I have a MacBook pro 15 inch mid-2010 i5 2,4 Ghz, which I already have upgraded to 8GB of RAM. I recently tried to upgrade my MacBook's RAM to 16GB on Yosemite and it gets a kernel panic, I know others Macbook Pros can do it. But now I have 16GB on my desk and I don't know if i should have a little of faith, wait until "el capitan" get released and the computer could support the 16GB or better to loose any hope and sell them.
Officially your Model only supports up to maximum of 8 GB RAM. So you are at maximum already.
Your alternative is to upgrade from Hard Drive to SSD, that would speed things up.
I partially disagree with the approved answer: I have a MacBook Pro 13 2010 with 12Gb RAM.
It's true that Apple OFFICIALLY says they support only 8GB because. There's a reason: there wasn't 1066Mhz 8GB RAM sticks at the time of 2010 release. The maximum size of a 1066Ghz stick was only 4GB. So i think their QA only tested the computer using 4GB sticks.
But there's a way which I use to reach 12GB. The trick is using a 4GB 1066Mhz stick in the slot 0 working together with an 8GB 1333Mhz stick in slot 1. This config clocks down the second stick to 1066Mhz and OSX works like a charm with 12Gb of RAM.
I've heard about a specialized vendor which sells 1066Mhz 8GB memory sticks compatible with 2010 model, which can upgrade your RAM to 16Gb, but I've never seen one of these.
But there's one thing that I agree the original answer: the SSD upgrade worths. 12Gb RAM + SSD you won't regret.