Messages in this thread | | | From | "Stephen C. Tweedie" <> | Date | Tue, 2 Nov 1999 14:32:16 +0000 (GMT) | Subject | Re: Linux Buffer Cache Does Not Support Mirroring |
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Hi,
On Mon, 01 Nov 1999 15:24:16 -0700, "Jeff V. Merkey" <jmerkey@timpanogas.com> said:
> There is also a very clean layer between disks and cache, unlike > Linux, which is quite frankly a big, nasty ***MESS*** between the disk > drivers and the buffer cache.
Sure it is. This is why, if you want a clean abstraction, you shouldn't use the buffer cache --- the buffer cache is not _meant_ to map cleanly to data, it is meant to map cleanly to specific disk blocks. The page cache is Linux's logical cache, and the buffer cache is its physical one. Don't blame the buffer cache for not doing what is better done in the page cache.
> There's no obvious method of supporting async callbacks (which will > increase file system performance by several hundred percent).
Sure there is --- as I wrote before, read buffer.c:brw_page(), which performs IO with async callbacks, bypassing the buffer cache entirely.
--Stephen
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