Am 2022-03-10 um 14:25 schrieb Matthew Wilcox:
On Thu, Mar 10, 2022 at 11:26:31AM -0600, Alex Sierra wrote:
@@ -606,7 +606,7 @@ static void print_bad_pte(struct vm_area_struct *vma, unsigned long addr,
* PFNMAP mappings in order to support COWable mappings.
*
*/
-struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
+struct page *vm_normal_any_page(struct vm_area_struct *vma, unsigned long addr,
pte_t pte)
{
unsigned long pfn = pte_pfn(pte);
@@ -620,8 +620,6 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
return NULL;
if (is_zero_pfn(pfn))
return NULL;
- if (pte_devmap(pte))
- return NULL;
print_bad_pte(vma, addr, pte, NULL);
return NULL;
... what?
Haven't you just made it so that a devmap page always prints a bad PTE
message, and then returns NULL anyway?
Yeah, that was stupid. :/ I think the long-term goal was to get rid of
pte_devmap. But for now, as long as we have pte_special with pte_devmap,
we'll need a special case to handle that like a normal page.
I only see the PFN_DEV|PFN_MAP flags set in a few places:
drivers/dax/device.c, drivers/nvdimm/pmem.c, fs/fuse/virtio_fs.c. I
guess we need to test at least one of them for this patch series to make
sure we're not breaking them.
Surely this should be:
if (pte_devmap(pte))
- return NULL;
+ return pfn_to_page(pfn);
or maybe
+ goto check_pfn;
But I don't know about that highest_memmap_pfn check.
Looks to me like it should work. highest_memmap_pfn gets updated in
memremap_pages -> pagemap_range -> move_pfn_range_to_zone ->
memmap_init_range.
Regards,
Felix
@@ -661,6 +659,22 @@ struct page *vm_normal_page(struct vm_area_struct *vma, unsigned long addr,
return pfn_to_page(pfn);
}
+/*
+ * vm_normal_lru_page -- This function gets the "struct page" associated
+ * with a pte only for page cache and anon page. These pages are LRU handled.
+ */
+struct page *vm_normal_lru_page(struct vm_area_struct *vma, unsigned long addr,
+ pte_t pte)
It seems a shame to add a new function without proper kernel-doc.
