Re: [PATCH] mm, soft-offline: convert parameter to pfn

From: Naoya Horiguchi
Date: Wed Oct 16 2019 - 04:28:59 EST


On Wed, Oct 16, 2019 at 09:56:19AM +0200, David Hildenbrand wrote:
> On 16.10.19 09:09, Naoya Horiguchi wrote:
> > Hi,
> >
> > I wrote a simple cleanup for parameter of soft_offline_page(),
> > based on thread https://lkml.org/lkml/2019/10/11/57.
> >
> > I know that we need more cleanup on hwpoison-inject, but I think
> > that will be mentioned in re-write patchset Oscar is preparing now.
> > So let me shared only this part as a separate one now.
...
>
> I think you should rebase that patch on linux-next (where the
> pfn_to_online_page() check is in place). I assume you'll want to move the
> pfn_to_online_page() check into soft_offline_page() then as well?

I rebased to next-20191016. And yes, we will move pfn_to_online_page()
into soft offline code. It seems that we can also move pfn_valid(),
but is simply moving like below good enough for you?

@@ -1877,11 +1877,17 @@ static int soft_offline_free_page(struct page *page)
* This is not a 100% solution for all memory, but tries to be
* ``good enough'' for the majority of memory.
*/
-int soft_offline_page(struct page *page, int flags)
+int soft_offline_page(unsigned long pfn, int flags)
{
int ret;
- unsigned long pfn = page_to_pfn(page);
+ struct page *page;

+ if (!pfn_valid(pfn))
+ return -ENXIO;
+ /* Only online pages can be soft-offlined (esp., not ZONE_DEVICE). */
+ if (!pfn_to_online_page(pfn))
+ return -EIO;
+ page = pfn_to_page(pfn);
if (is_zone_device_page(page)) {
pr_debug_ratelimited("soft_offline: %#lx page is device page\n",
pfn);
--

Or we might have an option to do as memory_failure() does like below:

int memory_failure(unsigned long pfn, int flags)
{
....
p = pfn_to_online_page(pfn);
if (!p) {
if (pfn_valid(pfn)) {
pgmap = get_dev_pagemap(pfn, NULL);
if (pgmap)
return memory_failure_dev_pagemap(pfn, flags,
pgmap);
}
pr_err("Memory failure: %#lx: memory outside kernel control\n",
pfn);
return -ENXIO;
}

Thanks,
Naoya Horiguchi