| Message ID | 20240402024934.1093361-1-tujinjiang@huawei.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/ksm: remove redundant code in ksm_fork | expand |
On Tue, 2 Apr 2024 10:49:34 +0800 Jinjiang Tu <tujinjiang@huawei.com> 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.
在 2024/4/4 23:34, David Hildenbrand 写道: > On 02.04.24 04:49, Jinjiang Tu 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(). >> >> Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com> >> --- >> include/linux/ksm.h | 12 ++---------- >> 1 file changed, 2 insertions(+), 10 deletions(-) >> >> diff --git a/include/linux/ksm.h b/include/linux/ksm.h >> index 401348e9f92b..2e61df795803 100644 >> --- 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; >> } > > I *think* this is correct. :) > > Did you run the new ksm_functional_tests in mm/mm-unstable to make > sure they still pass? If so > > Reviewed-by: David Hildenbrand <david@redhat.com> Sorry for late reply, I was on holiday. I have run the new ksm_functional_tests and the testcases still pass.
diff --git a/include/linux/ksm.h b/include/linux/ksm.h index 401348e9f92b..2e61df795803 100644 --- 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; }
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(). Signed-off-by: Jinjiang Tu <tujinjiang@huawei.com> --- include/linux/ksm.h | 12 ++---------- 1 file changed, 2 insertions(+), 10 deletions(-)