Questions tagged [memory-management]
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52 questions
1 vote
0 answers
97 views
Too slow Tiered Memory Demotion and CPU Lock-up(maybe) with cgroup v2 memory.high
We are currently testing tiered memory demotion on a machine equipped with a CXL device. To facilitate this, we created a specific script (https://github.com/hyun-sa/comem) and are using the memory....
- 11
10 votes
3 answers
1k views
Why can ZONE_NORMAL only go up to 896MiB on 32-bit x86 processors?
According to Linux Kernel Development by Robert Love, p. 233: Because of hardware limitations, the kernel cannot treat all pages as identical. Some pages, because of their physical address in memory, ...
- 103
0 votes
0 answers
195 views
Allocating contiguous physical memory using huge pages in kernel module
0 I need a kernel module that allocates 8MB of physically contiguous memory using 2MB huge pages, in response to a user-space mmap() request. While I’ve successfully used alloc_pages() with 4KB pages ...
4 votes
1 answer
1k views
Process memory layout - difference between heap, data and mmap areas
I see in the web many conflicting or unclear descriptions of the memory layout of a Linux process. Usually the common diagram looks like: And a common description would say that: The data segment ...
- 6,955
0 votes
1 answer
117 views
Memory total shown on Linux on 8GB memory PC is only 7038920 kB
Why linux /proc/meminfo show:" 1 MemTotal: 7038920 kB " (proc most likely is to mean Kibibyte) in a PC of 8 GB memory RAM, although its Kibibyte is 7812500 ?
user575072
4 votes
1 answer
3k views
How does mmio get routed to io devices?
I am trying to understand how IO devices are mapped into the 'regular' memory address space on modern x86 machines running Linux. Some details which I am trying to make sense of are: cat /proc/iomem ...
- 200
2 votes
1 answer
2k views
Can a Linux Swap Partition Be Too Big?
Can a Linux swap partition be too big? I'm pretty certain the answer is, "no" but I haven't found any resources on-point, so thought I'd ask. In contrast, the main Windows swap file, ...
- 399
0 votes
1 answer
227 views
Is vmalloc() allocate bytes of memory which is virtually contiguous maps to memory area from different physical pages?
vmalloc(size) allocates a memory of size long which is virtually contiguous but the physical mapping would not be contiguous. Does that mean the the virtually allocated size long memory actually lies ...
- 309