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1
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2answers
443 views

NAND flash memory wear & virtual memory page swap

For a linux kernel with virtual memory and disk storage, pages are swapped back and forth into swap area. But embedded systems generally use NAND flash instead of disk. A NAND flash has a limited ...
2
votes
2answers
798 views

How much RAM can an application allocate on 64-bit x86 Linux systems?

Is it true that a single application can not allocate more than 2 GiBs even if the system has GiBs more free memory when using a 32-bit x86 PAE Linux kernel? Is this limit loosened by 64-bit x86 Linux ...
2
votes
1answer
826 views

How often is PSS value updated for a given process in /proc/pid/smaps

So if n processes are sharing a library L with size M then the contribution to their PSS is M/n. Now imagine one of the process terminates. So the contribution would be M/(n-1). Q1: My question is ...
17
votes
1answer
11k views

Getting information about a process' memory usage from /proc/pid/smaps

For a given process in /proc/<pid>/smaps, for a given mapping entry what are: Shared_Clean Shared_Dirty Private_Clean Private_Dirty Is Shared_Clean + Shared_Dirty the amount of memory that ...
0
votes
1answer
251 views

Reading virtual memory

Is it possible to read virtual memory even if /dev/kmem is not available? I know that I can recompile kernel to allow this file, but that's not the solution I'm looking for. Is there some tricky way I ...
2
votes
1answer
596 views

tmpfs and vm.swappiness

I have started tuning a bit Linux VM performance on my system (yes. I know that vm.swappiness=0 will kill kittens but I found 30-40 as much better for me as it improved my latency - probably at cost ...
6
votes
1answer
744 views

User Kernel split in 64bit Linux

What is the default user/kernel split in the 64bit linux ? I read Documentation/x86_64/mm.txt (which someone pointed out), but I could not make out. Can somebody provide a direct answer (something ...
3
votes
1answer
894 views

Solaris swap allocation with mlocked shared memory

I'm having a hard time understanding how Solaris 10 x86 swap allocations work in the presence of mlocked share memory. I wrote a small program that: Gets a 1G SHM segment (shmget) Attaches it to ...
7
votes
1answer
8k views

Setting /proc/sys/vm/drop_caches to clear cache

As part of doing some cold cache timings, I'm trying to free the OS cache. The kernel documentation says: drop_caches Writing to this will cause the kernel to drop clean caches, dentries and inodes ...
5
votes
3answers
2k views

How to set up properly zram and swap

I'm configuring & compiling new 3.0 kernel. One of the goodies I planned to use for some time (by patching) that was merged into 3.0 is zram. Is it possible to set both hdd swap and zram swap so ...
8
votes
1answer
3k views

Unable to handle kernel paging request?

[Disclaimer: I was initially a little nervous about posting this here, so I asked on Meta if discussing homebrew / modding was acceptable. Based on the response I've gotten from several veteran ...
2
votes
3answers
2k views

How is paging managed in the absence of swapping?

How is paging managed in the absence of swapping. If that is the case, how will a page fault be managed? What I meant is, if there is no availability for swapping, then how is Paging managed. I ...