I ask a question, In my centos7,  why available value less than free sometimes I think available value is equal to free+buff+cache, available means when start a app how many memory can use?[root@izuf6dbkdletdzecvyepl8z ~]# free -m              total        used        free      shared  buff/cache   availableMem:            992         160         380         342         451          44Swap:             0           0           0   available          Estimation of how much memory is available for starting new applications, without swapping. Unlike the data provided by the  cache  or  free          fields,  this field takes into account page cache and also that not all reclaimable memory slabs will be reclaimed due to items being in use          (MemAvailable in /proc/meminfo, available on kernels 3.14, emulated on kernels 2.6.27+, otherwise the same as free)
why centos7 free command output available value less than free value
centos;memory