C ++代码内存泄漏

Question

I have C++ code executing on a ARM CPU hardware under Linux. I run my binary o the hardware and keep monitoring my process to see if its memory usage is growing over time, every half hour interval.

top -p pid-of-process

to see columns: RES memory and mem % in top output

and also check

cat /proc/pid-of-process/status 

to see field VMRSS : which is Resident Set size memory of my process.

I see that VMRSS and RES memory keeps increasing by some hundreds of KiloBytes every 1 hour. the process is just running, no tests are running so its doing same thing all the time, and load does not vary.

Now Question I have is: Does this mean there is a possible memory leak in my code.

or could this increase be attributed to something else, if any?

To check if there is memory leak:

1. I reviewed code to see every new(dynamic memory operator) had a corresponding delete (free memory)

2. Ran the whole process on valgrind memcheck, and in the report did not see any leaks. I see

definitely lost: 0 bytes in 0 blocks

indirectly lost: 0 bytes in 0 blocks

possibly lost: 1,008 bytes in 7 blocks

* *EDIT: To answer arne's comment below. The possibly lost blocks are from pthread_create and onwards glibc, so not sure how is that/what is going on?

720 bytes in 5 blocks are possibly lost in loss record 27 of 56

==11151== at 0x402732C: calloc (vg_replace_malloc.c:467)

==11151== by 0x4010C34: allocate_dtv (dl-tls.c:300)

==11151== by 0x40113D8: _dl_allocate_tls (dl-tls.c:464)

==11151== by 0x404746C: pthread_create@@GLIBC_2.1 (allocatestack.c:571)**

What could this increase in memory over time be? How could I debug further to find the cause?

Answer 1

Since you can't find a straightforward leak, you seem to need to compare snapshots of memory state to see what has changed. A quick search indicates that valgrind's massif can do snapshots, and there's a python script to compare them (but probably you can compare by hand if your program is small)