Enabling fadvise for removing data from page cache in disk mode
Enabling fadvise for removing data from page cache in disk mode

Summary: Enabling fadvise for removing data from page cache in disk mode

Differential Revision: D4959506

fbshipit-source-id: 85704f66d9b96d8b3792826711a53ca9014f45df

luluandleilei/wdt,luluandleilei/wdt,ldemailly/wdt,luluandleilei/wdt,ldemailly/wdt,ldemailly/wdt,ldemailly/wdt,luluandleilei/wdt