From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by kanga.kvack.org (Postfix) with ESMTP id C82ED8E0002 for ; Tue, 15 Jan 2019 13:18:41 -0500 (EST) Received: by mail-ed1-f69.google.com with SMTP id i55so1420730ede.14 for ; Tue, 15 Jan 2019 10:18:41 -0800 (PST) Received: from mx1.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id g1si1541226edh.399.2019.01.15.10.18.40 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 15 Jan 2019 10:18:40 -0800 (PST) Date: Tue, 15 Jan 2019 10:18:31 -0800 From: Davidlohr Bueso Subject: Re: [PATCH -next 0/6] mm: make pinned_vm atomic and simplify users Message-ID: <20190115181831.4zgrvyfjy2re7t43@linux-r8p5> References: <20190115181300.27547-1-dave@stgolabs.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: <20190115181300.27547-1-dave@stgolabs.net> Sender: owner-linux-mm@kvack.org List-ID: To: akpm@linux-foundation.org Cc: dledford@redhat.com, jgg@mellanox.com, linux-rdma@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Also Ccing lkml, sorry. On Tue, 15 Jan 2019, Davidlohr Bueso wrote: >Hi, > >The following patches aim to provide cleanups to users that pin pages >(mostly infiniband) by converting the counter to atomic -- note that >Daniel Jordan also has patches[1] for the locked_vm counterpart and vfio. > >Apart from removing a source of mmap_sem writer, we benefit in that >we can get rid of a lot of code that defers work when the lock cannot >be acquired, as well as drivers avoiding mmap_sem altogether by also >converting gup to gup_fast() and letting the mm handle it. Users >that do the gup_longterm() remain of course under at least reader mmap_sem. > >Everything has been compile-tested _only_ so I hope I didn't do anything >too stupid. Please consider for v5.1. > >On a similar topic and potential follow up, it would be nice to resurrect >Peter's VM_PINNED idea in that the broken semantics that occurred after >bc3e53f682 ("mm: distinguish between mlocked and pinned pages") are still >present. Also encapsulating internal mm logic via mm[un]pin() instead of >drivers having to know about internals and playing nice with compaction are >all wins. > >Thanks! > >[1] https://lkml.org/lkml/2018/11/5/854 > >Davidlohr Bueso (6): > mm: make mm->pinned_vm an atomic counter > mic/scif: do not use mmap_sem > drivers/IB,qib: do not use mmap_sem > drivers/IB,hfi1: do not se mmap_sem > drivers/IB,usnic: reduce scope of mmap_sem > drivers/IB,core: reduce scope of mmap_sem > > drivers/infiniband/core/umem.c | 47 +++----------------- > drivers/infiniband/hw/hfi1/user_pages.c | 12 ++--- > drivers/infiniband/hw/qib/qib_user_pages.c | 69 ++++++++++------------------- > drivers/infiniband/hw/usnic/usnic_ib_main.c | 2 - > drivers/infiniband/hw/usnic/usnic_uiom.c | 56 +++-------------------- > drivers/infiniband/hw/usnic/usnic_uiom.h | 1 - > drivers/misc/mic/scif/scif_rma.c | 38 +++++----------- > fs/proc/task_mmu.c | 2 +- > include/linux/mm_types.h | 2 +- > kernel/events/core.c | 8 ++-- > kernel/fork.c | 2 +- > mm/debug.c | 3 +- > 12 files changed, 57 insertions(+), 185 deletions(-) > >-- >2.16.4 >