Messages in this thread | | | Date | Mon, 20 Dec 2004 10:23:56 -0500 (EST) | From | Rik van Riel <> | Subject | Re: [PATCH][1/2] adjust dirty threshold for lowmem-only mappings |
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On Mon, 20 Dec 2004, Rik van Riel wrote:
> Simply running "dd if=/dev/zero of=/dev/hd<one you can miss>" will > result in OOM kills, with the dirty pagecache completely filling up > lowmem. This patch is part 1 to fixing that problem.
What I forgot to say is that in order to trigger this OOM kill the dirty_limit of 40% needs to be more memory than what fits in low memory. So this will work on x86 with 4GB RAM, since the dirty_limit is 1.6GB, but the block device cache cannot grow that big because it is restricted to low memory.
This has the effect of all low memory being tied up in dirty page cache and userspace try_to_free_pages() skipping the writeout of these pages because the block device is congested.
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