-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Jan Kara wrote: > Hi, > > just one note: I've looked to the in scan_bitmap() in bitmap.c. There is: > /* When the bitmap is more than 10% free, anyone can allocate. > * When it's less than 10% free, only files that already use the > * bitmap are allowed. Once we pass 80% full, this restriction > * is lifted. > * > * We do this so that files that grow later still have space > * close to > * their original allocation. This improves locality, and > * presumably > * performance as a result. > * > * This is only an allocation policy and does not make up for > * getting a > * bad hint. Decent hinting must be implemented for this to work > * well. > */ > if (TEST_OPTION(skip_busy, s) > && SB_FREE_BLOCKS(s) > SB_BLOCK_COUNT(s) / 20) { > > So the comment suggests we should lift the restriction when we are 80% > full but if you see the condition, it checks wherher we are 95% full! I > guess that is really asking for trouble and could explain the > behaviour... > Mike could you try changing that 20 in the test to 5? IMHO that could > fix your problem.
Shoot. I guess I never sent that mail out last night. I had discovered the same thing. The thing is, I don't think it will cause the kind of performance problem we're seeing here. Once it sees the 90% check it will bail out. Minor slowdown, not anything like we're seeing. - -Jeff - -- Jeff Mahoney SUSE Labs -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.2 (GNU/Linux) Comment: Using GnuPG with SUSE - http://enigmail.mozdev.org iD8DBQFErp76LPWxlyuTD7IRAqJ1AJ9ce8HTFNauhcriJzUlKJ1p68u4MwCdE4W/ IA09T6t/46TD+PSAQs/MHkk= =/9Xa -----END PGP SIGNATURE-----