Re: [SUGGESTION]: drop virtual merge accounting in I/O requests

From: Mikulas Patocka
Date: Sun Jul 13 2008 - 09:35:23 EST


Mikulas Patocka <mpatocka@xxxxxxxxxx> writes:

I'm getting crashes with InitIO A100u2w controller on Sparc64 (I had
to fix the endianity issues in the driver, but that's unrelated).

x86-64 (and powerpc) solved this a long time ago by only doing
opportunistic merging: as in don't announce to the block layer
that you can merge, but try to merge anyways. This way SG lists
are not necessarily filled completely, but it's still better
than overflowing them in some rare cases.

-Andi

There's option "biomerge" that enables that feature. I'm wondering, if there's some situation when it should be used.

Mikulas
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