Hi Tony,
On 7/2/24 2:46 PM, Tony Luck wrote:
On Tue, Jul 02, 2024 at 02:26:25PM -0700, Reinette Chatre wrote:
Hi Tony,
On 7/1/24 9:04 AM, Luck, Tony wrote:
+static bool cpus_offline_empty(void)
+{
+ char offline_cpus_str[64];
+ FILE *fp;
+
+ fp = fopen("/sys/devices/system/cpu/offline", "r");
Check for fp == NULL before using it.
+ if (fscanf(fp, "%s", offline_cpus_str) < 0) {
fscanf() seems like a heavy hammer.
Do you perhaps have any recommendations that should be used instead of
fscanf()? I checked with stat() but could not see a difference between
file with a CPU and a file without. Other alternative is
open()/read()/close()? Looks like when there are no offline CPUs then
the file will only contain '\n' so it may be possible to read one byte
from the file and confirm it is '\n' as a check for "cpus_offline_empty()".
Sorry. I replied with Outlook and didn't quote things properly
so my alternate suggestion didn't stand out. Here it is again:
if (fgets(offline_cpus_str, sizeof(offline_cpus_str), fp) == NULL) {
fclose(fp);
return true;
}
Apologies, missed this.
But that was with the assumption that /sys/devices/system/cpu/offline
would be empty. Not that it would conatain a single "\n" as you say
above.
So fgets( ...) followed with "if (offline_cpus_str[0] == '\n') "?
How about simplifying it more to "if (fgetc(fp) == '\n')" ?
Reinette
