There are two lines where Black opens up the queenside:
the Panno and the Byrne system (a6/c6/b5). imho the Byrne is underrated, and a stronger system than the Panno. Great choice by Svidler!
And, there are two schools of thought on how to treat these lines as White.
The Chris Ward school (as you can see in his Controversial Samisch repertoire book) will for instance, play 0-0-0 and go for a mating race. Against the Panno, their choice would be 9. g4, 9, h4 and 9. 0-0-0. Against the Byrne, they will play like Morozevich did against Svidler.
The Alexey Dreev school believes in castling kingside whenever Black becomes too frisky on the queenside, thus transposing into a good Classical system where Black has been very "cooperative" by opening up the queenside for White

So, against the Panno, White will play 9. Rc1, 9. Rb1 or 9. a3. And against the Byrne 1. d4 Nf6 2. c4 g6 3. Nc3 Bg7 4. e4 d6 5. f3 a6 6. Be3 c6 7. c5 or 7. Bd3! will both do the trick.
The strength of the Samisch lies in its flexibility. While the typical Samisch queenside-castle may be good for White after 6.Be3 e5 7. d5 , it is wiser to be more flexible in the Panno and Byrne. I tend to follow Dreev here and I don't think Black is okay.
Gallagher is a top KID expert who has spent a not inconsiderable amount of time on the Samisch, so believe him when he says 6... c5! is the best and most critical.