From: Samuel Holland <samuel.holland@sifive.com>
To: Palmer Dabbelt <palmer@dabbelt.com>, linux-riscv@lists.infradead.org
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Alexandre Ghiti <alexghiti@rivosinc.com>,
Samuel Holland <samuel.holland@sifive.com>
Subject: [PATCH v4 04/12] riscv: Only send remote fences when some other CPU is online
Date: Tue, 2 Jan 2024 14:00:41 -0800 [thread overview]
Message-ID: <20240102220134.3229156-5-samuel.holland@sifive.com> (raw)
In-Reply-To: <20240102220134.3229156-1-samuel.holland@sifive.com>
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>
---
Changes in v4:
- New patch for v4
arch/riscv/mm/cacheflush.c | 4 +++-
arch/riscv/mm/tlbflush.c | 4 +++-
2 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/riscv/mm/cacheflush.c b/arch/riscv/mm/cacheflush.c
index 47c485bc7df0..f7933ae88a55 100644
--- a/arch/riscv/mm/cacheflush.c
+++ b/arch/riscv/mm/cacheflush.c
@@ -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);
diff --git a/arch/riscv/mm/tlbflush.c b/arch/riscv/mm/tlbflush.c
index 2f18fe6fc4f3..37b3c93e3c30 100644
--- a/arch/riscv/mm/tlbflush.c
+++ b/arch/riscv/mm/tlbflush.c
@@ -73,7 +73,9 @@ 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);
--
2.42.0
next prev parent reply other threads:[~2024-01-02 22:01 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-01-02 22:00 [PATCH v4 00/12] riscv: ASID-related and UP-related TLB flush enhancements Samuel Holland
2024-01-02 22:00 ` [PATCH v4 01/12] riscv: Flush the instruction cache during SMP bringup Samuel Holland
2024-01-04 11:58 ` Alexandre Ghiti
2024-01-02 22:00 ` [PATCH v4 02/12] riscv: Use IPIs for remote cache/TLB flushes by default Samuel Holland
2024-01-04 12:09 ` Alexandre Ghiti
2024-01-02 22:00 ` [PATCH v4 03/12] riscv: mm: Broadcast kernel TLB flushes only when needed Samuel Holland
2024-01-04 12:15 ` Alexandre Ghiti
2024-01-02 22:00 ` Samuel Holland [this message]
2024-01-03 14:57 ` [PATCH v4 04/12] riscv: Only send remote fences when some other CPU is online Jisheng Zhang
2024-01-03 15:04 ` Jisheng Zhang
2024-01-04 12:33 ` Alexandre Ghiti
2024-01-04 15:33 ` Samuel Holland
2024-01-02 22:00 ` [PATCH v4 05/12] riscv: mm: Combine the SMP and UP TLB flush code Samuel Holland
2024-01-04 12:36 ` Alexandre Ghiti
2024-01-02 22:00 ` [PATCH v4 06/12] riscv: Apply SiFive CIP-1200 workaround to single-ASID sfence.vma Samuel Holland
2024-01-02 22:00 ` [PATCH v4 07/12] riscv: Avoid TLB flush loops when affected by SiFive CIP-1200 Samuel Holland
2024-01-02 22:00 ` [PATCH v4 08/12] riscv: mm: Introduce cntx2asid/cntx2version helper macros Samuel Holland
2024-01-04 12:39 ` Alexandre Ghiti
2024-01-04 15:42 ` Samuel Holland
2024-01-02 22:00 ` [PATCH v4 09/12] riscv: mm: Use a fixed layout for the MM context ID Samuel Holland
2024-01-04 12:42 ` Alexandre Ghiti
2024-01-02 22:00 ` [PATCH v4 10/12] riscv: mm: Make asid_bits a local variable Samuel Holland
2024-01-03 15:00 ` Jisheng Zhang
2024-01-04 15:49 ` Samuel Holland
2024-01-04 12:47 ` Alexandre Ghiti
2024-01-02 22:00 ` [PATCH v4 11/12] riscv: mm: Preserve global TLB entries when switching contexts Samuel Holland
2024-01-04 12:55 ` Alexandre Ghiti
2024-01-02 22:00 ` [PATCH v4 12/12] riscv: mm: Always use an ASID to flush mm contexts Samuel Holland
2024-01-03 15:02 ` Jisheng Zhang
2024-01-04 15:50 ` Samuel Holland
2024-01-04 13:01 ` Alexandre Ghiti
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