sysinfo() doesn't include all reclaimable memory. In particular it
excludes the majority of global_node_page_state(NR_FILE_PAGES),
reclaimable pages that are a copy of on-disk files It seems the only way
to obtain this counter is by parsing /proc/meminfo. For comparison,
check vm_enough_memory() which includes NR_FILE_PAGES as available
(sadly there's no way to call vm_enough_memory() directly either!)
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
---
lib/intel_os.c | 34 +++++++++++++++++++++++++++++-----
1 file changed, 29 insertions(+), 5 deletions(-)
diff --git a/lib/intel_os.c b/lib/intel_os.c
index 885ffdcec..a44f153d3 100644
--- a/lib/intel_os.c
+++ b/lib/intel_os.c
@@ -96,17 +96,41 @@ intel_get_avail_ram_mb(void)
uint64_t retval;
#ifdef HAVE_STRUCT_SYSINFO_TOTALRAM /* Linux */
- struct sysinfo sysinf;
+ char *info;
int fd;
fd = drm_open_driver(DRIVER_INTEL);
intel_purge_vm_caches(fd);
close(fd);
- igt_assert(sysinfo(&sysinf) == 0);
- retval = sysinf.freeram;
- retval += min(sysinf.freeswap, sysinf.bufferram);
- retval *= sysinf.mem_unit;
+ fd = open("/proc", O_RDONLY);
+ info = igt_sysfs_get(fd, "meminfo");
+ close(fd);
+
+ if (info) {
+ long val;
+
+ sscanf("MemAvailable: %lu", &val);
+ retval = val << 10;
+
+ sscanf("Buffers: %lu", &val);
+ retval += val << 10;
+
+ sscanf("Cached: %lu", &val);
+ retval += val << 10;
+
+ sscanf("SwapCached: %lu", &val);
+ retval += val << 10;
+
+ free(info);
+ } else {
+ struct sysinfo sysinf;
+
+ igt_assert(sysinfo(&sysinf) == 0);
+ retval = sysinf.freeram;
+ retval += min(sysinf.freeswap, sysinf.bufferram);
+ retval *= sysinf.mem_unit;
+ }
#elif defined(_SC_PAGESIZE) && defined(_SC_AVPHYS_PAGES) /* Solaris */
long pagesize, npages;
--
2.18.0.rc2
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