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kernel/system_info: Avoid malloc() in _user_get_cpu_info.

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This is called 15-30 times per second (15 by Pulse, 30 by ActivityMonitor),
so we want to keep it as low-profile as is possible.
This commit is contained in:
Augustin Cavalier 2019-07-12 21:22:09 -04:00
parent 6d336fda4a
commit fa146526b6
1 changed files with 18 additions and 17 deletions
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35
src/system/kernel/system_info.cpp
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@ -500,12 +500,28 @@ get_cpu_info(uint32 firstCPU, uint32 cpuCount, cpu_info* info)
uint32 count = std::min(cpuCount, smp_get_num_cpus() - firstCPU);
memset(info, 0, sizeof(cpu_info) * count);
// This function is called very often from userland by applications
// that display CPU usage information, so we want to keep this as
// optimized and touch as little as possible. Hence, no use of
// a temporary buffer.
if (IS_USER_ADDRESS(info)) {
if (user_memset(info, 0, sizeof(cpu_info) * count) != B_OK)
return B_BAD_ADDRESS;
set_ac();
} else {
memset(info, 0, sizeof(cpu_info) * count);
}
for (uint32 i = 0; i < count; i++) {
info[i].active_time = cpu_get_active_time(firstCPU + i);
info[i].enabled = !gCPU[firstCPU + i].disabled;
}
if (IS_USER_ADDRESS(info)) {
clear_ac();
}
return B_OK;
}
@ -561,23 +577,8 @@ _user_get_cpu_info(uint32 firstCPU, uint32 cpuCount, cpu_info* userInfo)
{
if (userInfo == NULL || !IS_USER_ADDRESS(userInfo))
return B_BAD_ADDRESS;
if (firstCPU >= (uint32)smp_get_num_cpus())
return B_BAD_VALUE;
if (cpuCount == 0)
return B_OK;
uint32 count = std::min(cpuCount, smp_get_num_cpus() - firstCPU);
cpu_info* cpuInfos = new(std::nothrow) cpu_info[count];
if (cpuInfos == NULL)
return B_NO_MEMORY;
ArrayDeleter<cpu_info> _(cpuInfos);
status_t error = get_cpu_info(firstCPU, count, cpuInfos);
if (error != B_OK)
return error;
return user_memcpy(userInfo, cpuInfos, sizeof(cpu_info) * count);
return get_cpu_info(firstCPU, cpuCount, userInfo);
}