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>,
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>
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>,
linuxppc-dev@lists.ozlabs.org, x86@kernel.org
Subject: [PATCH 10/16] powerpc/mm: Add speculative page fault
Date: Tue, 8 Aug 2017 16:35:43 +0200 [thread overview]
Message-ID: <1502202949-8138-11-git-send-email-ldufour@linux.vnet.ibm.com> (raw)
In-Reply-To: <1502202949-8138-1-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 WM_FAULT_RETRY, the mmap_sem is acquired and the
traditional page fault processing is done.
Signed-off-by: Laurent Dufour <ldufour@linux.vnet.ibm.com>
---
arch/powerpc/mm/fault.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/mm/fault.c b/arch/powerpc/mm/fault.c
index 4c422632047b..c6cd40901dd0 100644
--- a/arch/powerpc/mm/fault.c
+++ b/arch/powerpc/mm/fault.c
@@ -291,9 +291,31 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
if (is_write && is_user)
store_update_sp = store_updates_sp(regs);
- if (is_user)
+ if (is_user) {
flags |= FAULT_FLAG_USER;
+ /* let's try a speculative page fault without grabbing the
+ * mmap_sem.
+ */
+
+ /*
+ * flags is set later based on the VMA's flags, for the common
+ * speculative service, we need some flags to be set.
+ */
+ if (is_write)
+ flags |= FAULT_FLAG_WRITE;
+
+ fault = handle_speculative_fault(mm, address, flags);
+ if (!(fault & VM_FAULT_RETRY || fault & VM_FAULT_ERROR))
+ goto done;
+
+ /*
+ * Resetting flags since the following code assumes
+ * FAULT_FLAG_WRITE is not set.
+ */
+ flags &= ~FAULT_FLAG_WRITE;
+ }
+
/* 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
@@ -479,6 +501,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
rc = 0;
}
+done:
/*
* Major/minor page fault accounting.
*/
--
2.7.4
next prev parent reply other threads:[~2017-08-08 14:36 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-08 14:35 [PATCH 00/16] Speculative page faults Laurent Dufour
2017-08-08 14:35 ` [PATCH 01/16] mm: Dont assume page-table invariance during faults Laurent Dufour
2017-08-08 14:35 ` [PATCH 02/16] mm: Prepare for FAULT_FLAG_SPECULATIVE Laurent Dufour
2017-08-09 10:08 ` Kirill A. Shutemov
2017-08-09 10:54 ` Laurent Dufour
2017-08-08 14:35 ` [PATCH 03/16] mm: Introduce pte_spinlock " Laurent Dufour
2017-08-08 14:35 ` [PATCH 04/16] mm: VMA sequence count Laurent Dufour
2017-08-08 14:35 ` [PATCH 05/16] mm: Protect VMA modifications using " Laurent Dufour
2017-08-09 10:12 ` Kirill A. Shutemov
2017-08-09 10:43 ` Laurent Dufour
2017-08-10 0:58 ` Kirill A. Shutemov
2017-08-10 8:27 ` Laurent Dufour
2017-08-10 13:43 ` Kirill A. Shutemov
2017-08-10 18:16 ` Laurent Dufour
2017-08-08 14:35 ` [PATCH 06/16] mm: RCU free VMAs Laurent Dufour
2017-08-08 14:35 ` [PATCH 07/16] mm: Provide speculative fault infrastructure Laurent Dufour
2017-08-08 14:35 ` [PATCH 08/16] mm: Try spin lock in speculative path Laurent Dufour
2017-08-08 14:35 ` [PATCH 09/16] x86/mm: Add speculative pagefault handling Laurent Dufour
2017-08-08 14:35 ` Laurent Dufour [this message]
2017-08-08 14:35 ` [PATCH 11/16] mm: Introduce __page_add_new_anon_rmap() Laurent Dufour
2017-08-08 14:35 ` [PATCH 12/16] mm: Protect SPF handler against anon_vma changes Laurent Dufour
2017-08-08 14:35 ` [PATCH 13/16] perf: Add a speculative page fault sw events Laurent Dufour
2017-08-09 13:18 ` Michael Ellerman
2017-08-09 13:25 ` Laurent Dufour
2017-08-08 14:35 ` [PATCH 14/16] x86/mm: Add support for SPF events Laurent Dufour
2017-08-08 14:35 ` [PATCH 15/16] powerpc/mm: " Laurent Dufour
2017-08-08 14:35 ` [PATCH 16/16] perf tools: " Laurent Dufour
2017-08-09 1:43 ` Anshuman Khandual
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