Hi Kautuk,
On Sun, Mar 25, 2012 at 10:44, Kautuk Consul <consul.kautuk@xxxxxxxxx> wrote:
> did you get a chance to review this patch ?
Yes, I've just did. Sorry it took that long.
Looks good, so
Acked-by: <Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
BTW, what's the plan with this series? Will you take care of it, or should
all arch maintainers take their parts?
> can I improve this patch in any way ?
There are a few more or less minor things:
- You can remove "write" completely, as it's now superseded by
FAULT_FLAG_WRITE in "flags",
- Please also port the comments that were added to x86. They make
life easier for the casual reader.
Thanks!
> On Tue, Mar 20, 2012 at 12:05 PM, Kautuk Consul <consul.kautuk@xxxxxxxxx> wrote:
>> 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 m68k.
>>
>> Signed-off-by: Kautuk Consul <consul.kautuk@xxxxxxxxx>
>> ---
>> arch/m68k/mm/fault.c | 31 ++++++++++++++++++++++++++-----
>> 1 files changed, 26 insertions(+), 5 deletions(-)
>>
>> diff --git a/arch/m68k/mm/fault.c b/arch/m68k/mm/fault.c
>> index 2db6099..27879bd 100644
>> --- a/arch/m68k/mm/fault.c
>> +++ b/arch/m68k/mm/fault.c
>> @@ -74,6 +74,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
>> struct mm_struct *mm = current->mm;
>> struct vm_area_struct * vma;
>> int write, fault;
>> + unsigned int flags = FAULT_FLAG_ALLOW_RETRY | FAULT_FLAG_KILLABLE;
>>
>> #ifdef DEBUG
>> printk ("do page fault:\nregs->sr=%#x, regs->pc=%#lx, address=%#lx, %ld, %p\n",
>> @@ -88,6 +89,7 @@ int do_page_fault(struct pt_regs *regs, unsigned long address,
>> if (in_atomic() || !mm)
>> goto no_context;
>>
>> +retry:
>> down_read(&mm->mmap_sem);
>>
>> vma = find_vma(mm, address);
>> @@ -126,6 +128,7 @@ good_area:
>> if (!(vma->vm_flags & VM_WRITE))
>> goto acc_err;
>> write++;
>> + flags |= FAULT_FLAG_WRITE;
>> break;
>> case 1: /* read, present */
>> goto acc_err;
>> @@ -140,10 +143,14 @@ good_area:
>> * the fault.
>> */
>>
>> - fault = handle_mm_fault(mm, vma, address, write ? FAULT_FLAG_WRITE : 0);
>> + fault = handle_mm_fault(mm, vma, address, flags);
>> #ifdef DEBUG
>> printk("handle_mm_fault returns %d\n",fault);
>> #endif
>> +
>> + if ((fault & VM_FAULT_RETRY) && fatal_signal_pending(current))
>> + return 0;
>> +
>> if (unlikely(fault & VM_FAULT_ERROR)) {
>> if (fault & VM_FAULT_OOM)
>> goto out_of_memory;
>> @@ -151,10 +158,24 @@ good_area:
>> goto bus_err;
>> 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 0;
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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