APPLIED: [PATCH][unstable] UBUNTU: [Config] Enable CONFIG_PAGE_POISONING configs

Seth Forshee seth.forshee at canonical.com
Wed Aug 29 20:47:34 UTC 2018


On Fri, Aug 24, 2018 at 05:18:05PM +0100, Colin King wrote:
> From: Colin Ian King <colin.king at canonical.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1783651
> 
> As requested by Kees, enable the following to help with finding certain
> types of memory corruption:
> 
> CONFIG_PAGE_POISONING=y
> CONFIG_PAGE_POISONING_ZERO=y
> CONFIG_PAGE_POISONING_NO_SANITY=y
> 
> "this should have no impact on regular boots, and if someone boots with
> "page_poison=1" then they get page wiping when page_alloc pages are freed
> (and then GFP_ZERO is a no-op since it was already freed), so it becomes
> a reasonable trade-off on performance vs gaining the wipe-on-free ability
> of the buddy allocator."
> 
> This has been benchmarked, with the tests comparing kernels without the
> config, with the config and with the config with page_poison=1 for the
> 4.18 and 4.15 kernels. I ran nearly 200 stress-ng stress tests and
> gathered the throughput (based on bogo ops per second on the usr+sys time
> consumed) for each stress test. Each of the stress tests were run for 60
> seconds on an idle 8 thread Xeon i7-3770.
> 
> The bogo-ops data was then normalized against the kernel that didn't have
> the config changes. The data to look at is the geometric means of all the
> normalized test results:
> 
> 4.18 kernel, geometric mean of normalized bogo/ops throughput:
> 
> No page poisoning: 1.000
> Config page poisoning: 1.003
> Config page poionsing + page_poison=1: 0.991
> 
> 4.15 kernel, geometric mean of normalized bogo/ops throughput:
> 
> No page poisoning: 1.000
> Config page poisoning: 1.025
> Config page poionsing + page_poison=1: 0.977
> 
> where > 1.000 shows more throughput and < 1.000 shows degraded throughput
> 
> So it appears that enabling page poisoning configs does not degrade performance
> and setting page_poison=1 degrades performance by a very small amount.
> 
> Raw data for this can be found at:
> https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1783651/+attachment/5170997/+files/kernel-poison-page-analysis.ods
> 
> Signed-off-by: Colin Ian King <colin.king at canonical.com>

Applied to unstable/master. Also added enforcement to the annotations
file. Thanks!




More information about the kernel-team mailing list