Messages in this thread | | | Date | Wed, 10 Nov 1999 00:40:40 +0100 (CET) | From | Andrea Arcangeli <> | Subject | Re: PATCH 2.3.26: kmalloc GFP_ZEROt |
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On Wed, 10 Nov 1999, Gerard Roudier wrote:
>zeroed with the cache invalidating or snooping the accesses. May-be having >some pool of zeroed memory or zeroing some memory is useful for security >issue, but speaking of pooled or cached objects, we probably want to most
Yes, the _only_ point of the clear_page in the page fault path is security.
>only zero parts that need to be so. The bzero-mania does not look fine >programming to me.
Agreed. OTOH using a different chip for the bzero may really improve performances and scale better.
The bzero-mania with a minimal slowdown under heavy load still doesn't convince me instead...
>PS: If we want to be able to write zero-filled blocks to a disk without >bzero overhead, for example, we can reserve a small amount of physical >pages filled with zeros at startup.
Currently there's at least one page reserved that must stay zeroed all the time. It's the ZERO_PAGE(). mapping /dev/null always fallback on the ZERO_PAGE. you can read it as many times and whenever you want.
Andrea
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