unimore/kernel-hacking-2024-linux-steffo
unimore/kernel-hacking-2024-linux-steffo
1
Fork 0
Code Pull requests 5 Wiki Activity

riscv: Only send remote fences when some other CPU is online

Browse source 
If no other CPU is online, a local cache or TLB flush is sufficient.
These checks can be constant-folded when SMP is disabled.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Link: https://lore.kernel.org/r/20240327045035.368512-6-samuel.holland@sifive.com
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
This commit is contained in:
Samuel Holland 2024-03-26 21:49:46 -07:00 committed by Palmer Dabbelt
parent 038ac18aae
commit 9546f00410
No known key found for this signature in database
GPG key ID: 2E1319F35FBB1889
2 changed files with 6 additions and 2 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

4
arch/riscv/mm/cacheflush.c
View file

@ -21,7 +21,9 @@ void flush_icache_all(void)
{
local_flush_icache_all();
if (riscv_use_sbi_for_rfence())
if (num_online_cpus() < 2)
return;
else if (riscv_use_sbi_for_rfence())
sbi_remote_fence_i(NULL);
else
on_each_cpu(ipi_remote_fence_i, NULL, 1);

4
arch/riscv/mm/tlbflush.c
View file

@ -79,7 +79,9 @@ static void __ipi_flush_tlb_all(void *info)
void flush_tlb_all(void)
{
if (riscv_use_sbi_for_rfence())
if (num_online_cpus() < 2)
local_flush_tlb_all();
else if (riscv_use_sbi_for_rfence())
sbi_remote_sfence_vma_asid(NULL, 0, FLUSH_TLB_MAX_SIZE, FLUSH_TLB_NO_ASID);
else
on_each_cpu(__ipi_flush_tlb_all, NULL, 1);