correct rss calculation

Signed-off-by: Brian L. Troutwine <brian.troutwine@datadoghq.com>

Author: blt

CHANGELOG.md

@@ -6,6 +6,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## Unreleased
 
+## [0.17.2-rc3]
+### Changed
+ - Correct `rss` to be reported in terms of bytes, not pages, as before.
+
 ## [0.17.2-rc2]
 ### Removed
 - Observer no longer emits tick data for kernel and user-space time. 

lading/src/observer/linux.rs

@@ -34,6 +34,7 @@ pub(crate) struct Sampler {
     parent: Process,
     num_cores: usize,
     ticks_per_second: u64,
+    page_size: u64,
     previous_samples: FxHashMap<(i32, String), Sample>,
 }
 
@@ -45,6 +46,7 @@ impl Sampler {
             parent,
             num_cores: num_cpus::get(), // Cores, logical on Linux, obeying cgroup limits if present
             ticks_per_second: procfs::ticks_per_second(),
+            page_size: procfs::page_size(),
             previous_samples: FxHashMap::default(),
         })
     }
@@ -164,7 +166,7 @@ impl Sampler {
             // page. My VSize remains one page. Allocators muddy this even
             // further by trying to account for the behavior of the operating
             // system. Anyway, good luck out there. You'll be fine.
-            let rss: u64 = stats.rss;
+            let rss: u64 = stats.rss * self.page_size;
             let rsslim: u64 = stats.rsslim;
             let vsize: u64 = stats.vsize;