The patch titled Subject: mempolicy: mpol_shared_policy_init() without pseudo-vma has been added to the -mm mm-unstable branch. Its filename is mempolicy-mpol_shared_policy_init-without-pseudo-vma.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mempolicy-mpol_shared_policy_init-without-pseudo-vma.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Hugh Dickins <hughd@xxxxxxxxxx> Subject: mempolicy: mpol_shared_policy_init() without pseudo-vma Date: Tue, 3 Oct 2023 02:22:59 -0700 (PDT) mpol_shared_policy_init() does not need to use a pseudo-vma: it can use sp_alloc() and sp_insert() directly, since the object's shared policy tree is empty and inaccessible (needing no lock) at get_inode() time. Link: https://lkml.kernel.org/r/3bef62d8-ae78-4c2-533-56a44ae425c@xxxxxxxxxx Signed-off-by: Hugh Dickins <hughd@xxxxxxxxxx> Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx> Cc: Christoph Lameter <cl@xxxxxxxxx> Cc: David Hildenbrand <david@xxxxxxxxxx> Cc: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> Cc: "Huang, Ying" <ying.huang@xxxxxxxxx> Cc: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx> Cc: Mel Gorman <mgorman@xxxxxxxxxxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Cc: Nhat Pham <nphamcs@xxxxxxxxx> Cc: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> Cc: Suren Baghdasaryan <surenb@xxxxxxxxxx> Cc: Tejun heo <tj@xxxxxxxxxx> Cc: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx> Cc: Yang Shi <shy828301@xxxxxxxxx> Cc: Yosry Ahmed <yosryahmed@xxxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/mempolicy.c | 28 ++++++++++++++-------------- 1 file changed, 14 insertions(+), 14 deletions(-) --- a/mm/mempolicy.c~mempolicy-mpol_shared_policy_init-without-pseudo-vma +++ a/mm/mempolicy.c @@ -2736,30 +2736,30 @@ void mpol_shared_policy_init(struct shar rwlock_init(&sp->lock); if (mpol) { - struct vm_area_struct pvma; - struct mempolicy *new; + struct sp_node *sn; + struct mempolicy *npol; NODEMASK_SCRATCH(scratch); if (!scratch) goto put_mpol; - /* contextualize the tmpfs mount point mempolicy */ - new = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask); - if (IS_ERR(new)) + + /* contextualize the tmpfs mount point mempolicy to this file */ + npol = mpol_new(mpol->mode, mpol->flags, &mpol->w.user_nodemask); + if (IS_ERR(npol)) goto free_scratch; /* no valid nodemask intersection */ task_lock(current); - ret = mpol_set_nodemask(new, &mpol->w.user_nodemask, scratch); + ret = mpol_set_nodemask(npol, &mpol->w.user_nodemask, scratch); task_unlock(current); if (ret) - goto put_new; - - /* Create pseudo-vma that contains just the policy */ - vma_init(&pvma, NULL); - pvma.vm_end = TASK_SIZE; /* policy covers entire file */ - mpol_set_shared_policy(sp, &pvma, new); /* adds ref */ + goto put_npol; -put_new: - mpol_put(new); /* drop initial ref */ + /* alloc node covering entire file; adds ref to file's npol */ + sn = sp_alloc(0, MAX_LFS_FILESIZE >> PAGE_SHIFT, npol); + if (sn) + sp_insert(sp, sn); +put_npol: + mpol_put(npol); /* drop initial ref on file's npol */ free_scratch: NODEMASK_SCRATCH_FREE(scratch); put_mpol: _ Patches currently in -mm which might be from hughd@xxxxxxxxxx are hugetlbfs-drop-shared-numa-mempolicy-pretence.patch kernfs-drop-shared-numa-mempolicy-hooks.patch mempolicy-fix-migrate_pages2-syscall-return-nr_failed.patch mempolicy-trivia-delete-those-ancient-pr_debugs.patch mempolicy-trivia-slightly-more-consistent-naming.patch mempolicy-trivia-use-pgoff_t-in-shared-mempolicy-tree.patch mempolicy-mpol_shared_policy_init-without-pseudo-vma.patch mempolicy-remove-confusing-mpol_mf_lazy-dead-code.patch mm-add-page_rmappable_folio-wrapper.patch mempolicy-alloc_pages_mpol-for-numa-policy-without-vma.patch mempolicy-mmap_lock-is-not-needed-while-migrating-folios.patch mempolicy-migration-attempt-to-match-interleave-nodes.patch