2015-08-11 8:25 GMT-03:00 David Sorber <david.sorber@xxxxxxxxx>: > For example, on the last failure that I captured the page cache filled 27 GB > of the 32 GB of RAM on my system. I suspected that the page cache "fullness" > was causing dma_alloc_coherent calls to fail. To test this theory I manually > emptied the page cache using: > > # echo 1 > /proc/sys/vm/drop_caches > > This dropped the size of the cache from 27 GB to 94 MB and I was able to > allocate 20+ 1 GB DMA buffers with no issues. > > Clearly the page cache is a beneficial thing so I would prefer not to have > to completely empty it every time I run out of space when allocating DMA > buffers. My questions is this: how can I dynamically shrink the page cache > in kernel space such that if a call to dma_alloc_coherent fails I can > recover just enough space so that I can retry the call and have it succeed? > Any assistance with this would be greatly appreciated! The Linux memory management is not very good yet. Was researching more about the file system BTRFS is better. -- Albino B Neto www.bino.us "Debian. Freedom to code. Code to freedom!" faw _______________________________________________ Kernelnewbies mailing list Kernelnewbies@xxxxxxxxxxxxxxxxx http://lists.kernelnewbies.org/mailman/listinfo/kernelnewbies
