Messages in this thread | | | Subject | Re: [PATCH v4 2/2] mm/gup/writeback: add callbacks for inaccessible pages | From | Dave Hansen <> | Date | Thu, 16 Apr 2020 07:20:48 -0700 |
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On 4/16/20 5:15 AM, Claudio Imbrenda wrote: >> I assumed that this was all anonymous-only so it's always dirty before >> writeback starts. > it could also be mmapped
Let's say you have a mmap()'d ramfs file. Another process calls which doesn't have it mapped calls sys_write() and writes to the file.
This means that host host has to write to the physical page and must do arch_make_page_accessible() in the sys_write() path somewhere.
There is a get_user_pages() in that path, but it's on the _source_ buffer, not the ramfs page because the ramfs page is not mapped. There's also no __test_set_page_writeback() because you can't write back ramfs.
Where is the arch_make_page_accessible() in this case on the ramfs page?
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