From: Andy Lutomirski Date: Fri, 5 Sep 2014 22:13:56 +0000 (-0700) Subject: x86_64, entry: Use split-phase syscall_trace_enter for 64-bit syscalls X-Git-Tag: fixes-against-v3.18-rc2~86^2 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=1dcf74f6edfc3a9acd84d83d8865dd9e2a3b1d1e;p=pandora-kernel.git x86_64, entry: Use split-phase syscall_trace_enter for 64-bit syscalls On KVM on my box, this reduces the overhead from an always-accept seccomp filter from ~130ns to ~17ns. Most of that comes from avoiding IRET on every syscall when seccomp is enabled. In extremely approximate hacked-up benchmarking, just bypassing IRET saves about 80ns, so there's another 43ns of savings here from simplifying the seccomp path. The diffstat is also rather nice :) Signed-off-by: Andy Lutomirski Link: http://lkml.kernel.org/r/a3dbd267ee990110478d349f78cccfdac5497a84.1409954077.git.luto@amacapital.net Signed-off-by: H. Peter Anvin --- Reading git-diff-tree failed