linux-kernel - [PATCH v7 4/8] x86/tlb, mm/rmap: Separate arch_tlbbatch_clear() out of arch_tlbbatch

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Message-Id: <20240122010040.74346-5-byungchul@sk.com>
Date: Mon, 22 Jan 2024 10:00:36 +0900
From: Byungchul Park <byungchul@...com>
To: linux-kernel@...r.kernel.org,
	linux-mm@...ck.org
Cc: kernel_team@...ynix.com,
	akpm@...ux-foundation.org,
	ying.huang@...el.com,
	namit@...are.com,
	vernhao@...cent.com,
	mgorman@...hsingularity.net,
	hughd@...gle.com,
	willy@...radead.org,
	david@...hat.com,
	peterz@...radead.org,
	luto@...nel.org,
	tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	dave.hansen@...ux.intel.com,
	rjgolo@...il.com
Subject: [PATCH v7 4/8] x86/tlb, mm/rmap: Separate arch_tlbbatch_clear() out of arch_tlbbatch_flush()

This is a preparation for migrc mechanism that requires to avoid
redundant TLB flushes by manipulating tlb batch's arch data after
arch_tlbbatch_flush(). However, we cannot because the data is getting
cleared inside arch_tlbbatch_flush(). So separated the part clearing the
tlb batch's arch data out of arch_tlbbatch_flush().

Signed-off-by: Byungchul Park <byungchul@...com>
---
 arch/x86/mm/tlb.c | 2 --
 mm/rmap.c         | 1 +
 2 files changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 453ea95b667d..941f41df02f3 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -1268,8 +1268,6 @@ void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
 		local_irq_enable();
 	}
 
-	cpumask_clear(&batch->cpumask);
-
 	put_flush_tlb_info();
 	put_cpu();
 }
diff --git a/mm/rmap.c b/mm/rmap.c
index da36f23ff7b0..b484d659d0c1 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -643,6 +643,7 @@ void try_to_unmap_flush(void)
 		return;
 
 	arch_tlbbatch_flush(&tlb_ubc->arch);
+	arch_tlbbatch_clear(&tlb_ubc->arch);
 	tlb_ubc->flush_required = false;
 	tlb_ubc->writable = false;
 }
-- 
2.17.1