From: Laurent Dufour <ldufour@linux.vnet.ibm.com>
To: paulmck@linux.vnet.ibm.com, peterz@infradead.org,
akpm@linux-foundation.org, kirill@shutemov.name,
ak@linux.intel.com, mhocko@kernel.org, dave@stgolabs.net,
jack@suse.cz, Matthew Wilcox <willy@infradead.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
haren@linux.vnet.ibm.com, khandual@linux.vnet.ibm.com,
npiggin@gmail.com, bsingharora@gmail.com,
Tim Chen <tim.c.chen@linux.intel.com>
Subject: [RFC v5 10/11] x86/mm: Add speculative pagefault handling
Date: Fri, 16 Jun 2017 19:52:34 +0200 [thread overview]
Message-ID: <1497635555-25679-11-git-send-email-ldufour@linux.vnet.ibm.com> (raw)
In-Reply-To: <1497635555-25679-1-git-send-email-ldufour@linux.vnet.ibm.com>
From: Peter Zijlstra <peterz@infradead.org>
Try a speculative fault before acquiring mmap_sem, if it returns with
VM_FAULT_RETRY continue with the mmap_sem acquisition and do the
traditional fault.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[Clearing of FAULT_FLAG_ALLOW_RETRY is now done in
handle_speculative_fault()]
[Retry with usual fault path in the case VM_ERROR is returned by
handle_speculative_fault(). This allows signal to be delivered]
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
arch/x86/mm/fault.c | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index 8ad91a01cbc8..c62a7ea5e27b 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -1365,6 +1365,19 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
if (error_code & PF_INSTR)
flags |= FAULT_FLAG_INSTRUCTION;
+ if (error_code & PF_USER) {
+ fault = handle_speculative_fault(mm, address, flags);
+
+ /*
+ * We also check against VM_FAULT_ERROR because we have to
+ * raise a signal by calling later mm_fault_error() which
+ * requires the vma pointer to be set. So in that case,
+ * we fall through the normal path.
+ */
+ if (!(fault & VM_FAULT_RETRY || fault & VM_FAULT_ERROR))
+ goto done;
+ }
+
/*
* When running in the kernel we expect faults to occur only to
* addresses in user space. All other faults represent errors in
@@ -1474,6 +1487,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
return;
}
+done:
/*
* Major/minor page fault accounting. If any of the events
* returned VM_FAULT_MAJOR, we account it as a major fault.
--
2.7.4
next prev parent reply other threads:[~2017-06-16 17:53 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-16 17:52 [RFC v5 00/11] Speculative page faults Laurent Dufour
2017-06-16 17:52 ` [RFC v5 01/11] mm: Dont assume page-table invariance during faults Laurent Dufour
2017-07-07 7:07 ` Balbir Singh
2017-07-10 17:48 ` Laurent Dufour
2017-07-11 4:26 ` Balbir Singh
2017-08-08 10:04 ` Anshuman Khandual
2017-08-08 9:45 ` Anshuman Khandual
2017-08-08 12:11 ` Laurent Dufour
2017-06-16 17:52 ` [RFC v5 02/11] mm: Prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour
2017-08-08 10:24 ` Anshuman Khandual
2017-08-08 10:42 ` Peter Zijlstra
2017-06-16 17:52 ` [RFC v5 03/11] mm: Introduce pte_spinlock " Laurent Dufour
2017-08-08 10:35 ` Anshuman Khandual
2017-08-08 12:16 ` Laurent Dufour
2017-06-16 17:52 ` [RFC v5 04/11] mm: VMA sequence count Laurent Dufour
2017-08-08 10:59 ` Anshuman Khandual
2017-08-08 11:04 ` Peter Zijlstra
2017-06-16 17:52 ` [RFC v5 05/11] mm: fix lock dependency against mapping->i_mmap_rwsem Laurent Dufour
2017-08-08 11:17 ` Anshuman Khandual
2017-08-08 12:20 ` Laurent Dufour
2017-08-08 12:49 ` Jan Kara
2017-08-08 13:08 ` Laurent Dufour
2017-08-08 13:15 ` Peter Zijlstra
2017-08-08 13:34 ` Laurent Dufour
2017-06-16 17:52 ` [RFC v5 06/11] mm: Protect VMA modifications using VMA sequence count Laurent Dufour
2017-06-16 17:52 ` [RFC v5 07/11] mm: RCU free VMAs Laurent Dufour
2017-06-16 17:52 ` [RFC v5 08/11] mm: Provide speculative fault infrastructure Laurent Dufour
2017-06-16 17:52 ` [RFC v5 09/11] mm: Try spin lock in speculative path Laurent Dufour
2017-07-05 18:50 ` Peter Zijlstra
2017-07-06 13:46 ` Laurent Dufour
2017-07-06 14:48 ` Peter Zijlstra
2017-07-06 15:29 ` Laurent Dufour
2017-07-06 16:13 ` Peter Zijlstra
2017-06-16 17:52 ` Laurent Dufour [this message]
2017-06-16 17:52 ` [RFC v5 11/11] powerpc/mm: Add speculative page fault Laurent Dufour
2017-07-03 17:32 ` [RFC v5 00/11] Speculative page faults Laurent Dufour
2017-07-07 1:54 ` Balbir Singh
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