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Re: [Qemu-devel] [PATCH] linux-user: use default mmap_min_addr 65536 whe
From: |
Martin Jansa |
Subject: |
Re: [Qemu-devel] [PATCH] linux-user: use default mmap_min_addr 65536 when /proc/sys/vm/mmap_min_addr cannot be read |
Date: |
Thu, 13 May 2010 21:26:26 +0200 |
User-agent: |
Mutt/1.5.20 (2009-06-14) |
On Thu, May 13, 2010 at 09:59:24AM -0700, Richard Henderson wrote:
> On 05/13/2010 06:17 AM, Martin Jansa wrote:
> > @@ -2899,8 +2900,14 @@ int main(int argc, char **argv, char **envp)
> > if (fscanf(fp, "%lu", &tmp) == 1) {
> > mmap_min_addr = tmp;
> > qemu_log("host mmap_min_addr=0x%lx\n", mmap_min_addr);
> > + } else {
> > + qemu_log("cannot read value from
> > /proc/sys/vm/mmap_min_addr, assuming %d\n", MMAP_MIN_ADDR_DEFAULT);
> > + mmap_min_addr = MMAP_MIN_ADDR_DEFAULT;
> > }
> > fclose(fp);
> > + } else {
> > + qemu_log("cannot open /proc/sys/vm/mmap_min_addr for reading,
> > assuming %d\n", MMAP_MIN_ADDR_DEFAULT);
> > + mmap_min_addr = MMAP_MIN_ADDR_DEFAULT;
> > }
> > }
>
> Perhaps you can combine these two else clauses?
Sure it would be possible, but while trying to find why qemu doesn't
work on someone box but works on mine I wanted to distinguish between
cannot open and cannot read.
Also if I combine it in test ie initialize mmap_min_addr with -1, and
then check if it changed after read (because 0 is also valid value),
or moving fopen and fscanf to one condition, then it gets IMHO as
complicated as those 2 else clauses.
BTW: I noticed that qemu-arm works ok when mmap_min_addr is low enough
(and doesn't have to be zero).
my box had mmap_min_addr 4096 and qemu-arm worked fine even without
reading it
and the other boxes had mmap_min_addr = 64K and failed later to mmap.
Regards,
--
uin:136542059 jid:address@hidden
Jansa Martin sip:address@hidden
JaMa