[PATCH] Define struct pspace (3fbc9648) · Commits · 戴 / test

fs/proc/proc_misc.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -45,6 +45,7 @@
		#include <linux/sysrq.h>
		#include <linux/vmalloc.h>
		#include <linux/crash_dump.h>
		#include <linux/pspace.h>
		#include <asm/uaccess.h>
		#include <asm/pgtable.h>
		#include <asm/io.h>
		@@ -91,7 +92,7 @@ static int loadavg_read_proc(char page, char *start, off_t off,
		LOAD_INT(a), LOAD_FRAC(a),
		LOAD_INT(b), LOAD_FRAC(b),
		LOAD_INT(c), LOAD_FRAC(c),
		nr_running(), nr_threads, last_pid);
		nr_running(), nr_threads, init_pspace.last_pid);
		return proc_calc_metrics(page, start, off, count, eof, len);
		}

include/linux/pspace.h

+7 −0

Original line number	Diff line number	Diff line
		@@ -13,4 +13,11 @@ struct pidmap {

		#define PIDMAP_ENTRIES ((PID_MAX_LIMIT + 8*PAGE_SIZE - 1)/PAGE_SIZE/8)

		struct pspace {
		struct pidmap pidmap[PIDMAP_ENTRIES];
		int last_pid;
		};

		extern struct pspace init_pspace;

		#endif /* _LINUX_PSPACE_H */

include/linux/sched.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -118,7 +118,6 @@ extern unsigned long avenrun[]; /* Load averages */

		extern unsigned long total_forks;
		extern int nr_threads;
		extern int last_pid;
		DECLARE_PER_CPU(unsigned long, process_counts);
		extern int nr_processes(void);
		extern unsigned long nr_running(void);

kernel/pid.c

+31 −22

Original line number	Diff line number	Diff line
		@@ -34,7 +34,6 @@ static int pidhash_shift;
		static kmem_cache_t *pid_cachep;

		int pid_max = PID_MAX_DEFAULT;
		int last_pid;

		#define RESERVED_PIDS 300

		@@ -43,7 +42,12 @@ int pid_max_max = PID_MAX_LIMIT;

		#define BITS_PER_PAGE (PAGE_SIZE*8)
		#define BITS_PER_PAGE_MASK (BITS_PER_PAGE-1)
		#define mk_pid(map, off) (((map) - pidmap_array)*BITS_PER_PAGE + (off))

		static inline int mk_pid(struct pspace pspace, struct pidmap map, int off)
		{
		return (map - pspace->pidmap)*BITS_PER_PAGE + off;
		}

		#define find_next_offset(map, off) \
		find_next_zero_bit((map)->page, BITS_PER_PAGE, off)

		@@ -53,8 +57,12 @@ int pid_max_max = PID_MAX_LIMIT;
		* value does not cause lots of bitmaps to be allocated, but
		* the scheme scales to up to 4 million PIDs, runtime.
		*/
		static struct pidmap pidmap_array[PIDMAP_ENTRIES] =
		{ [ 0 ... PIDMAP_ENTRIES-1 ] = { ATOMIC_INIT(BITS_PER_PAGE), NULL } };
		struct pspace init_pspace = {
		.pidmap = {
		[ 0 ... PIDMAP_ENTRIES-1] = { ATOMIC_INIT(BITS_PER_PAGE), NULL }
		},
		.last_pid = 0
		};

		/*
		* Note: disable interrupts while the pidmap_lock is held as an
		@@ -69,40 +77,41 @@ static struct pidmap pidmap_array[PIDMAP_ENTRIES] =
		* irq handlers that take it we can leave the interrupts enabled.
		* For now it is easier to be safe than to prove it can't happen.
		*/

		static __cacheline_aligned_in_smp DEFINE_SPINLOCK(pidmap_lock);

		static fastcall void free_pidmap(int pid)
		static fastcall void free_pidmap(struct pspace *pspace, int pid)
		{
		struct pidmap *map = pidmap_array + pid / BITS_PER_PAGE;
		struct pidmap *map = pspace->pidmap + pid / BITS_PER_PAGE;
		int offset = pid & BITS_PER_PAGE_MASK;

		clear_bit(offset, map->page);
		atomic_inc(&map->nr_free);
		}

		static int alloc_pidmap(void)
		static int alloc_pidmap(struct pspace *pspace)
		{
		int i, offset, max_scan, pid, last = last_pid;
		int i, offset, max_scan, pid, last = pspace->last_pid;
		struct pidmap *map;

		pid = last + 1;
		if (pid >= pid_max)
		pid = RESERVED_PIDS;
		offset = pid & BITS_PER_PAGE_MASK;
		map = &pidmap_array[pid/BITS_PER_PAGE];
		map = &pspace->pidmap[pid/BITS_PER_PAGE];
		max_scan = (pid_max + BITS_PER_PAGE - 1)/BITS_PER_PAGE - !offset;
		for (i = 0; i <= max_scan; ++i) {
		if (unlikely(!map->page)) {
		unsigned long page = get_zeroed_page(GFP_KERNEL);
		void *page = kzalloc(PAGE_SIZE, GFP_KERNEL);
		/*
		* Free the page if someone raced with us
		* installing it:
		*/
		spin_lock_irq(&pidmap_lock);
		if (map->page)
		free_page(page);
		kfree(page);
		else
		map->page = (void *)page;
		map->page = page;
		spin_unlock_irq(&pidmap_lock);
		if (unlikely(!map->page))
		break;
		@@ -111,11 +120,11 @@ static int alloc_pidmap(void)
		do {
		if (!test_and_set_bit(offset, map->page)) {
		atomic_dec(&map->nr_free);
		last_pid = pid;
		pspace->last_pid = pid;
		return pid;
		}
		offset = find_next_offset(map, offset);
		pid = mk_pid(map, offset);
		pid = mk_pid(pspace, map, offset);
		/*
		* find_next_offset() found a bit, the pid from it
		* is in-bounds, and if we fell back to the last
		@@ -126,16 +135,16 @@ static int alloc_pidmap(void)
		(i != max_scan \|\| pid < last \|\|
		!((last+1) & BITS_PER_PAGE_MASK)));
		}
		if (map < &pidmap_array[(pid_max-1)/BITS_PER_PAGE]) {
		if (map < &pspace->pidmap[(pid_max-1)/BITS_PER_PAGE]) {
		++map;
		offset = 0;
		} else {
		map = &pidmap_array[0];
		map = &pspace->pidmap[0];
		offset = RESERVED_PIDS;
		if (unlikely(last == offset))
		break;
		}
		pid = mk_pid(map, offset);
		pid = mk_pid(pspace, map, offset);
		}
		return -1;
		}
		@@ -182,7 +191,7 @@ fastcall void free_pid(struct pid *pid)
		hlist_del_rcu(&pid->pid_chain);
		spin_unlock_irqrestore(&pidmap_lock, flags);

		free_pidmap(pid->nr);
		free_pidmap(&init_pspace, pid->nr);
		call_rcu(&pid->rcu, delayed_put_pid);
		}

		@@ -196,7 +205,7 @@ struct pid *alloc_pid(void)
		if (!pid)
		goto out;

		nr = alloc_pidmap();
		nr = alloc_pidmap(&init_pspace);
		if (nr < 0)
		goto out_free;

		@@ -363,10 +372,10 @@ void __init pidhash_init(void)

		void __init pidmap_init(void)
		{
		pidmap_array->page = (void *)get_zeroed_page(GFP_KERNEL);
		init_pspace.pidmap[0].page = kzalloc(PAGE_SIZE, GFP_KERNEL);
		/* Reserve PID 0. We never call free_pidmap(0) */
		set_bit(0, pidmap_array->page);
		atomic_dec(&pidmap_array->nr_free);
		set_bit(0, init_pspace.pidmap[0].page);
		atomic_dec(&init_pspace.pidmap[0].nr_free);

		pid_cachep = kmem_cache_create("pid", sizeof(struct pid),
		__alignof__(struct pid),

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