2013/8/13 Attilio Rao <atti...@freebsd.org>: > On Tue, Aug 13, 2013 at 4:22 PM, Ulrich Spörlein <u...@freebsd.org> wrote: >> On Fri, 2013-08-09 at 11:11:12 +0000, Attilio Rao wrote: >>> Author: attilio >>> Date: Fri Aug 9 11:11:11 2013 >>> New Revision: 254138 >>> URL: http://svnweb.freebsd.org/changeset/base/254138 >>> >>> Log: >>> The soft and hard busy mechanism rely on the vm object lock to work. >>> Unify the 2 concept into a real, minimal, sxlock where the shared >>> acquisition represent the soft busy and the exclusive acquisition >>> represent the hard busy. >>> The old VPO_WANTED mechanism becames the hard-path for this new lock >>> and it becomes per-page rather than per-object. >>> The vm_object lock becames an interlock for this functionality: >>> it can be held in both read or write mode. >>> However, if the vm_object lock is held in read mode while acquiring >>> or releasing the busy state, the thread owner cannot make any >>> assumption on the busy state unless it is also busying it. >>> >>> Also: >>> - Add a new flag to directly shared busy pages while vm_page_alloc >>> and vm_page_grab are being executed. This will be very helpful >>> once these functions happen under a read object lock. >>> - Move the swapping sleep into its own per-object flag >>> >>> The KPI is heavilly changed this is why the version is bumped. >>> It is very likely that some VM ports users will need to change >>> their own code. >>> >>> Sponsored by: EMC / Isilon storage division >>> Discussed with: alc >>> Reviewed by: jeff, kib >>> Tested by: gavin, bapt (older version) >>> Tested by: pho, scottl >> >> The changes to sys/vm/vm_fault.c introduce a call to >> vm_page_sleep_if_busy() where the return code is not checked. The other >> 5 places in the tree check the return code, please fix this here too. >> It's CID 1062398, and I would encourage folks to get an account with >> scan.coverity.com and have an eye on newly found defects. > > Not true. > The same call existed also before with exactly the same semantic. > The trick there is that it is not important to check for the return > value because we are going to retry the operation anyway. > The code looks ok to me.
Thanks for the explanation. The code shuffling meant that Coverity saw it as new code, that's what prompted me to email you. Cheers, Uli _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"
