From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benjamin Marzinski Subject: Re: [PATCH v3 00/10] multipath-tools: avoid I/O during uevent processing Date: Tue, 19 Mar 2019 13:37:46 -0500 Message-ID: <20190319183746.GL13295@octiron.msp.redhat.com> References: <20190318112445.6636-1-mwilck@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Content-Disposition: inline In-Reply-To: <20190318112445.6636-1-mwilck@suse.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: Martin Wilck Cc: dm-devel@redhat.com List-Id: dm-devel.ids 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 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