reserve 10% GPU in `get_balanced_memory` to avoid OOM (#1798)
* reserve 10% GPU to avoid OOM
* update warning message
Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>
* use logger.info
* clean up comment
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Co-authored-by: Sylvain Gugger <35901082+sgugger@users.noreply.github.com>