From: Nadav Amit <nadav.amit@gmail.com>
To: linux-mm@kvack.org, linux-kernel@vger.kernel.org
Cc: Nadav Amit <namit@vmware.com>,
Andrea Arcangeli <aarcange@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
Andy Lutomirski <luto@kernel.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Will Deacon <will@kernel.org>, Yu Zhao <yuzhao@google.com>,
Nick Piggin <npiggin@gmail.com>,
x86@kernel.org
Subject: [RFC 14/20] mm: move inc/dec_tlb_flush_pending() to mmu_gather.c
Date: Sat, 30 Jan 2021 16:11:26 -0800 [thread overview]
Message-ID: <20210131001132.3368247-15-namit@vmware.com> (raw)
In-Reply-To: <20210131001132.3368247-1-namit@vmware.com>
From: Nadav Amit <namit@vmware.com>
Reduce the chances that inc/dec_tlb_flush_pending() will be abused by
moving them into mmu_gather.c, which is more of their natural place.
This also allows to reduce the clutter on mm_types.h.
Signed-off-by: Nadav Amit <namit@vmware.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will@kernel.org>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: x86@kernel.org
---
include/linux/mm_types.h | 54 ----------------------------------------
mm/mmu_gather.c | 54 ++++++++++++++++++++++++++++++++++++++++
2 files changed, 54 insertions(+), 54 deletions(-)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 812ee0fd4c35..676795dfd5d4 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -615,60 +615,6 @@ static inline void init_tlb_flush_pending(struct mm_struct *mm)
atomic_set(&mm->tlb_flush_pending, 0);
}
-static inline void inc_tlb_flush_pending(struct mm_struct *mm)
-{
- atomic_inc(&mm->tlb_flush_pending);
- /*
- * The only time this value is relevant is when there are indeed pages
- * to flush. And we'll only flush pages after changing them, which
- * requires the PTL.
- *
- * So the ordering here is:
- *
- * atomic_inc(&mm->tlb_flush_pending);
- * spin_lock(&ptl);
- * ...
- * set_pte_at();
- * spin_unlock(&ptl);
- *
- * spin_lock(&ptl)
- * mm_tlb_flush_pending();
- * ....
- * spin_unlock(&ptl);
- *
- * flush_tlb_range();
- * atomic_dec(&mm->tlb_flush_pending);
- *
- * Where the increment if constrained by the PTL unlock, it thus
- * ensures that the increment is visible if the PTE modification is
- * visible. After all, if there is no PTE modification, nobody cares
- * about TLB flushes either.
- *
- * This very much relies on users (mm_tlb_flush_pending() and
- * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
- * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
- * locks (PPC) the unlock of one doesn't order against the lock of
- * another PTL.
- *
- * The decrement is ordered by the flush_tlb_range(), such that
- * mm_tlb_flush_pending() will not return false unless all flushes have
- * completed.
- */
-}
-
-static inline void dec_tlb_flush_pending(struct mm_struct *mm)
-{
- /*
- * See inc_tlb_flush_pending().
- *
- * This cannot be smp_mb__before_atomic() because smp_mb() simply does
- * not order against TLB invalidate completion, which is what we need.
- *
- * Therefore we must rely on tlb_flush_*() to guarantee order.
- */
- atomic_dec(&mm->tlb_flush_pending);
-}
-
static inline bool mm_tlb_flush_pending(struct mm_struct *mm)
{
/*
diff --git a/mm/mmu_gather.c b/mm/mmu_gather.c
index 5a659d4e59eb..13338c096cc6 100644
--- a/mm/mmu_gather.c
+++ b/mm/mmu_gather.c
@@ -249,6 +249,60 @@ void tlb_flush_mmu(struct mmu_gather *tlb)
tlb_flush_mmu_free(tlb);
}
+static inline void inc_tlb_flush_pending(struct mm_struct *mm)
+{
+ atomic_inc(&mm->tlb_flush_pending);
+ /*
+ * The only time this value is relevant is when there are indeed pages
+ * to flush. And we'll only flush pages after changing them, which
+ * requires the PTL.
+ *
+ * So the ordering here is:
+ *
+ * atomic_inc(&mm->tlb_flush_pending);
+ * spin_lock(&ptl);
+ * ...
+ * set_pte_at();
+ * spin_unlock(&ptl);
+ *
+ * spin_lock(&ptl)
+ * mm_tlb_flush_pending();
+ * ....
+ * spin_unlock(&ptl);
+ *
+ * flush_tlb_range();
+ * atomic_dec(&mm->tlb_flush_pending);
+ *
+ * Where the increment if constrained by the PTL unlock, it thus
+ * ensures that the increment is visible if the PTE modification is
+ * visible. After all, if there is no PTE modification, nobody cares
+ * about TLB flushes either.
+ *
+ * This very much relies on users (mm_tlb_flush_pending() and
+ * mm_tlb_flush_nested()) only caring about _specific_ PTEs (and
+ * therefore specific PTLs), because with SPLIT_PTE_PTLOCKS and RCpc
+ * locks (PPC) the unlock of one doesn't order against the lock of
+ * another PTL.
+ *
+ * The decrement is ordered by the flush_tlb_range(), such that
+ * mm_tlb_flush_pending() will not return false unless all flushes have
+ * completed.
+ */
+}
+
+static inline void dec_tlb_flush_pending(struct mm_struct *mm)
+{
+ /*
+ * See inc_tlb_flush_pending().
+ *
+ * This cannot be smp_mb__before_atomic() because smp_mb() simply does
+ * not order against TLB invalidate completion, which is what we need.
+ *
+ * Therefore we must rely on tlb_flush_*() to guarantee order.
+ */
+ atomic_dec(&mm->tlb_flush_pending);
+}
+
/**
* tlb_gather_mmu - initialize an mmu_gather structure for page-table tear-down
* @tlb: the mmu_gather structure to initialize
--
2.25.1
next prev parent reply other threads:[~2021-01-31 0:19 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-31 0:11 [RFC 00/20] TLB batching consolidation and enhancements Nadav Amit
2021-01-31 0:11 ` [RFC 01/20] mm/tlb: fix fullmm semantics Nadav Amit
2021-01-31 1:02 ` Andy Lutomirski
2021-01-31 1:19 ` Nadav Amit
2021-01-31 2:57 ` Andy Lutomirski
2021-02-01 7:30 ` Nadav Amit
2021-02-01 11:36 ` Peter Zijlstra
2021-02-02 9:32 ` Nadav Amit
2021-02-02 11:00 ` Peter Zijlstra
2021-02-02 21:35 ` Nadav Amit
2021-02-03 9:44 ` Will Deacon
2021-02-04 3:20 ` Nadav Amit
2021-01-31 0:11 ` [RFC 02/20] mm/mprotect: use mmu_gather Nadav Amit
2021-01-31 0:11 ` [RFC 03/20] mm/mprotect: do not flush on permission promotion Nadav Amit
2021-01-31 1:07 ` Andy Lutomirski
2021-01-31 1:17 ` Nadav Amit
2021-01-31 2:59 ` Andy Lutomirski
[not found] ` <7a6de15a-a570-31f2-14d6-a8010296e694@citrix.com>
2021-02-01 5:58 ` Nadav Amit
2021-02-01 15:38 ` Andrew Cooper
2021-01-31 0:11 ` [RFC 04/20] mm/mapping_dirty_helpers: use mmu_gather Nadav Amit
2021-01-31 0:11 ` [RFC 05/20] mm/tlb: move BATCHED_UNMAP_TLB_FLUSH to tlb.h Nadav Amit
2021-01-31 0:11 ` [RFC 06/20] fs/task_mmu: use mmu_gather interface of clear-soft-dirty Nadav Amit
2021-01-31 0:11 ` [RFC 07/20] mm: move x86 tlb_gen to generic code Nadav Amit
2021-01-31 18:26 ` Andy Lutomirski
2021-01-31 0:11 ` [RFC 08/20] mm: store completed TLB generation Nadav Amit
2021-01-31 20:32 ` Andy Lutomirski
2021-02-01 7:28 ` Nadav Amit
2021-02-01 16:53 ` Andy Lutomirski
2021-02-01 11:52 ` Peter Zijlstra
2021-01-31 0:11 ` [RFC 09/20] mm: create pte/pmd_tlb_flush_pending() Nadav Amit
2021-01-31 0:11 ` [RFC 10/20] mm: add pte_to_page() Nadav Amit
2021-01-31 0:11 ` [RFC 11/20] mm/tlb: remove arch-specific tlb_start/end_vma() Nadav Amit
2021-02-01 12:09 ` Peter Zijlstra
2021-02-02 6:41 ` Nicholas Piggin
2021-02-02 7:20 ` Nadav Amit
2021-02-02 9:31 ` Peter Zijlstra
2021-02-02 9:54 ` Nadav Amit
2021-02-02 11:04 ` Peter Zijlstra
2021-01-31 0:11 ` [RFC 12/20] mm/tlb: save the VMA that is flushed during tlb_start_vma() Nadav Amit
2021-02-01 12:28 ` Peter Zijlstra
2021-01-31 0:11 ` [RFC 13/20] mm/tlb: introduce tlb_start_ptes() and tlb_end_ptes() Nadav Amit
[not found] ` <YBaBcc2jEGaxuxH0@fedora.tometzki.de>
2021-02-01 7:29 ` Nadav Amit
2021-02-01 13:19 ` Peter Zijlstra
2021-02-01 23:00 ` Nadav Amit
2021-01-31 0:11 ` Nadav Amit [this message]
2021-01-31 0:11 ` [RFC 15/20] mm: detect deferred TLB flushes in vma granularity Nadav Amit
2021-02-01 22:04 ` Nadav Amit
2021-02-02 0:14 ` Andy Lutomirski
2021-02-02 20:51 ` Nadav Amit
2021-02-04 4:35 ` Andy Lutomirski
2021-01-31 0:11 ` [RFC 16/20] mm/tlb: per-page table generation tracking Nadav Amit
2021-01-31 0:11 ` [RFC 17/20] mm/tlb: updated completed deferred TLB flush conditionally Nadav Amit
2021-01-31 0:11 ` [RFC 18/20] mm: make mm_cpumask() volatile Nadav Amit
2021-01-31 0:11 ` [RFC 19/20] lib/cpumask: introduce cpumask_atomic_or() Nadav Amit
2021-01-31 0:11 ` [RFC 20/20] mm/rmap: avoid potential races Nadav Amit
2021-08-23 8:05 ` Huang, Ying
2021-08-23 15:50 ` Nadav Amit
2021-08-24 0:36 ` Huang, Ying
2021-01-31 0:39 ` [RFC 00/20] TLB batching consolidation and enhancements Andy Lutomirski
2021-01-31 1:08 ` Nadav Amit
2021-01-31 3:30 ` Nicholas Piggin
2021-01-31 7:57 ` Nadav Amit
2021-01-31 8:14 ` Nadav Amit
2021-02-01 12:44 ` Peter Zijlstra
2021-02-02 7:14 ` Nicholas Piggin
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