Commit 4b88c23a authored by David Hildenbrand's avatar David Hildenbrand Committed by Andrew Morton
Browse files

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: default avatarDavid Hildenbrand <david@redhat.com>
Reviewed-by: default avatarZi Yan <ziy@nvidia.com>
Reviewed-by: default avatarBaolin Wang <baolin.wang@linux.alibaba.com>
Cc: Donet Tom <donettom@linux.ibm.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 7d6be67c

mm/huge_memory.c

+2 −3
Original line number Diff line number Diff line
@@ -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 {

mm/memory.c

+1 −1
Original line number Diff line number Diff line
@@ -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 {

mm/migrate.c

+2 −2
Original line number Diff line number Diff line
@@ -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 */