Peter Zijlstra <pet...@infradead.org> writes: > On Mon, Sep 26, 2016 at 11:27:08AM +0300, Alexander Shishkin wrote: >> Peter Zijlstra <pet...@infradead.org> writes: >> >> > Well, we could 'force' inject a VMA into the process's address space, we >> > do that for a few other things as well. It also makes for less >> > exceptions with the actual core dumping. >> >> Threads then will end up with the same buffer (through sharing the mm), >> but they can't really share trace buffers. >> >> Also, system core dump is still a problem. > > Hurm, true on both counts.
OTOH, system core dump buffers don't need inheritance or memlock accounting. >> Or we can have per-cpu buffers for all user's tasks, record where each >> task starts and ends in each buffer and cut out only bits relevant to >> the task(s) that dump core. > > Which gets you the problem that when a task dumps core there might not > be any state in the buffer, because the previous task flushed it all out > :/ And also won't work with PMUs that don't generate PMIs, like ETMs. Regards, -- Alex
