On Thu, 11 Mar 2010 13:58:47 +0900 Daisuke Nishimura <nishimura@xxxxxxxxxxxxxxxxx> wrote: > > I'll consider yet another fix for race in account migration if I can. > > > me too. > How about this ? Assume that the race is very rare. 1. use trylock when updating statistics. If trylock fails, don't account it. 2. add PCG_FLAG for all status as + PCG_ACCT_FILE_MAPPED, /* page is accounted as file rss*/ + PCG_ACCT_DIRTY, /* page is dirty */ + PCG_ACCT_WRITEBACK, /* page is being written back to disk */ + PCG_ACCT_WRITEBACK_TEMP, /* page is used as temporary buffer for FUSE */ + PCG_ACCT_UNSTABLE_NFS, /* NFS page not yet committed to the server */ 3. At reducing counter, check PCG_xxx flags by TESTCLEARPCGFLAG() This is similar to an _used_ method of LRU accounting. And We can think this method's error-range never go too bad number. I think this kind of fuzzy accounting is enough for writeback status. Does anyone need strict accounting ? Thanks, -Kame -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>