linux-kernel - [PATCH 07/11] x86/mm: use broadcast TLB flushing for page reclaim TLB flushing

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Message-ID: <20241223025751.3268975-8-riel@surriel.com>
Date: Sun, 22 Dec 2024 21:55:13 -0500
From: Rik van Riel <riel@...riel.com>
To: x86@...nel.org
Cc: linux-kernel@...r.kernel.org,
	kernel-team@...a.com,
	dave.hansen@...ux.intel.com,
	luto@...nel.org,
	peterz@...radead.org,
	tglx@...utronix.de,
	mingo@...hat.com,
	bp@...en8.de,
	hpa@...or.com,
	akpm@...ux-foundation.org,
	linux-mm@...ck.org,
	Rik van Riel <riel@...riel.com>
Subject: [PATCH 07/11] x86/mm: use broadcast TLB flushing for page reclaim TLB flushing

In the page reclaim code, we only track the CPU(s) where the TLB needs
to be flushed, rather than all the individual mappings that may be getting
invalidated.

Use broadcast TLB flushing when that is available.

Signed-off-by: Rik van Riel <riel@...riel.com>
---
 arch/x86/mm/tlb.c | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/arch/x86/mm/tlb.c b/arch/x86/mm/tlb.c
index 266d5174fc7b..64f1679c37e1 100644
--- a/arch/x86/mm/tlb.c
+++ b/arch/x86/mm/tlb.c
@@ -1310,8 +1310,16 @@ EXPORT_SYMBOL_GPL(__flush_tlb_all);
 void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
 {
 	struct flush_tlb_info *info;
+	int cpu;
+
+	if (cpu_feature_enabled(X86_FEATURE_INVLPGB)) {
+		guard(preempt)();
+		invlpgb_flush_all_nonglobals();
+		tlbsync();
+		return;
+	}
 
-	int cpu = get_cpu();
+	cpu = get_cpu();
 
 	info = get_flush_tlb_info(NULL, 0, TLB_FLUSH_ALL, 0, false,
 				  TLB_GENERATION_INVALID);
-- 
2.47.1