Contents
What is DirectMap2M?
DirectMap2M: The amount of memory being mapped to hugepages (usually 2MB in size) DirectMap1G. The amount of memory being mapped to hugepages (usually 1GB in size)
What does the dirty field represent in Linux?
Dirty. The Dirty field refers to data that is stored in memory and still needs to be written to the disk. You can test this easily by writing to a temporary file and compare the value before and after. Note: if you repeat this command, you will see the effect of smart memory management.
What is slab allocator in Linux?
The slab allocator aims to to cache the freed object so that the basic structure is preserved between uses [ Bon94 ]. The slab allocator consists of a variable number of caches that are linked together on a doubly linked circular list called a cache chain.
What is VMallocUsed?
VMallocUsed — The total amount of memory, in kilobytes, of used virtual address space. VMallocChunk — The largest contiguous block of memory, in kilobytes, of available virtual address space. HugePages_Total — The total number of hugepages for the system.
What does it mean to have directmap fields in Linux?
These pages are useful for programs which make large memory allocations, but they do introduce constraints — in particular they can’t be swapped out. As mentioned in what does mean by HardwareCorrupted, DirectMap4k, DirectMap2M fields in “/proc/meminfo” file of Linux?, DirectMap is an x86-specific implementation detail.
What does directmap mean in Linux proc / meminfo file?
As mentioned in what does mean by HardwareCorrupted, DirectMap4k, DirectMap2M fields in “/proc/meminfo” file of Linux?, DirectMap is an x86-specific implementation detail. It measures the use of page maps for pages of various sizes, by the kernel; this shows how much the kernel has been able to map pages as huge pages of various sizes.
What’s the purpose of NR _ hugepages in Linux?
The purpose of nr_hugepages is to make huge pages available to userspace programs, via hugetlbfs or shared memory or mmap.