CODEWITHSUNDEEP
c++linuxmmap
sean
sean

Reputation: 73

mmap a 10 GB file and load it into memory

if I want to mmap a 10 GB file and load the whole file into physical memory immediately, how can I do so?
I don't want to use function like mlock because it needs root privileges.
Is there a system call which can satisfy my demand?

(I have more than enough memory.)

Upvotes: 6

Views: 820

Answers (1)

Deduplicator
Deduplicator

Reputation: 45654

Read the man-page for mmap:

MAP_POPULATE (since Linux 2.5.46)

Populate (prefault) page tables for a mapping. For a file mapping, this causes read-ahead on the file. Later accesses to the mapping will not be blocked by page faults. MAP_POPULATE is supported for private mappings only since Linux 2.6.23

Issue your request, and be prepared for a short wait (unless you exceed the processes limits) (depending on disk-bandwidth and cache).

Upvotes: 5

Related Questions