Re: [PATCH 03/10] mm: Add support for a filesystem to control swap files
From: Mel Gorman <mgorman@suse.de>
Date: 2011-09-09 13:15:58
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linux-mm, linux-nfs, lkml
On Fri, Sep 09, 2011 at 09:00:08AM -0400, Christoph Hellwig wrote:
On Fri, Sep 09, 2011 at 12:00:47PM +0100, Mel Gorman wrote:quoted
Currently swapfiles are managed entirely by the core VM by using ->bmap to allocate space and write to the blocks directly. This patch adds address_space_operations methods that allow a filesystem to optionally control the swapfile. int swap_activate(struct file *); int swap_deactivate(struct file *); int swap_writepage(struct file *, struct page *, struct writeback_control *); int swap_readpage(struct file *, struct page *);Just as the last two dozen times this came up: NAK The right fix is to add a filesystem method to support direct-I/O on arbitrary kernel pages, instead of letting the wap abstraction leak into the filesystem.
Ok. I confess I haven't investigated this direction at all yet. Is it correct that your previous objection was http://linux.derkeiler.com/Mailing-Lists/Kernel/2009-10/msg00455.html and the direct-IO patchset you were thinking of was http://copilotco.com/mail-archives/linux-kernel.2009/msg87176.html ? If so, are you suggesting that instead of swap_readpage and swap_writepage I look into what is required for swap to use ->readpage method and ->direct_IO aops? -- Mel Gorman SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>