Upper bound for $\min_{x \geq 0} e^{t x} \cdot \int_0^\infty e^{-x u} f(u) du$

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I am dealing with the following function:

$$m(t) = \min_{x \geq 0} e^{t x} \cdot \int_0^\infty e^{-x u} f(u) du,$$

where $t \geq 0$ and $f(u)$ is a pdf of a random variable $X$ distributed over $[0, \infty)$. It is clear that $m(0) = 0$, and $m(t)$ is increasing in $t$.

My question is: Is the function $m(t)$ continuous at $t = 0$? I conjecture that this can be bounded by some linear function, i.e., $m(t) \leq c \cdot t$ for constant $c > 0$, but I am unsure how to do.

Thank you in advance.