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Date: Wed, 9 Jan 2008 09:20:08 +0800 From: "Changli Gao" <xiaosuo@...il.com> To: "Andi Kleen" <andi@...stfloor.org> Cc: linux-kernel@...r.kernel.org Subject: Re: [PATCH] Improve scalability of epoll_ctl On Jan 9, 2008 12:56 AM, Andi Kleen <andi@...stfloor.org> wrote: > > Are you sure it's faster? vmalloc/vfree can be quite slow because > they have to change the MMU state of the kernel and take global > locks. I don't think so. In fact, the memory of fdtable is allocated by vmalloc when its size is bigger than PAGE_SIZE: static inline void * alloc_fdmem(unsigned int size) { if (size <= PAGE_SIZE) return kmalloc(size, GFP_KERNEL); else return vmalloc(size); } > > The other problem is that on 32bit systems vmalloc space is somewhat > limited -- you might have added an unintended scaling limit. As I have talked above, I am sure open(), socket() and etc. will first encounter it. -- Regards, Changli Gao(xiaosuo@...il.com) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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