From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail202.messagelabs.com (mail202.messagelabs.com [216.82.254.227]) by kanga.kvack.org (Postfix) with ESMTP id A0A676B01F1 for ; Wed, 18 Aug 2010 02:56:47 -0400 (EDT) Received: from d03relay01.boulder.ibm.com (d03relay01.boulder.ibm.com [9.17.195.226]) by e32.co.us.ibm.com (8.14.4/8.13.1) with ESMTP id o7I6mTmw010561 for ; Wed, 18 Aug 2010 00:48:29 -0600 Received: from d03av04.boulder.ibm.com (d03av04.boulder.ibm.com [9.17.195.170]) by d03relay01.boulder.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id o7I6uVAh151538 for ; Wed, 18 Aug 2010 00:56:34 -0600 Received: from d03av04.boulder.ibm.com (loopback [127.0.0.1]) by d03av04.boulder.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id o7I6uUjV024634 for ; Wed, 18 Aug 2010 00:56:30 -0600 Date: Wed, 18 Aug 2010 12:26:07 +0530 From: Balbir Singh Subject: Re: [PATCH] Export mlock information via smaps Message-ID: <20100818065607.GC28417@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <201008171039.31070.knikanth@suse.de> <201008181023.41378.knikanth@suse.de> <20100818055253.GA28417@balbir.in.ibm.com> <201008181219.51915.knikanth@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <201008181219.51915.knikanth@suse.de> Sender: owner-linux-mm@kvack.org To: Nikanth Karthikesan Cc: Matt Mackall , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: * Nikanth Karthikesan [2010-08-18 12:19:51]: > On Wednesday 18 August 2010 11:22:53 Balbir Singh wrote: > > * Nikanth Karthikesan [2010-08-18 10:23:41]: > > > On Tuesday 17 August 2010 21:55:36 Matt Mackall wrote: > > > > On Tue, 2010-08-17 at 10:39 +0530, Nikanth Karthikesan wrote: > > > > > Currently there is no way to find whether a process has locked its > > > > > pages in memory or not. And which of the memory regions are locked in > > > > > memory. > > > > > > > > > > Add a new field to perms field 'l' to export this information. The > > > > > information exported via maps file is not changed. > > > > > > > > I'm worried that your new 'l' flag will fatally surprise some naive > > > > parser of this file. > > > > > > So how to proceed? Create another "ssmaps" file or something? :) Or is > > > the following patch any better? Even the "Yes"/"No" could be changed to > > > "0 kB" or "x kB", if it would make it better. > > > > > > Thanks > > > Nikanth > > > > > > Currently there is no way to find whether a process has locked its pages > > > in memory or not. And which of the memory regions are locked in memory. > > > > > > Add a new field "Locked" to export this information via smaps file. > > > > > > Signed-off-by: Nikanth Karthikesan > > > > > > --- > > > > > > diff --git a/Documentation/filesystems/proc.txt > > > b/Documentation/filesystems/proc.txt index a6aca87..6eafd26 100644 > > > --- a/Documentation/filesystems/proc.txt > > > +++ b/Documentation/filesystems/proc.txt > > > @@ -373,6 +373,7 @@ Referenced: 892 kB > > > Swap: 0 kB > > > KernelPageSize: 4 kB > > > MMUPageSize: 4 kB > > > +Locked: No > > > > > > The first of these lines shows the same information as is displayed > > > for the mapping in /proc/PID/maps. The remaining lines show the size of > > > the mapping, @@ -397,6 +398,8 @@ To clear the bits for the file mapped > > > pages associated with the process > > > > > > > echo 3 > /proc/PID/clear_refs > > > > > > Any other value written to /proc/PID/clear_refs will have no effect. > > > > > > +The "Locked" indicates whether the mapping is locked in memory or not. > > > + > > > > > > 1.2 Kernel data > > > --------------- > > > diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c > > > index aea1d3f..7bafbcf 100644 > > > --- a/fs/proc/task_mmu.c > > > +++ b/fs/proc/task_mmu.c > > > @@ -405,7 +405,8 @@ static int show_smap(struct seq_file *m, void *v) > > > "Referenced: %8lu kB\n" > > > "Swap: %8lu kB\n" > > > "KernelPageSize: %8lu kB\n" > > > - "MMUPageSize: %8lu kB\n", > > > + "MMUPageSize: %8lu kB\n" > > > + "Locked: %s\n", > > > (vma->vm_end - vma->vm_start) >> 10, > > > mss.resident >> 10, > > > (unsigned long)(mss.pss >> (10 + PSS_SHIFT)), > > > @@ -416,7 +417,8 @@ static int show_smap(struct seq_file *m, void *v) > > > mss.referenced >> 10, > > > mss.swap >> 10, > > > vma_kernel_pagesize(vma) >> 10, > > > - vma_mmu_pagesize(vma) >> 10); > > > + vma_mmu_pagesize(vma) >> 10, > > > + (vma->vm_flags & VM_LOCKED) ? "Yes" : "No"); > > > > Why not show the Locked as kB as well? I know that the entire VMA is > > locked, but ideally if we can show mss.pss as locked, one can write > > a simple script to accumulate locked memory for the process. NOTE: > > One could choose RSS or PSS, but I'd prefer PSS (even though the > > value is not stable across the system) since it is more accurate > > representation of the truly locked memory. > > > > Agreed. Attached patch does this, i.e, uses PSS as amount of locked memory. > > Matt, will this be okay? > > Thanks > Nikanth > > Currently there is no way to find whether a process has locked its pages in > memory or not. And which of the memory regions are locked in memory. > > Add a new field "Locked" to export this information via smaps file. > > Signed-off-by: Nikanth Karthikesan > Acked-by: Balbir Singh -- Three Cheers, Balbir -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. 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