On Tue, 2 Apr 2024 10:49:34 +0800 Jinjiang Tu <tujinjiang@xxxxxxxxxx> wrote:
> Since commit 3c6f33b7273a ("mm/ksm: support fork/exec for prctl"), when a
> child process is forked, the MMF_VM_MERGE_ANY flag will be inherited in
> mm_init(). So, it's unnecessary to set the flag in ksm_fork().
>
> ...
>
> --- a/include/linux/ksm.h
> +++ b/include/linux/ksm.h
> @@ -45,16 +45,8 @@ static inline void ksm_might_unmap_zero_page(struct mm_struct *mm, pte_t pte)
>
> static inline int ksm_fork(struct mm_struct *mm, struct mm_struct *oldmm)
> {
> - int ret;
> -
> - if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags)) {
> - ret = __ksm_enter(mm);
> - if (ret)
> - return ret;
> - }
> -
> - if (test_bit(MMF_VM_MERGE_ANY, &oldmm->flags))
> - set_bit(MMF_VM_MERGE_ANY, &mm->flags);
> + if (test_bit(MMF_VM_MERGEABLE, &oldmm->flags))
> + return __ksm_enter(mm);
>
> return 0;
Thanks, I shall queue this up for testing and shall await review input
from Stefan and hopefully others.
