| Message ID | 20220516231432.20200-12-alex.sierra@amd.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | Add MEMORY_DEVICE_COHERENT for coherent device memory mapping | expand |
Technically I think this patch should be earlier in the series. As I understand it patch 1 allows DEVICE_COHERENT pages to be inserted in the page tables and therefore makes it possible for page table walkers to see non-LRU pages. Some more comments below: Alex Sierra <alex.sierra@amd.com> writes: > 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. > > We also introduced a FOLL_LRU flag that adds the same behaviour to > follow_page and related APIs, to allow callers to specify that they > expect to put pages on an LRU list. This means by default GUP can return non-LRU pages. I didn't see anywhere that would be a problem but I didn't check everything. Did you check this or is there some other reason I've missed that makes this not a problem? [...] > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index a4e5eaf3eb01..eb3cfd679800 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -627,7 +627,7 @@ 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; > } > @@ -1276,7 +1276,7 @@ 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; > } > @@ -1484,7 +1484,8 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) > goto abort; > > page = vm_normal_page(vma, addr, *pte); > - > + if (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. > @@ -1502,6 +1503,8 @@ 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 (page && is_zone_device_page(page)) > + goto abort; Are either of these two cases actually possible? DEVICE_COHERENT doesn't currently support THP, so if I'm understanding correctly we couldn't have a pte mapped DEVICE_COHERENT THP right? Assuming that's the case I think WARN_ON_ONCE() would be better. Otherwise I think everything else looks reasonable. > page_remove_rmap(page, vma, false); > } > > diff --git a/mm/ksm.c b/mm/ksm.c > index 063a48eeb5ee..f16056efca21 100644 > --- a/mm/ksm.c > +++ b/mm/ksm.c > @@ -474,7 +474,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr) > do { > cond_resched(); > page = follow_page(vma, addr, > - FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); > + FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE | FOLL_LRU); > if (IS_ERR_OR_NULL(page)) > break; > if (PageKsm(page)) > @@ -559,7 +559,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item) > if (!vma) > goto out; > > - page = follow_page(vma, addr, FOLL_GET); > + page = follow_page(vma, addr, FOLL_GET | FOLL_LRU); > if (IS_ERR_OR_NULL(page)) > goto out; > if (PageAnon(page)) { > @@ -2288,7 +2288,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) > while (ksm_scan.address < vma->vm_end) { > if (ksm_test_exit(mm)) > break; > - *page = follow_page(vma, ksm_scan.address, FOLL_GET); > + *page = follow_page(vma, ksm_scan.address, FOLL_GET | FOLL_LRU); > if (IS_ERR_OR_NULL(*page)) { > ksm_scan.address += PAGE_SIZE; > cond_resched(); > diff --git a/mm/madvise.c b/mm/madvise.c > index 1873616a37d2..e9c24c834e98 100644 > --- a/mm/madvise.c > +++ b/mm/madvise.c > @@ -413,7 +413,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, > continue; > > page = vm_normal_page(vma, addr, ptent); > - if (!page) > + if (!page || is_zone_device_page(page)) > continue; > > /* > @@ -628,7 +628,7 @@ 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; > > /* > diff --git a/mm/memory.c b/mm/memory.c > index 76e3af9639d9..571a26805ee1 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -621,6 +621,13 @@ 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 uers 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); > @@ -4422,7 +4429,7 @@ 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 */ > diff --git a/mm/mempolicy.c b/mm/mempolicy.c > index 8c74107a2b15..e32edbecb0cd 100644 > --- a/mm/mempolicy.c > +++ b/mm/mempolicy.c > @@ -528,7 +528,7 @@ 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 > diff --git a/mm/migrate.c b/mm/migrate.c > index 6c31ee1e1c9b..c5d50e96ecd7 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1611,7 +1611,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, > goto out; > > /* FOLL_DUMP to ignore special (like zero) pages */ > - page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); > + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP | FOLL_LRU); > > err = PTR_ERR(page); > if (IS_ERR(page)) > @@ -1802,7 +1802,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, > goto set_status; > > /* FOLL_DUMP to ignore special (like zero) pages */ > - page = follow_page(vma, addr, FOLL_DUMP); > + page = follow_page(vma, addr, FOLL_DUMP | FOLL_LRU); > > err = PTR_ERR(page); > if (IS_ERR(page)) > diff --git a/mm/mlock.c b/mm/mlock.c > index 716caf851043..b14e929084cc 100644 > --- a/mm/mlock.c > +++ b/mm/mlock.c > @@ -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; > diff --git a/mm/mprotect.c b/mm/mprotect.c > index b69ce7a7b2b7..a6f3587ea29a 100644 > --- a/mm/mprotect.c > +++ b/mm/mprotect.c > @@ -91,7 +91,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, > 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 */
On 5/23/2022 7:02 AM, Alistair Popple wrote: > Technically I think this patch should be earlier in the series. As I > understand it patch 1 allows DEVICE_COHERENT pages to be inserted in the > page tables and therefore makes it possible for page table walkers to > see non-LRU pages. Patch will reordered in V3. Regards, Alex Sierra > > Some more comments below: > > Alex Sierra <alex.sierra@amd.com> writes: > >> 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. >> >> We also introduced a FOLL_LRU flag that adds the same behaviour to >> follow_page and related APIs, to allow callers to specify that they >> expect to put pages on an LRU list. > This means by default GUP can return non-LRU pages. I didn't see > anywhere that would be a problem but I didn't check everything. Did you > check this or is there some other reason I've missed that makes this not > a problem? I have double checked all gup and pin_user_pages callers and none of them seem to have interaction with LRU APIs. Regards, Alex Sierra > > [...] > >> diff --git a/mm/khugepaged.c b/mm/khugepaged.c >> index a4e5eaf3eb01..eb3cfd679800 100644 >> --- a/mm/khugepaged.c >> +++ b/mm/khugepaged.c >> @@ -627,7 +627,7 @@ 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; >> } >> @@ -1276,7 +1276,7 @@ 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; >> } >> @@ -1484,7 +1484,8 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) >> goto abort; >> >> page = vm_normal_page(vma, addr, *pte); >> - >> + if (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. >> @@ -1502,6 +1503,8 @@ 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 (page && is_zone_device_page(page)) >> + goto abort; > Are either of these two cases actually possible? DEVICE_COHERENT doesn't > currently support THP, so if I'm understanding correctly we couldn't > have a pte mapped DEVICE_COHERENT THP right? Assuming that's the case I > think WARN_ON_ONCE() would be better. Correct, change included in V3 patch series. Regards, Alex > > Otherwise I think everything else looks reasonable. > >> page_remove_rmap(page, vma, false); >> } >> >> diff --git a/mm/ksm.c b/mm/ksm.c >> index 063a48eeb5ee..f16056efca21 100644 >> --- a/mm/ksm.c >> +++ b/mm/ksm.c >> @@ -474,7 +474,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr) >> do { >> cond_resched(); >> page = follow_page(vma, addr, >> - FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); >> + FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE | FOLL_LRU); >> if (IS_ERR_OR_NULL(page)) >> break; >> if (PageKsm(page)) >> @@ -559,7 +559,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item) >> if (!vma) >> goto out; >> >> - page = follow_page(vma, addr, FOLL_GET); >> + page = follow_page(vma, addr, FOLL_GET | FOLL_LRU); >> if (IS_ERR_OR_NULL(page)) >> goto out; >> if (PageAnon(page)) { >> @@ -2288,7 +2288,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) >> while (ksm_scan.address < vma->vm_end) { >> if (ksm_test_exit(mm)) >> break; >> - *page = follow_page(vma, ksm_scan.address, FOLL_GET); >> + *page = follow_page(vma, ksm_scan.address, FOLL_GET | FOLL_LRU); >> if (IS_ERR_OR_NULL(*page)) { >> ksm_scan.address += PAGE_SIZE; >> cond_resched(); >> diff --git a/mm/madvise.c b/mm/madvise.c >> index 1873616a37d2..e9c24c834e98 100644 >> --- a/mm/madvise.c >> +++ b/mm/madvise.c >> @@ -413,7 +413,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, >> continue; >> >> page = vm_normal_page(vma, addr, ptent); >> - if (!page) >> + if (!page || is_zone_device_page(page)) >> continue; >> >> /* >> @@ -628,7 +628,7 @@ 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; >> >> /* >> diff --git a/mm/memory.c b/mm/memory.c >> index 76e3af9639d9..571a26805ee1 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -621,6 +621,13 @@ 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 uers 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); >> @@ -4422,7 +4429,7 @@ 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 */ >> diff --git a/mm/mempolicy.c b/mm/mempolicy.c >> index 8c74107a2b15..e32edbecb0cd 100644 >> --- a/mm/mempolicy.c >> +++ b/mm/mempolicy.c >> @@ -528,7 +528,7 @@ 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 >> diff --git a/mm/migrate.c b/mm/migrate.c >> index 6c31ee1e1c9b..c5d50e96ecd7 100644 >> --- a/mm/migrate.c >> +++ b/mm/migrate.c >> @@ -1611,7 +1611,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, >> goto out; >> >> /* FOLL_DUMP to ignore special (like zero) pages */ >> - page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); >> + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP | FOLL_LRU); >> >> err = PTR_ERR(page); >> if (IS_ERR(page)) >> @@ -1802,7 +1802,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, >> goto set_status; >> >> /* FOLL_DUMP to ignore special (like zero) pages */ >> - page = follow_page(vma, addr, FOLL_DUMP); >> + page = follow_page(vma, addr, FOLL_DUMP | FOLL_LRU); >> >> err = PTR_ERR(page); >> if (IS_ERR(page)) >> diff --git a/mm/mlock.c b/mm/mlock.c >> index 716caf851043..b14e929084cc 100644 >> --- a/mm/mlock.c >> +++ b/mm/mlock.c >> @@ -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; >> diff --git a/mm/mprotect.c b/mm/mprotect.c >> index b69ce7a7b2b7..a6f3587ea29a 100644 >> --- a/mm/mprotect.c >> +++ b/mm/mprotect.c >> @@ -91,7 +91,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, >> 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 */
diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c index f46060eb91b5..5d620733f173 100644 --- a/fs/proc/task_mmu.c +++ b/fs/proc/task_mmu.c @@ -1785,7 +1785,7 @@ 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)) diff --git a/include/linux/mm.h b/include/linux/mm.h index 9f44254af8ce..d7f253a0c41e 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -601,7 +601,7 @@ struct vm_operations_struct { #endif /* * Called by vm_normal_page() for special PTEs to find the - * page for @addr. This is useful if the default behavior + * page for @addr. This is useful if the default behavior * (using pte_page()) would not find the correct page. */ struct page *(*find_special_page)(struct vm_area_struct *vma, @@ -2929,6 +2929,7 @@ struct page *follow_page(struct vm_area_struct *vma, unsigned long address, #define FOLL_NUMA 0x200 /* force NUMA hinting page fault */ #define FOLL_MIGRATION 0x400 /* wait for page to replace migration entry */ #define FOLL_TRIED 0x800 /* a retry, previous pass started an IO */ +#define FOLL_LRU 0x1000 /* return only LRU (anon or page cache) */ #define FOLL_REMOTE 0x2000 /* we are working on non-current tsk/mm */ #define FOLL_COW 0x4000 /* internal GUP flag */ #define FOLL_ANON 0x8000 /* don't do file mappings */ diff --git a/mm/gup.c b/mm/gup.c index a214c8df7140..13bf04bce132 100644 --- a/mm/gup.c +++ b/mm/gup.c @@ -479,6 +479,8 @@ static struct page *follow_page_pte(struct vm_area_struct *vma, } page = vm_normal_page(vma, address, pte); + if ((flags & FOLL_LRU) && page && is_zone_device_page(page)) + page = NULL; if (!page && pte_devmap(pte) && (flags & (FOLL_GET | FOLL_PIN))) { /* * Only return device mapping pages in the FOLL_GET or FOLL_PIN diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 910a138e9859..eed80696c5fd 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -2856,7 +2856,7 @@ static int split_huge_pages_pid(int pid, unsigned long vaddr_start, } /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP | FOLL_LRU); if (IS_ERR(page)) continue; diff --git a/mm/khugepaged.c b/mm/khugepaged.c index a4e5eaf3eb01..eb3cfd679800 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -627,7 +627,7 @@ 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; } @@ -1276,7 +1276,7 @@ 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; } @@ -1484,7 +1484,8 @@ void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr) goto abort; page = vm_normal_page(vma, addr, *pte); - + if (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. @@ -1502,6 +1503,8 @@ 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 (page && is_zone_device_page(page)) + goto abort; page_remove_rmap(page, vma, false); } diff --git a/mm/ksm.c b/mm/ksm.c index 063a48eeb5ee..f16056efca21 100644 --- a/mm/ksm.c +++ b/mm/ksm.c @@ -474,7 +474,7 @@ static int break_ksm(struct vm_area_struct *vma, unsigned long addr) do { cond_resched(); page = follow_page(vma, addr, - FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE); + FOLL_GET | FOLL_MIGRATION | FOLL_REMOTE | FOLL_LRU); if (IS_ERR_OR_NULL(page)) break; if (PageKsm(page)) @@ -559,7 +559,7 @@ static struct page *get_mergeable_page(struct rmap_item *rmap_item) if (!vma) goto out; - page = follow_page(vma, addr, FOLL_GET); + page = follow_page(vma, addr, FOLL_GET | FOLL_LRU); if (IS_ERR_OR_NULL(page)) goto out; if (PageAnon(page)) { @@ -2288,7 +2288,7 @@ static struct rmap_item *scan_get_next_rmap_item(struct page **page) while (ksm_scan.address < vma->vm_end) { if (ksm_test_exit(mm)) break; - *page = follow_page(vma, ksm_scan.address, FOLL_GET); + *page = follow_page(vma, ksm_scan.address, FOLL_GET | FOLL_LRU); if (IS_ERR_OR_NULL(*page)) { ksm_scan.address += PAGE_SIZE; cond_resched(); diff --git a/mm/madvise.c b/mm/madvise.c index 1873616a37d2..e9c24c834e98 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -413,7 +413,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd, continue; page = vm_normal_page(vma, addr, ptent); - if (!page) + if (!page || is_zone_device_page(page)) continue; /* @@ -628,7 +628,7 @@ 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; /* diff --git a/mm/memory.c b/mm/memory.c index 76e3af9639d9..571a26805ee1 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -621,6 +621,13 @@ 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 uers 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); @@ -4422,7 +4429,7 @@ 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 */ diff --git a/mm/mempolicy.c b/mm/mempolicy.c index 8c74107a2b15..e32edbecb0cd 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -528,7 +528,7 @@ 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 diff --git a/mm/migrate.c b/mm/migrate.c index 6c31ee1e1c9b..c5d50e96ecd7 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -1611,7 +1611,7 @@ static int add_page_for_migration(struct mm_struct *mm, unsigned long addr, goto out; /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP); + page = follow_page(vma, addr, FOLL_GET | FOLL_DUMP | FOLL_LRU); err = PTR_ERR(page); if (IS_ERR(page)) @@ -1802,7 +1802,7 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, goto set_status; /* FOLL_DUMP to ignore special (like zero) pages */ - page = follow_page(vma, addr, FOLL_DUMP); + page = follow_page(vma, addr, FOLL_DUMP | FOLL_LRU); err = PTR_ERR(page); if (IS_ERR(page)) diff --git a/mm/mlock.c b/mm/mlock.c index 716caf851043..b14e929084cc 100644 --- a/mm/mlock.c +++ b/mm/mlock.c @@ -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; diff --git a/mm/mprotect.c b/mm/mprotect.c index b69ce7a7b2b7..a6f3587ea29a 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -91,7 +91,7 @@ static unsigned long change_pte_range(struct vm_area_struct *vma, pmd_t *pmd, 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 */