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[192.55.52.88]) by mx.google.com with ESMTPS id a13si414319pgl.508.2019.05.29.11.04.48 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Wed, 29 May 2019 11:04:49 -0700 (PDT) Received-SPF: pass (google.com: domain of ira.weiny@intel.com designates 192.55.52.88 as permitted sender) client-ip=192.55.52.88; Authentication-Results: mx.google.com; spf=pass (google.com: domain of ira.weiny@intel.com designates 192.55.52.88 as permitted sender) smtp.mailfrom=ira.weiny@intel.com; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=intel.com X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 May 2019 11:04:48 -0700 X-ExtLoop1: 1 Received: from iweiny-desk2.sc.intel.com ([10.3.52.157]) by orsmga002.jf.intel.com with ESMTP; 29 May 2019 11:04:46 -0700 Date: Wed, 29 May 2019 11:05:48 -0700 From: Ira Weiny To: Daniel Jordan Cc: akpm@linux-foundation.org, Alexey Kardashevskiy , Alan Tull , Alex Williamson , Benjamin Herrenschmidt , Christoph Lameter , Christophe Leroy , Davidlohr Bueso , Jason Gunthorpe , Mark Rutland , Michael Ellerman , Moritz Fischer , Paul Mackerras , Steve Sistare , Wu Hao , linux-mm@kvack.org, kvm@vger.kernel.org, kvm-ppc@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-fpga@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2] mm: add account_locked_vm utility function Message-ID: <20190529180547.GA16182@iweiny-DESK2.sc.intel.com> References: <20190524175045.26897-1-daniel.m.jordan@oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190524175045.26897-1-daniel.m.jordan@oracle.com> User-Agent: Mutt/1.11.1 (2018-12-01) X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Fri, May 24, 2019 at 01:50:45PM -0400, Daniel Jordan wrote: [snip] > diff --git a/include/linux/mm.h b/include/linux/mm.h > index 0e8834ac32b7..72c1034d2ec7 100644 > --- a/include/linux/mm.h > +++ b/include/linux/mm.h > @@ -1564,6 +1564,25 @@ long get_user_pages_unlocked(unsigned long start, unsigned long nr_pages, > int get_user_pages_fast(unsigned long start, int nr_pages, > unsigned int gup_flags, struct page **pages); > > +int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc, > + struct task_struct *task, bool bypass_rlim); > + > +static inline int account_locked_vm(struct mm_struct *mm, unsigned long pages, > + bool inc) > +{ > + int ret; > + > + if (pages == 0 || !mm) > + return 0; > + > + down_write(&mm->mmap_sem); > + ret = __account_locked_vm(mm, pages, inc, current, > + capable(CAP_IPC_LOCK)); > + up_write(&mm->mmap_sem); > + > + return ret; > +} > + > /* Container for pinned pfns / pages */ > struct frame_vector { > unsigned int nr_allocated; /* Number of frames we have space for */ > diff --git a/mm/util.c b/mm/util.c > index e2e4f8c3fa12..bd3bdf16a084 100644 > --- a/mm/util.c > +++ b/mm/util.c > @@ -6,6 +6,7 @@ > #include > #include > #include > +#include > #include > #include > #include > @@ -346,6 +347,51 @@ int __weak get_user_pages_fast(unsigned long start, > } > EXPORT_SYMBOL_GPL(get_user_pages_fast); > > +/** > + * __account_locked_vm - account locked pages to an mm's locked_vm > + * @mm: mm to account against, may be NULL This kernel doc is wrong. You dereference mm straight away... > + * @pages: number of pages to account > + * @inc: %true if @pages should be considered positive, %false if not > + * @task: task used to check RLIMIT_MEMLOCK > + * @bypass_rlim: %true if checking RLIMIT_MEMLOCK should be skipped > + * > + * Assumes @task and @mm are valid (i.e. at least one reference on each), and > + * that mmap_sem is held as writer. > + * > + * Return: > + * * 0 on success > + * * 0 if @mm is NULL (can happen for example if the task is exiting) > + * * -ENOMEM if RLIMIT_MEMLOCK would be exceeded. > + */ > +int __account_locked_vm(struct mm_struct *mm, unsigned long pages, bool inc, > + struct task_struct *task, bool bypass_rlim) > +{ > + unsigned long locked_vm, limit; > + int ret = 0; > + > + locked_vm = mm->locked_vm; here... Perhaps the comment was meant to document account_locked_vm()? Or should the parameter checks be moved here? Ira > + if (inc) { > + if (!bypass_rlim) { > + limit = task_rlimit(task, RLIMIT_MEMLOCK) >> PAGE_SHIFT; > + if (locked_vm + pages > limit) > + ret = -ENOMEM; > + } > + if (!ret) > + mm->locked_vm = locked_vm + pages; > + } else { > + WARN_ON_ONCE(pages > locked_vm); > + mm->locked_vm = locked_vm - pages; > + } > + > + pr_debug("%s: [%d] caller %ps %c%lu %lu/%lu%s\n", __func__, task->pid, > + (void *)_RET_IP_, (inc) ? '+' : '-', pages << PAGE_SHIFT, > + locked_vm << PAGE_SHIFT, task_rlimit(task, RLIMIT_MEMLOCK), > + ret ? " - exceeded" : ""); > + > + return ret; > +} > +EXPORT_SYMBOL_GPL(__account_locked_vm); > > + > unsigned long vm_mmap_pgoff(struct file *file, unsigned long addr, > unsigned long len, unsigned long prot, > unsigned long flag, unsigned long pgoff) > > base-commit: a188339ca5a396acc588e5851ed7e19f66b0ebd9 > -- > 2.21.0 >