Messages in this thread | | | Date | Thu, 29 Oct 1998 09:57:04 +0100 (CET) | From | Andrea Arcangeli <> | Subject | Re: 4MB pages and framebuffer access, x11perf results, 2.1.125 |
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On Wed, 28 Oct 1998, MOLNAR Ingo wrote:
>+ pgd_val(*pgd) = _PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED >+ | _PAGE_DIRTY | _PAGE_USER | _PAGE_4M >+ | _PAGE_GLOBAL | offset;
Is really right to set the global flag? I understand that such flag cause the entry to remain in the TLB all the time also for other processes... Do I understood right the meaning of such flag?
--- this what I read in intel docs --- Global (G) flag, bit 8 (Introduced in the Pentium Pro processor.) Indicates a global page when set. When a page is marked global and the page global enable (PGE) flag in register CR4 is set, the page-table or page-directory entry for the page is not invalidated in the TLB when register CR3 is loaded or a task switch occurs. This flag is provided to prevent frequently used pages (such as pages that contain kernel or other operating system or executive code) from being flushed from the TLB. Only software can set or clear this flag. For page-directory entries that point to page tables, this flag is ignored and the global characteristics of a page are set in the page-table entries. See Section 3.7., "Translation Lookaside Buffers (TLBs)", for more information about the use of this flag. (This bit is reserved in Pentium and earlier Intel Architecture processors.) Reserved --- this what I read in intel docs ---
Andrea Arcangeli
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