On 21.11.18 00:13, Dan Williams wrote:
> In preparation for consolidating all ZONE_DEVICE enabling via
> devm_memremap_pages(), teach it how to handle the constraints of
> MEMORY_DEVICE_PRIVATE ranges.
>
> Reviewed-by: Jérôme Glisse <jgli...@redhat.com>
> [jglisse: call move_pfn_range_to_zone for MEMORY_DEVICE_PRIVATE]
> Acked-by: Christoph Hellwig <h...@lst.de>
> Reported-by: Logan Gunthorpe <log...@deltatee.com>
> Reviewed-by: Logan Gunthorpe <log...@deltatee.com>
> Signed-off-by: Dan Williams <dan.j.willi...@intel.com>
> ---
> kernel/memremap.c | 53
> +++++++++++++++++++++++++++++++++++++++++------------
> 1 file changed, 41 insertions(+), 12 deletions(-)
>
> diff --git a/kernel/memremap.c b/kernel/memremap.c
> index 5e45f0c327a5..3eef989ef035 100644
> --- a/kernel/memremap.c
> +++ b/kernel/memremap.c
> @@ -98,9 +98,15 @@ static void devm_memremap_pages_release(void *data)
> - align_start;
>
> mem_hotplug_begin();
> - arch_remove_memory(align_start, align_size, pgmap->altmap_valid ?
> - &pgmap->altmap : NULL);
> - kasan_remove_zero_shadow(__va(align_start), align_size);
> + if (pgmap->type == MEMORY_DEVICE_PRIVATE) {
> + pfn = align_start >> PAGE_SHIFT;
> + __remove_pages(page_zone(pfn_to_page(pfn)), pfn,
> + align_size >> PAGE_SHIFT, NULL);
> + } else {
> + arch_remove_memory(align_start, align_size,
> + pgmap->altmap_valid ? &pgmap->altmap : NULL);
> + kasan_remove_zero_shadow(__va(align_start), align_size);
> + }
> mem_hotplug_done();
>
> untrack_pfn(NULL, PHYS_PFN(align_start), align_size);
> @@ -187,17 +193,40 @@ void *devm_memremap_pages(struct device *dev, struct
> dev_pagemap *pgmap)
> goto err_pfn_remap;
>
> mem_hotplug_begin();
> - error = kasan_add_zero_shadow(__va(align_start), align_size);
> - if (error) {
> - mem_hotplug_done();
> - goto err_kasan;
> +
> + /*
> + * For device private memory we call add_pages() as we only need to
> + * allocate and initialize struct page for the device memory. More-
> + * over the device memory is un-accessible thus we do not want to
> + * create a linear mapping for the memory like arch_add_memory()
> + * would do.
> + *
> + * For all other device memory types, which are accessible by
> + * the CPU, we do want the linear mapping and thus use
> + * arch_add_memory().
> + */
I consider this comment really useful. :)
Short question: Right now, MEMORY_DEVICE_PRIVATE always indicates HMM,
correct? (I am just confused by the naming but I assume
MEMORY_DEVICE_PRIVATE is more generic than HMM)
--
Thanks,
David / dhildenb
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