• R
    gfs2: Fix lru_count going negative · bac85208
    Ross Lagerwall 提交于
    [ Upstream commit 7881ef3f33bb80f459ea6020d1e021fc524a6348 ]
    
    Under certain conditions, lru_count may drop below zero resulting in
    a large amount of log spam like this:
    
    vmscan: shrink_slab: gfs2_dump_glock+0x3b0/0x630 [gfs2] \
        negative objects to delete nr=-1
    
    This happens as follows:
    1) A glock is moved from lru_list to the dispose list and lru_count is
       decremented.
    2) The dispose function calls cond_resched() and drops the lru lock.
    3) Another thread takes the lru lock and tries to add the same glock to
       lru_list, checking if the glock is on an lru list.
    4) It is on a list (actually the dispose list) and so it avoids
       incrementing lru_count.
    5) The glock is moved to lru_list.
    5) The original thread doesn't dispose it because it has been re-added
       to the lru list but the lru_count has still decreased by one.
    
    Fix by checking if the LRU flag is set on the glock rather than checking
    if the glock is on some list and rearrange the code so that the LRU flag
    is added/removed precisely when the glock is added/removed from lru_list.
    Signed-off-by: NRoss Lagerwall <ross.lagerwall@citrix.com>
    Signed-off-by: NAndreas Gruenbacher <agruenba@redhat.com>
    Signed-off-by: NSasha Levin <sashal@kernel.org>
    bac85208
glock.c 54.4 KB