From mboxrd@z Thu Jan 1 00:00:00 1970 From: Kautuk Consul Subject: [PATCH 02/19 v2] alpha/mm/fault.c: Port OOM changes to do_page_fault Date: Sat, 31 Mar 2012 07:59:26 -0400 Message-ID: <1333195166-4978-1-git-send-email-consul.kautuk@gmail.com> Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=from:to:cc:subject:date:message-id:x-mailer; bh=38Y37cTwrK+R74kxLLzQDDlmBGRTuk0HUGA4K0IuhnI=; b=FkZbOLRRYGzVjoYG5MGwsN/jBaxwXkdYYXTMM5dzlz/FtQyrcZNASPq/od+GHrw16d 54Kl+W3JEKjNCii6TMLDk2WlNbWWJzs4Fatabja+HOLwGcM8BsCjj6yIqnLd9K0iODkI /IE7eKRHztn41Wwii1pd34748pVHY9YWr+2Xd+JOjVRwa1WKWkCABnezEB6SJRz5ASdQ Hq+X/kNg2t0gLZUs7p+O0Vy9i5qi0z6HA45j8wCWblLbE5Xu0ZwNM7wyjWHI6/SS+Ay6 I65Ly4pcsdSc98rvRm+9gx3ni9LDUtaIw/lvIphPq4mhqNHxYwzdYX4j+6qdOS9smwKS nW5w== Sender: linux-alpha-owner@vger.kernel.org List-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Richard Henderson , Ivan Kokshaysky , Matt Turner Cc: linux-alpha@vger.kernel.org, linux-kernel@vger.kernel.org, Kautuk Consul , "Mohd. Faris" 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 ALPHA. Signed-off-by: Mohd. Faris Signed-off-by: Kautuk Consul Acked-by: Matt Turner --- arch/alpha/mm/fault.c | 36 ++++++++++++++++++++++++++++++------ 1 files changed, 30 insertions(+), 6 deletions(-) diff --git a/arch/alpha/mm/fault.c b/arch/alpha/mm/fault.c index 5eecab1..0c4132d 100644 --- a/arch/alpha/mm/fault.c +++ b/arch/alpha/mm/fault.c @@ -89,6 +89,8 @@ do_page_fault(unsigned long address, unsigned long mmcsr, const struct exception_table_entry *fixup; int fault, si_code = SEGV_MAPERR; siginfo_t info; + unsigned int flags = (FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE | + (cause > 0 ? FAULT_FLAG_WRITE : 0)); /* As of EV6, a load into $31/$f31 is a prefetch, and never faults (or is suppressed by the PALcode). Support that for older CPUs @@ -114,6 +116,7 @@ do_page_fault(unsigned long address, unsigned long mmcsr, goto vmalloc_fault; #endif +retry: down_read(&mm->mmap_sem); vma = find_vma(mm, address); if (!vma) @@ -144,8 +147,11 @@ do_page_fault(unsigned long address, unsigned long mmcsr, /* If for any reason at all we couldn't handle the fault, make sure we exit gracefully rather than endlessly redo the fault. */ - fault = handle_mm_fault(mm, vma, address, cause > 0 ? FAULT_FLAG_WRITE : 0); - up_read(&mm->mmap_sem); + 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; @@ -153,10 +159,26 @@ do_page_fault(unsigned long address, unsigned long mmcsr, goto do_sigbus; BUG(); } - 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; + + /* 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; /* Something tried to access memory that isn't in our memory map. @@ -186,12 +208,14 @@ do_page_fault(unsigned long address, unsigned long mmcsr, /* We ran out of memory, or some other thing happened to us that made us unable to handle the page fault gracefully. */ out_of_memory: + up_read(&mm->mmap_sem); if (!user_mode(regs)) goto no_context; pagefault_out_of_memory(); return; do_sigbus: + up_read(&mm->mmap_sem); /* Send a sigbus, regardless of whether we were in kernel or user mode. */ info.si_signo = SIGBUS; -- 1.7.5.4