Messages in this thread | | | From | Andy Lutomirski <> | Subject | [PATCH v3 0/5] x86 entry stuff, maybe for 4.4 | Date | Thu, 12 Nov 2015 12:58:59 -0800 |
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The first patch is a bit ugly, but it fixes a bug that could affect lockdep. That bug is very minor and may not be observable at all, but I don't really want to bet on it.
The other three are intended to fix a performance regression in the entry rework that Frédéric objected to. They're much later than I'd like to have sent them for 4.4, but they're kind-of sort-of regression fixes, so maybe they're still okay. They would certainly need careful review, though.
I don't have a great benchmark for them. The biggest impact is likely to be to user page fault latency on CONFIG_CONTEXT_TRACKING=y kernels (i.e. distro kernels) that don't use context tracking (i.e. most users).
Changes from v3: Actually send entire series (patch 1 was missing)
Changes from v1: - CALL_ENTER_FROM_USER_MODE is now CALL_enter_from_user_mode (Ingo) - STATIC_JUMP_IF_{TRUE,FALSE} now cannot be (mis-)used on non-jump-label kernels (Thomas) - Comments are better (Borislav)
This doesn't really address Thomas' objections to the HAVE_JUMP_LABEL stuff, but it's more robust now, and maybe that's good enough.
Andy Lutomirski (5): x86/entry/64: Fix irqflag tracing wrt context tracking context_tracking: Switch to new static_branch API x86/asm: Error out if asm/jump_label.h is included inappropriately x86/asm: Add asm macros for static keys/jump labels x86/entry/64: Bypass enter_from_user_mode on non-context-tracking boots
arch/x86/entry/calling.h | 15 ++++++++ arch/x86/entry/entry_64.S | 27 +++++++++++---- arch/x86/include/asm/jump_label.h | 63 ++++++++++++++++++++++++++++++---- include/linux/context_tracking_state.h | 4 +-- kernel/context_tracking.c | 4 +-- 5 files changed, 95 insertions(+), 18 deletions(-)
-- 2.5.0
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