Update hsFlowd to close the pipe immediately

[vivekrnv]

Why I did it

sflowmgrd is taking 10-20 mins to finish command service restart hsflowd in Debian 13

As you can see from the hsflowd backtrace, getdtablesize is returning a really huge number and the currently logic loops from ~100M to 0 and close each of fd, Which is taking a lot of time.

Alternatively, close_range can make a single call to close all the fds in the given range which is much faster

Work item tracking

• Microsoft ADO (number only):

How I did it

sflowmgrd trace

0  read () from /lib/x86_64-linux-gnu/libc.so.6
1  _IO_file_underflow () from /lib/x86_64-linux-gnu/libc.so.6 
2  _IO_default_uflow () from /lib/x86_64-linux-gnu/libc.so.6 
3  _IO_getline_info () from /lib/x86_64-linux-gnu/libc.so.6 
4  fgets () from /lib/x86_64-linux-gnu/libc.so.6
5  swss::exec(std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > const&, std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> >&) () from /lib/x86_64-linux-gnu/libswsscommon.so.0 6  swss::SflowMgr::sflowHandleService (this=this@entry=0x7ffdc4ae6dc0,
    enable=enable@entry=true) at ./cfgmgr/sflowmgr.cpp:67
7  swss::SflowMgr::doTask (this=<optimized out>, consumer=...)
    at ./cfgmgr/sflowmgr.cpp:459
8  Consumer::execute (this=0x556f0715b280) at ../orchagent/orch.cpp:338 9  main (argc=<optimized out>, argv=<optimized out>)
    at ./cfgmgr/sflowmgrd.cpp:74

hsflowd trace:

(gdb) bt
close () from /lib/x86_64-linux-gnu/libc.so.6
main (argc=<optimized out>, argv=<optimized out>) at hsflowd.c:1927 
(gdb) f 1
1927	hsflowd.c: No such file or directory.
(gdb) p i
$1 = 1035943704
(gdb) c
Continuing.
^C
Program received signal SIGINT, Interrupt.
0x00007fa33f48d9e0 in close () from /lib/x86_64-linux-gnu/libc.so.6 (gdb) f 1
1927	in hsflowd.c
(gdb) p i
$2 = 1024299507

During this time, CPU usage for hsflowd is very high

    PID USER      PR  NI    VIRT    RES    SHR S  %CPU  %MEM     TIME+ COMMAND
     48 root      20   0    2652    928    820 R  92.4   0.0   5:24.66 hsflowd

How to verify it

Which release branch to backport (provide reason below if selected)

• 202205
• 202211
• 202305
• 202311
• 202405
• 202411
• 202505

Tested branch (Please provide the tested image version)

Description for the changelog

Link to config_db schema for YANG module changes

A picture of a cute animal (not mandatory but encouraged)