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Message-ID: <1305625541.2850.29.camel@edumazet-laptop> Date: Tue, 17 May 2011 11:45:41 +0200 From: Eric Dumazet <eric.dumazet@...il.com> To: Tejun Heo <tj@...nel.org> Cc: Shaohua Li <shaohua.li@...el.com>, "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>, "akpm@...ux-foundation.org" <akpm@...ux-foundation.org>, "cl@...ux.com" <cl@...ux.com>, "npiggin@...nel.dk" <npiggin@...nel.dk> Subject: Re: [patch V3] percpu_counter: scalability works Le mardi 17 mai 2011 à 11:11 +0200, Tejun Heo a écrit : > I'm completely fine with #1. I'm not that crazy but I don't really > want to take #2 - that makes the whole _sum() interface almost > pointless. Hi Tejun _sum() is a bit more precise than percpu_counter_read(), but to make it really precise, we means we have to stop concurrent activities, and we never did in previous/current implementation. We could add this (as Shaohua and myself tried in various patches) later, if needed, but nowhere in kernel we currently need that. Even /proc/meminfo doesnt call _sum(&vm_committed_as) but the lazy percpu_counter_read_positive() function... Reammy _sum() gives a good approximation of the counter, more precise because of the percpu s32 folding, but no guarantee of deviation. -- 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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