On Sat, Apr 7, 2018 at 2:28 AM, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > On Fri, Apr 06, 2018 at 07:20:47AM +0000, Chandan Vn wrote: >> Hi, >> >> I would like to start contributing to linux-mm community. >> Could you please let me know the current work items which I can start >> working on. >> >> Please note that I have been working on linux-mm from past 4 years but >> mostly proprietary or not yet mainlined vendor codebase. > > We had a report of a problem a few weeks ago that I don't know if anybody > is looking at yet. Perhaps you'd like to try fixing it. > > The report says that, under some unidentified workload, calling vmalloc > can take many hundreds of milliseconds, and the problem is in > alloc_vmap_area(). > > So a good plan of work would be to devise a kernel module which can > produce a highly-fragmented vmap area, and demonstrate the problem. > Once you've got a reliable reproducer, you can look at how to fix this > problem. We probably need a better data structure; either enhance > the existing rbtree of free areas, or change the data structure. Sure. I would work on this.
