Date: Tue, 25 Jan 2011 12:07:13 -0500 From: John Baldwin <jhb@freebsd.org> To: Alexander Motin <mav@freebsd.org> Cc: svn-src-projects@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r217828 - projects/graid/head/sys/geom/raid Message-ID: <201101251207.13859.jhb@freebsd.org> In-Reply-To: <4D3EFB3F.8020508@FreeBSD.org> References: <201101251534.p0PFY7cF039182@svn.freebsd.org> <201101251117.49069.jhb@freebsd.org> <4D3EFB3F.8020508@FreeBSD.org>
next in thread | previous in thread | raw e-mail | index | archive | help
On Tuesday, January 25, 2011 11:33:03 am Alexander Motin wrote: > On 25.01.2011 18:17, John Baldwin wrote: > > On Tuesday, January 25, 2011 10:34:07 am Alexander Motin wrote: > >> Author: mav > >> Date: Tue Jan 25 15:34:07 2011 > >> New Revision: 217828 > >> URL: http://svn.freebsd.org/changeset/base/217828 > >> > >> Log: > >> Implement kernel dumping to geom_raid volumes. Dumping mechanism supports > >> any RAID levels without any additional magic. Dumping to RAID0 and RAID1 > >> verified to work right now. > >> > >> Modified: > >> projects/graid/head/sys/geom/raid/g_raid.c > >> projects/graid/head/sys/geom/raid/g_raid.h > >> projects/graid/head/sys/geom/raid/md_intel.c > >> > >> Modified: projects/graid/head/sys/geom/raid/g_raid.c > >> > > ============================================================================== > >> --- projects/graid/head/sys/geom/raid/g_raid.c Tue Jan 25 15:18:10 2011 > > (r217827) > >> +++ projects/graid/head/sys/geom/raid/g_raid.c Tue Jan 25 15:34:07 2011 > > (r217828) > >> +static int > >> +g_raid_dump(void *arg, > >> + void *virtual, vm_offset_t physical, off_t offset, size_t length) > >> +{ > >> + struct g_raid_softc *sc; > >> + struct g_raid_volume *vol; > >> + struct bio *bp; > >> + > >> + vol = (struct g_raid_volume *)arg; > >> + sc = vol->v_softc; > >> + G_RAID_DEBUG(3, "Dumping at off %llu len %llu.", > >> + (long long unsigned)offset, (long long unsigned)length); > >> + > >> + bp = g_alloc_bio(); > >> + bp->bio_cmd = BIO_WRITE; > >> + bp->bio_done = g_raid_dumpdone; > >> + bp->bio_attribute = NULL; > >> + bp->bio_offset = offset; > >> + bp->bio_length = length; > >> + bp->bio_data = virtual; > >> + bp->bio_to = vol->v_provider; > >> + > >> + g_raid_start(bp); > >> + > >> + while (!(bp->bio_flags& BIO_DONE)) { > >> + G_RAID_DEBUG(4, "Poll..."); > >> + g_raid_poll(sc); > >> + DELAY(10); > >> + } > >> + > >> + G_RAID_DEBUG(3, "Dumping at off %llu len %llu done.", > >> + (long long unsigned)offset, (long long unsigned)length); > >> + > >> + g_destroy_bio(bp); > >> + return (0); > >> +} > > > > Hmm, so this allocates bio's to make the dump work. I believer other dump > > routines in other drivers do not do this, but instead use pre-allocated > > commands to schedule dump I/O requests. Would it be possible to pre-allocate > > the bio that is used here when dumping is enabled and reuse it for each > > g_raid_dump() call without free'ing it when the I/O is finished? > > Actually I've also thought about it. It is trivial to use static > variable in this particular place. But transformation modules > (RAID0/RAID1/...) are also allocating some BIOs via g_clone_bio() and > there it can be more difficult to fix, as several BIOs are allocated > same time to fulfill original request. Hummm. That's a bit unfortunate. > When testing with minidump enabled I've noticed errors about attempts to > write after the dump device end. Is it unavoidable consequence of these > allocations? Possibly. That I can't say for certain. -- John Baldwin
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?201101251207.13859.jhb>