It may be of interest that the D&D troll was inspired by Poul Anderson's book Three Hearts and Three Lions (e.g., the book is explicitly referenced in Gygax's proto-D&D game, Chainmail Fantasy, in 1972). Part of the action there is that the troll goes down and tricks the protagonists, no one knowing about their regeneration ability before then. From Chapter 22:
... The troll went on his face, Papillon [the warhorse] reared to his full
terrifying height and came down again. The troll's head was shattered.
"Merciful heaven," gasped Carahue. He crossed himself. Turning to
Holger, he called gaily, "That wasn't too bad, though, was it?"
Holger looked at his own caved-in shield. "No," he said in a rueful
mood. "Except for my own performance."
The mare still shivered, but had calmed enough for Alianora to stroke
her neck. "Come, let's gang on oot," said Hugi. "The fetor here's like
a melt ma nase."
Holger nodded. "Shouldn't be far -- Jesu Kriste!"
Like a huge green spider, the troll's severed hand ran on its fingers.
Across the mounded floor, up onto a log with one taloned forefinger to
hook it over the bark, down again it scrambled, until it found the cut
wrist. And there it grew fast. The troll's smashed head seethed and
knit together. He clambered back on his feet and grinned at them...
Three Hearts and Three Lions* arguably has the densest ratio of D&D idiom-inspirations, page-for-page, of any classic pulp book I know. It also set the blueprint for D&D-style paladins, holy swords, fighter/wizard elves, swanmays, rustic Scottish-speaking dwarves, lycanthropes, alignment system, certain spells and magic items, etc., etc. (More on my blog.) Highly recommended reading for D&D players of any edition.
Likewise, the 1988 AD&D Pool of Radiance computer game handles trolls at 0 hit points by removing them from the board (so there's no way to interact with them), and only bringing them back once they've entirely healed back up to maximum -- which is quite terrifying to deal with as a player. Modern DMs can weigh if they want this "play possum" trick in their toolkit or not.