UVM_HOTPLUG(9) | Kernel Developer's Manual | UVM_HOTPLUG(9) |
uvm_physseg_init
,
uvm_physseg_valid
,
uvm_physseg_get_start
,
uvm_physseg_get_end
,
uvm_physseg_get_avail_start
,
uvm_physseg_get_avail_end
,
uvm_physseg_get_pg
,
uvm_physseg_get_pmseg
,
uvm_physseg_get_free_list
,
uvm_physseg_get_start_hint
,
uvm_physseg_set_start_hint
,
uvm_physseg_get_next
,
uvm_physseg_get_prev
,
uvm_physseg_get_first
,
uvm_physseg_get_last
,
uvm_physseg_get_highest_frame
,
uvm_physseg_find
,
uvm_page_physload
,
uvm_page_physunload
,
uvm_page_physunload_force
,
uvm_physseg_plug
,
uvm_physseg_unplug
,
uvm_physseg_set_avail_start
,
uvm_physseg_set_avail_end
—
#include <uvm/uvm_physseg.h>
void
uvm_physseg_init
(void);
uvm_physseg_t
uvm_page_physload
(paddr_t
start, paddr_t end,
paddr_t avail_start,
paddr_t avail_end,
int free_list);
bool
uvm_page_physunload
(uvm_physseg_t
upm, int free_list,
paddr_t *paddrp);
bool
uvm_page_physunload_force
(uvm_physseg_t
upm, int free_list,
paddr_t *paddrp);
bool
uvm_physseg_plug
(paddr_t
pfn, size_t npages,
uvm_physseg_t *upmp);
bool
uvm_physseg_unplug
(paddr_t
pfn, size_t
npages);
'options
UVM_HOTPLUG'
, memory segments are handled in a dynamic data structure
(rbtree(3)) compared to a static
array when not. This enables kernel code to add or remove information about
memory segments at any point after boot - thus "hotplug".
uvm_page_physload
(),
uvm_page_physunload
(), and
uvm_page_physunload_force
() are legacy interfaces
which may be removed in the future. They must never be used after
uvm_init(9).
WARNING: This is an experimental feature and
should not be used in production environments. Furthermore, attempting to
"hotplug" without 'options UVM_HOTPLUG'
after boot will almost certainly end in a
panic(9).
uvm_physseg_init
() initializes the hotplug
subsystem. This is expected to happen exactly once, at boot time, and from MD
code.
uvm_page_physload
() registers
uvm(9) with a memory segment span,
and on a specified free_list. It must be called at
system boot time as part of setting up memory management. The arguments
describe the start and end of the physical addresses of the segment, and the
available start and end addresses of pages not already in use. If a system has
memory banks of different speeds the slower memory should be given a higher
free_list value.
This function returns a valid
uvm_physseg_t
handle when a successful plug occurs,
else it will return UVM_PHYSSEG_TYPE_INVALID
when
the plug fails.
uvm_physseg_plug
() registers
uvm(9) with a memory segment
span. It can also be called to initiate a hotplug and register a newly
"hotplugged" physical memory range into the VM. Unlike
uvm_page_physload
() this function can, if
'options UVM_HOTPLUG'
is enabled at compile time, be
used after uvm_init(9). The
arguments describe the start page frame, the number of pages to plug
starting from the start page frame and an optional return variable, which
points to a valid uvm_physseg_t handle when a
successful plug occurs.
NULL
, then on a successful plug, a
valid pointer to the uvm_physseg_t handle for the segment which was
plugged is returned.This function returns true when a successful plug occurs, false otherwise.
uvm_page_physunload
(),
uvm_page_physunload_force
(), and
uvm_physseg_unplug
() make
uvm(9) forget about previously
registered memory segments or portions of such.
uvm_page_physunload
() unloads pages from a
segment (from the front or from the back) depending on its availability.
When the last page is removed, the segment handle is invalidated and
supporting metadata is freed.
Note: This function can only be used during boot time. Pages, once
unloaded, are unregistered from uvm and are therefore assumed to be managed
by the code which called
uvm_page_physunload
(9)
(usually boot time MD code, for boottime memory "allocation").
The arguments are:
If the unload was successful, true is returned, false otherwise.
uvm_page_physunload_force
()
unconditionally unloads pages from a segment. When the last page is removed,
the segment handle is invalidated and supporting metadata is freed.
Note: This function can only be used during boot time. Pages, once
unloaded, are unregistered from uvm and are therefore assumed to be managed
by the code which called
uvm_page_physunload_force
(9)
(usually boot time MD code, for boottime memory "allocation").
The arguments are:
If the unload was successful true is returned, false otherwise.
uvm_physseg_unplug
() can be called to
unplug an existing physical memory segment. Unlike
uvm_page_physunload
() and
uvm_page_physunload_force
(), it can be called after
uvm_init(9), if
'options UVM_HOTPLUG'
is enabled at compile time.
uvm_hotplug
(9) makes no effort
to manage the state of the underlying physical memory. It is up to the
caller to ensure that it is not in use, either by
uvm(9), or by any other
sub-system. Further, any hardware quiescing that may be required is the
responsibility of MD code. The arguments describe the start page frame and
the number of pages to unplug. The arguments are:
Returns true or false depending on success or failure respectively.
uvm_physseg_valid
(uvm_physseg_t
upm)uvm_physseg_get_start
(uvm_physseg_t
upm)uvm_physseg_get_end
(uvm_physseg_t
upm)uvm_physseg_get_avail_start
(uvm_physseg_t
upm)uvm_physseg_get_avail_end
(uvm_physseg_t
upm)uvm_physseg_get_pg
(uvm_physseg_t
upm, paddr_t index)uvm_physseg_get_pmesg
(uvm_physseg_t
upm)uvm_physseg_get_free_list
(uvm_physseg_t
upm)uvm_physseg_get_start_hint
(uvm_physseg_t
upm)uvm_physseg_set_start_hint
(uvm_physseg_t
upm, u_int start_hint)uvm_physseg_get_next
(uvm_physseg_t
upm)uvm_physseg_get_prev
(uvm_physseg_t
upm)uvm_physseg_get_first
(void)uvm_physseg_get_last
(void)uvm_physseg_get_highest_frame
(void)uvm_physseg_find
(paddr
pframe, psize_t *offsetp)uvm_physseg_set_avail_start
(uvm_physseg_t
upm, paddr_t avail_start)uvm_physseg_set_avail_end
(uvm_physseg_t
upm, paddr_t avail_end)uvm_physseg_valid
() validates a handle
that is passed in, returns true if the given handle is
valid, false otherwise.
uvm_physseg_get_start
() if a valid
uvm_physseg_t handle is passed in, it returns the
starting physical address of the segment. The returned value is of type
paddr_t. In case the handle is invalid the returned
value will match (paddr_t) -1.
uvm_physseg_get_end
() if a valid
uvm_physseg_t handle is passed in, it returns the
ending physical address of the segment. The returned value is of type
paddr_t. In case the handle is invalid the returned
value will match (paddr_t) -1.
uvm_physseg_get_avail_start
() if a valid
uvm_physseg_t handle is passed in, it returns the
available starting physical address of the segment. The returned value is of
type paddr_t. In case the handle is invalid the
returned value will match (paddr_t) -1.
uvm_physseg_get_avail_end
() if a valid
uvm_physseg_t handle is passed in, it returns the
available ending physical address of the segment. The returned value is of
type paddr_t. In case the handle is invalid the
returned value will match (paddr_t) -1.
uvm_physseg_get_pg
() if a valid
uvm_physseg_t handle along with an index value is
passed in, it returns the struct vm_page * object
contained in that location.
uvm_physseg_get_pmseg
() if a valid
uvm_physseg_t handle is passed in, it returns the
struct pmap_physseg * object contained in the
handle.
uvm_physseg_get_free_list
() if a valid
uvm_physseg_t handle is passed in, it returns the
free_list type for which the current segment is
associated with. The returned value is of type
int.
uvm_physseg_get_start_hint
() if a valid
uvm_physseg_t handle is passed in, it returns the
start_hint type for the current segment. The returned
value is of type u_int.
uvm_physseg_set_start_hint
() if a valid
handle along with the start_hint is passed in, the
value is set in the segment. And a true is returned to
indicate a successful value setting. In case the handle is invalid a
false is returned.
uvm_physseg_get_next
() if a valid handle
is passed in, it returns the next valid uvm_physseg_t
handle in the sequence. However if the handle passed is the last segment in
the sequence the function returns
UVM_PHYSSEG_TYPE_INVALID_OVERFLOW. Passing an invalid
handle is not fatal, and returns
UVM_PHYSSEG_TYPE_INVALID.
uvm_physseg_get_prev
() if a valid handle
is passed in, it returns the previous validh
uvm_physseg_t handle in the sequence. However if the
handle passed is the first segment in the sequence the function returns
UVM_PHYSSEG_TYPE_INVALID_EMPTY. Passing an invalid
handle is not fatal, and returns
UVM_PHYSSEG_TYPE_INVALID.
uvm_physseg_get_first
() returns the first
valid uvm_physseg_t handle in the sequence. However if
there are no valid handles in the sequence yet, the function returns
UVM_PHYSSEG_TYPE_INVALID_EMPTY.
uvm_physseg_get_last
() returns the last
valid uvm_physseg_t handle in the sequence. However if
there are no valid handles in the sequence yet, the function returns
UVM_PHYSSEG_TYPE_INVALID_EMPTY.
uvm_physseg_get_highest_frame
() returns
the frame number of the highest registered physical page frame which is of
type paddr_t. XXX: Searching on empty sequences are
not yet processed in the function.
uvm_physseg_find
() searches for a given
segment containing the page frame (paddr_t) passed in.
If a segment that falls between starting and ending addresses is found, the
corresponding uvm_physseg_t handle is returned else a
UVM_PHYSSEG_TYPE_INVALID is returned. The second
parameter, if not set to NULL
, the offset value of
the page frame passed in with respect to the starting address is set to the
appropriate psize_t value if the search was successful
in finding the segment.
uvm_physseg_set_avail_start
() if a valid
uvm_physseg_t handle is passed in along with the
available starting physical address of the segment of type
paddr_t, the value is set in the segment.
uvm_physseg_set_avail_end
() if a valid
uvm_physseg_t handle is passed in along with the
available ending physical address of the segment of type
paddr_t, the value is set in the segment.
uvm_physseg_plug
() and
uvm_physseg_unplug
() must never be used after
uvm_init(9) in a kernel build
where 'options UVM_HOTPLUG'
is not enabled.
uvm_physseg_init
are in
tests/sys/uvm.
Unit / functional tests are in
tests/sys/uvm/t_uvm_physseg.c. These tests focus on
the expected working of the uvm_physseg_init
API and
its utility functions.
Load tests can be found in
tests/sys/uvm/t_uvm_physseg_load.c. These tests
focus on stressing the uvm_physseg_init
implementation in order to make performance comparisons between kernel
builds with and without 'options UVM_HOTPLUG'
Santhosh N. Raju <santhosh.raju@gmail.com> implemented the dynamic segment handling code and all tests for this API.
Nick Hudson <skrll@NetBSD.org> contributed bugfixes and testing on a wide range of hardware ports.
November 20, 2016 | NetBSD 9.2 |