From 4b88c23ab8c9bc3857f7c8847e2c6bed95185530 Mon Sep 17 00:00:00 2001 From: David Hildenbrand Date: Thu, 20 Jun 2024 23:29:34 +0200 Subject: [PATCH] mm/migrate: make migrate_misplaced_folio() return 0 on success Patch series "mm/migrate: move NUMA hinting fault folio isolation + checks under PTL". Let's just return 0 on success, which is less confusing. ... especially because we got it wrong in the migrate.h stub where we have "return -EAGAIN; /* can't migrate now */" instead of "return 0;". Likely this wrong return value doesn't currently matter, but it certainly adds confusion. We'll add migrate_misplaced_folio_prepare() next, where we want to use the same "return 0 on success" approach, so let's just clean this up. Link: https://lkml.kernel.org/r/20240620212935.656243-1-david@redhat.com Link: https://lkml.kernel.org/r/20240620212935.656243-2-david@redhat.com Signed-off-by: David Hildenbrand Reviewed-by: Zi Yan Reviewed-by: Baolin Wang Cc: Donet Tom Signed-off-by: Andrew Morton --- mm/huge_memory.c | 5 ++--- mm/memory.c | 2 +- mm/migrate.c | 4 ++-- 3 files changed, 5 insertions(+), 6 deletions(-) diff --git a/mm/huge_memory.c b/mm/huge_memory.c index be598e9a5f98..69ca52620236 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1653,7 +1653,7 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) unsigned long haddr = vmf->address & HPAGE_PMD_MASK; int nid = NUMA_NO_NODE; int target_nid, last_cpupid = (-1 & LAST_CPUPID_MASK); - bool migrated = false, writable = false; + bool writable = false; int flags = 0; vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); @@ -1697,8 +1697,7 @@ vm_fault_t do_huge_pmd_numa_page(struct vm_fault *vmf) spin_unlock(vmf->ptl); writable = false; - migrated = migrate_misplaced_folio(folio, vma, target_nid); - if (migrated) { + if (!migrate_misplaced_folio(folio, vma, target_nid)) { flags |= TNF_MIGRATED; nid = target_nid; } else { diff --git a/mm/memory.c b/mm/memory.c index 9e87932c30ec..395f6e7ea575 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -5357,7 +5357,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf) ignore_writable = true; /* Migrate to the requested node */ - if (migrate_misplaced_folio(folio, vma, target_nid)) { + if (!migrate_misplaced_folio(folio, vma, target_nid)) { nid = target_nid; flags |= TNF_MIGRATED; } else { diff --git a/mm/migrate.c b/mm/migrate.c index 72ca341982b9..45e47125c975 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2618,11 +2618,11 @@ int migrate_misplaced_folio(struct folio *folio, struct vm_area_struct *vma, nr_succeeded); } BUG_ON(!list_empty(&migratepages)); - return isolated; + return isolated ? 0 : -EAGAIN; out: folio_put(folio); - return 0; + return -EAGAIN; } #endif /* CONFIG_NUMA_BALANCING */ #endif /* CONFIG_NUMA */