFT_DIRTY 0x00000 +#endif /* * We need to differentiate between explicit huge page and THP huge --- 4.4-next/arch/powerpc/include/asm/book3s/64/pgtable.h 2016-01-06 11:54:01.377508976 -0800 +++ linux/arch/powerpc/include/asm/book3s/64/pgtable.h 2016-01-09 13:54:24.410893347 -0800 @@ -162,8 +162,13 @@ static inline void pgd_set(pgd_t *pgdp, #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val((pte)) }) #define __swp_entry_to_pte(x) __pte((x).val) -#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY +#ifdef CONFIG_MEM_SOFT_DIRTY #define _PAGE_SWP_SOFT_DIRTY (1UL << (SWP_TYPE_BITS + _PAGE_BIT_SWAP_TYPE)) +#else +#define _PAGE_SWP_SOFT_DIRTY 0UL +#endif /* CONFIG_MEM_SOFT_DIRTY */ + +#ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY static inline pte_t pte_swp_mksoft_dirty(pte_t pte) { return __pte(pte_val(pte) | _PAGE_SWP_SOFT_DIRTY); @@ -176,8 +181,6 @@ static inline pte_t pte_swp_clear_soft_d { return __pte(pte_val(pte) & ~_PAGE_SWP_SOFT_DIRTY); } -#else -#define _PAGE_SWP_SOFT_DIRTY 0 #endif /* CONFIG_HAVE_ARCH_SOFT_DIRTY */ void pgtable_cache_add(unsigned shift, void (*ctor)(void *));