On Sun, Dec 26, 2021 at 10:34:33PM +0800, Shiyang Ruan wrote:
> When memory-failure occurs, we call this function which is implemented
> by each kind of devices. For the fsdax case, pmem device driver
> implements it. Pmem device driver will find out the filesystem in which
> the corrupted page located in.
>
> With dax_holder notify support, we are able to notify the memory failure
> from pmem driver to upper layers. If there is something not support in
> the notify routine, memory_failure will fall back to the generic hanlder.
>
> Signed-off-by: Shiyang Ruan <ruansy.fnst@xxxxxxxxxxx>
> Reviewed-by: Christoph Hellwig <hch@xxxxxx>
> ---
> drivers/nvdimm/pmem.c | 16 ++++++++++++++++
> include/linux/memremap.h | 9 +++++++++
> mm/memory-failure.c | 14 ++++++++++++++
> 3 files changed, 39 insertions(+)
>
> diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c
> index 4190c8c46ca8..2114554358eb 100644
> --- a/drivers/nvdimm/pmem.c
> +++ b/drivers/nvdimm/pmem.c
> @@ -386,6 +386,20 @@ static void pmem_release_disk(void *__pmem)
> blk_cleanup_disk(pmem->disk);
> }
>
> +static int pmem_pagemap_memory_failure(struct dev_pagemap *pgmap,
> + unsigned long pfn, u64 len, int mf_flags)
> +{
> + struct pmem_device *pmem =
> + container_of(pgmap, struct pmem_device, pgmap);
> + loff_t offset = PFN_PHYS(pfn) - pmem->phys_addr - pmem->data_offset;
Use u64 here ^^^ because this isn't a file offset, this is a physical
offset. Also, loff_t is signed, which you probably don't want.
> +
> + return dax_holder_notify_failure(pmem->dax_dev, offset, len, mf_flags);
> +}
> +
> +static const struct dev_pagemap_ops fsdax_pagemap_ops = {
> + .memory_failure = pmem_pagemap_memory_failure,
> +};
> +
> static int pmem_attach_disk(struct device *dev,
> struct nd_namespace_common *ndns)
> {
> @@ -448,6 +462,7 @@ static int pmem_attach_disk(struct device *dev,
> pmem->pfn_flags = PFN_DEV;
> if (is_nd_pfn(dev)) {
> pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
> + pmem->pgmap.ops = &fsdax_pagemap_ops;
> addr = devm_memremap_pages(dev, &pmem->pgmap);
> pfn_sb = nd_pfn->pfn_sb;
> pmem->data_offset = le64_to_cpu(pfn_sb->dataoff);
> @@ -461,6 +476,7 @@ static int pmem_attach_disk(struct device *dev,
> pmem->pgmap.range.end = res->end;
> pmem->pgmap.nr_range = 1;
> pmem->pgmap.type = MEMORY_DEVICE_FS_DAX;
> + pmem->pgmap.ops = &fsdax_pagemap_ops;
> addr = devm_memremap_pages(dev, &pmem->pgmap);
> pmem->pfn_flags |= PFN_MAP;
> bb_range = pmem->pgmap.range;
> diff --git a/include/linux/memremap.h b/include/linux/memremap.h
> index c0e9d35889e8..820c2f33b163 100644
> --- a/include/linux/memremap.h
> +++ b/include/linux/memremap.h
> @@ -87,6 +87,15 @@ struct dev_pagemap_ops {
> * the page back to a CPU accessible page.
> */
> vm_fault_t (*migrate_to_ram)(struct vm_fault *vmf);
> +
> + /*
> + * Handle the memory failure happens on a range of pfns. Notify the
> + * processes who are using these pfns, and try to recover the data on
> + * them if necessary. The mf_flags is finally passed to the recover
> + * function through the whole notify routine.
Might want to state here that the generic implementation will be used if
->memory_failure is NULL or calling the function returns -EOPNOTSUPP.
--D
> + */
> + int (*memory_failure)(struct dev_pagemap *pgmap, unsigned long pfn,
> + u64 len, int mf_flags);
> };
>
> #define PGMAP_ALTMAP_VALID (1 << 0)
> diff --git a/mm/memory-failure.c b/mm/memory-failure.c
> index 1ee7d626fed7..3cc612b29f89 100644
> --- a/mm/memory-failure.c
> +++ b/mm/memory-failure.c
> @@ -1625,6 +1625,20 @@ static int memory_failure_dev_pagemap(unsigned long pfn, int flags,
> if (!pgmap_pfn_valid(pgmap, pfn))
> goto out;
>
> + /*
> + * Call driver's implementation to handle the memory failure, otherwise
> + * fall back to generic handler.
> + */
> + if (pgmap->ops->memory_failure) {
> + rc = pgmap->ops->memory_failure(pgmap, pfn, PAGE_SIZE, flags);
> + /*
> + * Fall back to generic handler too if operation is not
> + * supported inside the driver/device/filesystem.
> + */
> + if (rc != -EOPNOTSUPP)
> + goto out;
> + }
> +
> rc = mf_generic_kill_procs(pfn, flags, pgmap);
> out:
> /* drop pgmap ref acquired in caller */
> --
> 2.34.1
>
>
>
