99f8955183
Every inode in /proc holds a reference to a struct task_struct. If a directory or file is opened and remains open after the the task exits this pinning continues. With 8K stacks on a 32bit machine the amount pinned per file descriptor is about 10K. Normally I would figure a reasonable per user process limit is about 100 processes. With 80 processes, with a 1000 file descriptors each I can trigger the 00M killer on a 32bit kernel, because I have pinned about 800MB of useless data. This patch replaces the struct task_struct pointer with a pointer to a struct task_ref which has a struct task_struct pointer. The so the pinning of dead tasks does not happen. The code now has to contend with the fact that the task may now exit at any time. Which is a little but not muh more complicated. With this change it takes about 1000 processes each opening up 1000 file descriptors before I can trigger the OOM killer. Much better. [mlp@google.com: task_mmu small fixes] Signed-off-by: Eric W. Biederman <ebiederm@xmission.com> Cc: Trond Myklebust <trond.myklebust@fys.uio.no> Cc: Paul Jackson <pj@sgi.com> Cc: Oleg Nesterov <oleg@tv-sign.ru> Cc: Albert Cahalan <acahalan@gmail.com> Signed-off-by: Prasanna Meda <mlp@google.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
68 lines
1.9 KiB
C
68 lines
1.9 KiB
C
/* internal.h: internal procfs definitions
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/proc_fs.h>
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#include <linux/task_ref.h>
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struct vmalloc_info {
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unsigned long used;
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unsigned long largest_chunk;
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};
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#ifdef CONFIG_MMU
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#define VMALLOC_TOTAL (VMALLOC_END - VMALLOC_START)
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extern void get_vmalloc_info(struct vmalloc_info *vmi);
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#else
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#define VMALLOC_TOTAL 0UL
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#define get_vmalloc_info(vmi) \
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do { \
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(vmi)->used = 0; \
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(vmi)->largest_chunk = 0; \
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} while(0)
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#endif
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extern void create_seq_entry(char *name, mode_t mode, const struct file_operations *f);
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extern int proc_exe_link(struct inode *, struct dentry **, struct vfsmount **);
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extern int proc_tid_stat(struct task_struct *, char *);
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extern int proc_tgid_stat(struct task_struct *, char *);
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extern int proc_pid_status(struct task_struct *, char *);
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extern int proc_pid_statm(struct task_struct *, char *);
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extern struct file_operations proc_maps_operations;
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extern struct file_operations proc_numa_maps_operations;
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extern struct file_operations proc_smaps_operations;
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extern struct file_operations proc_maps_operations;
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extern struct file_operations proc_numa_maps_operations;
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extern struct file_operations proc_smaps_operations;
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void free_proc_entry(struct proc_dir_entry *de);
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int proc_init_inodecache(void);
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static inline struct task_ref *proc_tref(struct inode *inode)
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{
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return PROC_I(inode)->tref;
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}
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static inline struct task_struct *get_proc_task(struct inode *inode)
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{
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return get_tref_task(proc_tref(inode));
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}
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static inline int proc_fd(struct inode *inode)
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{
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return PROC_I(inode)->fd;
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}
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