On 1/21/20 9:38 AM, Mike Kravetz wrote: > On 12/17/19 3:16 PM, Mina Almasry wrote: >> A follow up patch in this series adds hugetlb cgroup uncharge info the > > *nit* > A follow up patch in this series adds hugetlb cgroup uncharge info to the > >> file_region entries in resv->regions. The cgroup uncharge info may >> differ for different regions, so they can no longer be coalesced at >> region_add time. So, disable region coalescing in region_add in this >> patch. >> >> Behavior change: >> >> Say a resv_map exists like this [0->1], [2->3], and [5->6]. >> >> Then a region_chg/add call comes in region_chg/add(f=0, t=5). >> >> Old code would generate resv->regions: [0->5], [5->6]. >> New code would generate resv->regions: [0->1], [1->2], [2->3], [3->5], >> [5->6]. >> >> Special care needs to be taken to handle the resv->adds_in_progress >> variable correctly. In the past, only 1 region would be added for every >> region_chg and region_add call. But now, each call may add multiple >> regions, so we can no longer increment adds_in_progress by 1 in region_chg, >> or decrement adds_in_progress by 1 after region_add or region_abort. Instead, >> region_chg calls add_reservation_in_range() to count the number of regions >> needed and allocates those, and that info is passed to region_add and >> region_abort to decrement adds_in_progress correctly. >> >> We've also modified the assumption that region_add after region_chg >> never fails. region_chg now pre-allocates at least 1 region for >> region_add. If region_add needs more regions than region_chg has >> allocated for it, then it may fail. >> >> Signed-off-by: Mina Almasry <almasrymina@xxxxxxxxxx> >> Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> > > Thanks for the updated comments. Still, > Reviewed-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx> Sorry, that comment was directed at V10 of the patch. -- Mike Kravetz
