Números de uso da memória No topo / htop

Alguém pode por favor explicar esta saída superior. Cada processo PHP usa 30% da memória total ou da memória usada? Além disso, como pode a memória usada combinada em todos os processos PHP exceder em muito a memória do meu sistema? Essa é a memória compartilhada?

desde já, obrigado

top - 14:15:34 up 2 days, 12:38,  1 user,  load average: 0.97, 1.03, 0.93
Tasks: 124 total,   1 running, 123 sleeping,   0 stopped,   0 zombie
Cpu(s):  4.9%us,  0.3%sy,  0.0%ni, 94.6%id,  0.0%wa,  0.0%hi,  0.1%si,  0.1%st
Mem:   1029508k total,   992140k used,    37368k free,   150404k buffers
Swap:   262136k total,     2428k used,   259708k free,   551500k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
 6695 www-data  20   0  548m 307m 292m S    0 30.6   8:06.55 php-fpm
 6697 www-data  20   0  547m 306m 292m S    0 30.4   7:59.64 php-fpm
 6691 www-data  20   0  547m 305m 291m S    2 30.4   8:04.96 php-fpm
 6689 www-data  20   0  547m 305m 291m S    2 30.3   8:07.55 php-fpm
 6696 www-data  20   0  540m 298m 292m S    1 29.7   8:13.43 php-fpm
 6705 www-data  20   0  540m 298m 292m S    0 29.7   8:17.24 php-fpm
 6699 www-data  20   0  540m 298m 291m S    4 29.7   8:07.39 php-fpm
 6701 www-data  20   0  541m 297m 289m S    0 29.6   7:59.87 php-fpm
 6700 www-data  20   0  540m 297m 290m S    0 29.5   8:09.92 php-fpm
 6694 www-data  20   0  541m 296m 288m S    2 29.5   8:05.18 php-fpm
 6707 www-data  20   0  541m 296m 288m S    0 29.5   8:09.40 php-fpm
 6692 www-data  20   0  541m 296m 289m S    0 29.5   8:14.23 php-fpm
 6706 www-data  20   0  541m 296m 289m S    3 29.5   8:07.59 php-fpm
 6698 www-data  20   0  541m 295m 288m S    4 29.4   8:04.85 php-fpm
 6704 www-data  20   0  539m 295m 289m S    2 29.4   8:13.58 php-fpm
 6708 www-data  20   0  540m 295m 288m S    1 29.4   8:14.27 php-fpm
 6802 www-data  20   0  540m 295m 288m S    3 29.3   8:11.63 php-fpm
 6690 www-data  20   0  541m 294m 287m S    3 29.3   8:14.54 php-fpm
 6693 www-data  20   0  539m 293m 287m S    2 29.2   8:16.33 php-fpm
 6702 www-data  20   0  540m 293m 286m S    0 29.2   8:12.41 php-fpm
 8641 www-data  20   0  540m 292m 285m S    4 29.1   6:45.87 php-fpm
 8640 www-data  20   0  539m 291m 285m S    2 29.0   6:47.01 php-fpm
 6703 www-data  20   0  539m 291m 285m S    2 29.0   8:17.77 php-fpm
 8642 www-data  20   0  540m 291m 284m S    0 29.0   6:42.98 php-fpm
 8646 www-data  20   0  540m 291m 284m S    0 28.9   6:41.18 php-fpm
10974 www-data  20   0  539m 285m 279m S    2 28.4   5:07.02 php-fpm
11827 www-data  20   0  539m 282m 275m S    0 28.1   4:28.41 php-fpm

Sim, cada processo php está usando 30% da memória total .

Um sim novamente, a memória compartilhada é o motivo pelo qual você não pode simplesmente adicionar. Veja a coluna "SHR", este é o valor da memória compartilhada, RES significa residente. De "man top":

   n: %MEM  --  Memory usage (RES)
      A task's currently used share of available physical memory.


   o: VIRT  --  Virtual Image (kb)
      The total amount of virtual memory used by the task.  It includes all code, data and shared libraries plus pages that have been swapped out.

      VIRT = SWAP + RES.


   p: SWAP  --  Swapped size (kb)
      The swapped out portion of a task's total virtual memory image.


   q: RES  --  Resident size (kb)
      The non-swapped physical memory a task has used.

      RES = CODE + DATA.


   r: CODE  --  Code size (kb)
      The amount of physical memory devoted to executable code, also known as the 'text resident set' size or TRS.


   s: DATA  --  Data+Stack size (kb)
      The amount of physical memory devoted to other than executable code, also known as the 'data resident set' size or DRS.


   t: SHR  --  Shared Mem size (kb)
      The amount of shared memory used by a task.  It simply reflects memory that could be potentially shared with other processes.