From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org,
Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>,
Zi Yan <zi.yan@cs.rutgers.edu>,
Dave Hansen <dave.hansen@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>,
Anshuman Khandual <khandual@linux.vnet.ibm.com>,
David Nellans <dnellans@nvidia.com>, Ingo Molnar <mingo@elte.hu>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Mel Gorman <mgorman@techsingularity.net>,
Minchan Kim <minchan@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Vlastimil Babka <vbabka@suse.cz>,
Andrea Arcangeli <aarcange@redhat.com>,
Michal Hocko <mhocko@kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
David Woodhouse <dwmw@amazon.co.uk>,
Guenter Roeck <linux@roeck-us.net>
Subject: [PATCH 4.4 24/43] mm: x86: move _PAGE_SWP_SOFT_DIRTY from bit 7 to bit 1
Date: Tue, 14 Aug 2018 19:18:00 +0200 [thread overview]
Message-ID: <20180814171518.700511001@linuxfoundation.org> (raw)
In-Reply-To: <20180814171517.014285600@linuxfoundation.org>
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
commit eee4818baac0f2b37848fdf90e4b16430dc536ac upstream
_PAGE_PSE is used to distinguish between a truly non-present
(_PAGE_PRESENT=0) PMD, and a PMD which is undergoing a THP split and
should be treated as present.
But _PAGE_SWP_SOFT_DIRTY currently uses the _PAGE_PSE bit, which would
cause confusion between one of those PMDs undergoing a THP split, and a
soft-dirty PMD. Dropping _PAGE_PSE check in pmd_present() does not work
well, because it can hurt optimization of tlb handling in thp split.
Thus, we need to move the bit.
In the current kernel, bits 1-4 are not used in non-present format since
commit 00839ee3b299 ("x86/mm: Move swap offset/type up in PTE to work
around erratum"). So let's move _PAGE_SWP_SOFT_DIRTY to bit 1. Bit 7
is used as reserved (always clear), so please don't use it for other
purpose.
[dwmw2: Pulled in to 4.9 backport to support L1TF changes]
Link: http://lkml.kernel.org/r/20170717193955.20207-3-zi.yan@sent.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Signed-off-by: Zi Yan <zi.yan@cs.rutgers.edu>
Acked-by: Dave Hansen <dave.hansen@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Anshuman Khandual <khandual@linux.vnet.ibm.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Minchan Kim <minchan@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Michal Hocko <mhocko@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/x86/include/asm/pgtable_64.h | 12 +++++++++---
arch/x86/include/asm/pgtable_types.h | 10 +++++-----
2 files changed, 14 insertions(+), 8 deletions(-)
--- a/arch/x86/include/asm/pgtable_64.h
+++ b/arch/x86/include/asm/pgtable_64.h
@@ -166,15 +166,21 @@ static inline int pgd_large(pgd_t pgd) {
/*
* Encode and de-code a swap entry
*
- * | ... | 11| 10| 9|8|7|6|5| 4| 3|2|1|0| <- bit number
- * | ... |SW3|SW2|SW1|G|L|D|A|CD|WT|U|W|P| <- bit names
- * | OFFSET (14->63) | TYPE (9-13) |0|X|X|X| X| X|X|X|0| <- swp entry
+ * | ... | 11| 10| 9|8|7|6|5| 4| 3|2| 1|0| <- bit number
+ * | ... |SW3|SW2|SW1|G|L|D|A|CD|WT|U| W|P| <- bit names
+ * | OFFSET (14->63) | TYPE (9-13) |0|0|X|X| X| X|X|SD|0| <- swp entry
*
* G (8) is aliased and used as a PROT_NONE indicator for
* !present ptes. We need to start storing swap entries above
* there. We also need to avoid using A and D because of an
* erratum where they can be incorrectly set by hardware on
* non-present PTEs.
+ *
+ * SD (1) in swp entry is used to store soft dirty bit, which helps us
+ * remember soft dirty over page migration
+ *
+ * Bit 7 in swp entry should be 0 because pmd_present checks not only P,
+ * but also L and G.
*/
#define SWP_TYPE_FIRST_BIT (_PAGE_BIT_PROTNONE + 1)
#define SWP_TYPE_BITS 5
--- a/arch/x86/include/asm/pgtable_types.h
+++ b/arch/x86/include/asm/pgtable_types.h
@@ -70,15 +70,15 @@
/*
* Tracking soft dirty bit when a page goes to a swap is tricky.
* We need a bit which can be stored in pte _and_ not conflict
- * with swap entry format. On x86 bits 6 and 7 are *not* involved
- * into swap entry computation, but bit 6 is used for nonlinear
- * file mapping, so we borrow bit 7 for soft dirty tracking.
+ * with swap entry format. On x86 bits 1-4 are *not* involved
+ * into swap entry computation, but bit 7 is used for thp migration,
+ * so we borrow bit 1 for soft dirty tracking.
*
* Please note that this bit must be treated as swap dirty page
- * mark if and only if the PTE has present bit clear!
+ * mark if and only if the PTE/PMD has present bit clear!
*/
#ifdef CONFIG_MEM_SOFT_DIRTY
-#define _PAGE_SWP_SOFT_DIRTY _PAGE_PSE
+#define _PAGE_SWP_SOFT_DIRTY _PAGE_RW
#else
#define _PAGE_SWP_SOFT_DIRTY (_AT(pteval_t, 0))
#endif
next prev parent reply other threads:[~2018-08-14 17:46 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-14 17:17 [PATCH 4.4 00/43] 4.4.148-stable review Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 01/43] ext4: fix check to prevent initializing reserved inodes Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 02/43] tpm: fix race condition in tpm_common_write() Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 03/43] ipv4+ipv6: Make INET*_ESP select CRYPTO_ECHAINIV Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 04/43] fork: unconditionally clear stack on fork Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 05/43] parisc: Enable CONFIG_MLONGCALLS by default Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 07/43] xen/netfront: dont cache skb_shinfo() Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 08/43] ACPI / LPSS: Add missing prv_offset setting for byt/cht PWM devices Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 09/43] scsi: sr: Avoid that opening a CD-ROM hangs with runtime power management enabled Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 10/43] root dentries need RCU-delayed freeing Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 11/43] fix mntput/mntput race Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 12/43] fix __legitimize_mnt()/mntput() race Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 13/43] IB/core: Make testing MR flags for writability a static inline function Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 14/43] IB/mlx4: Mark user MR as writable if actual virtual memory is writable Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 15/43] IB/ocrdma: fix out of bounds access to local buffer Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 16/43] ARM: dts: imx6sx: fix irq for pcie bridge Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 17/43] x86/paravirt: Fix spectre-v2 mitigations for paravirt guests Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 18/43] x86/speculation: Protect against userspace-userspace spectreRSB Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 19/43] kprobes/x86: Fix %p uses in error messages Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 20/43] x86/irqflags: Provide a declaration for native_save_fl Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 21/43] x86/speculation/l1tf: Increase 32bit PAE __PHYSICAL_PAGE_SHIFT Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 22/43] x86/mm: Move swap offset/type up in PTE to work around erratum Greg Kroah-Hartman
2018-08-14 17:17 ` [PATCH 4.4 23/43] x86/mm: Fix swap entry comment and macro Greg Kroah-Hartman
2018-08-14 17:18 ` Greg Kroah-Hartman [this message]
2018-08-14 17:18 ` [PATCH 4.4 25/43] x86/speculation/l1tf: Change order of offset/type in swap entry Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 26/43] x86/speculation/l1tf: Protect swap entries against L1TF Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 27/43] x86/speculation/l1tf: Protect PROT_NONE PTEs against speculation Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 28/43] x86/speculation/l1tf: Make sure the first page is always reserved Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 29/43] x86/speculation/l1tf: Add sysfs reporting for l1tf Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 30/43] mm: Add vm_insert_pfn_prot() Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 31/43] mm: fix cache mode tracking in vm_insert_mixed() Greg Kroah-Hartman
2018-09-07 17:05 ` Ben Hutchings
2018-09-07 20:03 ` Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 32/43] x86/speculation/l1tf: Disallow non privileged high MMIO PROT_NONE mappings Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 33/43] x86/speculation/l1tf: Limit swap file size to MAX_PA/2 Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 34/43] x86/bugs: Move the l1tf function and define pr_fmt properly Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 35/43] x86/speculation/l1tf: Extend 64bit swap file size limit Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 36/43] x86/cpufeatures: Add detection of L1D cache flush support Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 37/43] x86/speculation/l1tf: Protect PAE swap entries against L1TF Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 38/43] x86/speculation/l1tf: Fix up pte->pfn conversion for PAE Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 39/43] x86/speculation/l1tf: Invert all not present mappings Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 40/43] x86/speculation/l1tf: Make pmd/pud_mknotpresent() invert Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 41/43] x86/mm/pat: Make set_memory_np() L1TF safe Greg Kroah-Hartman
2018-09-09 16:46 ` Ben Hutchings
2018-09-09 17:06 ` Guenter Roeck
2018-09-10 7:16 ` Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 42/43] x86/mm/kmmio: Make the tracer robust against L1TF Greg Kroah-Hartman
2018-08-14 17:18 ` [PATCH 4.4 43/43] x86/speculation/l1tf: Fix up CPU feature flags Greg Kroah-Hartman
2018-08-15 6:15 ` [PATCH 4.4 00/43] 4.4.148-stable review Greg Kroah-Hartman
2018-08-15 13:10 ` Guenter Roeck
2018-08-15 20:52 ` Dan Rue
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