From 5b3e444a4f10bc0c41a03196921ebbc2a18f7793 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20G=C3=B6ttsche?= <cgzones@googlemail.com>
Date: Mon, 17 Apr 2023 19:04:09 +0200
Subject: [PATCH] Linux: reorder some calls in
 LinuxProcessList_recurseProcTree()

Improve maintainability by reordering calls in
LinuxProcessList_recurseProcTree() to group them by side-effect or
interdependency.
---
 linux/LinuxProcessList.c | 57 +++++++++++++++++++++-------------------
 1 file changed, 30 insertions(+), 27 deletions(-)

diff --git a/linux/LinuxProcessList.c b/linux/LinuxProcessList.c
index 83112b702..1b48e46dd 100644
--- a/linux/LinuxProcessList.c
+++ b/linux/LinuxProcessList.c
@@ -1636,11 +1636,6 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, openat_arg_
          continue;
       }
 
-      const bool scanMainThread = !hideUserlandThreads && !Process_isKernelThread(proc) && !mainTask;
-
-      if (ss->flags & PROCESS_FLAG_IO)
-         LinuxProcessList_readIoFile(lp, procFd, scanMainThread, pl->realtimeMs);
-
       if (!LinuxProcessList_readStatmFile(lp, procFd, mainTask))
          goto errorReadingProcess;
 
@@ -1669,20 +1664,7 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, openat_arg_
             proc->mergedCommand.lastUpdate = 0;
       }
 
-      if ((ss->flags & PROCESS_FLAG_LINUX_SMAPS) && !Process_isKernelThread(proc)) {
-         if (!mainTask) {
-            // Read smaps file of each process only every second pass to improve performance
-            static int smaps_flag = 0;
-            if ((pid & 1) == smaps_flag) {
-               LinuxProcessList_readSmapsFile(lp, procFd, this->haveSmapsRollup);
-            }
-            if (pid == 1) {
-               smaps_flag = !smaps_flag;
-            }
-         } else {
-            lp->m_pss = ((const LinuxProcess*)mainTask)->m_pss;
-         }
-      }
+      const bool scanMainThread = !hideUserlandThreads && !Process_isKernelThread(proc) && !mainTask;
 
       char statCommand[MAX_NAME + 1];
       unsigned long long int lasttimes = (lp->utime + lp->stime);
@@ -1699,10 +1681,6 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, openat_arg_
          proc->tty_name = LinuxProcessList_updateTtyDevice(this->ttyDrivers, proc->tty_nr);
       }
 
-      if (ss->flags & PROCESS_FLAG_LINUX_IOPRIO) {
-         LinuxProcess_updateIOPriority(lp);
-      }
-
       /*
        * - period might be 0 after system sleep
        * - stime/utime might drop when switching to scan the main thread instead of the whole process
@@ -1776,6 +1754,27 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, openat_arg_
          }
       }
 
+      if ((ss->flags & PROCESS_FLAG_LINUX_SMAPS) && !Process_isKernelThread(proc)) {
+         if (!mainTask) {
+            // Read smaps file of each process only every second pass to improve performance
+            static int smaps_flag = 0;
+            if ((pid & 1) == smaps_flag) {
+               LinuxProcessList_readSmapsFile(lp, procFd, this->haveSmapsRollup);
+            }
+            if (pid == 1) {
+               smaps_flag = !smaps_flag;
+            }
+         } else {
+            lp->m_pss   = ((const LinuxProcess*)mainTask)->m_pss;
+            lp->m_swap  = ((const LinuxProcess*)mainTask)->m_swap;
+            lp->m_psswp = ((const LinuxProcess*)mainTask)->m_psswp;
+         }
+      }
+
+      if (ss->flags & PROCESS_FLAG_IO) {
+         LinuxProcessList_readIoFile(lp, procFd, scanMainThread, pl->realtimeMs);
+      }
+
       #ifdef HAVE_DELAYACCT
       if (ss->flags & PROCESS_FLAG_LINUX_DELAYACCT) {
          LinuxProcessList_readDelayAcctData(this, lp);
@@ -1786,6 +1785,10 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, openat_arg_
          LinuxProcessList_readOomData(lp, procFd, mainTask);
       }
 
+      if (ss->flags & PROCESS_FLAG_LINUX_IOPRIO) {
+         LinuxProcess_updateIOPriority(lp);
+      }
+
       if (ss->flags & PROCESS_FLAG_LINUX_SECATTR) {
          LinuxProcessList_readSecattrData(lp, procFd, mainTask);
       }
@@ -1804,15 +1807,15 @@ static bool LinuxProcessList_recurseProcTree(LinuxProcessList* this, openat_arg_
       }
       #endif
 
+      /*
+       * Final section after all data has been gathered
+       */
+
       if (!proc->cmdline && statCommand[0] &&
           (proc->state == ZOMBIE || Process_isKernelThread(proc) || settings->showThreadNames)) {
          Process_updateCmdline(proc, statCommand, 0, strlen(statCommand));
       }
 
-      /*
-       * Final section after all data has been gathered
-       */
-
       proc->updated = true;
       Compat_openatArgClose(procFd);