81 lines
2.9 KiB
Diff
81 lines
2.9 KiB
Diff
From 59b3b252a8cb61232283dabf05fd284deffb8365 Mon Sep 17 00:00:00 2001
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Message-Id: <59b3b252a8cb61232283dabf05fd284deffb8365.1601675152.git.zanussi@kernel.org>
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In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org>
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From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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Date: Thu, 12 Oct 2017 18:37:12 +0200
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Subject: [PATCH 162/333] srcu: replace local_irqsave() with a locallock
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Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz
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There are two instances which disable interrupts in order to become a
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stable this_cpu_ptr() pointer. The restore part is coupled with
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spin_unlock_irqrestore() which does not work on RT.
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Replace the local_irq_save() call with the appropriate local_lock()
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version of it.
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Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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---
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kernel/rcu/srcutree.c | 14 +++++++++-----
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1 file changed, 9 insertions(+), 5 deletions(-)
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diff --git a/kernel/rcu/srcutree.c b/kernel/rcu/srcutree.c
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index df0375453ba1..0f09a1a9e17c 100644
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--- a/kernel/rcu/srcutree.c
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+++ b/kernel/rcu/srcutree.c
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@@ -39,6 +39,7 @@
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#include <linux/module.h>
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#include <linux/srcu.h>
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#include <linux/cpu.h>
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+#include <linux/locallock.h>
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#include "rcu.h"
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#include "rcu_segcblist.h"
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@@ -760,6 +761,8 @@ static void srcu_flip(struct srcu_struct *sp)
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* negligible when amoritized over that time period, and the extra latency
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* of a needlessly non-expedited grace period is similarly negligible.
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*/
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+static DEFINE_LOCAL_IRQ_LOCK(sp_llock);
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+
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static bool srcu_might_be_idle(struct srcu_struct *sp)
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{
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unsigned long curseq;
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@@ -768,13 +771,13 @@ static bool srcu_might_be_idle(struct srcu_struct *sp)
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unsigned long t;
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/* If the local srcu_data structure has callbacks, not idle. */
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- local_irq_save(flags);
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+ local_lock_irqsave(sp_llock, flags);
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sdp = this_cpu_ptr(sp->sda);
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if (rcu_segcblist_pend_cbs(&sdp->srcu_cblist)) {
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- local_irq_restore(flags);
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+ local_unlock_irqrestore(sp_llock, flags);
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return false; /* Callbacks already present, so not idle. */
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}
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- local_irq_restore(flags);
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+ local_unlock_irqrestore(sp_llock, flags);
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/*
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* No local callbacks, so probabalistically probe global state.
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@@ -852,7 +855,7 @@ void __call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
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return;
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}
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rhp->func = func;
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- local_irq_save(flags);
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+ local_lock_irqsave(sp_llock, flags);
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sdp = this_cpu_ptr(sp->sda);
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spin_lock_rcu_node(sdp);
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rcu_segcblist_enqueue(&sdp->srcu_cblist, rhp, false);
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@@ -868,7 +871,8 @@ void __call_srcu(struct srcu_struct *sp, struct rcu_head *rhp,
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sdp->srcu_gp_seq_needed_exp = s;
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needexp = true;
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}
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- spin_unlock_irqrestore_rcu_node(sdp, flags);
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+ spin_unlock_rcu_node(sdp);
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+ local_unlock_irqrestore(sp_llock, flags);
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if (needgp)
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srcu_funnel_gp_start(sp, sdp, s, do_norm);
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else if (needexp)
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--
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2.17.1
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