On Fri, Jun 16, 2023 at 12:48:02PM -0400, Kent Overstreet wrote: > On Fri, Jun 16, 2023 at 11:50:28AM +0300, Mike Rapoport wrote: > > From: "Mike Rapoport (IBM)" <rppt@xxxxxxxxxx> > > > > module_alloc() is used everywhere as a mean to allocate memory for code. > > > > Beside being semantically wrong, this unnecessarily ties all subsystems > > that need to allocate code, such as ftrace, kprobes and BPF to modules > > and puts the burden of code allocation to the modules code. > > > > Several architectures override module_alloc() because of various > > constraints where the executable memory can be located and this causes > > additional obstacles for improvements of code allocation. > > > > Start splitting code allocation from modules by introducing > > execmem_text_alloc(), execmem_free(), jit_text_alloc(), jit_free() APIs. > > > > Initially, execmem_text_alloc() and jit_text_alloc() are wrappers for > > module_alloc() and execmem_free() and jit_free() are replacements of > > module_memfree() to allow updating all call sites to use the new APIs. > > > > The intention semantics for new allocation APIs: > > > > * execmem_text_alloc() should be used to allocate memory that must reside > > close to the kernel image, like loadable kernel modules and generated > > code that is restricted by relative addressing. > > > > * jit_text_alloc() should be used to allocate memory for generated code > > when there are no restrictions for the code placement. For > > architectures that require that any code is within certain distance > > from the kernel image, jit_text_alloc() will be essentially aliased to > > execmem_text_alloc(). > > > > The names execmem_text_alloc() and jit_text_alloc() emphasize that the > > allocated memory is for executable code, the allocations of the > > associated data, like data sections of a module will use > > execmem_data_alloc() interface that will be added later. > > I like the API split - at the risk of further bikeshedding, perhaps > near_text_alloc() and far_text_alloc()? Would be more explicit. With near and far it should mention from where and that's getting too long. I don't mind changing the names, but I couldn't think about something better than Song's execmem and your jit. > Reviewed-by: Kent Overstreet <kent.overstreet@xxxxxxxxx> Thanks! -- Sincerely yours, Mike.
