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Date: Fri, 11 Apr 2008 22:44:55 -0600
From: Scott Long <scottl@samsco.org>
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To: Julian Elischer <julian@elischer.org>
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Cc: FreeBSD Current <current@freebsd.org>
Subject: Re: stack hogs in kernel
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Julian Elischer wrote:
> 
> A few years ago I took a profile of stack hogs in the kernel.
> I just redid the exercise...
> 
>   http://people.freebsd.org/~julian/stack-hogs.txt
> 
> 
> the worst offenders in MY (2 month old) kernel are:
> 
> 0xc05667e3 kldstat [kernel]:                2100
> 0xc07214f8 sendsig [kernel]:                1416
> 0xc04fb426 ugenread [kernel]:                1200
> 0xc070616b ipmi_smbios_identify [kernel]:        1136
> 0xc050bd26 usbd_new_device [kernel]:            1128
> 0xc0525a83 pfs_readlink [kernel]:            1092
> 0xc04fb407 ugenwrite [kernel]:                1056
> 0xc055ea33 prison_enforce_statfs [kernel]:        1044
> 0xc0686e8a nfsrv_rename [kernel]:            984
> 0xc05d0886 m_copymdata [kernel]:            956
> 0xc06605a3 nfs4_mount [kernel]:                884
> 0xc0561e25 kse_switchin [kernel]:            848
> 0xc0680ac6 nfsrv_statfs [kernel]:            828
> 0xc0439473 cam_periph_error [kernel]:            820
> 0xc071ff36 sigreturn [kernel]:                812
> 0xc067e876 nfsrv_fsinfo [kernel]:            804
> 0xc05fe7b3 freebsd4_fhstatfs [kernel]:            804
> 0xc0571272 sysctl_out_proc [kernel]:            804
> 0xc067ebf7 nfsrv_fsinfo [kernel]:            804
> 0xc0571006 sysctl_out_proc [kernel]:            804
> 0xc044b743 cddone [kernel]:                800
> 0xc06862cf nfsrv_link [kernel]:                796

I'll take a look at cddone().  I see where the problem is, but it's hard
to fix correctly.  However, the call chain leading to and from cddone is
pretty small and unlikely to recurse; I seriously doubt that it will
cause problems.

Scott