Date: Mon, 03 Aug 2015 03:52:21 -0700 From: Peter Wemm <peter@wemm.org> To: svn-src-all@freebsd.org Cc: Steven Hartland <steven@multiplay.co.uk>, Slawa Olhovchenkov <slw@zxy.spb.ru>, svn-src-head@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r286223 - head/sys/cddl/contrib/opensolaris/uts/common/fs/zfs Message-ID: <2757800.HIDNx1G49O@overcee.wemm.org> In-Reply-To: <55BF431E.3020601@freebsd.org> References: <201508030934.t739YAkT026668@repo.freebsd.org> <20150803094730.GA24698@zxy.spb.ru> <55BF431E.3020601@freebsd.org>
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[-- Attachment #1 --] On Monday, August 03, 2015 11:31:58 AM Steven Hartland wrote: > On 03/08/2015 10:47, Slawa Olhovchenkov wrote: > > On Mon, Aug 03, 2015 at 09:34:10AM +0000, Steven Hartland wrote: > >> Author: smh > >> Date: Mon Aug 3 09:34:09 2015 > >> New Revision: 286223 > >> URL: https://svnweb.freebsd.org/changeset/base/286223 > >> > >> Log: > >> Fix KSTACK_PAGES check in ZFS module > >> > >> The check introduced by r285946 failed to add the dependency on > >> opt_kstack_pages.h which meant the default value for the platform > >> instead > >> of the customised options KSTACK_PAGES=X was being tested. > >> > >> Also wrap in #ifdef __FreeBSD__ for portability. > > > > /usr/src/sys/kern/kern_proc.c:int kstack_pages = KSTACK_PAGES; > > > > May be check variable kstack_pages is best way? > > Eliminate dependency on foreign opt_XXXX. > > I did think of that but as other modules such as dtrace, which is also > cddl code, already have this dependency I went with this. > > I'm easy though, if there's a concusses that kstack_pages or possibly > curthread->td_kstack_pages, which would take into account the > possibility of varied thread stack sizes, then I can make that change. > > What do others think? The whole thing has missing the point. Changing the default for the entire kernel just because the zfs compat wrappers can't be bothered requesting a suitable value is.. unfortunate.. particularly when it is in freebsd-provided code, not upstream zfs code. Fix the kproc_kthread_add() calls in do_thread_create() and zvol_geom_run() instead. Enforce a lower bound there for zfs threads instead of making the entire rest of the kernel use more memory. eg: I'm thinking along these lines: Index: cddl/compat/opensolaris/sys/proc.h ==================================================== --- cddl/compat/opensolaris/sys/proc.h (revision 286224) +++ cddl/compat/opensolaris/sys/proc.h (working copy) @@ -77,6 +77,8 @@ ASSERT(state == TS_RUN); ASSERT(pp == &p0); + if (stksize < 16384) + stksize = 16384; /* Enforce lower bound on ZFS threads */ error = kproc_kthread_add(proc, arg, &zfsproc, &td, RFSTOPPED, stksize / PAGE_SIZE, "zfskern", "solthread %p", proc); if (error == 0) { Beware, some platforms have large pages (eg: ia64 in -stable has 8k, 16k or 32k pages, from memory). Specifying an arbitrary number of pages in code that's supposed to be portable isn't a good idea. -- Peter Wemm - peter@wemm.org; peter@FreeBSD.org; peter@yahoo-inc.com; KI6FJV UTF-8: for when a ' or ... just won\342\200\231t do\342\200\246 [-- Attachment #2 --] -----BEGIN PGP SIGNATURE----- Version: GnuPG v2 iQEcBAABCAAGBQJVv0flAAoJEDXWlwnsgJ4ELMUIAK1tbIolkh8SIGfIo1A5Vw+n AzTThK+ccU3rm+PWWEjbJLd8vBMHmSNnbR/V3CgvKN58z6dpRUYQHl1jY0HFp8AH M71sG7cw6HPQ2mlJYzslYyGSPndtDRAjBVYAlXxWVwNAmXHuuq/pEliGX1nPKSIo A6ZBbb1++UrG3dq0qc1U51XZTqG0al36S3N4XRSWAvL+HZf57xCqPjlvd7sRh/lC tuPxTbAbPNb6z2xDpxf4pFwfj+Yj+yZ5vajRV3vvABIRHbPh+JRzfUtnxt6PaPRy B6Ujzt4EeNIlMbbPaRyf6Z3aoJt74K4VdocIJERDvXhGPvWcuIYNAiBfWRrtNuk= =LYLt -----END PGP SIGNATURE-----
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