Author: avg
Date: Fri Jul 23 16:46:42 2010
New Revision: 210422
URL: http://svn.freebsd.org/changeset/base/210422
Log:
cpufreq: allocate long-lived buffer for handling of sysctl requests
At present the cpufreq sysctl handler for current level setting would
allocate and deallocate a temporary buffer of 24KB even to handle a
read-only query. This puts unnecessary load on memory subsystem when
current level is checked frequently, e.g. when the likes of powerd
and system monitoring software are running.
Change the strategy to allocating a long-lived buffer for handling the
requests.
Reviewed by: njl
MFC after: 2 weeks
Modified:
head/sys/kern/kern_cpu.c
Modified: head/sys/kern/kern_cpu.c
==============================================================================
--- head/sys/kern/kern_cpu.c Fri Jul 23 15:32:44 2010 (r210421)
+++ head/sys/kern/kern_cpu.c Fri Jul 23 16:46:42 2010 (r210422)
@@ -76,6 +76,7 @@ struct cpufreq_softc {
device_t dev;
struct sysctl_ctx_list sysctl_ctx;
struct task startup_task;
+ struct cf_level *levels_buf;
};
struct cf_setting_array {
@@ -180,6 +181,8 @@ cpufreq_attach(device_t dev)
CF_DEBUG("initializing one-time data for %s\n",
device_get_nameunit(dev));
+ sc->levels_buf = malloc(CF_MAX_LEVELS * sizeof(*sc->levels_buf),
+ M_DEVBUF, M_WAITOK);
SYSCTL_ADD_PROC(&sc->sysctl_ctx,
SYSCTL_CHILDREN(device_get_sysctl_tree(parent)),
OID_AUTO, "freq", CTLTYPE_INT | CTLFLAG_RW, sc, 0,
@@ -227,6 +230,7 @@ cpufreq_detach(device_t dev)
numdevs = devclass_get_count(cpufreq_dc);
if (numdevs == 1) {
CF_DEBUG("final shutdown for %s\n", device_get_nameunit(dev));
+ free(sc->levels_buf, M_DEVBUF);
}
return (0);
@@ -870,9 +874,7 @@ cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS)
devs = NULL;
sc = oidp->oid_arg1;
- levels = malloc(CF_MAX_LEVELS * sizeof(*levels), M_TEMP, M_NOWAIT);
- if (levels == NULL)
- return (ENOMEM);
+ levels = sc->levels_buf;
error = CPUFREQ_GET(sc->dev, &levels[0]);
if (error)
@@ -915,8 +917,6 @@ cpufreq_curr_sysctl(SYSCTL_HANDLER_ARGS)
out:
if (devs)
free(devs, M_TEMP);
- if (levels)
- free(levels, M_TEMP);
return (error);
}
@@ -934,7 +934,7 @@ cpufreq_levels_sysctl(SYSCTL_HANDLER_ARG
/* Get settings from the device and generate the output string. */
count = CF_MAX_LEVELS;
- levels = malloc(count * sizeof(*levels), M_TEMP, M_NOWAIT);
+ levels = sc->levels_buf;
if (levels == NULL) {
sbuf_delete(&sb);
return (ENOMEM);
@@ -957,7 +957,6 @@ cpufreq_levels_sysctl(SYSCTL_HANDLER_ARG
error = sysctl_handle_string(oidp, sbuf_data(&sb), sbuf_len(&sb), req);
out:
- free(levels, M_TEMP);
sbuf_delete(&sb);
return (error);
}
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