Messages in this thread | | | Date | Tue, 22 Aug 2006 10:33:45 -0500 | From | David Masover <> | Subject | Re: [PATCH] reiserfs: eliminate minimum window size for bitmap searching |
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Jeff Mahoney wrote: > When a file system becomes fragmented (using MythTV, for example), the > bigalloc window searching ends up causing huge performance problems. In > a file system presented by a user experiencing this bug, the file system > was 90% free, but no 32-block free windows existed on the entire file system. > This causes the allocator to scan the entire file system for each 128k write > before backing down to searching for individual blocks.
Question: Would it be better to take that performance hit once, then cache the result for awhile? If we can't find enough consecutive space, such space isn't likely to appear until a lot of space is freed or a repacker is run.
> In the end, finding a contiguous window for all the blocks in a write is > an advantageous special case, but one that can be found naturally when > such a window exists anyway.
Hmm. Ok, I don't understand how this works, so I'll shut up. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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