Re: [PATCH] Writeback page range hint

From: Dave Jones
Date: Mon Aug 23 2004 - 20:22:18 EST


On Mon, Aug 23, 2004 at 07:59:27PM +0000, Linux Kernel wrote:
> ChangeSet 1.2034, 2004/08/23 12:59:27-07:00, akpm@xxxxxxxx
>
> [PATCH] Writeback page range hint
>
> Modify mpage_writepages to optionally only write back dirty pages within a
> specified range in a file (as in the case of O_SYNC). Cheat a little to avoid
> changes to prototypes of aops - just put the <start, end> hint into the
> writeback_control struct instead. If <start, end> are not set, then default
> to writing back all the mapping's dirty pages.

FYI, this chunk...

> long pages_skipped; /* Pages which were not written */
> - int nonblocking; /* Don't get stuck on request queues */
> - int encountered_congestion; /* An output: a queue is full */
> - int for_kupdate; /* A kupdate writeback */
> - int for_reclaim; /* Invoked from the page allocator */
> +
> + /*
> + * For a_ops->writepages(): is start or end are non-zero then this is
> + * a hint that the filesystem need only write out the pages inside that
> + * byterange. The byte at `end' is included in the writeout request.
> + */
> + loff_t start;
> + loff_t end;
> +
> + int nonblocking:1; /* Don't get stuck on request queues */
> + int encountered_congestion:1; /* An output: a queue is full */
> + int for_kupdate:1; /* A kupdate writeback */
> + int for_reclaim:1; /* Invoked from the page allocator */

Causes sparse spew..

include/linux/writeback.h:54:19: warning: dubious one-bit signed bitfield
include/linux/writeback.h:55:30: warning: dubious one-bit signed bitfield
include/linux/writeback.h:56:19: warning: dubious one-bit signed bitfield
include/linux/writeback.h:57:19: warning: dubious one-bit signed bitfield

Dave

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