Date: Mon, 28 Sep 2015 11:34:32 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-net@FreeBSD.org Subject: [Bug 203409] page fault in tcp_do_segment (r287759 suspected) Message-ID: <bug-203409-2472-rycyl2glmW@https.bugs.freebsd.org/bugzilla/> In-Reply-To: <bug-203409-2472@https.bugs.freebsd.org/bugzilla/> References: <bug-203409-2472@https.bugs.freebsd.org/bugzilla/>
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https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=203409 --- Comment #1 from Andriy Gapon <avg@FreeBSD.org> --- Created attachment 161483 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=161483&action=edit fix / work-around The attached trivial patch seems to make the issue go away. But I am not sure if that's a correct fix as not firing the probe at all could result in an incomplete event trail. As a side note, in my opinion the use of mtod() with the SDT probes in tcp_do_segment() is slightly against the recommended SDT usage. Typically an SDT probe's arguments are values that are actually used near the probe and thus have a high chance of being in CPU registers or in the L1 cache. In tcp_do_segment() there does not seem to be any access to m_data, so the probes have a bigger overhead because of the extra memory access. m_data's value might still be in the L1 cache, though. -- You are receiving this mail because: You are the assignee for the bug.
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