From: Peter Zijlstra <peterz@infradead.org>
To: will.deacon@arm.com, aneesh.kumar@linux.vnet.ibm.com,
akpm@linux-foundation.org, npiggin@gmail.com
Cc: linux-arch@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, peterz@infradead.org,
linux@armlinux.org.uk, heiko.carstens@de.ibm.com,
riel@surriel.com
Subject: [PATCH v6 05/18] asm-generic/tlb: Provide generic tlb_flush() based on flush_tlb_mm()
Date: Tue, 19 Feb 2019 11:31:53 +0100 [thread overview]
Message-ID: <20190219103233.148854086@infradead.org> (raw)
In-Reply-To: 20190219103148.192029670@infradead.org
When an architecture does not have (an efficient) flush_tlb_range(),
but instead always uses full TLB invalidates, the current generic
tlb_flush() is sub-optimal, for it will generate extra flushes in
order to keep the range small.
But if we cannot do range flushes, that is a moot concern. Optionally
provide this simplified default.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
include/asm-generic/tlb.h | 41 ++++++++++++++++++++++++++++++++++++++++-
1 file changed, 40 insertions(+), 1 deletion(-)
--- a/include/asm-generic/tlb.h
+++ b/include/asm-generic/tlb.h
@@ -114,7 +114,8 @@
* returns the smallest TLB entry size unmapped in this range.
*
* If an architecture does not provide tlb_flush() a default implementation
- * based on flush_tlb_range() will be used.
+ * based on flush_tlb_range() will be used, unless MMU_GATHER_NO_RANGE is
+ * specified, in which case we'll default to flush_tlb_mm().
*
* Additionally there are a few opt-in features:
*
@@ -140,6 +141,9 @@
* the page-table pages. Required if you use HAVE_RCU_TABLE_FREE and your
* architecture uses the Linux page-tables natively.
*
+ * MMU_GATHER_NO_RANGE
+ *
+ * Use this if your architecture lacks an efficient flush_tlb_range().
*/
#define HAVE_GENERIC_MMU_GATHER
@@ -302,12 +306,45 @@ static inline void __tlb_reset_range(str
*/
}
+#ifdef CONFIG_MMU_GATHER_NO_RANGE
+
+#if defined(tlb_flush) || defined(tlb_start_vma) || defined(tlb_end_vma)
+#error MMU_GATHER_NO_RANGE relies on default tlb_flush(), tlb_start_vma() and tlb_end_vma()
+#endif
+
+/*
+ * When an architecture does not have efficient means of range flushing TLBs
+ * there is no point in doing intermediate flushes on tlb_end_vma() to keep the
+ * range small. We equally don't have to worry about page granularity or other
+ * things.
+ *
+ * All we need to do is issue a full flush for any !0 range.
+ */
+static inline void tlb_flush(struct mmu_gather *tlb)
+{
+ if (tlb->end)
+ flush_tlb_mm(tlb->mm);
+}
+
+static inline void
+tlb_update_vma_flags(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
+
+#define tlb_end_vma tlb_end_vma
+static inline void tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma) { }
+
+#else /* CONFIG_MMU_GATHER_NO_RANGE */
+
#ifndef tlb_flush
#if defined(tlb_start_vma) || defined(tlb_end_vma)
#error Default tlb_flush() relies on default tlb_start_vma() and tlb_end_vma()
#endif
+/*
+ * When an architecture does not provide its own tlb_flush() implementation
+ * but does have a reasonably efficient flush_vma_range() implementation
+ * use that.
+ */
static inline void tlb_flush(struct mmu_gather *tlb)
{
if (tlb->fullmm || tlb->need_flush_all) {
@@ -348,6 +385,8 @@ tlb_update_vma_flags(struct mmu_gather *
#endif
+#endif /* CONFIG_MMU_GATHER_NO_RANGE */
+
static inline void tlb_flush_mmu_tlbonly(struct mmu_gather *tlb)
{
if (!tlb->end)
next prev parent reply other threads:[~2019-02-19 10:33 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-19 10:31 [PATCH v6 00/18] generic mmu_gather patches Peter Zijlstra
2019-02-19 10:31 ` [PATCH v6 01/18] asm-generic/tlb: Provide a comment Peter Zijlstra
2019-02-19 10:31 ` [PATCH v6 02/18] asm-generic/tlb: Provide HAVE_MMU_GATHER_PAGE_SIZE Peter Zijlstra
2019-02-19 10:31 ` [PATCH v6 03/18] asm-generic/tlb: Provide generic VIPT cache flush Peter Zijlstra
2019-02-19 10:31 ` [PATCH v6 04/18] asm-generic/tlb: Provide generic tlb_flush() based on flush_tlb_range() Peter Zijlstra
2019-02-19 10:31 ` Peter Zijlstra [this message]
2019-02-19 12:47 ` [PATCH v6 05/18] asm-generic/tlb: Provide generic tlb_flush() based on flush_tlb_mm() Will Deacon
2019-02-19 10:31 ` [PATCH v6 06/18] asm-generic/tlb: Conditionally provide tlb_migrate_finish() Peter Zijlstra
2019-02-19 12:47 ` Will Deacon
2019-02-19 13:41 ` Peter Zijlstra
2019-02-20 14:47 ` Will Deacon
2019-02-20 15:02 ` Matthew Wilcox
2019-02-19 10:31 ` [PATCH v6 07/18] asm-generic/tlb: Invert HAVE_RCU_TABLE_INVALIDATE Peter Zijlstra
2019-02-19 10:31 ` [PATCH v6 08/18] arm/tlb: Convert to generic mmu_gather Peter Zijlstra
2019-02-19 10:31 ` [PATCH v6 09/18] ia64/tlb: Conver " Peter Zijlstra
2019-02-19 12:47 ` Will Deacon
2019-02-21 2:52 ` Souptick Joarder
2019-02-19 10:31 ` [PATCH v6 10/18] sh/tlb: Convert SH " Peter Zijlstra
2019-12-03 11:19 ` Geert Uytterhoeven
2019-12-04 10:47 ` Peter Zijlstra
2019-12-04 12:32 ` Geert Uytterhoeven
2019-12-04 13:22 ` Guenter Roeck
2019-12-04 15:17 ` Geert Uytterhoeven
2019-12-04 19:03 ` Guenter Roeck
2019-12-04 13:34 ` Peter Zijlstra
2019-12-04 15:07 ` Geert Uytterhoeven
2019-12-04 16:41 ` Peter Zijlstra
2019-12-05 15:26 ` Geert Uytterhoeven
2020-07-15 19:45 ` John Paul Adrian Glaubitz
2019-12-05 19:24 ` Rob Landley
2019-12-05 19:23 ` Rich Felker
2020-07-15 19:49 ` John Paul Adrian Glaubitz
2019-12-05 19:30 ` John Paul Adrian Glaubitz
2019-12-05 22:56 ` Guenter Roeck
2019-12-06 13:38 ` John Paul Adrian Glaubitz
2019-12-06 14:03 ` Guenter Roeck
2019-02-19 10:31 ` [PATCH v6 11/18] um/tlb: Convert " Peter Zijlstra
2019-02-19 10:32 ` [PATCH v6 12/18] arch/tlb: Clean up simple architectures Peter Zijlstra
2019-02-19 10:32 ` [PATCH v6 13/18] asm-generic/tlb: Introduce HAVE_MMU_GATHER_NO_GATHER Peter Zijlstra
2019-02-19 12:47 ` Will Deacon
2019-02-19 10:32 ` [PATCH v6 14/18] s390/tlb: convert to generic mmu_gather Peter Zijlstra
2019-02-19 12:47 ` Will Deacon
2019-02-19 10:32 ` [PATCH v6 15/18] asm-generic/tlb: Remove arch_tlb*_mmu() Peter Zijlstra
2019-02-19 10:32 ` [PATCH v6 16/18] asm-generic/tlb: Remove HAVE_GENERIC_MMU_GATHER Peter Zijlstra
2019-02-19 10:32 ` [PATCH v6 17/18] asm-generic/tlb: Remove tlb_flush_mmu_free() Peter Zijlstra
2019-02-19 10:32 ` [PATCH v6 18/18] asm-generic/tlb: Remove tlb_table_flush() Peter Zijlstra
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