On 28/10/25 16:59, Frederic Weisbecker wrote: > Le Fri, Oct 10, 2025 at 05:38:37PM +0200, Valentin Schneider a écrit : >> @@ -171,8 +172,27 @@ For 32-bit we have the following conventions - kernel >> is built with >> andq $(~PTI_USER_PGTABLE_AND_PCID_MASK), \reg >> .endm >> >> -.macro COALESCE_TLBI >> +.macro COALESCE_TLBI scratch_reg:req >> #ifdef CONFIG_COALESCE_TLBI >> + /* No point in doing this for housekeeping CPUs */ >> + movslq PER_CPU_VAR(cpu_number), \scratch_reg >> + bt \scratch_reg, tick_nohz_full_mask(%rip) >> + jnc .Lend_tlbi_\@ > > I assume it's not possible to have a static call/branch to > take care of all this ? >
I think technically yes, but that would have to be a per-cpu patchable location, which would mean something like each CPU having its own copy of that text page... Unless there's some existing way to statically optimize if (cpumask_test_cpu(smp_processor_id(), mask)) where @mask is a boot-time constant (i.e. the nohz_full mask). > Thanks. > > -- > Frederic Weisbecker > SUSE Labs
