linux-kernel - [PATCH] x86_64 : vsyscall_gtod_data diet and vgettimeofday() fix

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Message-id: <460AA6E3.50109@cosmosbay.com>
Date:	Wed, 28 Mar 2007 19:33:23 +0200
From:	Eric Dumazet <dada1@...mosbay.com>
To:	Andrew Morton <akpm@...ux-foundation.org>
Cc:	Andi Kleen <ak@...e.de>,
	Linux kernel <linux-kernel@...r.kernel.org>
Subject: [PATCH] x86_64 : vsyscall_gtod_data diet and vgettimeofday() fix

Hi Andrew

This patch should be applied after x86_64 : fix vtime() vsyscall

Thank you

[PATCH] x86_64 : vsyscall_gtod_data diet and vgettimeofday() fix

Current vsyscall_gtod_data is large (3 or 4 cache lines dirtied at timer 
interrupt). We can shrink it to exactly 64 bytes (1 cache line on AMD64)

Instead of copying a whole struct clocksource, we copy only needed fields.

I deleted an unused field : offset_base

This patch fixes one oddity in vgettimeofday(): It can returns a timeval with 
tv_usec = 1000000. Maybe not a bug, but why not doing the right thing ?

Signed-off-by: Eric Dumazet <dada1@...mosbay.com>

View attachment "vsyscall_gtod_data_diet.patch" of type "text/plain" (3337 bytes)