Today my system crashed with:
Feb 24 20:07:34 kernel: [46929872.935456] [<ffffffff81141073>] ? out_of_memory+0x473/0x4b0
But I was able to still login to SHH and open the top, many aplications crashed and refused to start, but in the top only 50% of my memory was marked as "used" and another 50% of the memory was marked as "cached Mem".
I always thought that cached memory is used to cache files to reduce write/reads from drive and when program needs to allocate more memory, some files are dropped from the cache and used for running programs. But apparently that is not true, because 50% of my total memory was used for cache and system still crashed while it should just drop some cache.
Can someone give me some deeper explanation of how cached memory works ? Thanks.