Hi Andrew,
Thanks for your review!
On 02/02/2012 06:43 AM, Andrew Morton wrote:
> On Fri, 13 Jan 2012 19:45:45 +0800
> Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx> wrote:
>
>> Search again only if some holes may be skipped in the first time
>>
>> Signed-off-by: Xiao Guangrong <xiaoguangrong@xxxxxxxxxxxxxxxxxx>
>> ---
>> arch/x86/mm/hugetlbpage.c | 8 ++++----
>> 1 files changed, 4 insertions(+), 4 deletions(-)
>>
>> diff --git a/arch/x86/mm/hugetlbpage.c b/arch/x86/mm/hugetlbpage.c
>> index e12debc..6bf5735 100644
>> --- a/arch/x86/mm/hugetlbpage.c
>> +++ b/arch/x86/mm/hugetlbpage.c
>> @@ -309,9 +309,8 @@ static unsigned long hugetlb_get_unmapped_area_topdown(struct file *file,
>> struct hstate *h = hstate_file(file);
>> struct mm_struct *mm = current->mm;
>> struct vm_area_struct *vma;
>> - unsigned long base = mm->mmap_base, addr = addr0;
>> + unsigned long base = mm->mmap_base, addr = addr0, start_addr;
>
> grr. The multiple-definitions-per-line thing is ugly, makes for more
> patch conflicts and reduces opportunities to add useful comments.
Yes, thanks.
>> try_again:
>> + start_addr = mm->free_area_cache;
>> +
>> /* make sure it can fit in the remaining address space */
>> if (mm->free_area_cache < len)
>> goto fail;
>> @@ -357,10 +358,9 @@ fail:
>> * if hint left us with no space for the requested
>> * mapping then try again:
>> */
>> - if (first_time) {
>> + if (start_addr != base) {
>> mm->free_area_cache = base;
>> largest_hole = 0;
>> - first_time = 0;
>> goto try_again;
>
> The code used to retry a single time. With this change the retrying is
> potentially infinite. What is the reason for this change? What is the
> potential for causing a lockup?
>
Actually, it is not infinite, after retry, we set "mm->free_area_cache = base",
"start_addr" will set to "base" in the second search, so the condition of
"goto try_again" will be unsatisfied.
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