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CPLGetPhysicalRAM(): cache result to avoid multiple file openings on …
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…repeated calls
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@rouault
rouault committed Jan 30, 2025
1 parent 73eca73 commit 4a05058
Showing 1 changed file with 129 additions and 121 deletions.
250 changes: 129 additions & 121 deletions port/cpl_vsisimple.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -1391,162 +1391,170 @@ char *VSIStrerror(int nErrno)
*/
GIntBig CPLGetPhysicalRAM(void)
{
const long nPhysPages = sysconf(_SC_PHYS_PAGES);
const long nPageSize = sysconf(_SC_PAGESIZE);
if (nPhysPages <= 0 || nPageSize <= 0 ||
nPhysPages > std::numeric_limits<GIntBig>::max() / nPageSize)
static const GIntBig nPhysicalRAM = []() -> GIntBig
{
return 0;
}
GIntBig nVal = static_cast<GIntBig>(nPhysPages) * nPageSize;
const long nPhysPages = sysconf(_SC_PHYS_PAGES);
const long nPageSize = sysconf(_SC_PAGESIZE);
if (nPhysPages <= 0 || nPageSize <= 0 ||
nPhysPages > std::numeric_limits<GIntBig>::max() / nPageSize)
{
return 0;
}

GIntBig nVal = static_cast<GIntBig>(nPhysPages) * nPageSize;

#ifdef __linux
{
// Take into account MemTotal in /proc/meminfo
// which seems to be necessary for some container solutions
// Cf https://lists.osgeo.org/pipermail/gdal-dev/2023-January/056784.html
FILE *f = fopen("/proc/meminfo", "rb");
if (f)
{
char szLine[256];
while (fgets(szLine, sizeof(szLine), f))
// Take into account MemTotal in /proc/meminfo
// which seems to be necessary for some container solutions
// Cf https://lists.osgeo.org/pipermail/gdal-dev/2023-January/056784.html
FILE *f = fopen("/proc/meminfo", "rb");
if (f)
{
// Find line like "MemTotal: 32525176 kB"
if (strncmp(szLine, "MemTotal:", strlen("MemTotal:")) == 0)
char szLine[256];
while (fgets(szLine, sizeof(szLine), f))
{
char *pszVal = szLine + strlen("MemTotal:");
pszVal += strspn(pszVal, " ");
char *pszEnd = strstr(pszVal, " kB");
if (pszEnd)
// Find line like "MemTotal: 32525176 kB"
if (strncmp(szLine, "MemTotal:", strlen("MemTotal:")) == 0)
{
*pszEnd = 0;
if (CPLGetValueType(pszVal) == CPL_VALUE_INTEGER)
char *pszVal = szLine + strlen("MemTotal:");
pszVal += strspn(pszVal, " ");
char *pszEnd = strstr(pszVal, " kB");
if (pszEnd)
{
const GUIntBig nLimit =
CPLScanUIntBig(
pszVal, static_cast<int>(strlen(pszVal))) *
1024;
nVal = static_cast<GIntBig>(
std::min(static_cast<GUIntBig>(nVal), nLimit));
*pszEnd = 0;
if (CPLGetValueType(pszVal) == CPL_VALUE_INTEGER)
{
const GUIntBig nLimit =
CPLScanUIntBig(
pszVal,
static_cast<int>(strlen(pszVal))) *
1024;
nVal = static_cast<GIntBig>(std::min(
static_cast<GUIntBig>(nVal), nLimit));
}
}
break;
}
break;
}
fclose(f);
}
fclose(f);
}
}

char szGroupName[256];
bool bFromMemory = false;
szGroupName[0] = 0;
{
FILE *f = fopen("/proc/self/cgroup", "rb");
if (f)
char szGroupName[256];
bool bFromMemory = false;
szGroupName[0] = 0;
{
char szLine[256];
// Find line like "6:memory:/user.slice/user-1000.slice/[email protected]"
// and store "/user.slice/user-1000.slice/[email protected]" in
// szMemoryPath for cgroup V1 or single line "0::/...." for cgroup V2.
while (fgets(szLine, sizeof(szLine), f))
FILE *f = fopen("/proc/self/cgroup", "rb");
if (f)
{
const char *pszMemory = strstr(szLine, ":memory:");
if (pszMemory)
char szLine[256];
// Find line like "6:memory:/user.slice/user-1000.slice/[email protected]"
// and store "/user.slice/user-1000.slice/[email protected]" in
// szMemoryPath for cgroup V1 or single line "0::/...." for cgroup V2.
while (fgets(szLine, sizeof(szLine), f))
{
bFromMemory = true;
snprintf(szGroupName, sizeof(szGroupName), "%s",
pszMemory + strlen(":memory:"));
char *pszEOL = strchr(szGroupName, '\n');
if (pszEOL)
*pszEOL = '\0';
break;
}
if (strncmp(szLine, "0::", strlen("0::")) == 0)
{
snprintf(szGroupName, sizeof(szGroupName), "%s",
szLine + strlen("0::"));
char *pszEOL = strchr(szGroupName, '\n');
if (pszEOL)
*pszEOL = '\0';
break;
const char *pszMemory = strstr(szLine, ":memory:");
if (pszMemory)
{
bFromMemory = true;
snprintf(szGroupName, sizeof(szGroupName), "%s",
pszMemory + strlen(":memory:"));
char *pszEOL = strchr(szGroupName, '\n');
if (pszEOL)
*pszEOL = '\0';
break;
}
if (strncmp(szLine, "0::", strlen("0::")) == 0)
{
snprintf(szGroupName, sizeof(szGroupName), "%s",
szLine + strlen("0::"));
char *pszEOL = strchr(szGroupName, '\n');
if (pszEOL)
*pszEOL = '\0';
break;
}
}
fclose(f);
}
fclose(f);
}
}
if (szGroupName[0])
{
char szFilename[256 + 64];
if (bFromMemory)
if (szGroupName[0])
{
// cgroup V1
// Read memory.limit_in_byte in the whole szGroupName hierarchy
// Make sure to end up by reading
// /sys/fs/cgroup/memory/memory.limit_in_bytes itself, for
// scenarios like https://github.com/OSGeo/gdal/issues/8968
while (true)
char szFilename[256 + 64];
if (bFromMemory)
{
snprintf(szFilename, sizeof(szFilename),
"/sys/fs/cgroup/memory/%s/memory.limit_in_bytes",
szGroupName);
FILE *f = fopen(szFilename, "rb");
if (f)
// cgroup V1
// Read memory.limit_in_byte in the whole szGroupName hierarchy
// Make sure to end up by reading
// /sys/fs/cgroup/memory/memory.limit_in_bytes itself, for
// scenarios like https://github.com/OSGeo/gdal/issues/8968
while (true)
{
// If no limitation, on 64 bit, 9223372036854771712 is returned.
char szBuffer[32];
const int nRead = static_cast<int>(
fread(szBuffer, 1, sizeof(szBuffer) - 1, f));
szBuffer[nRead] = 0;
fclose(f);
const GUIntBig nLimit = CPLScanUIntBig(szBuffer, nRead);
nVal = static_cast<GIntBig>(
std::min(static_cast<GUIntBig>(nVal), nLimit));
snprintf(szFilename, sizeof(szFilename),
"/sys/fs/cgroup/memory/%s/memory.limit_in_bytes",
szGroupName);
FILE *f = fopen(szFilename, "rb");
if (f)
{
// If no limitation, on 64 bit, 9223372036854771712 is returned.
char szBuffer[32];
const int nRead = static_cast<int>(
fread(szBuffer, 1, sizeof(szBuffer) - 1, f));
szBuffer[nRead] = 0;
fclose(f);
const GUIntBig nLimit = CPLScanUIntBig(szBuffer, nRead);
nVal = static_cast<GIntBig>(
std::min(static_cast<GUIntBig>(nVal), nLimit));
}
char *pszLastSlash = strrchr(szGroupName, '/');
if (!pszLastSlash)
break;
*pszLastSlash = '\0';
}
char *pszLastSlash = strrchr(szGroupName, '/');
if (!pszLastSlash)
break;
*pszLastSlash = '\0';
}
}
else
{
// cgroup V2
// Read memory.max in the whole szGroupName hierarchy
while (true)
else
{
snprintf(szFilename, sizeof(szFilename),
"/sys/fs/cgroup/%s/memory.max", szGroupName);
FILE *f = fopen(szFilename, "rb");
if (f)
// cgroup V2
// Read memory.max in the whole szGroupName hierarchy
while (true)
{
// If no limitation, "max" is returned.
char szBuffer[32];
int nRead = static_cast<int>(
fread(szBuffer, 1, sizeof(szBuffer) - 1, f));
szBuffer[nRead] = 0;
if (nRead > 0 && szBuffer[nRead - 1] == '\n')
snprintf(szFilename, sizeof(szFilename),
"/sys/fs/cgroup/%s/memory.max", szGroupName);
FILE *f = fopen(szFilename, "rb");
if (f)
{
nRead--;
// If no limitation, "max" is returned.
char szBuffer[32];
int nRead = static_cast<int>(
fread(szBuffer, 1, sizeof(szBuffer) - 1, f));
szBuffer[nRead] = 0;
if (nRead > 0 && szBuffer[nRead - 1] == '\n')
{
nRead--;
szBuffer[nRead] = 0;
}
fclose(f);
if (CPLGetValueType(szBuffer) == CPL_VALUE_INTEGER)
{
const GUIntBig nLimit =
CPLScanUIntBig(szBuffer, nRead);
nVal = static_cast<GIntBig>(
std::min(static_cast<GUIntBig>(nVal), nLimit));
}
}
fclose(f);
if (CPLGetValueType(szBuffer) == CPL_VALUE_INTEGER)
{
const GUIntBig nLimit = CPLScanUIntBig(szBuffer, nRead);
nVal = static_cast<GIntBig>(
std::min(static_cast<GUIntBig>(nVal), nLimit));
}
char *pszLastSlash = strrchr(szGroupName, '/');
if (!pszLastSlash || pszLastSlash == szGroupName)
break;
*pszLastSlash = '\0';
}
char *pszLastSlash = strrchr(szGroupName, '/');
if (!pszLastSlash || pszLastSlash == szGroupName)
break;
*pszLastSlash = '\0';
}
}
}
#endif

return nVal;
return nVal;
}();

return nPhysicalRAM;
}

#elif defined(__MACH__) && defined(__APPLE__)
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