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From: Dave Chinner <david@fromorbit.com>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Linux Memory Management List <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	xfs@oss.sgi.com, Christoph Hellwig <hch@infradead.org>,
	Tejun Heo <tj@kernel.org>, Dave Chinner <dchinner@redhat.com>,
	linux-fsdevel@vger.kernel.org,
	Andrew Morton <akpm@linux-foundation.org>
Subject: Re: [PATCH] mm: add gfp_mask parameter to vm_map_ram()
Date: Thu, 14 Jun 2012 12:15:47 +1000	[thread overview]
Message-ID: <20120614021547.GC7339@dastard> (raw)
In-Reply-To: <20120614014902.GB7289@localhost>

On Thu, Jun 14, 2012 at 09:49:02AM +0800, Fengguang Wu wrote:
> On Thu, Jun 14, 2012 at 11:20:26AM +1000, Dave Chinner wrote:
> > 
> > Bug in vm_map_ram - it does an unconditional GFP_KERNEL allocation
> > here, and we are in a GFP_NOFS context. We can't pass a gfp_mask to
> > vm_map_ram(), so until vm_map_ram() grows that we can't fix it...
> 
> This trivial patch should fix it.
> 
> The only behavior change is the XFS part:
> 
> @@ -406,7 +406,7 @@ _xfs_buf_map_pages(
>  
>                 do {
>                         bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
> -                                               -1, PAGE_KERNEL);
> +                                               -1, GFP_NOFS, PAGE_KERNEL);

This function isn't always called in GFP_NOFS context - readahead
uses different memory allocation semantics (no retry, no warn), so
there are flags that tell it what to do. i.e.

-						-1, PAGE_KERNEL);
+						-1, xb_to_gfp(flags), PAGE_KERNEL);

Otherwise looks fine to me...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

_______________________________________________
xfs mailing list
xfs@oss.sgi.com
http://oss.sgi.com/mailman/listinfo/xfs

WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Dave Chinner <dchinner@redhat.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-fsdevel@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tejun Heo <tj@kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	xfs@oss.sgi.com
Subject: Re: [PATCH] mm: add gfp_mask parameter to vm_map_ram()
Date: Thu, 14 Jun 2012 12:15:47 +1000	[thread overview]
Message-ID: <20120614021547.GC7339@dastard> (raw)
In-Reply-To: <20120614014902.GB7289@localhost>

On Thu, Jun 14, 2012 at 09:49:02AM +0800, Fengguang Wu wrote:
> On Thu, Jun 14, 2012 at 11:20:26AM +1000, Dave Chinner wrote:
> > 
> > Bug in vm_map_ram - it does an unconditional GFP_KERNEL allocation
> > here, and we are in a GFP_NOFS context. We can't pass a gfp_mask to
> > vm_map_ram(), so until vm_map_ram() grows that we can't fix it...
> 
> This trivial patch should fix it.
> 
> The only behavior change is the XFS part:
> 
> @@ -406,7 +406,7 @@ _xfs_buf_map_pages(
>  
>                 do {
>                         bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
> -                                               -1, PAGE_KERNEL);
> +                                               -1, GFP_NOFS, PAGE_KERNEL);

This function isn't always called in GFP_NOFS context - readahead
uses different memory allocation semantics (no retry, no warn), so
there are flags that tell it what to do. i.e.

-						-1, PAGE_KERNEL);
+						-1, xb_to_gfp(flags), PAGE_KERNEL);

Otherwise looks fine to me...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

--
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Chinner <david@fromorbit.com>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Dave Chinner <dchinner@redhat.com>,
	Christoph Hellwig <hch@infradead.org>,
	linux-fsdevel@vger.kernel.org,
	LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Tejun Heo <tj@kernel.org>,
	Linux Memory Management List <linux-mm@kvack.org>,
	xfs@oss.sgi.com
Subject: Re: [PATCH] mm: add gfp_mask parameter to vm_map_ram()
Date: Thu, 14 Jun 2012 12:15:47 +1000	[thread overview]
Message-ID: <20120614021547.GC7339@dastard> (raw)
In-Reply-To: <20120614014902.GB7289@localhost>

On Thu, Jun 14, 2012 at 09:49:02AM +0800, Fengguang Wu wrote:
> On Thu, Jun 14, 2012 at 11:20:26AM +1000, Dave Chinner wrote:
> > 
> > Bug in vm_map_ram - it does an unconditional GFP_KERNEL allocation
> > here, and we are in a GFP_NOFS context. We can't pass a gfp_mask to
> > vm_map_ram(), so until vm_map_ram() grows that we can't fix it...
> 
> This trivial patch should fix it.
> 
> The only behavior change is the XFS part:
> 
> @@ -406,7 +406,7 @@ _xfs_buf_map_pages(
>  
>                 do {
>                         bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
> -                                               -1, PAGE_KERNEL);
> +                                               -1, GFP_NOFS, PAGE_KERNEL);

This function isn't always called in GFP_NOFS context - readahead
uses different memory allocation semantics (no retry, no warn), so
there are flags that tell it what to do. i.e.

-						-1, PAGE_KERNEL);
+						-1, xb_to_gfp(flags), PAGE_KERNEL);

Otherwise looks fine to me...

Cheers,

Dave.
-- 
Dave Chinner
david@fromorbit.com

  parent reply	other threads:[~2012-06-14  2:15 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20120612012134.GA7706@localhost>
2012-06-12 12:11 ` rcu-torture boot hang Fengguang Wu
2012-06-12 12:30   ` Paul E. McKenney
2012-06-13 12:49   ` Fengguang Wu
2012-06-14  2:55     ` Steven Rostedt
2012-06-14  5:35       ` Fengguang Wu
2012-06-13 12:39 ` xfs ip->i_lock: inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage Fengguang Wu
2012-06-14  1:20   ` Dave Chinner
2012-06-14  1:49     ` [PATCH] mm: add gfp_mask parameter to vm_map_ram() Fengguang Wu
2012-06-14  1:49       ` Fengguang Wu
2012-06-14  1:49       ` Fengguang Wu
2012-06-14  1:49       ` Fengguang Wu
2012-06-14  2:07       ` Minchan Kim
2012-06-14  2:07         ` Minchan Kim
2012-06-14  2:07         ` Minchan Kim
2012-06-14  2:21         ` Tejun Heo
2012-06-14  2:21           ` Tejun Heo
2012-06-14  2:21           ` Tejun Heo
2012-06-14  2:39           ` Minchan Kim
2012-06-14  2:39             ` Minchan Kim
2012-06-14  2:39             ` Minchan Kim
2012-06-14  3:34         ` Dave Chinner
2012-06-14  3:34           ` Dave Chinner
2012-06-14  3:34           ` Dave Chinner
2012-06-14  3:53           ` David Rientjes
2012-06-14  3:53             ` David Rientjes
2012-06-14  3:53             ` David Rientjes
2012-06-14  5:51           ` Minchan Kim
2012-06-14  5:51             ` Minchan Kim
2012-06-14  5:51             ` Minchan Kim
2012-06-14  7:52           ` Andreas Dilger
2012-06-14  7:52             ` Andreas Dilger
2012-06-14  7:52             ` Andreas Dilger
2012-06-14  2:15       ` Dave Chinner [this message]
2012-06-14  2:15         ` Dave Chinner
2012-06-14  2:15         ` Dave Chinner
2012-06-14  1:22   ` xfs ip->i_lock: inconsistent {IN-RECLAIM_FS-W} -> {RECLAIM_FS-ON-W} usage Dave Chinner
2012-06-14  1:29     ` Fengguang Wu

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