Memory disclaiming on Linux 32bit?

[Former Member]

I have a NW 7.0 (SPS17) instance on Oracle 10.2.0.4

and SLES10 SP2. The SAP kernel is 7.00 patchlevel 185 (32bit).

In the developer trace files I can find these messages:

X Linux: Kernel supports shared memory disclaiming

X Linux: using madvise(<pointer>, <size>, 9).

X Linux: disclaiming for shared memory enabled

The profile parameters are set:

em/blocksize_KB = 1024

em/initial_size_MB = 1512

es/disclaim_threshold_MB = 256

When I run a testjob which allocates 512 MB of extended memory

and terminate the transaction then I can via strace see lots of calls like:

madvise(0x7c42c000, 1048576, 0x9 /* MADV_??? */) = 0

Is there any way in which I can verify that the disclaiming works correctly,

e.g. by analyzing the results of "cat /proc/meminfo" ? I already

had a look at the numbers, but all I saw was that MemFree increased.

What really confuses me is that I cannot see any difference between

the settings es/implementation=std and es/implementation=map.

Is this normal for 32bit kernels that memory disclaiming is always on?

Does memory disclaiming on Linux work with both std + map implementation

and also for 64 bit kernels?

Regards,

Mark

P.S.: Output of /proc/meminfo after allocating 512 MB extended memory:

MemTotal: 1556660 kB

MemFree: 271348 kB

Buffers: 2420 kB

Cached: 843272 kB

SwapCached: 248928 kB

Active: 375252 kB

Inactive: 864076 kB

HighTotal: 655296 kB

HighFree: 1156 kB

LowTotal: 901364 kB

LowFree: 270192 kB

SwapTotal: 3145720 kB

SwapFree: 2450960 kB

Dirty: 512 kB

Writeback: 0 kB

AnonPages: 159324 kB

Mapped: 809436 kB

Slab: 18200 kB

CommitLimit: 3924048 kB

Committed_AS: 5972384 kB

PageTables: 18264 kB

VmallocTotal: 114680 kB

VmallocUsed: 8720 kB

VmallocChunk: 104952 kB

HugePages_Total: 0

HugePages_Free: 0

HugePages_Rsvd: 0

Hugepagesize: 4096 kB

Output of /proc/meminfo after releasing the 512 MB extened memory:

MemTotal: 1556660 kB

MemFree: 660332 kB

Buffers: 2684 kB

Cached: 452676 kB

SwapCached: 248568 kB

Active: 386108 kB

Inactive: 463816 kB

HighTotal: 655296 kB

HighFree: 209316 kB

LowTotal: 901364 kB

LowFree: 451016 kB

SwapTotal: 3145720 kB

SwapFree: 2460552 kB

Dirty: 1668 kB

Writeback: 0 kB

AnonPages: 160816 kB

Mapped: 406304 kB

Slab: 18108 kB

CommitLimit: 3924048 kB

Committed_AS: 5986332 kB

PageTables: 18412 kB

VmallocTotal: 114680 kB

VmallocUsed: 8720 kB

VmallocChunk: 104952 kB

HugePages_Total: 0

HugePages_Free: 0

HugePages_Rsvd: 0

Hugepagesize: 4096 kB

[Former Member · Accepted solution]

Refer to 386605 (SAP Memory Management for Linux)

Regards

SAP AGS