From 91d5354a2ce810d848eca6ecf9da1027aeb2be6d Mon Sep 17 00:00:00 2001 From: John Baldwin 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/vm/vm_unix.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) (limited to 'sys/vm/vm_unix.c') diff --git a/sys/vm/vm_unix.c b/sys/vm/vm_unix.c index 877609f1eb77..6313cc1125a0 100644 --- a/sys/vm/vm_unix.c +++ b/sys/vm/vm_unix.c @@ -77,10 +77,16 @@ obreak(td, uap) { struct vmspace *vm = td->td_proc->p_vmspace; vm_offset_t new, old, base; + rlim_t datalim, vmemlim; int rv; int error = 0; boolean_t do_map_wirefuture; + PROC_LOCK(td->td_proc); + datalim = lim_cur(td->td_proc, RLIMIT_DATA); + vmemlim = lim_cur(td->td_proc, RLIMIT_VMEM); + PROC_UNLOCK(td->td_proc); + do_map_wirefuture = FALSE; new = round_page((vm_offset_t)uap->nsize); vm_map_lock(&vm->vm_map); @@ -92,8 +98,7 @@ obreak(td, uap) * Check the resource limit, but allow a process to reduce * its usage, even if it remains over the limit. */ - if (new - base > td->td_proc->p_rlimit[RLIMIT_DATA].rlim_cur && - new > old) { + if (new - base > datalim && new > old) { error = ENOMEM; goto done; } @@ -111,8 +116,7 @@ obreak(td, uap) goto done; } if (new > old) { - if (vm->vm_map.size + (new - old) > - td->td_proc->p_rlimit[RLIMIT_VMEM].rlim_cur) { + if (vm->vm_map.size + (new - old) > vmemlim) { error = ENOMEM; goto done; } -- cgit v1.2.3