On 3/4/21 1:35 AM, David Hildenbrand wrote: > On 19.02.21 20:14, Mike Kravetz wrote: >> On 2/19/21 4:39 AM, Chen Wandun wrote: >>> If hugetlb_cma is enabled, it will skip boot time allocation >>> when allocating gigantic page, that doesn't means allocation >>> failure, so suppress this warning info. >>> >> >> Normally the addition of warning messages is discouraged. However, in >> this case the additional message provides value. Why? >> >> Prior to the commit cf11e85fc08c, one could have a kernel command line >> that contains: >> >> hugepagesz=1G hugepages=16 >> >> This would allocate 16 1G pages at boot time. >> >> After the commit, someone could specify a command line containing: >> >> hugepagesz=1G hugepages=16 hugetlb_cma=16G >> >> In this case, 16G of CMA will be reserved for 1G huge page allocations >> after boot time. The parameter 'hugepages=16' is ignored, and the warning >> message is logged. The warning message should only be logged when the >> kernel parameter 'hugepages=' is ignored. >> >> IMO, it make sense to log a warning if ignoring a user specified parameter. >> The user should not be attempting boot time allocation and CMA reservation >> for 1G pages. >> >> I do not think we should drop the warning as the it tells the user thay >> have specified two incompatible allocation options. >> > > I agree. It has value. > Hi David, Sorry my above reply was too quick as I did not take a close look at the code/patch. See, https://lore.kernel.org/mm-commits/YDAbeDsG7GhV6s6B@xxxxxxxxxxxxxxxxxxxxxxxxxxx/ This patch is actually in Andrew's tree. -- Mike Kravetz
