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| author | John Baldwin <jhb@FreeBSD.org> | 2001-10-24 22:15:38 +0000 |
|---|---|---|
| committer | John Baldwin <jhb@FreeBSD.org> | 2001-10-24 22:15:38 +0000 |
| commit | 882bcf5879dfb26b6c35784e9020676122b37a33 (patch) | |
| tree | 7c0f033b626d825696123f875ee72308bcded23a /sys/kern/subr_pcpu.c | |
| parent | 02185af5a923aaf16e1109a61a1d46e6f166ff69 (diff) | |
| download | src-882bcf5879dfb26b6c35784e9020676122b37a33.tar.gz src-882bcf5879dfb26b6c35784e9020676122b37a33.zip | |
Document the requirements and nature of the logical CPU IDs. It isn't
very strict and leaves much up to the platform so that it can define a
convenient mapping.
Requested by: mjacob
Notes
Notes:
svn path=/head/; revision=85444
Diffstat (limited to 'sys/kern/subr_pcpu.c')
| -rw-r--r-- | sys/kern/subr_pcpu.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/sys/kern/subr_pcpu.c b/sys/kern/subr_pcpu.c index 47ac12e12edf..10a0d988ea42 100644 --- a/sys/kern/subr_pcpu.c +++ b/sys/kern/subr_pcpu.c @@ -32,6 +32,16 @@ /* * This module provides MI support for per-cpu data. + * + * Each architecture determines the mapping of logical CPU IDs to physical + * CPUs. The requirements of this mapping are as follows: + * - Logical CPU IDs must reside in the range 0 ... MAXCPU - 1. + * - The mapping is not required to be dense. That is, there may be + * gaps in the mappings. + * - The platform sets the value of MAXCPU in <machine/param.h>. + * - It is suggested, but not required, that in the non-SMP case, the + * platform define MAXCPU to be 1 and define the logical ID of the + * sole CPU as 0. */ #include <sys/param.h> |