The criticism of Linux focuses on issues concerning use of operating systems which use the Linux kernel. While the Linux-based Android operating system dominates the smartphone market in many countries, and Linux is used on the New York Stock Exchange and most supercomputers, it is used in few desktop and laptop computers. Much of the criticism of Linux is related to the lack of desktop and laptop adoption, although as of 2015 there has been growing unease with the project's perspective on security and its adoption of systemd has been controversial. Linux kernel criticisms Kernel development politics Some security professionals say that the rise in prominence of operating system-level virtualization using Linux has raised the profile of attacks against the kernel, and that Linus Torvalds is reticent to add mitigations against kernel-level attacks in official releases. Linux 4.12, released in 2017, enabled KASLR by default, but its effectiveness is debated. Con Kolivas, a former kernel developer, tried to optimize the kernel scheduler for interactive desktop use. He finally dropped the support for his patches due to the lack of appreciation for his development. In the 2007 interview Why I quit: kernel developer Con Kolivas he stated: Kernel performance At LinuxCon 2009, Linux creator Linus Torvalds said that the Linux kernel has become "bloated and huge": At LinuxCon 2014, Torvalds said he thinks the bloat situation is better because modern PCs are a lot faster: Kernel code quality In an interview with German newspaper Zeit Online in November 2011, Linus Torvalds stated that Linux has become "too complex" and he was concerned that developers would not be able to find their way through the software anymore. He complained that even subsystems have become very complex and he told the publication that he is "afraid of the day" when there will be an error that "cannot be evaluated anymore." Andrew Morton, one of Linux kernel lead developers, explains that many bugs identified in Linux are never fixed: Theo de Raadt, founder of OpenBSD, compares OpenBSD development process to Linux: Desktop use Critics of Linux on the desktop have frequently argued that a lack of top-selling video games on the platform holds adoption back. For instance, as of September 2015, the Steam gaming service has 1,500 games available on Linux, compared to 2,323 games for Mac and 6,500 Windows games. As of October 2021, Proton, a Steam-backed development effort descended from Wine provides