Date: Tue, 17 Jun 2008 23:19:19 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: Maxim Sobolev <sobomax@freebsd.org>, src-committers@freebsd.org, Ed Schouten <ed@80386.nl>, cvs-src@freebsd.org, cvs-all@freebsd.org, David Xu <davidxu@freebsd.org> Subject: Re: cvs commit: src/include Makefile spawn.h unistd.h src/lib/libc/gen Makefile.inc Symbol.map exec.3 exec.c posix_spawn.c Message-ID: <20080617201919.GQ82830@deviant.kiev.zoral.com.ua> In-Reply-To: <200806171122.41340.jhb@freebsd.org> References: <200806170633.m5H6XMJH084600@repoman.freebsd.org> <20080617140600.GE1176@hoeg.nl> <4857D508.8070907@FreeBSD.org> <200806171122.41340.jhb@freebsd.org>
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--MXxcbiX/Q4+iy5U7 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Tue, Jun 17, 2008 at 11:22:40AM -0400, John Baldwin wrote: > On Tuesday 17 June 2008 11:15:20 am Maxim Sobolev wrote: > > Ed Schouten wrote: > > > * David Schultz <das@FreeBSD.ORG> wrote: > > >> I have no objections to this, but doesn't it defeat the whole > > >> purpose to implement posix_spawn() as a library function that just > > >> calls fork/exec? > > >=20 > > > When (if?) applications start to use posix_spawn() we may decide to m= ove > > > it into the kernel at any time. It should be okay for now. > >=20 > > Are there any benefits of doing it in the kernel vs. doing it via fork+= exec? >=20 > Speed. You don't have to go mark all your pages as COW or some such only= to=20 > turn around and throw the new mappings away and undo that. The committed implementation uses vfork(). No COW is needed. On the other hand, after single-threading of the parent process have been removed from fork1(9), vfork(2) could have interesting consequences when done from the multithreaded process. --MXxcbiX/Q4+iy5U7 Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (FreeBSD) iEYEARECAAYFAkhYHEcACgkQC3+MBN1Mb4jU9ACg755WAFYGlWv7yMUTQDaVmMXX aU8AoKKl15j6n5JsftOx1x4FTAbMx5Gt =J1n7 -----END PGP SIGNATURE----- --MXxcbiX/Q4+iy5U7--
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