From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ua0-f199.google.com (mail-ua0-f199.google.com [209.85.217.199]) by kanga.kvack.org (Postfix) with ESMTP id 94A6F6B0003 for ; Sat, 7 Apr 2018 00:19:36 -0400 (EDT) Received: by mail-ua0-f199.google.com with SMTP id w16so2308182uad.0 for ; Fri, 06 Apr 2018 21:19:36 -0700 (PDT) Received: from mail-sor-f41.google.com (mail-sor-f41.google.com. [209.85.220.41]) by mx.google.com with SMTPS id b25sor4516357uam.238.2018.04.06.21.19.35 for (Google Transport Security); Fri, 06 Apr 2018 21:19:35 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20180406205828.GA9618@bombadil.infradead.org> References: <20180406205828.GA9618@bombadil.infradead.org> From: Chandan Vn Date: Sat, 7 Apr 2018 09:48:54 +0530 Message-ID: Subject: Re: Requesting to share current work items Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Matthew Wilcox Cc: linux-mm@kvack.org On Sat, Apr 7, 2018 at 2:28 AM, Matthew Wilcox 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.