0.24.2: avoid unrelated RSS reads during unit memory observation

README.md

@@ -8,7 +8,7 @@ for Linux, written on the kernel's own system-call interface.
 openkal = "0.23.0"
 
 [target.'cfg(os = "linux")'.dependencies]
-openkal-linux = "0.24.1"
+openkal-linux = "0.24.2"
 ```
 
 ## Why it does not use a C library
@@ -227,7 +227,9 @@ and later) instead of polling.
 
 A unit is a process group, and its use is the sum over the entries of /proc
 whose group is the unit's --- every program in it, including those its members
-started; one read per program on the machine, made only when a caller asks.
+started. Every visible program's group is queried; resident memory is read for
+matching programs. If the group query is refused, the same /proc record supplies
+both membership and memory. Nothing is retained between observations.
 `KAL_PROCESS_PROP_JOB_USAGE` is claimed.
 
 **A limit on a unit is supervised.** `kal_process_job_limit` starts, with the

mcpp.toml

@@ -1,7 +1,7 @@
 [package]
 namespace   = "mcpplibs"
 name        = "openkal-linux"
-version     = "0.24.1"
+version     = "0.24.2"
 description = "The reference implementation of openkal for Linux, written on the kernel's own system-call interface so that it can be placed beneath a C library as well as above one."
 license     = "Apache-2.0"
 

src/process.cpp

@@ -1767,6 +1767,12 @@ kal_u32 members_of(okl_long unit, okl_u64& memory) {
             if (name[0] < '1' || name[0] > '9') continue;
             okl_long pid = 0;
             for (const char* c = name; *c; ++c) pid = pid * 10 + (*c - '0');
+            // Most visible programs belong to other units. Ask for the group
+            // before opening a record whose memory will then be discarded.
+            // A denied or unavailable query keeps the record-reading path;
+            // even a positive query is checked again in that same RSS record.
+            const okl_long group = okl::sys(okl::nr_getpgid, pid);
+            if (!okl::failed(group) && group != unit) continue;
             char b[1024];
             const okl_long len = read_stat(pid, b);
             if (len <= 0) continue;

src/sys.h

@@ -115,7 +115,7 @@ enum : okl_long {
     // openkal 0.13: whether a node may be started
     nr_fchmodat = 268,
     // openkal 0.11: the directory a started program runs in, and the unit it joins
-    nr_fchdir = 81, nr_setpgid = 109, nr_rt_sigaction = 13,
+    nr_fchdir = 81, nr_setpgid = 109, nr_getpgid = 121, nr_rt_sigaction = 13,
     // openkal.net and openkal.datagram
     nr_socket = 41, nr_connect = 42, nr_accept = 43, nr_sendto = 44,
     nr_recvfrom = 45, nr_shutdown = 48, nr_bind = 49, nr_listen = 50,
@@ -223,7 +223,7 @@ enum : okl_long {
     // openkal 0.13: whether a node may be started
     nr_fchmodat = 53,
     // openkal 0.11: the directory a started program runs in, and the unit it joins
-    nr_fchdir = 50, nr_setpgid = 154, nr_rt_sigaction = 134,
+    nr_fchdir = 50, nr_setpgid = 154, nr_getpgid = 155, nr_rt_sigaction = 134,
     // openkal.net and openkal.datagram
     nr_socket = 198, nr_connect = 203, nr_accept = 202, nr_sendto = 206,
     nr_recvfrom = 207, nr_shutdown = 210, nr_bind = 200, nr_listen = 201,