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authorDavid S. Miller <davem@davemloft.net>2017-10-30 14:10:01 +0900
committerDavid S. Miller <davem@davemloft.net>2017-10-30 21:09:24 +0900
commite1ea2f9856b765a2eaabb403a6751f70efc9ba4c (patch)
tree771f0f96fdab1b27757730e96d911c73f5499ee4 /arch/x86/include/asm/tlbflush.h
parentaad93c70b9a3b80dbc383a31e77a119f69bdd856 (diff)
parent0b07194bb55ed836c2cc7c22e866b87a14681984 (diff)
downloadop-kernel-dev-e1ea2f9856b765a2eaabb403a6751f70efc9ba4c.zip
op-kernel-dev-e1ea2f9856b765a2eaabb403a6751f70efc9ba4c.tar.gz
Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net
Several conflicts here. NFP driver bug fix adding nfp_netdev_is_nfp_repr() check to nfp_fl_output() needed some adjustments because the code block is in an else block now. Parallel additions to net/pkt_cls.h and net/sch_generic.h A bug fix in __tcp_retransmit_skb() conflicted with some of the rbtree changes in net-next. The tc action RCU callback fixes in 'net' had some overlap with some of the recent tcf_block reworking. Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/x86/include/asm/tlbflush.h')
-rw-r--r--arch/x86/include/asm/tlbflush.h21
1 files changed, 15 insertions, 6 deletions
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index d362161..c4aed0d 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -82,12 +82,21 @@ static inline u64 inc_mm_tlb_gen(struct mm_struct *mm)
#define __flush_tlb_single(addr) __native_flush_tlb_single(addr)
#endif
-/*
- * If tlb_use_lazy_mode is true, then we try to avoid switching CR3 to point
- * to init_mm when we switch to a kernel thread (e.g. the idle thread). If
- * it's false, then we immediately switch CR3 when entering a kernel thread.
- */
-DECLARE_STATIC_KEY_TRUE(tlb_use_lazy_mode);
+static inline bool tlb_defer_switch_to_init_mm(void)
+{
+ /*
+ * If we have PCID, then switching to init_mm is reasonably
+ * fast. If we don't have PCID, then switching to init_mm is
+ * quite slow, so we try to defer it in the hopes that we can
+ * avoid it entirely. The latter approach runs the risk of
+ * receiving otherwise unnecessary IPIs.
+ *
+ * This choice is just a heuristic. The tlb code can handle this
+ * function returning true or false regardless of whether we have
+ * PCID.
+ */
+ return !static_cpu_has(X86_FEATURE_PCID);
+}
/*
* 6 because 6 should be plenty and struct tlb_state will fit in
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