mirror of https://github.com/mkerrisk/man-pages
shmop.2: Explain SHMLBA in much more detail
Signed-off-by: Michael Kerrisk <mtk.manpages@gmail.com>
This commit is contained in:
parent
e530d422dc
commit
2d2c6782ae
16
man2/shmop.2
16
man2/shmop.2
|
@ -282,14 +282,16 @@ The following system parameter affects
|
||||||
.\" of SHMLBA would be useful here
|
.\" of SHMLBA would be useful here
|
||||||
.B SHMLBA
|
.B SHMLBA
|
||||||
Segment low boundary address multiple.
|
Segment low boundary address multiple.
|
||||||
Must be page aligned.
|
When explicitly specifying an attach address in a call to
|
||||||
For the current implementation, the
|
.BR shmat (),
|
||||||
|
the caller should ensure that the address is a multiple of this value.
|
||||||
|
This is necessary on some architectures,
|
||||||
|
in order either to ensure good CPU cache performance or to ensure that
|
||||||
|
different attaches of the same segment have consistent views
|
||||||
|
within the CPU cache.
|
||||||
.B SHMLBA
|
.B SHMLBA
|
||||||
value is
|
is normally some multiple of the system page size
|
||||||
.BR PAGE_SIZE .
|
(on many Linux architectures, it is the same as the system page size).
|
||||||
.\" FIXME That last sentence isn't true for all Linux
|
|
||||||
.\" architectures (i.e., SHMLBA != PAGE_SIZE for some architectures)
|
|
||||||
.\" -- MTK, Nov 04
|
|
||||||
.PP
|
.PP
|
||||||
The implementation places no intrinsic per-process limit on the
|
The implementation places no intrinsic per-process limit on the
|
||||||
number of shared memory segments
|
number of shared memory segments
|
||||||
|
|
Loading…
Reference in New Issue