{Memory,Swap}Meter: add "compressed memory" metrics

For now, the semantics are mostly fit for Linux zswap subsystem. For
instance, we add the third swap usage metric that indicates the amount
of memory that is accounted to swap but in fact stored elsewhere. This
exactly matches the definition of frontswap/zswap, and is probably of
little use to all other platforms.

1 files changed, 2 insertions, 0 deletions

diff --git a/pcp/Platform.c b/pcp/Platform.c
index 22963dda..87de2c2f 100644
--- a/pcp/Platform.c
+++ b/pcp/Platform.c
@@ -537,6 +537,7 @@ void Platform_setMemoryValues(Meter* this) {
    this->values[MEMORY_METER_USED] = pl->usedMem;
    this->values[MEMORY_METER_BUFFERS] = pl->buffersMem;
    this->values[MEMORY_METER_SHARED] = pl->sharedMem;
+   // this->values[MEMORY_METER_COMPRESSED] = "compressed memory, like zswap on linux"
    this->values[MEMORY_METER_CACHE] = pl->cachedMem;
    this->values[MEMORY_METER_AVAILABLE] = pl->availableMem;
 
@@ -556,6 +557,7 @@ void Platform_setSwapValues(Meter* this) {
    this->total = pl->totalSwap;
    this->values[SWAP_METER_USED] = pl->usedSwap;
    this->values[SWAP_METER_CACHE] = pl->cachedSwap;
+   // this->values[SWAP_METER_FRONTSWAP] = "pages that are accounted to swap but stored elsewhere, like frontswap on linux"
 }
 
 void Platform_setZramValues(Meter* this) {