81 lines
2.6 KiB
Diff
81 lines
2.6 KiB
Diff
From: Thomas Gleixner <tglx@linutronix.de>
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Date: Sun, 17 Jul 2011 21:33:18 +0200
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Subject: radix-tree: Make RT aware
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patches-4.9-rt1.tar.xz
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Disable radix_tree_preload() on -RT. This functions returns with
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preemption disabled which may cause high latencies and breaks if the
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user tries to grab any locks after invoking it.
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Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
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---
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include/linux/radix-tree.h | 12 +++++++++++-
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lib/radix-tree.c | 5 ++++-
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2 files changed, 15 insertions(+), 2 deletions(-)
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--- a/include/linux/radix-tree.h
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+++ b/include/linux/radix-tree.h
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@@ -289,9 +289,19 @@ unsigned int radix_tree_gang_lookup(stru
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unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root,
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void ***results, unsigned long *indices,
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unsigned long first_index, unsigned int max_items);
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+#ifdef CONFIG_PREEMPT_RT_FULL
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+static inline int radix_tree_preload(gfp_t gm) { return 0; }
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+static inline int radix_tree_maybe_preload(gfp_t gfp_mask) { return 0; }
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+static inline int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order)
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+{
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+ return 0;
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+};
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+
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+#else
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int radix_tree_preload(gfp_t gfp_mask);
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int radix_tree_maybe_preload(gfp_t gfp_mask);
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int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order);
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+#endif
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void radix_tree_init(void);
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void *radix_tree_tag_set(struct radix_tree_root *root,
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unsigned long index, unsigned int tag);
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@@ -316,7 +326,7 @@ unsigned long radix_tree_locate_item(str
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static inline void radix_tree_preload_end(void)
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{
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- preempt_enable();
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+ preempt_enable_nort();
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}
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/**
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--- a/lib/radix-tree.c
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+++ b/lib/radix-tree.c
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@@ -290,13 +290,14 @@ radix_tree_node_alloc(struct radix_tree_
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* succeed in getting a node here (and never reach
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* kmem_cache_alloc)
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*/
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- rtp = this_cpu_ptr(&radix_tree_preloads);
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+ rtp = &get_cpu_var(radix_tree_preloads);
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if (rtp->nr) {
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ret = rtp->nodes;
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rtp->nodes = ret->private_data;
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ret->private_data = NULL;
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rtp->nr--;
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}
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+ put_cpu_var(radix_tree_preloads);
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/*
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* Update the allocation stack trace as this is more useful
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* for debugging.
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@@ -336,6 +337,7 @@ radix_tree_node_free(struct radix_tree_n
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call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
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}
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+#ifndef CONFIG_PREEMPT_RT_FULL
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/*
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* Load up this CPU's radix_tree_node buffer with sufficient objects to
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* ensure that the addition of a single element in the tree cannot fail. On
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@@ -455,6 +457,7 @@ int radix_tree_maybe_preload_order(gfp_t
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return __radix_tree_preload(gfp_mask, nr_nodes);
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}
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+#endif
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/*
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* The maximum index which can be stored in a radix tree
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