From: Hugh Dickins <hughd@google.com> mainline inclusion from mainline-v6.7-rc1 commit 2cafb582173f3870240af90de3f31d18b0728882 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I9OHHN Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... -------------------------------- v3.8 commit b24f53a0bea3 ("mm: mempolicy: Add MPOL_MF_LAZY") introduced MPOL_MF_LAZY, and included it in the MPOL_MF_VALID flags; but a720094ded8 ("mm: mempolicy: Hide MPOL_NOOP and MPOL_MF_LAZY from userspace for now") immediately removed it from MPOL_MF_VALID flags, pending further review. "This will need to be revisited", but it has not been reinstated. The present state is confusing: there is dead code in mm/mempolicy.c to handle MPOL_MF_LAZY cases which can never occur. Remove that: it can be resurrected later if necessary. But keep the definition of MPOL_MF_LAZY, which must remain in the UAPI, even though it always fails with EINVAL. https://lore.kernel.org/linux-mm/1553041659-46787-1-git-send-email-yang.shi@... links to a previous request to remove MPOL_MF_LAZY. Link: https://lkml.kernel.org/r/80c9665c-1c3f-17ba-21a3-f6115cebf7d@google.com Signed-off-by: Hugh Dickins <hughd@google.com> Reviewed-by: Matthew Wilcox (Oracle) <willy@infradead.org> Reviewed-by: Yang Shi <shy828301@gmail.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Christoph Lameter <cl@linux.com> Cc: David Hildenbrand <david@redhat.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Huang, Ying" <ying.huang@intel.com> Cc: Kefeng Wang <wangkefeng.wang@huawei.com> Cc: Mel Gorman <mgorman@techsingularity.net> Cc: Michal Hocko <mhocko@suse.com> Cc: Mike Kravetz <mike.kravetz@oracle.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Sidhartha Kumar <sidhartha.kumar@oracle.com> Cc: Suren Baghdasaryan <surenb@google.com> Cc: Tejun heo <tj@kernel.org> Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Ze Zuo <zuoze1@huawei.com> --- include/uapi/linux/mempolicy.h | 2 +- mm/mempolicy.c | 18 ------------------ 2 files changed, 1 insertion(+), 19 deletions(-) diff --git a/include/uapi/linux/mempolicy.h b/include/uapi/linux/mempolicy.h index 8494de333376..1f9bb10d1a47 100644 --- a/include/uapi/linux/mempolicy.h +++ b/include/uapi/linux/mempolicy.h @@ -49,7 +49,7 @@ enum { #define MPOL_MF_MOVE (1<<1) /* Move pages owned by this process to conform to policy */ #define MPOL_MF_MOVE_ALL (1<<2) /* Move every page to conform to policy */ -#define MPOL_MF_LAZY (1<<3) /* Modifies '_MOVE: lazy migrate on fault */ +#define MPOL_MF_LAZY (1<<3) /* UNSUPPORTED FLAG: Lazy migrate on fault */ #define MPOL_MF_INTERNAL (1<<4) /* Internal flags start here */ #define MPOL_MF_VALID (MPOL_MF_STRICT | \ diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 16fbf5067359..16bafc304f7f 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -649,12 +649,6 @@ unsigned long change_prot_numa(struct vm_area_struct *vma, return nr_updated; } -#else -static unsigned long change_prot_numa(struct vm_area_struct *vma, - unsigned long addr, unsigned long end) -{ - return 0; -} #endif /* CONFIG_NUMA_BALANCING */ static int queue_pages_test_walk(unsigned long start, unsigned long end, @@ -693,14 +687,6 @@ static int queue_pages_test_walk(unsigned long start, unsigned long end, if (endvma > end) endvma = end; - if (flags & MPOL_MF_LAZY) { - /* Similar to task_numa_work, skip inaccessible VMAs */ - if (!is_vm_hugetlb_page(vma) && vma_is_accessible(vma) && - !(vma->vm_flags & VM_MIXEDMAP)) - change_prot_numa(vma, start, endvma); - return 1; - } - /* * Check page nodes, and queue pages to move, in the current vma. * But if no moving, and no strict checking, the scan can be skipped. @@ -1437,9 +1423,6 @@ long __do_mbind(unsigned long start, unsigned long len, if (IS_ERR(new)) return PTR_ERR(new); - if (flags & MPOL_MF_LAZY) - new->flags |= MPOL_F_MOF; - /* * If we are using the default policy then operation * on discontinuous address spaces is okay after all @@ -1484,7 +1467,6 @@ long __do_mbind(unsigned long start, unsigned long len, if (!err) { if (!list_empty(&pagelist)) { - WARN_ON_ONCE(flags & MPOL_MF_LAZY); nr_failed |= migrate_pages(&pagelist, new_folio, NULL, start, MIGRATE_SYNC, MR_MEMPOLICY_MBIND, NULL); } -- 2.25.1