Messages in this thread | | | Date | Wed, 16 Mar 2022 16:07:31 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH V3 4/7] x86/entry: move PUSH_AND_CLEAR_REGS out of error_entry |
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On Tue, Mar 15, 2022 at 03:39:46PM +0800, Lai Jiangshan wrote: > From: Lai Jiangshan <jiangshan.ljs@antgroup.com> > > Moving PUSH_AND_CLEAR_REGS out of error_entry doesn't change any > functionality. > > It makes error_entry() do not fiddle with the stack. > > It will enlarge the size: > > size arch/x86/entry/entry_64.o.before: > text data bss dec hex filename > 17916 384 0 18300 477c arch/x86/entry/entry_64.o > > size --format=SysV arch/x86/entry/entry_64.o.before: > .entry.text 5528 0 > .orc_unwind 6456 0 > .orc_unwind_ip 4304 0 > > size arch/x86/entry/entry_64.o.after: > text data bss dec hex filename > 26868 384 0 27252 6a74 arch/x86/entry/entry_64.o > > size --format=SysV arch/x86/entry/entry_64.o.after: > .entry.text 8200 0 > .orc_unwind 10224 0 > .orc_unwind_ip 6816 0 > > But .entry.text in x86_64 is 2M aligned, enlarging it to 8.2k doesn't > enlarge the final text size.
So I don't much care about the orc data, that's only used when unwinding, a relatively rare occasion, anyway. But the text increase does bother me a little, this can blow up I$ misses on syscall heavy workloads.
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