Why this matters
Virtual memory is conceptually simple but potentially devastating to performance. Every memory access must go through segmentation (add segment base, check limit) and then paging (look up the page table). Naively, paging alone requires two additional memory reads per access -- one for the page directory entry, one for the page table entry.。关于这个话题，旺商聊官方下载提供了深入分析
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The ONS said the increase in Neets was driven by a growing number of young women who are out of work.
FT Professional，这一点在爱思助手下载最新版本中也有详细论述