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1970dc6f52
Now that pages are "DMA-pinned" via pin_user_page*(), and unpinned via
unpin_user_pages*(), we need some visibility into whether all of this is
working correctly.
Add two new fields to /proc/vmstat:
nr_foll_pin_acquired
nr_foll_pin_released
These are documented in Documentation/core-api/pin_user_pages.rst. They
represent the number of pages (since boot time) that have been pinned
("nr_foll_pin_acquired") and unpinned ("nr_foll_pin_released"), via
pin_user_pages*() and unpin_user_pages*().
In the absence of long-running DMA or RDMA operations that hold pages
pinned, the above two fields will normally be equal to each other.
Also: update Documentation/core-api/pin_user_pages.rst, to remove an
earlier (now confirmed untrue) claim about a performance problem with
/proc/vmstat.
Also: update Documentation/core-api/pin_user_pages.rst to rename the new
/proc/vmstat entries, to the names listed here.
Signed-off-by: John Hubbard <jhubbard@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Reviewed-by: Jan Kara <jack@suse.cz>
Acked-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200211001536.1027652-9-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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|---|---|---|
| .. | ||
| assoc_array.rst | ||
| atomic_ops.rst | ||
| boot-time-mm.rst | ||
| cachetlb.rst | ||
| circular-buffers.rst | ||
| cpu_hotplug.rst | ||
| debug-objects.rst | ||
| errseq.rst | ||
| genalloc.rst | ||
| generic-radix-tree.rst | ||
| genericirq.rst | ||
| gfp_mask-from-fs-io.rst | ||
| idr.rst | ||
| index.rst | ||
| kernel-api.rst | ||
| kobject.rst | ||
| librs.rst | ||
| local_ops.rst | ||
| memory-allocation.rst | ||
| memory-hotplug.rst | ||
| mm-api.rst | ||
| packing.rst | ||
| padata.rst | ||
| pin_user_pages.rst | ||
| printk-formats.rst | ||
| protection-keys.rst | ||
| refcount-vs-atomic.rst | ||
| symbol-namespaces.rst | ||
| timekeeping.rst | ||
| tracepoint.rst | ||
| workqueue.rst | ||
| xarray.rst | ||