Re: [PATCH 6/10] lguest code: the little linux hypervisor.
From: Zachary Amsden <hidden>
Date: 2007-02-09 11:13:54
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Rusty Russell wrote:
On Fri, 2007-02-09 at 01:35 -0800, Andrew Morton wrote:quoted
On Fri, 09 Feb 2007 20:20:27 +1100 Rusty Russell [off-list ref] wrote:quoted
+#define log(...) \ + do { \ + mm_segment_t oldfs = get_fs(); \ + char buf[100]; \ + sprintf(buf, "lguest:" __VA_ARGS__); \ + set_fs(KERNEL_DS); \ + sys_write(1, buf, strlen(buf)); \ + set_fs(oldfs); \ + } while(0)Due to gcc shortcomings, each instance of this will chew an additional 100 bytes of stack. Unless they fixed it recently. Is a bit of a timebomb. I guess ksaprintf() could be used. It also looks a bit, umm, innovative.It's also unused 8) It's an extremely useful macro for doing grossly invasive logging of the guest. I'll drop it if you prefer.
Yes, it is a bit, umm, innovative. If it is going to be kept, even if just for devel logging, you should disable interrupts around it. Changing segments is not a normal thing to do. Zach