Alistair Popple writes:
> John Hubbard writes:
>
>> On 3/28/23 20:16, Matthew Wilcox wrote:
>> ...
+ if (!get_page_unless_zero(vmf->page))
+ return 0;
>>> From a folio point of view: what the hell are you doing here? Tail
>>> pages don't have individual refcounts; all
John Hubbard writes:
> On 3/28/23 20:16, Matthew Wilcox wrote:
> ...
>>> + if (!get_page_unless_zero(vmf->page))
>>> + return 0;
>> From a folio point of view: what the hell are you doing here? Tail
>> pages don't have individual refcounts; all the refcounts are actually
I had
On 3/28/23 20:16, Matthew Wilcox wrote:
...
+ if (!get_page_unless_zero(vmf->page))
+ return 0;
From a folio point of view: what the hell are you doing here? Tail
pages don't have individual refcounts; all the refcounts are actually
ohh, and I really should have caught
On Tue, Mar 28, 2023 at 01:14:34PM +1100, Alistair Popple wrote:
> +++ b/mm/memory.c
> @@ -3623,8 +3623,19 @@ static vm_fault_t remove_device_exclusive_entry(struct
> vm_fault *vmf)
> struct vm_area_struct *vma = vmf->vma;
> struct mmu_notifier_range range;
>
> - if
John Hubbard writes:
>> warnings such as PAGE_FLAGS_CHECK_AT_FREE due to the page being locked
>> when the refcount drops to zero. Note that during removal of the
>> device exclusive entry the PTE is currently re-checked under the PTL
>> so no futher bad page accesses occur once it is locked.
On 3/27/23 19:14, Alistair Popple wrote:
Device exclusive page table entries are used to prevent CPU access to
a page whilst it is being accessed from a device. Typically this is
used to implement atomic operations when the underlying bus does not
support atomic access. When a CPU thread
On Mon, 27 Mar 2023 23:25:49 -0700 John Hubbard wrote:
> On the patch process, I see that this applies to linux-stable's 6.1.y
> branch. I'd suggest two things:
>
> 1) Normally, what I've seen done is to post against either the current
> top of tree linux.git, or else against one of the
On 3/27/23 19:14, Alistair Popple wrote:
> Device exclusive page table entries are used to prevent CPU access to
> a page whilst it is being accessed from a device. Typically this is
> used to implement atomic operations when the underlying bus does not
> support atomic access. When a CPU thread
Device exclusive page table entries are used to prevent CPU access to
a page whilst it is being accessed from a device. Typically this is
used to implement atomic operations when the underlying bus does not
support atomic access. When a CPU thread encounters a device exclusive
entry it locks the
