I've used the documentation from PostgreSQL to set it for example this config:

>>> cat /proc/meminfo 
MemTotal:       16345480 kB
MemFree:         1770128 kB
Buffers:          382184 kB
Cached:         10432632 kB
SwapCached:            0 kB
Active:          9228324 kB
Inactive:        4621264 kB
Active(anon):    7019996 kB
Inactive(anon):   548528 kB
Active(file):    2208328 kB
Inactive(file):  4072736 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:              3432 kB
Writeback:             0 kB
AnonPages:       3034588 kB
Mapped:          4243720 kB
Shmem:           4533752 kB
Slab:             481728 kB
SReclaimable:     440712 kB
SUnreclaim:        41016 kB
KernelStack:        1776 kB
PageTables:        39208 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:     8172740 kB
Committed_AS:   14935216 kB
VmallocTotal:   34359738367 kB
VmallocUsed:      399340 kB
VmallocChunk:   34359334908 kB
HardwareCorrupted:     0 kB
AnonHugePages:    456704 kB
HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
DirectMap4k:       12288 kB
DirectMap2M:    16680960 kB

>>> ipcs -l          

------ Shared Memory Limits --------
max number of segments = 4096
max seg size (kbytes) = 4316816
max total shared memory (kbytes) = 4316816
min seg size (bytes) = 1

------ Semaphore Limits --------
max number of arrays = 128
max semaphores per array = 250
max semaphores system wide = 32000
max ops per semop call = 32
semaphore max value = 32767

------ Messages Limits --------
max queues system wide = 31918
max size of message (bytes) = 8192
default max size of queue (bytes) = 16384

sysctl.conf extract:

kernel.shmall = 1079204
kernel.shmmax = 4420419584

postgresql.conf non defaults:

max_connections = 60            # (change requires restart)
shared_buffers = 4GB            # min 128kB
work_mem = 4MB              # min 64kB
wal_sync_method = open_sync     # the default is the first option
checkpoint_segments = 16        # in logfile segments, min 1, 16MB each
checkpoint_completion_target = 0.9  # checkpoint target duration, 0.0 - 1.0
effective_cache_size = 6GB

Is this appropriate ? If not (or not necessarily), in which case would it be appropriate ?

We did note nice performance improvements with this config, how would you improve it ?

How should kernel memory management parameters be set ?

Can anybody explain how to really set them from the ground up ?