From: Christoph Hellwig <hch@infradead.org>
To: Damien Le Moal <damien.lemoal@wdc.com>
Cc: Theodore Ts'o <tytso@mit.edu>,
Andreas Dilger <adilger.kernel@dilger.ca>,
linux-ext4@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, Christoph Hellwig <hch@lst.de>,
Johannes Thumshirn <jthumshirn@suse.de>,
Naohiro Aota <naohiro.aota@wdc.com>,
Masato Suzuki <masato.suzuki@wdc.com>
Subject: Re: [PATCH] ext4: Fix deadlock on page reclaim
Date: Thu, 25 Jul 2019 04:54:42 -0700 [thread overview]
Message-ID: <20190725115442.GA15733@infradead.org> (raw)
In-Reply-To: <20190725093358.30679-1-damien.lemoal@wdc.com>
On Thu, Jul 25, 2019 at 06:33:58PM +0900, Damien Le Moal wrote:
> + gfp_t gfp_mask;
> +
> switch (ext4_inode_journal_mode(inode)) {
> case EXT4_INODE_ORDERED_DATA_MODE:
> case EXT4_INODE_WRITEBACK_DATA_MODE:
> @@ -4019,6 +4019,14 @@ void ext4_set_aops(struct inode *inode)
> inode->i_mapping->a_ops = &ext4_da_aops;
> else
> inode->i_mapping->a_ops = &ext4_aops;
> +
> + /*
> + * Ensure all page cache allocations are done from GFP_NOFS context to
> + * prevent direct reclaim recursion back into the filesystem and blowing
> + * stacks or deadlocking.
> + */
> + gfp_mask = mapping_gfp_mask(inode->i_mapping);
> + mapping_set_gfp_mask(inode->i_mapping, (gfp_mask & ~(__GFP_FS)));
This looks like something that could hit every file systems, so
shouldn't we fix this in common code? We could also look into
just using memalloc_nofs_save for the page cache allocation path
instead of the per-mapping gfp_mask.
> }
>
> static int __ext4_block_zero_page_range(handle_t *handle,
> --
> 2.21.0
>
---end quoted text---
next prev parent reply other threads:[~2019-07-25 11:54 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-25 9:33 [PATCH] ext4: Fix deadlock on page reclaim Damien Le Moal
2019-07-25 11:54 ` Christoph Hellwig [this message]
2019-07-25 19:57 ` Andreas Dilger
2019-07-26 2:24 ` Damien Le Moal
2019-07-26 22:44 ` Dave Chinner
2019-07-26 22:55 ` Theodore Y. Ts'o
2019-07-27 2:59 ` Damien Le Moal
2019-07-28 23:41 ` Dave Chinner
2019-07-29 1:07 ` Damien Le Moal
2019-07-29 18:40 ` Andreas Dilger
2019-07-30 2:06 ` Damien Le Moal
2019-07-30 23:47 ` Dave Chinner
2019-07-31 4:37 ` Damien Le Moal
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