diff options
| -rw-r--r-- | mm/ksm.c | 12 |
1 files changed, 5 insertions, 7 deletions
@@ -420,17 +420,15 @@ static inline bool ksm_test_exit(struct mm_struct *mm) } /* - * We use break_ksm to break COW on a ksm page: it's a stripped down + * We use break_ksm to break COW on a ksm page by triggering unsharing, + * such that the ksm page will get replaced by an exclusive anonymous page. * - * if (get_user_pages(addr, 1, FOLL_WRITE, &page, NULL) == 1) - * put_page(page); - * - * but taking great care only to touch a ksm page, in a VM_MERGEABLE vma, + * We take great care only to touch a ksm page, in a VM_MERGEABLE vma, * in case the application has unmapped and remapped mm,addr meanwhile. * Could a ksm page appear anywhere else? Actually yes, in a VM_PFNMAP * mmap of /dev/mem, where we would not want to touch it. * - * FAULT_FLAG/FOLL_REMOTE are because we do this outside the context + * FAULT_FLAG_REMOTE/FOLL_REMOTE are because we do this outside the context * of the process that owns 'vma'. We also do not want to enforce * protection keys here anyway. */ @@ -454,7 +452,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr) if (!ksm_page) return 0; ret = handle_mm_fault(vma, addr, - FAULT_FLAG_WRITE | FAULT_FLAG_REMOTE, + FAULT_FLAG_UNSHARE | FAULT_FLAG_REMOTE, NULL); } while (!(ret & (VM_FAULT_SIGBUS | VM_FAULT_SIGSEGV | VM_FAULT_OOM))); /* |