From: Helge Deller <deller@gmx.de>
To: linux-parisc@vger.kernel.org,
James Bottomley <James.Bottomley@hansenpartnership.com>,
John David Anglin <dave.anglin@bell.net>
Subject: [PATCH] parisc: speed up flush_tlb_all_local with qemu
Date: Mon, 12 Aug 2019 19:13:20 +0200 [thread overview]
Message-ID: <20190812171320.GA28951@ls3530.fritz.box> (raw)
When started in qemu, we know that qemu will drop all local TLB entries
on any pxtlbe instruction. So, if we detect qemu, replace the whole
flush_tlb_all_local function by one pdtlbe instruction.
Signed-off-by: Helge Deller <deller@gmx.de>
diff --git a/arch/parisc/kernel/pacache.S b/arch/parisc/kernel/pacache.S
index df46b0e5a915..fa092ed1e837 100644
--- a/arch/parisc/kernel/pacache.S
+++ b/arch/parisc/kernel/pacache.S
@@ -174,6 +174,15 @@ fdtdone:
2: bv %r0(%r2)
nop
+
+ /*
+ * When running in qemu, drop whole flush_tlb_all_local function and
+ * replace by one pdtlbe instruction, for which QEMU will drop all
+ * local TLB entries.
+ */
+3: pdtlbe %r0(%sr1,%r0)
+ bv,n %r0(%r2)
+ ALTERNATIVE_CODE(flush_tlb_all_local, 2, ALT_COND_RUN_ON_QEMU, 3b)
ENDPROC_CFI(flush_tlb_all_local)
.import cache_info,data
reply other threads:[~2019-08-12 17:13 UTC|newest]
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