Date: Fri, 20 Aug 2010 22:42:27 +0300 From: Kostik Belousov <kostikbel@gmail.com> To: John Baldwin <jhb@freebsd.org> Cc: pluknet <pluknet@gmail.com>, FreeBSD Current <freebsd-current@freebsd.org> Subject: Re: LOR on nfs: vfs_vnops.c:301 kern_descrip.c:1580 Message-ID: <20100820194227.GO2396@deviant.kiev.zoral.com.ua> In-Reply-To: <201008201535.48560.jhb@freebsd.org> References: <AANLkTimJ=d06D2z24QyRQ98zEa1Pemk4=vkNGLNiX90N@mail.gmail.com> <AANLkTin43JMZppMGgFDVhDKxbeE89ydkxwnFANfkrLc4@mail.gmail.com> <20100820191953.GN2396@deviant.kiev.zoral.com.ua> <201008201535.48560.jhb@freebsd.org>
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--J58k4iUnqtw3lv0j Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Fri, Aug 20, 2010 at 03:35:48PM -0400, John Baldwin wrote: > On Friday, August 20, 2010 3:19:53 pm Kostik Belousov wrote: > > It seems nobody replied to the mdf@ objection against wait of the > > new proc startup being equivalent to the LOR. I think that the wait > > is safe, because the task is executed in the context of > > the different process then the enqueue request. > > This might be worth noting in the comment or commit message. >=20 > I do wonder if we could get away with not waiting at all and always retur= n -1? > You could have the task handler actually finish the toggle of the tristat= e in > the array. Potentially you could even dispense with the linked list of > malloc'd structures and just walk the array creating processes for any en= tries > in the "in-progress" state in the task handler. You might also want to a= void > submitting entries for new threads if there is already a pending one? If= that > is the case it could be further simplified by having the task always crea= te a > single kthread when scheduled and just scheduling the task anytime a requ= est > needs one. I think this is not that easy. Please take a look at nfs_asyncio(). There is a lot of logic what to do in case an nfsiod thread was found or not etc. --J58k4iUnqtw3lv0j Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.10 (FreeBSD) iEYEARECAAYFAkxu2qIACgkQC3+MBN1Mb4hzEgCgpzwzjn+luvtYc0FHy/CXTtnV KaEAoJRoPIv9a8wdCm5YuuTRxXrX4Vrz =XFvO -----END PGP SIGNATURE----- --J58k4iUnqtw3lv0j--
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