From: Laurent Dufour <ldufour@linux.vnet.ibm.com>
To: akpm@linux-foundation.org, mhocko@kernel.org,
peterz@infradead.org, kirill@shutemov.name, ak@linux.intel.com,
dave@stgolabs.net, jack@suse.cz,
Matthew Wilcox <willy@infradead.org>,
khandual@linux.vnet.ibm.com, aneesh.kumar@linux.vnet.ibm.com,
benh@kernel.crashing.org, mpe@ellerman.id.au, paulus@samba.org,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>,
hpa@zytor.com, Will Deacon <will.deacon@arm.com>,
Sergey Senozhatsky <sergey.senozhatsky@gmail.com>,
sergey.senozhatsky.work@gmail.com,
Andrea Arcangeli <aarcange@redhat.com>,
Alexei Starovoitov <alexei.starovoitov@gmail.com>,
kemi.wang@intel.com, Daniel Jordan <daniel.m.jordan@oracle.com>,
David Rientjes <rientjes@google.com>,
Jerome Glisse <jglisse@redhat.com>,
Ganesh Mahendran <opensource.ganesh@gmail.com>,
Minchan Kim <minchan@kernel.org>,
Punit Agrawal <punitagrawal@gmail.com>,
vinayak menon <vinayakm.list@gmail.com>,
Yang Shi <yang.shi@linux.alibaba.com>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
haren@linux.vnet.ibm.com, npiggin@gmail.com,
bsingharora@gmail.com, paulmck@linux.vnet.ibm.com,
Tim Chen <tim.c.chen@linux.intel.com>,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org
Subject: [PATCH v11 25/26] powerpc/mm: add speculative page fault
Date: Thu, 17 May 2018 13:06:32 +0200 [thread overview]
Message-ID: <1526555193-7242-26-git-send-email-ldufour@linux.vnet.ibm.com> (raw)
In-Reply-To: <1526555193-7242-1-git-send-email-ldufour@linux.vnet.ibm.com>
This patch enable the speculative page fault on the PowerPC
architecture.
This will try a speculative page fault without holding the mmap_sem,
if it returns with VM_FAULT_RETRY, the mmap_sem is acquired and the
traditional page fault processing is done.
The speculative path is only tried for multithreaded process as there is no
risk of contention on the mmap_sem otherwise.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
arch/powerpc/mm/fault.c | 16 ++++++++++++++++
1 file changed, 16 insertions(+)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index ef268d5d9db7..d7b5742ffb2b 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -465,6 +465,21 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
if (is_exec)
flags |= FAULT_FLAG_INSTRUCTION;
+ /*
+ * Try speculative page fault before grabbing the mmap_sem.
+ * The Page fault is done if VM_FAULT_RETRY is not returned.
+ * But if the memory protection keys are active, we don't know if the
+ * fault is due to key mistmatch or due to a classic protection check.
+ * To differentiate that, we will need the VMA we no more have, so
+ * let's retry with the mmap_sem held.
+ */
+ fault = handle_speculative_fault(mm, address, flags);
+ if (fault != VM_FAULT_RETRY && (IS_ENABLED(CONFIG_PPC_MEM_KEYS) &&
+ fault != VM_FAULT_SIGSEGV)) {
+ perf_sw_event(PERF_COUNT_SW_SPF, 1, regs, address);
+ goto done;
+ }
+
/* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in the
* kernel and should generate an OOPS. Unfortunately, in the case of an
@@ -565,6 +580,7 @@ static int __do_page_fault(struct pt_regs *regs, unsigned long address,
up_read(¤t->mm->mmap_sem);
+done:
if (unlikely(fault & VM_FAULT_ERROR))
return mm_fault_error(regs, address, fault);
--
2.7.4
next prev parent reply other threads:[~2018-05-17 11:07 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-05-17 11:06 [PATCH v11 00/26] Speculative page faults Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 01/26] mm: introduce CONFIG_SPECULATIVE_PAGE_FAULT Laurent Dufour
2018-05-17 16:36 ` Randy Dunlap
2018-05-17 17:19 ` Matthew Wilcox
2018-05-17 17:34 ` Randy Dunlap
2018-05-22 12:00 ` [FIX PATCH " Laurent Dufour
2018-05-22 11:44 ` [PATCH " Laurent Dufour
2018-05-22 11:47 ` Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 02/26] x86/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 03/26] powerpc/mm: set ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 04/26] arm64/mm: define ARCH_SUPPORTS_SPECULATIVE_PAGE_FAULT Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 05/26] mm: prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 06/26] mm: introduce pte_spinlock " Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 07/26] mm: make pte_unmap_same compatible with SPF Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 08/26] mm: introduce INIT_VMA() Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 09/26] mm: VMA sequence count Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 10/26] mm: protect VMA modifications using " Laurent Dufour
2018-11-05 7:04 ` vinayak menon
2018-11-05 18:22 ` Laurent Dufour
2018-11-06 9:28 ` Vinayak Menon
2018-05-17 11:06 ` [PATCH v11 11/26] mm: protect mremap() against SPF hanlder Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 12/26] mm: protect SPF handler against anon_vma changes Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 13/26] mm: cache some VMA fields in the vm_fault structure Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 14/26] mm/migrate: Pass vm_fault pointer to migrate_misplaced_page() Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 15/26] mm: introduce __lru_cache_add_active_or_unevictable Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 16/26] mm: introduce __vm_normal_page() Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 17/26] mm: introduce __page_add_new_anon_rmap() Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 18/26] mm: protect mm_rb tree with a rwlock Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 19/26] mm: provide speculative fault infrastructure Laurent Dufour
2018-07-24 14:26 ` zhong jiang
2018-07-24 16:10 ` Laurent Dufour
2018-07-25 9:04 ` zhong jiang
2018-07-25 10:44 ` Laurent Dufour
2018-07-25 11:23 ` zhong jiang
2018-05-17 11:06 ` [PATCH v11 20/26] mm: adding speculative page fault failure trace events Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 21/26] perf: add a speculative page fault sw event Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 22/26] perf tools: add support for the SPF perf event Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 23/26] mm: add speculative page fault vmstats Laurent Dufour
2018-05-17 11:06 ` [PATCH v11 24/26] x86/mm: add speculative pagefault handling Laurent Dufour
2018-05-17 11:06 ` Laurent Dufour [this message]
2018-05-17 11:06 ` [PATCH v11 26/26] arm64/mm: add speculative page fault Laurent Dufour
2018-05-28 5:23 ` [PATCH v11 00/26] Speculative page faults Song, HaiyanX
2018-05-28 7:51 ` Laurent Dufour
[not found] ` <20180528082235.e5x4oiaaf7cjoddr@haiyan.lkp.sh.intel.com>
[not found] ` <316c6936-203d-67e9-c18c-6cf10d0d4bee@linux.vnet.ibm.com>
2018-05-28 11:04 ` Wang, Kemi
2018-11-05 10:42 ` Balbir Singh
2018-11-05 16:08 ` Laurent Dufour
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