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mm: handling Non-LRU pages returned by vm_normal_pages 

With DEVICE_COHERENT, we'll soon have vm_normal_pages() return
device-managed anonymous pages that are not LRU pages.  Although they
behave like normal pages for purposes of mapping in CPU page, and for COW.
They do not support LRU lists, NUMA migration or THP.

Callers to follow_page() currently don't expect ZONE_DEVICE pages,
however, with DEVICE_COHERENT we might now return ZONE_DEVICE.  Check for
ZONE_DEVICE pages in applicable users of follow_page() as well.

Link: https://lkml.kernel.org/r/20220715150521.18165-5-alex.sierra@amd.com
Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Acked-by: Felix Kuehling <Felix.Kuehling@amd.com>	[v2]
Reviewed-by: Alistair Popple <apopple@nvidia.com>	[v6]
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Alex Sierra 2022-07-15 10:05:11 -05:00 committed by akpm
parent f25cbb7a95
commit 3218f8712d
10 changed files with 27 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
fs/proc/task_mmu.c
View File

@ -1795,7 +1795,7 @@ static struct page *can_gather_numa_stats(pte_t pte, struct vm_area_struct *vma,
return NULL;
page = vm_normal_page(vma, addr, pte);
if (!page)
if (!page || is_zone_device_page(page))
return NULL;
if (PageReserved(page))

2
mm/huge_memory.c
View File

@ -2910,7 +2910,7 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start,
if (IS_ERR(page))
continue;
if (!page)
if (!page || is_zone_device_page(page))
continue;
if (!is_transparent_hugepage(page))

9
mm/khugepaged.c
View File

@ -611,7 +611,7 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
goto out;
}
page = vm_normal_page(vma, address, pteval);
if (unlikely(!page)) {
if (unlikely(!page) || unlikely(is_zone_device_page(page))) {
result = SCAN_PAGE_NULL;
goto out;
}
@ -1261,7 +1261,7 @@ static int khugepaged_scan_pmd(struct mm_struct *mm,
writable = true;
page = vm_normal_page(vma, _address, pteval);
if (unlikely(!page)) {
if (unlikely(!page) || unlikely(is_zone_device_page(page))) {
result = SCAN_PAGE_NULL;
goto out_unmap;
}
@ -1472,7 +1472,8 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
goto abort;
page = vm_normal_page(vma, addr, *pte);
if (WARN_ON_ONCE(page && is_zone_device_page(page)))
page = NULL;
/*
* Note that uprobe, debugger, or MAP_PRIVATE may change the
* page table, but the new page will not be a subpage of hpage.
@ -1490,6 +1491,8 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr)
if (pte_none(*pte))
continue;
page = vm_normal_page(vma, addr, *pte);
if (WARN_ON_ONCE(page && is_zone_device_page(page)))
goto abort;
page_remove_rmap(page, vma, false);
}

6
mm/ksm.c
View File

@ -475,7 +475,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr)
cond_resched();
page = follow_page(vma, addr,
FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE);
if (IS_ERR_OR_NULL(page))
if (IS_ERR_OR_NULL(page) || is_zone_device_page(page))
break;
if (PageKsm(page))
ret = handle_mm_fault(vma, addr,
@ -560,7 +560,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item)
goto out;
page = follow_page(vma, addr, FOLL_GET);
if (IS_ERR_OR_NULL(page))
if (IS_ERR_OR_NULL(page) || is_zone_device_page(page))
goto out;
if (PageAnon(page)) {
flush_anon_page(vma, page, addr);
@ -2308,7 +2308,7 @@ next_mm:
if (ksm_test_exit(mm))
break;
*page = follow_page(vma, ksm_scan.address, FOLL_GET);
if (IS_ERR_OR_NULL(*page)) {
if (IS_ERR_OR_NULL(*page) || is_zone_device_page(*page)) {
ksm_scan.address += PAGE_SIZE;
cond_resched();
continue;

4
mm/madvise.c
View File

@ -421,7 +421,7 @@ regular_page:
continue;
page = vm_normal_page(vma, addr, ptent);
if (!page)
if (!page || is_zone_device_page(page))
continue;
/*
@ -639,7 +639,7 @@ static int madvise_free_pte_range(pmd_t *pmd, unsigned long addr,
}
page = vm_normal_page(vma, addr, ptent);
if (!page)
if (!page || is_zone_device_page(page))
continue;
/*

10
mm/memory.c
View File

@ -624,6 +624,14 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
if (is_zero_pfn(pfn))
return NULL;
if (pte_devmap(pte))
/*
* NOTE: New users of ZONE_DEVICE will not set pte_devmap()
* and will have refcounts incremented on their struct pages
* when they are inserted into PTEs, thus they are safe to
* return here. Legacy ZONE_DEVICE pages that set pte_devmap()
* do not have refcounts. Example of legacy ZONE_DEVICE is
* MEMORY_DEVICE_FS_DAX type in pmem or virtio_fs drivers.
*/
return NULL;
print_bad_pte(vma, addr, pte, NULL);
@ -4693,7 +4701,7 @@ static vm_fault_t do_numa_page(struct vm_fault *vmf)
pte = pte_modify(old_pte, vma->vm_page_prot);
page = vm_normal_page(vma, vmf->address, pte);
if (!page)
if (!page || is_zone_device_page(page))
goto out_map;
/* TODO: handle PTE-mapped THP */

2
mm/mempolicy.c
View File

@ -523,7 +523,7 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr,
if (!pte_present(*pte))
continue;
page = vm_normal_page(vma, addr, *pte);
if (!page)
if (!page || is_zone_device_page(page))
continue;
/*
* vm_normal_page() filters out zero pages, but there might

4
mm/migrate.c
View File

@ -1630,7 +1630,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr,
goto out;
err = -ENOENT;
if (!page)
if (!page || is_zone_device_page(page))
goto out;
err = 0;
@ -1821,7 +1821,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages,
if (IS_ERR(page))
goto set_status;
if (page) {
if (page && !is_zone_device_page(page)) {
err = page_to_nid(page);
put_page(page);
} else {

2
mm/mlock.c
View File

@ -333,7 +333,7 @@ static int mlock_pte_range(pmd_t *pmd, unsigned long addr,
if (!pte_present(*pte))
continue;
page = vm_normal_page(vma, addr, *pte);
if (!page)
if (!page || is_zone_device_page(page))
continue;
if (PageTransCompound(page))
continue;

2
mm/mprotect.c
View File

@ -127,7 +127,7 @@ static unsigned long change_pte_range(struct mmu_gather *tlb,
continue;
page = vm_normal_page(vma, addr, oldpte);
if (!page || PageKsm(page))
if (!page || is_zone_device_page(page) || PageKsm(page))
continue;
/* Also skip shared copy-on-write pages */