Date: Fri, 12 Apr 2019 15:28:26 +0100 From: Edward Napierala <trasz@freebsd.org> To: Conrad Meyer <cem@freebsd.org> Cc: src-committers <src-committers@freebsd.org>, svn-src-all <svn-src-all@freebsd.org>, svn-src-head <svn-src-head@freebsd.org> Subject: Re: svn commit: r346120 - head/sys/kern Message-ID: <CAFLM3-rhdQcZNVovR=_6pZnuvspKO4v8irZApSxKCkn7mkg_eQ@mail.gmail.com> In-Reply-To: <CAG6CVpXo%2BBwML8z%2BsNZ-d2cHLoym0nAeZ3WP60ugZVn85FqT-A@mail.gmail.com> References: <201904111121.x3BBLj2K023087@repo.freebsd.org> <CAG6CVpXo%2BBwML8z%2BsNZ-d2cHLoym0nAeZ3WP60ugZVn85FqT-A@mail.gmail.com>
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On Thu, 11 Apr 2019 at 17:26, Conrad Meyer <cem@freebsd.org> wrote: > > Hi Edward, > > I have a question about this change below. > > On Thu, Apr 11, 2019 at 4:22 AM Edward Tomasz Napierala > <trasz@freebsd.org> wrote: > > > > Author: trasz > > Date: Thu Apr 11 11:21:45 2019 > > New Revision: 346120 > > URL: https://svnweb.freebsd.org/changeset/base/346120 > > > > Log: > > Use shared vnode locks for the ELF interpreter. [..] > On the one hand, perhaps VOP_IS_TEXT() is rarely false for common > interpreters anyway. On the other hand, there is sort of a > renaissance of static linking happening. So maybe the thought is, > !VOP_IS_TEXT is likely to be rare, and LK_UPGRADE success even more > rare, so why bother writing additional code for it? Konstantin already answered to most of the points, but regarding this one: that's exactly the case. In a typical case, the number of times this code path will be executed is zero. I'd expect one - when running dynamically linked ELF binary for the first time - but for some reason in that case lookup() returns with the exclusive vnode lock already held.
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