Linus Torvalds is the creator of the Linux kernel. His preferred programming language is C. Linus started out programming in what he assumed to be "assembler" when he was really just hard-coding binaries with 0's and 1's. This may be why he is very good at micro-optimizations when coding in C.
Creator of the Linux Kernel
Torvalds wrote this in the "Notes for linux release 0.01" when he first released his kernel to the public in 1991:
"This is a free minix-like kernel for i386(+) based AT-machines. Full source is included, and this source has been used to produce a running kernel on two different machines. Currently there are no kernelbinaries for public viewing, as they have to be recompiled for different machines. You need to compile it with gcc (I use 1.40, don't know if 1.37.1 will handle all __asm__-directives), after having changed the relevant configuration file(s). "
View on C++
Torvalds had this to say about C++ in an e-mail exchange in 2007:
"C++ is a horrible language. It's made more horrible by the fact that a lot of substandard programmers use it, to the point where it's much much easier to generate total and utter crap with it. Quite frankly, even if the choice of C were to do *nothing* but keep the C++ programmers out, that in itself would be a huge reason to use C."
Kernel development model
The Linux kernel is known to be very stable. This is in a large part due to Linus policy of "We do NOT break user-space". If a kernel change breaks a user-space program then it is, in his view, a kernel bug - regardless even if it's because a user-space program relies on some quirk in the kernel.
Ability to say no
Torvalds has known to be a bit harsh when he has had to explain kernel development fundamentals to incompetent people. This resulted in him being sent to a re-education camp and the introduction of a CoC with Linux Kernel 4.19. Many feared that this would hamper his ability to clearly say no to buggy code and foolish design decisions. These fears were unfounded and Linus remains very based.