On Sat, 16 Sep 2000, Rik van Riel wrote:
> MemFree: memory on the freelist, contains no data
> Buffers: buffer cache memory
> Cached: page cache memory
>
> Active: buffer or page cache memory which is in active
> use (that is, page->age > 0 or many references)
> Inact_dirty: buffer or cache pages with page->age == 0 that
> /might/ be freeable
> (page->buffers is set or page->count == 2 when
> we add the page ... while holding a reference)
> Inact_clean: page cache pages with page->age == 0 of which
> we are /certain/ that they are freeable, these
> are counted almost as free pages
> Inact_target: the net amount of allocations we get per second,
> averaged over one minute
I think I understand what those numbers mean, now. :)
But, I guess I'm still looking for a calculation that tells me exactly how many
free (non-in-use) pages that I can allocate before running out of memory. In
other words, how many KB of memory processes are actually taking up, versus
buffer/cache space.
For example, this doesn't tell me how much memory I can allocate before I
get to the point where swapping is inevitable:
root:~/local/benchmarks> cat /proc/meminfo; free
[stuff omitted]
Buffers: 16648 kB
Cached: 35276 kB
Active: 2036 kB
Inact_dirty: 37264 kB
Inact_clean: 12624 kB
Inact_target: 4 kB
total used free shared buffers cached
Mem: 126516 98852 27664 0 16648 35276
-/+ buffers/cache: 46928 79588
Swap: 32124 0 32124
So I take a guess and allocate that much memory.
root:~/local/benchmarks> ./memspeed 88
Memory read 88M: 784.57 MB/s
Memory fill 88M: 347.12 MB/s
8-byte fill 88M: 344.73 MB/s
Memory copy 44M: 163.47 MB/s
8-byte copy 44M: 231.42 MB/s
Memory cmp 44M: 100.46 MB/s (Test OK)
Mem search 88M: 254.24 MB/s
Overall Memory Performance: 343.56 MB/s
root:~/local/benchmarks> echo $[27664+16648+35276]
79588
root:~/local/benchmarks> cat /proc/meminfo; free
[stuff omitted]
Buffers: 264 kB
Cached: 7836 kB
Active: 5080 kB
Inact_dirty: 956 kB
Inact_clean: 2064 kB
Inact_target: 0 kB
total used free shared buffers cached
Mem: 126516 34728 91788 0 264 7836
-/+ buffers/cache: 26628 99888
Swap: 32124 964 31160
Here, the value 26628+964 is closer to what the 'actual' amount of RAM usage
really is by processes (minus shared mem, buffers, and cache). But I was unable
to find that without the allocation. So, my question is, is it possible to add
a line to /proc/meminfo that tells us this information? Or am I going against
the whole grain of the VM management system?
-Byron
-- Byron Stanoszek Ph: (330) 644-3059 Systems Programmer Fax: (330) 644-8110 Commercial Timesharing Inc. Email: bstanoszek@comtime.com- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Sat Sep 16 2000 - 14:58:57 EDT