pmemblk_ctl_get(3)

1()                         PMDK Programmer's Manual                         ()
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NAME

6       pmemblk_ctl_get()(DEPRECATED),   pmemblk_ctl_set()(DEPRECATED),   pmem‐
7       blk_ctl_exec()(DEPRECATED) - Query and modify libpmemblk  internal  be‐
8       havior (EXPERIMENTAL)
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SYNOPSIS

11              #include <libpmemblk.h>
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13              int pmemblk_ctl_get(PMEMblkpool *pbp, const char *name, void *arg); (EXPERIMENTAL)
14              int pmemblk_ctl_set(PMEMblkpool *pbp, const char *name, void *arg); (EXPERIMENTAL)
15              int pmemblk_ctl_exec(PMEMblkpool *pbp, const char *name, void *arg); (EXPERIMENTAL)
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DESCRIPTION

18       The  pmemblk_ctl_get(),  pmemblk_ctl_set() and pmemblk_ctl_exec() func‐
19       tions provide a uniform interface for querying and modifying the inter‐
20       nal behavior of libpmemblk(7) through the control (CTL) namespace.
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22       The  name argument specifies an entry point as defined in the CTL name‐
23       space specification.  The entry point description specifies whether the
24       extra  arg  is  required.   Those  two parameters together create a CTL
25       query.  The functions and the entry points are thread-safe unless indi‐
26       cated  otherwise below.  If there are special conditions for calling an
27       entry point, they are explicitly stated in its description.  The  func‐
28       tions propagate the return value of the entry point.  If either name or
29       arg is invalid, -1 is returned.
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31       If the provided ctl query is valid, the CTL functions will  always  re‐
32       turn  0 on success and -1 on failure, unless otherwise specified in the
33       entry point description.
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35       See more in pmem_ctl(5) man page.
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CTL NAMESPACE

38       prefault.at_create | rw | global | int | int | - | boolean
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40       If set, every page of the pool will be touched and written to when  the
41       pool  is  created, in order to trigger page allocation and minimize the
42       performance impact of pagefaults.  Affects  only  the  pmemblk_create()
43       function.
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45       Always returns 0.
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47       prefault.at_open | rw | global | int | int | - | boolean
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49       If  set, every page of the pool will be touched and written to when the
50       pool is opened, in order to trigger page allocation  and  minimize  the
51       performance  impact  of  pagefaults.   Affects  only the pmemblk_open()
52       function.
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54       Always returns 0.
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56       sds.at_create | rw | global | int | int | - | boolean
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58       If set, force-enables or force-disables SDS feature  during  pool  cre‐
59       ation.   Affects only the pmemblk_create() function.  See pmempool_fea‐
60       ture_query(3) for information about SDS (SHUTDOWN_STATE) feature.
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62       Always returns 0.
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64       copy_on_write.at_open | rw | global | int | int | - | boolean
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66       If set, pool is mapped in such a way that modifications don’t reach the
67       underlying  medium.   From  the user’s perspective this means that when
68       the pool is closed all changes are reverted.  This feature is not  sup‐
69       ported for pools located on Device DAX.
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71       Always returns 0.
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CTL EXTERNAL CONFIGURATION

74       In addition to direct function call, each write entry point can also be
75       set using two alternative methods.
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77       The first method is to load a configuration  directly  from  the  PMEM‐
78       BLK_CONF environment variable.
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80       The  second  method  of loading an external configuration is to set the
81       PMEMBLK_CONF_FILE environment variable to point to a file that contains
82       a sequence of ctl queries.
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84       See more in pmem_ctl(5) man page.
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NAME

SYNOPSIS

DESCRIPTION

CTL NAMESPACE

CTL EXTERNAL CONFIGURATION

SEE ALSO