| Message ID | 20221111005135.1344004-1-apopple@nvidia.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | mm/migrate_device: Return number of migrating pages in args->cpages | expand |
On 11/10/22 16:51, Alistair Popple wrote: > migrate_vma->cpages originally contained a count of the number of > pages migrating including non-present pages which can be poluated "populated" > directly on the target. > > Commit 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and > migrate_deivce_coherent_page()") inadvertantly changed this to contain > just the number of pages that were unmapped. Usage of > migrate_vma->cpages isn't documented, but most drivers use it to see > if all the requested addresses can be migrated so restore the original > behaviour. > > Fixes: 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()") > Signed-off-by: Alistair Popple <apopple@nvidia.com> > Reported-by: Ralph Campbell <rcampbell@nvidia.com> You can add Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> Thanks!
Hi Andrew, I realize it's getting late in the cycle but any chance you could take this one as well for v6.1-rc6? It fixes a minor bug introduced in v6.1-rc1 which could cause some drivers to think they can't migrate pages when they can. Thanks. Ralph Campbell <rcampbell@nvidia.com> writes: > On 11/10/22 16:51, Alistair Popple wrote: >> migrate_vma->cpages originally contained a count of the number of >> pages migrating including non-present pages which can be poluated > > "populated" > >> directly on the target. >> >> Commit 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and >> migrate_deivce_coherent_page()") inadvertantly changed this to contain >> just the number of pages that were unmapped. Usage of >> migrate_vma->cpages isn't documented, but most drivers use it to see >> if all the requested addresses can be migrated so restore the original >> behaviour. >> >> Fixes: 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()") >> Signed-off-by: Alistair Popple <apopple@nvidia.com> >> Reported-by: Ralph Campbell <rcampbell@nvidia.com> > > You can add > Reviewed-by: Ralph Campbell <rcampbell@nvidia.com> > > Thanks!
diff --git a/mm/migrate_device.c b/mm/migrate_device.c index 6fa682eef7a0..721b2365dbca 100644 --- a/mm/migrate_device.c +++ b/mm/migrate_device.c @@ -357,7 +357,8 @@ static bool migrate_vma_check_page(struct page *page, struct page *fault_page) } /* - * Unmaps pages for migration. Returns number of unmapped pages. + * Unmaps pages for migration. Returns number of source pfns marked as + * migrating. */ static unsigned long migrate_device_unmap(unsigned long *src_pfns, unsigned long npages, @@ -373,8 +374,11 @@ static unsigned long migrate_device_unmap(unsigned long *src_pfns, struct page *page = migrate_pfn_to_page(src_pfns[i]); struct folio *folio; - if (!page) + if (!page) { + if (src_pfns[i] & MIGRATE_PFN_MIGRATE) + unmapped++; continue; + } /* ZONE_DEVICE pages are not on LRU */ if (!is_zone_device_page(page)) {
migrate_vma->cpages originally contained a count of the number of pages migrating including non-present pages which can be poluated directly on the target. Commit 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()") inadvertantly changed this to contain just the number of pages that were unmapped. Usage of migrate_vma->cpages isn't documented, but most drivers use it to see if all the requested addresses can be migrated so restore the original behaviour. Fixes: 241f68859656 ("mm/migrate_device.c: refactor migrate_vma and migrate_deivce_coherent_page()") Signed-off-by: Alistair Popple <apopple@nvidia.com> Reported-by: Ralph Campbell <rcampbell@nvidia.com> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Alex Sierra <alex.sierra@amd.com> Cc: Ben Skeggs <bskeggs@redhat.com> Cc: Felix Kuehling <Felix.Kuehling@amd.com> Cc: Lyude Paul <lyude@redhat.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Michael Ellerman <mpe@ellerman.id.au> --- Hi Andrew, hoping you can merge this small fix which Ralph reported to me for v6.1-rcX. --- mm/migrate_device.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)