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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: E8C83C0007 X-Stat-Signature: zz6ko9s74wnj946sgx74yqkhsqjbczb3 X-Rspam-User: X-HE-Tag: 1713785104-232054 X-HE-Meta: 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 FcBj1URD rUxlkmPmJFgYKzUnIKw+VDXpFtViB7mRiiHzNclADGa96UXJksoNz2mIxLpO5qGrTbqLVJeIQc9zo4FYvxhrnRtGx0XcGHFRQGqB+9RYtWc9IW03eCqQF9K6jSeh3ehb8VX13gK75Pby2yrtqjaYRCf69Ig7HG853kj9+b8Hfa3wtY/9uQ4A7NNivKw== X-Bogosity: Ham, tests=bogofilter, spamicity=0.004322, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024/4/22 18:52, Yajun Deng wrote: > page_table_lock is a lock that for page table, we won't change page > table in __anon_vma_prepare(). As we can see, it works well in > anon_vma_clone(). They do the same operation. > > Remove unnecessary page_table_lock in __anon_vma_prepare(). IIUC, the page_table_lock here is not to protect page table, but as mentioned in the comments, to prevent concurrent modification by multiple threads. > > Signed-off-by: Yajun Deng > --- > mm/rmap.c | 4 ---- > 1 file changed, 4 deletions(-) > > diff --git a/mm/rmap.c b/mm/rmap.c > index 2608c40dffad..e894640a9327 100644 > --- a/mm/rmap.c > +++ b/mm/rmap.c > @@ -187,7 +187,6 @@ static void anon_vma_chain_link(struct vm_area_struct *vma, > */ > int __anon_vma_prepare(struct vm_area_struct *vma) > { > - struct mm_struct *mm = vma->vm_mm; > struct anon_vma *anon_vma, *allocated; > struct anon_vma_chain *avc; > > @@ -208,8 +207,6 @@ int __anon_vma_prepare(struct vm_area_struct *vma) > } > > anon_vma_lock_write(anon_vma); > - /* page_table_lock to protect against threads */ > - spin_lock(&mm->page_table_lock); > if (likely(!vma->anon_vma)) { > vma->anon_vma = anon_vma; > anon_vma_chain_link(vma, avc, anon_vma); > @@ -217,7 +214,6 @@ int __anon_vma_prepare(struct vm_area_struct *vma) > allocated = NULL; > avc = NULL; > } > - spin_unlock(&mm->page_table_lock); > anon_vma_unlock_write(anon_vma); > > if (unlikely(allocated))