Hi! > Documentation-wise, I have posted a rseq man page rfc here: > > https://lkml.kernel.org/r/20180616195803.29877-1-mathieu.desnoyers@xxxxxxxxxxxx > > comments are welcome! Thanks for pointer. +Restartable sequences are atomic with respect to preemption (making it +atomic with respect to other threads running on the same CPU), as well +as signal delivery (user-space execution contexts nested over the same +thread). So the threads are protected against sigkill when running the restartable sequence? +Restartable sequences must not perform system calls. Doing so may result +in termination of the process by a segmentation fault. + "may result"? It would be nice to always catch that. +Optimistic cache of the CPU number on which the current thread is +running. Its value is guaranteed to always be a possible CPU number, +even when rseq is not initialized. The value it contains should always +be confirmed by reading the cpu_id field. I'm not sure what "optimistic cache" is... +Flags indicating the restart behavior for the current thread. This is +mainly used for debugging purposes. Can be either: +.IP \[bu] +RSEQ_CS_FLAG_NO_RESTART_ON_PREEMPT +.IP \[bu] +RSEQ_CS_FLAG_NO_RESTART_ON_SIGNAL +.IP \[bu] Flags tell me there may be more then one, but "can be either" tells me just one flag is allowed. +.B Structure alignment +This structure is aligned on multiples of 32 bytes. +.TP +.B Structure size +This structure has a fixed size of 32 bytes. +.B Structure alignment +This structure is aligned on multiples of 32 bytes. +.TP +.B Structure size +This structure has a fixed size of 32 bytes. I believe we normally say "is aligned on 32-bytes boundary". (Will not this need to be bigger on machines with bigger cache sizes?) above it says: +.B Structure size +This structure is extensible. Its size is passed as parameter to the +rseq system call. I'm reading source, so maybe it refers to different structure. Thanks, Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
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