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From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: linux-mm@kvack.org, npiggin@kernel.dk, xfs@oss.sgi.com
Subject: Re: [PATCH] xfs: flush vmap aliases when mapping fails
Date: Thu, 10 Mar 2011 02:37:51 -0500	[thread overview]
Message-ID: <20110310073751.GB25374@infradead.org> (raw)
In-Reply-To: <1299713876-7747-1-git-send-email-david@fromorbit.com>

On Thu, Mar 10, 2011 at 10:37:56AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> On 32 bit systems, vmalloc space is limited and XFS can chew through
> it quickly as the vmalloc space is lazily freed. This can result in
> failure to map buffers, even when there is apparently large amounts
> of vmalloc space available. Hence, if we fail to map a buffer, purge
> the aliases that have not yet been freed to hopefuly free up enough
> vmalloc space to allow a retry to succeed.

IMHO this should be done by vm_map_ram internally.  If we can't get the
core code fixes we can put this in as a last resort.

> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/linux-2.6/xfs_buf.c |   14 +++++++++++---
>  1 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
> index 3cc671c..a5a260f 100644
> --- a/fs/xfs/linux-2.6/xfs_buf.c
> +++ b/fs/xfs/linux-2.6/xfs_buf.c
> @@ -455,9 +455,17 @@ _xfs_buf_map_pages(
>  		bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
>  		bp->b_flags |= XBF_MAPPED;
>  	} else if (flags & XBF_MAPPED) {
> -		bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
> -					-1, PAGE_KERNEL);
> -		if (unlikely(bp->b_addr == NULL))
> +		int retried = 0;
> +
> +		do {
> +			bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
> +						-1, PAGE_KERNEL);
> +			if (bp->b_addr)
> +				break;
> +			vm_unmap_aliases();
> +		} while (retried++ <= 1);
> +
> +		if (!bp->b_addr)
>  			return -ENOMEM;
>  		bp->b_addr += bp->b_offset;
>  		bp->b_flags |= XBF_MAPPED;
> -- 
> 1.7.2.3
> 
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
---end quoted text---

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

WARNING: multiple messages have this Message-ID (diff)
From: Christoph Hellwig <hch@infradead.org>
To: Dave Chinner <david@fromorbit.com>
Cc: xfs@oss.sgi.com, npiggin@kernel.dk, linux-mm@kvack.org
Subject: Re: [PATCH] xfs: flush vmap aliases when mapping fails
Date: Thu, 10 Mar 2011 02:37:51 -0500	[thread overview]
Message-ID: <20110310073751.GB25374@infradead.org> (raw)
In-Reply-To: <1299713876-7747-1-git-send-email-david@fromorbit.com>

On Thu, Mar 10, 2011 at 10:37:56AM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> On 32 bit systems, vmalloc space is limited and XFS can chew through
> it quickly as the vmalloc space is lazily freed. This can result in
> failure to map buffers, even when there is apparently large amounts
> of vmalloc space available. Hence, if we fail to map a buffer, purge
> the aliases that have not yet been freed to hopefuly free up enough
> vmalloc space to allow a retry to succeed.

IMHO this should be done by vm_map_ram internally.  If we can't get the
core code fixes we can put this in as a last resort.

> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/linux-2.6/xfs_buf.c |   14 +++++++++++---
>  1 files changed, 11 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/xfs/linux-2.6/xfs_buf.c b/fs/xfs/linux-2.6/xfs_buf.c
> index 3cc671c..a5a260f 100644
> --- a/fs/xfs/linux-2.6/xfs_buf.c
> +++ b/fs/xfs/linux-2.6/xfs_buf.c
> @@ -455,9 +455,17 @@ _xfs_buf_map_pages(
>  		bp->b_addr = page_address(bp->b_pages[0]) + bp->b_offset;
>  		bp->b_flags |= XBF_MAPPED;
>  	} else if (flags & XBF_MAPPED) {
> -		bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
> -					-1, PAGE_KERNEL);
> -		if (unlikely(bp->b_addr == NULL))
> +		int retried = 0;
> +
> +		do {
> +			bp->b_addr = vm_map_ram(bp->b_pages, bp->b_page_count,
> +						-1, PAGE_KERNEL);
> +			if (bp->b_addr)
> +				break;
> +			vm_unmap_aliases();
> +		} while (retried++ <= 1);
> +
> +		if (!bp->b_addr)
>  			return -ENOMEM;
>  		bp->b_addr += bp->b_offset;
>  		bp->b_flags |= XBF_MAPPED;
> -- 
> 1.7.2.3
> 
> _______________________________________________
> xfs mailing list
> xfs@oss.sgi.com
> http://oss.sgi.com/mailman/listinfo/xfs
---end quoted text---

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  reply	other threads:[~2011-03-10  7:35 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-03-09 23:37 [PATCH] xfs: flush vmap aliases when mapping fails Dave Chinner
2011-03-10  7:37 ` Christoph Hellwig [this message]
2011-03-10  7:37   ` Christoph Hellwig
2011-03-10 22:49   ` Dave Chinner
2011-03-10 22:49     ` Dave Chinner
2011-03-17 14:24     ` Christoph Hellwig
2011-03-17 14:24       ` Christoph Hellwig
2011-03-21 12:25     ` Johannes Weiner
2011-03-21 12:25       ` Johannes Weiner
2011-03-22 12:57       ` Johannes Weiner
2011-03-22 12:57         ` Johannes Weiner
2011-03-27 23:54         ` Dave Chinner
2011-03-27 23:54           ` Dave Chinner
2011-03-18 14:24   ` Johannes Weiner
2011-03-18 14:24     ` Johannes Weiner

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