Shaohua Li <shaohua.li@xxxxxxxxx> writes: > If we only change vma->vm_end, we can avoid taking anon_vma lock even 'insert' > isn't NULL, which is the case of split_vma. > From my understanding, we need the lock before because rmap must get the > 'insert' VMA when we adjust old VMA's vm_end (the 'insert' VMA is linked to > anon_vma list in __insert_vm_struct before). > But now this isn't true any more. The 'insert' VMA is already linked to > anon_vma list in __split_vma(with anon_vma_clone()) instead of > __insert_vm_struct. There is no race rmap can't get required VMAs. > So the anon_vma lock is unnecessary, and this can reduce one locking in brk > case and improve scalability. Looks good to me. -Andi -- ak@xxxxxxxxxxxxxxx -- Speaking for myself only -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>