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Date: Sat, 31 Mar 2012 08:00:05 -0400 From: Kautuk Consul <consul.kautuk@...il.com> To: Chen Liqin <liqin.chen@...plusct.com>, Lennox Wu <lennox.wu@...il.com> Cc: linux-kernel@...r.kernel.org, Kautuk Consul <consul.kautuk@...il.com>, "Mohd. Faris" <mohdfarisq2010@...il.com> Subject: [PATCH 03/19 v2] score/mm/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 score. Signed-off-by: Mohd. Faris <mohdfarisq2010@...il.com> Signed-off-by: Kautuk Consul <consul.kautuk@...il.com> --- arch/score/mm/fault.c | 30 +++++++++++++++++++++++++----- 1 files changed, 25 insertions(+), 5 deletions(-) diff --git a/arch/score/mm/fault.c b/arch/score/mm/fault.c index 47b600e..f263ba7 100644 --- a/arch/score/mm/fault.c +++ b/arch/score/mm/fault.c @@ -49,6 +49,8 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write, const int field = sizeof(unsigned long) * 2; siginfo_t info; int fault; + unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE | + (write ? FAULT_FLAG_WRITE : 0)); info.si_code = SEGV_MAPERR; @@ -75,6 +77,7 @@ asmlinkage void do_page_fault(struct pt_regs *regs, unsigned long write, if (in_atomic() || !mm) goto bad_area_nosemaphore; +retry: down_read(&mm->mmap_sem); vma = find_vma(mm, address); if (!vma) @@ -106,7 +109,11 @@ survive: * make sure we exit gracefully rather than endlessly redo * the fault. */ - fault = handle_mm_fault(mm, vma, address, write); + fault = handle_mm_fault(mm, vma, address, flags); + + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current)) + return; + if (unlikely(fault & VM_FAULT_ERROR)) { if (fault & VM_FAULT_OOM) goto out_of_memory; @@ -114,10 +121,23 @@ survive: goto do_sigbus; BUG(); } - if (fault & VM_FAULT_MAJOR) - tsk->maj_flt++; - else - tsk->min_flt++; + + if (flags & FAULT_FLAG_ALLOW_RETRY) { + if (fault & VM_FAULT_MAJOR) + tsk->maj_flt++; + else + tsk->min_flt++; + if (fault & VM_FAULT_RETRY) { + flags &= ~FAULT_FLAG_ALLOW_RETRY; + + /* No need to up_read(&mm->mmap_sem) as we would + * have already released it in __lock_page_or_retry + * in mm/filemap.c. + */ + + goto retry; + } + } up_read(&mm->mmap_sem); return; -- 1.7.5.4 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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