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Message-Id: <1332249813-2970-1-git-send-email-consul.kautuk@gmail.com>
Date: Tue, 20 Mar 2012 09:23:33 -0400
From: Kautuk Consul <consul.kautuk@...il.com>
To: Richard Kuo <rkuo@...eaurora.org>,
Linas Vepstas <linas@...eaurora.org>,
Arnd Bergmann <arnd@...db.de>
Cc: linux-hexagon@...r.kernel.org, linux-kernel@...r.kernel.org,
Kautuk Consul <consul.kautuk@...il.com>
Subject: [PATCH 11/20] hexagon/mm/vm_fault.c: Port OOM changes to do_page_fault
Commit d065bd810b6deb67d4897a14bfe21f8eb526ba99
(mm: retry page fault when blocking on disk transfer) and
commit 37b23e0525d393d48a7d59f870b3bc061a30ccdb
(x86,mm: make pagefault killable)
The above commits introduced changes into the x86 pagefault handler
for making the page fault handler retryable as well as killable.
These changes reduce the mmap_sem hold time, which is crucial
during OOM killer invocation.
Port these changes to hexagon.
Signed-off-by: Kautuk Consul <consul.kautuk@...il.com>
---
arch/hexagon/mm/vm_fault.c | 22 +++++++++++++++++-----
1 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/arch/hexagon/mm/vm_fault.c b/arch/hexagon/mm/vm_fault.c
index c10b76f..06695cc 100644
--- a/arch/hexagon/mm/vm_fault.c
+++ b/arch/hexagon/mm/vm_fault.c
@@ -53,6 +53,8 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
int si_code = SEGV_MAPERR;
int fault;
const struct exception_table_entry *fixup;
+ unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE |
+ (cause > 0 ? FAULT_FLAG_WRITE : 0);
/*
* If we're in an interrupt or have no user context,
@@ -63,6 +65,7 @@ void do_page_fault(unsigned long address, long cause, struct pt_regs *regs)
local_irq_enable();
+retry:
down_read(&mm->mmap_sem);
vma = find_vma(mm, address);
if (!vma)
@@ -96,14 +99,23 @@ good_area:
break;
}
- fault = handle_mm_fault(mm, vma, address, (cause > 0));
+ fault = handle_mm_fault(mm, vma, address, flags);
+
+ if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
+ return;
/* The most common case -- we are done. */
if (likely(!(fault & VM_FAULT_ERROR))) {
- if (fault & VM_FAULT_MAJOR)
- current->maj_flt++;
- else
- current->min_flt++;
+ if (flags & FAULT_FLAG_ALLOW_RETRY) {
+ if (fault & VM_FAULT_MAJOR)
+ current->maj_flt++;
+ else
+ current->min_flt++;
+ if (fault & VM_FAULT_RETRY) {
+ flags &= ~FAULT_FLAG_ALLOW_RETRY;
+ goto retry;
+ }
+ }
up_read(&mm->mmap_sem);
return;
--
1.7.5.4
--
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