01-22-2009
Memory Usage on Linux server
Hi Jay
Monitoring the memory usage of BW processes is not so easy as they are Java processes. Top doesn't show the sum of native memory and heap used by the Java processes. From the administrator you can check the heap used by each process, while the native usually doesn't change very much. If you can modify the deployment configuration I suggest you to enable the jconsole and use it to monitor the processes.
In any case the drop in the memory usage is strange. But many things could have happened:
1) Another process was taking a lot of memory, but Top didn't show it (still a heap and native memory issue)
2) Actually something is not working. From the administrator you can check the activity of the BW processes
3) Simply someone modified the configuration of the virtual machine adding some memory (the left hand doesn't know ... happens often)
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LEARN ABOUT LINUX
malloc_trim
MALLOC_TRIM(3) Linux Programmer's Manual MALLOC_TRIM(3)
NAME
malloc_trim - release free memory from the top of the heap
SYNOPSIS
#include <malloc.h>
int malloc_trim(size_t pad);
DESCRIPTION
The malloc_trim() function attempts to release free memory at the top of the heap (by calling sbrk(2) with a suitable argument).
The pad argument specifies the amount of free space to leave untrimmed at the top of the heap. If this argument is 0, only the minimum
amount of memory is maintained at the top of the heap (i.e., one page or less). A nonzero argument can be used to maintain some trailing
space at the top of the heap in order to allow future allocations to be made without having to extend the heap with sbrk(2).
RETURN VALUE
The malloc_trim() function returns 1 if memory was actually released back to the system, or 0 if it was not possible to release any memory.
ERRORS
No errors are defined.
CONFORMING TO
This function is a GNU extension.
NOTES
This function is automatically called by free(3) in certain circumstances; see the discussion of M_TOP_PAD and M_TRIM_THRESHOLD in mal-
lopt(3).
This function cannot release free memory located at places other than the top of the heap.
This function releases only memory in the main arena.
SEE ALSO
sbrk(2), malloc(3), mallopt(3)
Linux 2014-05-28 MALLOC_TRIM(3)