I'd like to add one more question... when I explicitly clean out the page cache, so as to force reads to be satisfied from the fscache, I frequently find that not all of my pages are available from the fscache. I don't know why this is, but I suspect that calling my releasepage method (from an ioctl, after loading the cache & fscache) sometimes frees the page(s) before fscache gets around to storing them...though that doesn't make sense if fscache bumps the page reference count until it has made a copy or written it out. (does fscache consider my page dirty for the purpose of writing to cachefiles, or does it make a copy, and is it susceptible to having a page freed out from under it?...in which case is there a way to perform an explicit flush [preferably on the whole file/object rather than one page at a time]? I would appreciate suggestions as to how to sort this out. Thanks, John Groves On Mon, Nov 10, 2008 at 6:03 PM, John Groves <John@xxxxxxxxxx> wrote: > I have modified the lustre client filesystem to use fscache, and it is in a > rudimentary working state. Among my most pressing requirements is to purge > the fscache for any extent for which a DLM lock is revoked. > > To the end of proving that functionality, I would like to give myself a > file ioctl that would determine what is in the fscache for a given file. > Since this is for testing, performance isn't a major concern. I'm already > doing this with the page cache, and I hope something similar would be > possible with the fscache. > > Is there a supported way to query whether a given page_index is in the > fscache? If not, I'd appreciate suggestions as to how to go about this (or > insight into how other implementers have proven functionality without this > feature). I'm fairly ignorant as to the internals of fscache... > > Thanks, > John Groves > -- Linux-cachefs mailing list Linux-cachefs@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/linux-cachefs
