sure, in your btree.c code, when you do btree gc, you update the bucket's used sectors by min(unsigned, GC_SECTORS_USED(b)+key_size(), 1<<14-1). this might get you larger than the bucket size. since the newly allocated bucket is set to bucket size already. so each round you will accumulate the key_size(). i print the information at that point, and see GC_SECTORS_USED > bucket size. Thanks, Sheng On Thu, Jul 11, 2013 at 10:25 PM, Kent Overstreet <kmo@xxxxxxxxxxxxx> wrote: > On Thu, Jul 11, 2013 at 10:22:02PM -0400, sheng qiu wrote: >> Hi Kent, >> >> thanks for the explain above. my concern is that the GC_SECTORS_USED >> does not get you the correct valid data size within each bucket. for >> example, the GC_SECTORS_USED might return you larger than the bucket >> size, while when you go to match the reserved_sectors, you might get >> wrong. i do not know if you get my meaning. A simple way is run some >> test while enable the GC code, you will see how it work actually. If >> it's my misunderstanding, i am glad to hear from you later. > > I'm not sure I follow - if GC_SECTORS_USED was > bucket size that'd > probably be a bug, but I don't see how that could happen - could you > explain? -- Sheng Qiu Texas A & M University Room 332B Wisenbaker email: herbert1984106@xxxxxxxxx College Station, TX 77843-3259 -- To unsubscribe from this list: send the line "unsubscribe linux-bcache" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
