Messages in this thread | | | Date | Sat, 09 Dec 2000 19:11:57 +0100 | From | Roberto Fichera <> | Subject | Re: [PATCH] mm->rss is modified without page_table_lock held |
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At 07.00 09/12/00 -0800, David S. Miller wrote:
> Date: Sat, 09 Dec 2000 16:07:03 +0100 > From: Roberto Fichera <kernel@tekno-soft.it> > > 8 bits for a spinlock ? What kind of use we have here ? > >Sparc32 (like some other older architectures) do not have a >word atomic update instruction, but it does have a byte spinlock. >To conserve space and implement the atomic update properly, we >use a spinlock in the top byte of the word.
There's any possibility ;-) to define it as
typedef struct { volatile char spinlock, volatile long counter } atomic_t;
>Also, this sematic was decided upon many eons ago, changing it a month >before 2.4.0 just to deal with this mm->rss atomicity issue is not >going to happen. The spinlock patch exists, and if nothing better >comes up, we should just use it.
Indeed! You are right! I was thinking to optimize it, using a spinlock/unlock we spent several time for a inc.
Roberto Fichera.
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