On Thu 11-03-21 12:36:51, Peter Zijlstra wrote: [...] > Also, Linus hates constructs like this: > > https://lkml.kernel.org/r/CAHk-=wht7kAeyR5xEW2ORj7m0hibVxZ3t+2ie8vNHLQfdbN2_g@xxxxxxxxxxxxxx Btw. I would really appreciate if somebody would explain why it is _fundamentally broken_ to check for an atomic context and chose a different handling in a code path, like put_page, which is out of hands of the called context? This can be called from a wide variety of contexts. There is no way to pass a context information to the called function. I do recognize that this is not an act of beauty but why fundamentally broken? The put_page context can certainly work towards robustness and operate on the most restrictive context grounds (I really hope nobody will ever come up with an idea that put_page can be called from nmi context). This can make the code more complex and less optimal in normal case (e.g. hugetlb is almost never freed from an atomic context - one has to be really creative to achieve that). So where do we draw a line? -- Michal Hocko SUSE Labs
