From 279b2b827810d149b5b8453900cdea57874ae234 Mon Sep 17 00:00:00 2001 From: jhb Date: Wed, 4 Feb 2004 21:52:57 +0000 Subject: Locking for the per-process resource limits structure. - struct plimit includes a mutex to protect a reference count. The plimit structure is treated similarly to struct ucred in that is is always copy on write, so having a reference to a structure is sufficient to read from it without needing a further lock. - The proc lock protects the p_limit pointer and must be held while reading limits from a process to keep the limit structure from changing out from under you while reading from it. - Various global limits that are ints are not protected by a lock since int writes are atomic on all the archs we support and thus a lock wouldn't buy us anything. - All accesses to individual resource limits from a process are abstracted behind a simple lim_rlimit(), lim_max(), and lim_cur() API that return either an rlimit, or the current or max individual limit of the specified resource from a process. - dosetrlimit() was renamed to kern_setrlimit() to match existing style of other similar syscall helper functions. - The alpha OSF/1 compat layer no longer calls getrlimit() and setrlimit() (it didn't used the stackgap when it should have) but uses lim_rlimit() and kern_setrlimit() instead. - The svr4 compat no longer uses the stackgap for resource limits calls, but uses lim_rlimit() and kern_setrlimit() instead. - The ibcs2 compat no longer uses the stackgap for resource limits. It also no longer uses the stackgap for accessing sysctl's for the ibcs2_sysconf() syscall but uses kernel_sysctl() instead. As a result, ibcs2_sysconf() no longer needs Giant. - The p_rlimit macro no longer exists. Submitted by: mtm (mostly, I only did a few cleanups and catchups) Tested on: i386 Compiled on: alpha, amd64 --- sys/kern/subr_trap.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) (limited to 'sys/kern/subr_trap.c') diff --git a/sys/kern/subr_trap.c b/sys/kern/subr_trap.c index 2390087..a556d0e 100644 --- a/sys/kern/subr_trap.c +++ b/sys/kern/subr_trap.c @@ -143,7 +143,7 @@ ast(struct trapframe *framep) struct proc *p; struct kse *ke; struct ksegrp *kg; - struct rlimit *rlim; + struct rlimit rlim; u_int prticks, sticks; int sflag; int flags; @@ -223,13 +223,13 @@ ast(struct trapframe *framep) } if (sflag & PS_XCPU) { PROC_LOCK(p); - rlim = &p->p_rlimit[RLIMIT_CPU]; + lim_rlimit(p, RLIMIT_CPU, &rlim); mtx_lock_spin(&sched_lock); - if (p->p_runtime.sec >= rlim->rlim_max) { + if (p->p_runtime.sec >= rlim.rlim_max) { mtx_unlock_spin(&sched_lock); killproc(p, "exceeded maximum CPU limit"); } else { - if (p->p_cpulimit < rlim->rlim_max) + if (p->p_cpulimit < rlim.rlim_max) p->p_cpulimit += 5; mtx_unlock_spin(&sched_lock); psignal(p, SIGXCPU); -- cgit v1.1