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15 .\" FIXME Should programs normally be using move_pages() directly, or should
16 .\" they rather be using interfaces in the numactl package?
17 .\" (e.g., compare with recommendation in mbind(2)).
18 .\" Does this page need to give advise on this topic?
19 .TH MOVE_PAGES 2 2010-06-11 "Linux" "Linux Programmer's Manual"
21 move_pages \- move individual pages of a process to another node
24 .B #include <numaif.h>
26 .BI "long move_pages(int " pid ", unsigned long count, void **" pages ,
27 .BI " const int *" nodes ", int *" status ", int " flags );
30 Link with \fI\-lnuma\fP.
37 to the memory nodes specified by
39 The result of the move is reflected in
43 indicate constraints on the pages to be moved.
46 is the ID of the process in which pages are to be moved.
47 To move pages in another process,
48 the caller must be privileged
50 or the real or effective user ID of the calling process must match the
51 real or saved-set user ID of the target process.
56 moves pages of the calling process.
59 is the number of pages to move.
60 It defines the size of the three arrays
67 is an array of pointers to the pages that should be moved.
68 These are pointers that should be aligned to page boundaries.
69 .\" FIXME Describe the result if pointers in the 'pages' array are
70 .\" not aligned to page boundaries
71 Addresses are specified as seen by the process specified by
75 is an array of integers that specify the desired location for each page.
76 Each element in the array is a node number.
78 can also be NULL, in which case
80 does not move any pages but instead will return the node
81 where each page currently resides, in the
84 Obtaining the status of each page may be necessary to determine
85 pages that need to be moved.
88 is an array of integers that return the status of each page.
89 The array contains valid values only if
91 did not return an error.
94 specify what types of pages to move.
96 means that only pages that are in exclusive use by the process
99 means that pages shared between multiple processes can also be moved.
100 The process must be privileged
103 .BR MPOL_MF_MOVE_ALL .
104 .SS Page states in the status array
105 The following values can be returned in each element of the
110 Identifies the node on which the page resides.
113 The page is mapped by multiple processes and can be moved only if
118 The page is currently busy and cannot be moved.
120 This occurs if a page is undergoing I/O or another kernel subsystem
121 is holding a reference to the page.
124 This is a zero page or the memory area is not mapped by the process.
127 Unable to write back a page.
128 The page has to be written back
129 in order to move it since the page is dirty and the filesystem
130 does not provide a migration function that would allow the move
134 A dirty page cannot be moved.
135 The filesystem does not
136 provide a migration function and has no ability to write back pages.
139 The page is not present.
142 Unable to allocate memory on target node.
147 .\" FIXME . Is the following quite true: does the wrapper in numactl
148 .\" do the right thing?
149 On error, it returns \-1, and sets
151 to indicate the error.
155 Too many pages to move.
158 .\" FIXME Clarify "current cpuset" in the description of the EACCESS error.
159 .\" Is that the cpuset of the caller or the target?
160 One of the target nodes is not allowed by the current cpuset.
163 Parameter array could not be accessed.
170 was specified or an attempt was made to migrate pages of a kernel thread.
173 One of the target nodes is not online.
176 No pages were found that require moving.
177 All pages are either already
178 on the target node, not present, had an invalid address or could not be
179 moved because they were mapped by multiple processes.
184 without sufficient privileges
185 .RB ( CAP_SYS_NICE ).
186 Or, the caller attempted to move pages of a process belonging
187 to another user but did not have privilege to do so
188 .RB ( CAP_SYS_NICE ).
191 Process does not exist.
194 first appeared on Linux in version 2.6.18.
196 This system call is Linux-specific.
198 For information on library support, see
202 .BR get_mempolicy (2)
204 .B MPOL_F_MEMS_ALLOWED
205 flag to obtain the set of nodes that are allowed by
206 .\" FIXME Clarify "current cpuset". Is that the cpuset of the caller
209 Note that this information is subject to change at any
210 time by manual or automatic reconfiguration of the cpuset.
212 Use of this function may result in pages whose location
213 (node) violates the memory policy established for the
214 specified addresses (See
216 and/or the specified process (See
217 .BR set_mempolicy (2)).
218 That is, memory policy does not constrain the destination
224 header is not included with glibc, but requires installing
226 or a similar package.
228 .BR get_mempolicy (2),
230 .BR set_mempolicy (2),
235 .BR migratepages (8),
238 This page is part of release 3.79 of the Linux
241 A description of the project,
242 information about reporting bugs,
243 and the latest version of this page,
245 \%http://www.kernel.org/doc/man\-pages/.