Hi, My system experiencing problems with atomic memory allocations. Device drivers are not able to allocate contiguous memory regions due to a high fragmentation level. At the time of failure: /proc/meminfo shows the following information: MemTotal: 4021820 Kb MemFree: 121912 Kb Active: 1304396 Kb Inactive: 2377124 Kb Most of the memory is consumed by the LRU inactive list and only 121 Mb is available to the system. By using a tracer, I found that most of the pages in the inactive list are created by the ext4 journal during a truncate operation. The call stack of the allocation is: [ __alloc_pages_nodemask alloc_pages_current __page_cache_alloc find_or_create_page __getblk jbd2_journal_get_descriptor_buffer jbd2_journal_commit_transaction kjournald2 kthread ] The problem is easily reproducible using the following script: #!/bin/bash while true; do dd if=/dev/zero of=output.dat bs=100M count=1 done Is that a normal behavior ? I know that the philosophy of memory management in Linux is to use the available memory as much as possible, but what is the need of keeping truncated pages in the LRU if we know that they are not even accessible ? The problem of the inactive list growth occurs only with the journal mode of ext4, not with the write-back mode. A chart representing the utilization of memory during the test is provided in this link: http://secretaire.dorsal.polymtl.ca/~hdaoud/ext4_journal_meminfo.png Thanks, Houssem _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
