Re: [PATCH] writeback: Per-block device bdi->dirty_writeback_interval and bdi->dirty_expire_interval.
From: Artem Bityutskiy <dedekind1@gmail.com>
Date: 2011-08-19 11:55:43
Also in:
linux-fsdevel, lkml
On Thu, 2011-08-18 at 21:13 +0800, Wu Fengguang wrote:
Thinking twice about it, I find that the different requirements for interval flash/external microSD can also be solved by this scheme. Introduce a per-bdi dirty_background_time (and optionally dirty_time) as the counterpart of (and works in parallel to) global dirty[_background]_ratio, however with unit "milliseconds worth of data". The per-bdi dirty_background_time will be set low for external microSD and high for internal flash. Then you get timely writeouts for microSD and reasonably delayed writes for internal flash (controllable by the global dirty_expire_centisecs). The dirty_background_time will actually work more reliable than dirty_expire_centisecs because it will checked immediately after the application dirties more pages. And the dirty_time could provide strong data integrity guarantee -- much stronger than dirty_expire_centisecs -- if used. Does that sound reasonable?
Yes, this would probably work. But note, we do not have this problem anymore, I was just talking about the past experience, so I cannot validate any possible patch. Thanks. -- Best Regards, Artem Bityutskiy -- 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>