Messages in this thread | | | Date | Sat, 28 Jan 2006 03:46:27 +0100 | From | Bart Samwel <> | Subject | [PATCH 0/3] Fix overflow issues with sysctl values in centiseconds/seconds |
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Hi Andrew,
Here's a threesome of patches to fix up some issues with the following sysctl values:
/proc/sys/vm/laptop_mode /proc/sys/vm/dirty_writeback_centisecs /proc/sys/vm/dirty_expire_centisecs
The issues: 1. The values are not range checked when they are set. They all have a range smaller than the full integer range. 2. Conversion from these centisecond/second values is done on-the-fly wherever they are used. This wastes some resources. 3. The conversions are done badly. Conversion from USER_HZ to HZ is done by doing "value * USER_HZ / HZ". One day expressed in centiseconds already causes an overflow at HZ = 250. This should use clock_t_to_jiffies() instead.
The approach: 1. Represent everything in jiffies internally. 2. Do the conversion and range checking in the sysctl interface.
Cheers, Bart - 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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