On 2024-10-09 14:12, mark.yagnatin...@barclays.com wrote:
With mmap(), the kernel just needs to set up a bit of book-keeping
Yes, I'm sure than in some cases mmap would be a win. However, all in all it was found not to be, and I expect that the hassle of maintaining the mmap variant wasn't worth whatever benefits it provided. As I recall 'grep' wants to modify its input buffers for other efficiency reasons, and mmap CoW likely won't be a performance win over page-aligned read.
We could be proved wrong by someone taking the time to resurrect --mmap and doing performance measurements of realistic benchmarks. I don't have the time for that, myself.
