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Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/vm/hmm.rst | 26 |
1 files changed, 0 insertions, 26 deletions
diff --git a/Documentation/vm/hmm.rst b/Documentation/vm/hmm.rst index 7cdf7282e022..50e1380950a9 100644 --- a/Documentation/vm/hmm.rst +++ b/Documentation/vm/hmm.rst @@ -329,32 +329,6 @@ directly using struct page for device memory which left most kernel code paths unaware of the difference. We only need to make sure that no one ever tries to map those pages from the CPU side. -HMM provides a set of helpers to register and hotplug device memory as a new -region needing a struct page. This is offered through a very simple API:: - - struct hmm_devmem *hmm_devmem_add(const struct hmm_devmem_ops *ops, - struct device *device, - unsigned long size); - void hmm_devmem_remove(struct hmm_devmem *devmem); - -The hmm_devmem_ops is where most of the important things are:: - - struct hmm_devmem_ops { - void (*free)(struct hmm_devmem *devmem, struct page *page); - int (*fault)(struct hmm_devmem *devmem, - struct vm_area_struct *vma, - unsigned long addr, - struct page *page, - unsigned flags, - pmd_t *pmdp); - }; - -The first callback (free()) happens when the last reference on a device page is -dropped. This means the device page is now free and no longer used by anyone. -The second callback happens whenever the CPU tries to access a device page -which it cannot do. This second callback must trigger a migration back to -system memory. - Migration to and from device memory =================================== |