Hi,
When can I see this in linux-next ?
Thanks,
Kautuk.
On Sat, Mar 31, 2012 at 5:29 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 ALPHA.
>
> Signed-off-by: Mohd. Faris <mohdfarisq2010@xxxxxxxxx>
> Signed-off-by: Kautuk Consul <consul.kautuk@xxxxxxxxx>
> Acked-by: Matt Turner <mattst88@xxxxxxxxx>
> ---
> 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
>
--
To unsubscribe from this list: send the line "unsubscribe linux-alpha" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
