On Mon, 4 May 2020 11:38:43 -0400 (EDT) Mathieu Desnoyers <[email protected]> wrote:
> ----- On May 4, 2020, at 11:31 AM, Joerg Roedel [email protected] wrote: > > > On Mon, May 04, 2020 at 11:28:46AM -0400, Mathieu Desnoyers wrote: > >> ----- On May 4, 2020, at 11:12 AM, Joerg Roedel [email protected] wrote: > >> Placing this here is inefficient. It syncs mappings for each percpu > >> allocation. > >> I would recommend moving it right after __vmalloc() is called to allocate > >> the > >> underlying memory chunk instead: > >> > >> static void *pcpu_mem_zalloc(size_t size, gfp_t gfp) > >> { > > > > Tried this before, actually I put it into the caller of > > pcpu_mem_zalloc(), but that didn't fix the problem for me. Stevens > > test-case still hangs the machine. > > That's unexpected. > > Did you confirm that those hangs were also caused by percpu allocations ? > > Maybe adding the vmalloc_sync_mappings() at each percpu allocation happens > to luckily sync mappings after some other vmalloc. > It doesn't surprise me because my alloc_percpu() call never gets to that path. But systemd does hit it for me earlier on. -- Steve
