Red Hat Enterprise Linux 4 system deadlocked under low memory

Issue

• System deadlocked under low memory
• A process is stuck in io_schedule() via mempool_alloc():

PID: 106    TASK: f7d652f0  CPU: 3   COMMAND: "kswapd0"
#0 [f7d36af0] schedule at c02dbcc9
#1 [f7d36b54] io_schedule at c02dc45d
#2 [f7d36b60] mempool_alloc at c0144959
#3 [f7d36bb8] cfq_set_request at c02335eb
#4 [f7d36bc8] elv_set_request at c022982d
#5 [f7d36bd0] get_request at c022b35e
#6 [f7d36bf4] get_request_wait at c022b4bb
#7 [f7d36c4c] __make_request at c022c24a
#8 [f7d36c78] emcp_mrf at f8cdc8c2
#9 [f7d36c7c] generic_make_request at c022c563
#10 [f7d36cc0] __clone_and_map at f892988a
#11 [f7d36d24] __split_bio at f8929b86
#12 [f7d36d64] dm_request at f8929d88
#13 [f7d36d74] generic_make_request at c022c563
#14 [f7d36db8] submit_bio at c022c650
#15 [f7d36dec] swap_writepage at c01563be
#16 [f7d36e04] pageout at c014b967
#17 [f7d36e44] shrink_list at c014bbdf
#18 [f7d36eb4] shrink_cache at c014bfa2
#19 [f7d36f18] shrink_zone at c014c717
#20 [f7d36f34] balance_pgdat at c014cbdd
#21 [f7d36f98] kswapd at c014cdf7
#22 [f7d36ff0] kernel_thread_helper at c01041f3