From owner-svn-src-all@freebsd.org Fri Apr 12 14:28:46 2019 Return-Path: Delivered-To: svn-src-all@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 06997157DEBA; Fri, 12 Apr 2019 14:28:46 +0000 (UTC) (envelope-from etnapierala@gmail.com) Received: from mail-oi1-f172.google.com (mail-oi1-f172.google.com [209.85.167.172]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "GTS CA 1O1" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 91DC275834; Fri, 12 Apr 2019 14:28:45 +0000 (UTC) (envelope-from etnapierala@gmail.com) Received: by mail-oi1-f172.google.com with SMTP id n187so8099378oih.6; Fri, 12 Apr 2019 07:28:45 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=Pk01HWqcJlSl+OHh3Stc+l28ZdzsxcxT1YJViwaW06E=; b=fHvstquL+EvIfMOd0xH9u9CTtr1QRUqBlvMaidlqOqD59sb8o/7BYfLEH5x1HaWAlO wyxzbdZ37PZolPuTwmuzo5e4kGvUFv9sUeU5rg0TrUVZAP5mlJkzqN3iro7McOOu21vJ rQqKS+Ppfg+IOTEZJs+nsIWvUoHYs/TgOeo3/l2W6zM+zTUEp+HdJb67gJMe0Nf88Po4 iV5h8oTnaKax+L90T6E8tkYNs7Gb1iyeFzQ4Ai454bKDQ4ozoPeCnJD5+/OeUysWgCWS sO89pRuol2ILBlt0ueLG6iaYxjcl6YiDYYiQLaMvWcuWlGci7TdmG2jzZDIU9MeMUmrb pD8g== X-Gm-Message-State: APjAAAUt8s5393k+DgiXjafUWBzWb/VEpbMpi5LcWrTLEfKSXdQQBclm nzNo/iMaBIjSW0fxn8FombLQdLyC3z6/QVLeCwsTKw== X-Google-Smtp-Source: APXvYqzRelHR2+08xftsVHssuJsNTVBirfYjdWAK+EbpQjm+WJGDRJ5WY4z56EJ039cXEWj9jk4L8FsCI0DYPS73ubQ= X-Received: by 2002:aca:d595:: with SMTP id m143mr10231633oig.31.1555079318540; Fri, 12 Apr 2019 07:28:38 -0700 (PDT) MIME-Version: 1.0 References: <201904111121.x3BBLj2K023087@repo.freebsd.org> In-Reply-To: From: Edward Napierala Date: Fri, 12 Apr 2019 15:28:26 +0100 Message-ID: Subject: Re: svn commit: r346120 - head/sys/kern To: Conrad Meyer Cc: src-committers , svn-src-all , svn-src-head Content-Type: text/plain; charset="UTF-8" X-Rspamd-Queue-Id: 91DC275834 X-Spamd-Bar: ------ Authentication-Results: mx1.freebsd.org X-Spamd-Result: default: False [-6.93 / 15.00]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; REPLY(-4.00)[]; NEURAL_HAM_SHORT(-0.93)[-0.931,0] X-BeenThere: svn-src-all@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: "SVN commit messages for the entire src tree \(except for " user" and " projects" \)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 12 Apr 2019 14:28:46 -0000 On Thu, 11 Apr 2019 at 17:26, Conrad Meyer wrote: > > Hi Edward, > > I have a question about this change below. > > On Thu, Apr 11, 2019 at 4:22 AM Edward Tomasz Napierala > 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.