[dm-devel] [PATCH v3 00/10] multipath-tools: avoid I/O during uevent processing
Benjamin Marzinski
bmarzins at redhat.com
Tue Mar 19 18:37:46 UTC 2019
On Mon, Mar 18, 2019 at 12:24:35PM +0100, Martin Wilck wrote:
> Hi Christophe, hi Ben,
>
> the bulk of this series attempts to avoid unnecessary I/O for "multipath -u"
> calls from udev rules. I came up with it in a recent attempt to debug
> avoid "multipath -u" hangups during boot. I found that the detect_alua()
> call in the get_refwwid->pathinfo->scsi_ioctl_pathinfo call sequence would
> cause an sg ioctl to be sent for every "multipath -u" invocation. That's
> obvious nonsense, we don't need to detect ALUA capabilities to find out
> if a device is a potential multipath member.
>
> So, rather than setting pp->tpgs in pathinfo, I resorted to a "lazy"
> approach where ALUA capabilities are probed when they are needed, no
> sooner. I also cleaned up the ALUA code a bit (still some more to go),
> and made it attempt to read INQUIRY data from sysfs.
>
> Regards,
> Martin
Reviewed-by: Benjamin Marzinski <bmarzins at redhat.com>
for the set.
> Changes v2->v3:
>
> - added 8/10 "tidy up do_set_from_hwe() with statement expression"
> (Hannes), renumber subsequent patches accordingly.
> - 9/10: cleanup ugly macro usage; do retrieve VPD for "unknown"
> SCSI storage devices
>
> Changes v1->v2:
>
> - 6/9: remove one remaining direct access to pp->tpgs
> - 9/9: use non-personal email address for maintainer
>
> Martin Wilck (10):
> libmultipath: add sysfs_get_inquiry()
> libmultipath: alua: make API more consistent
> libmultipath: alua: try to retrieve inquiry data from sysfs
> libmultipath: constify sysfs_get_timeout()
> libmultipath: detect_alua(): use system timeout
> libmultipath: lazy tpgs probing
> libmultipath: don't link alua_rtpg.o twice
> libmultipath: tidy up do_set_from_hwe() with statement expression
> libmultipath: check_rdac(): pre-check in hwtable
> libmultipath: hwtable: add Lenovo DE series
>
> libmultipath/discovery.c | 46 +++++++++++++++++-------
> libmultipath/discovery.h | 10 +++---
> libmultipath/hwtable.c | 20 +++++++++++
> libmultipath/prioritizers/Makefile | 3 --
> libmultipath/prioritizers/alua.c | 4 +--
> libmultipath/prioritizers/alua_rtpg.c | 45 +++++++++++++++++------
> libmultipath/prioritizers/alua_rtpg.h | 7 ++--
> libmultipath/propsel.c | 52 ++++++++++++++++++---------
> multipathd/main.c | 7 ++--
> 9 files changed, 139 insertions(+), 55 deletions(-)
>
> --
> 2.21.0
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