Messages in this thread Patch in this message | | | Date | Thu, 25 Aug 2005 10:45:12 +0200 | From | Eric Dumazet <> | Subject | [PATCH] removes filp_count_lock and changes nr_files type to atomic_t |
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This patch removes filp_count_lock spinlock, used to protect files_stat.nr_files.
Just use atomic_t type and atomic_inc()/atomic_dec() operations.
This patch assumes that atomic_read() is a plain {return v->counter;} on all architectures. (keywords : sysctl, /proc/sys/fs/file-nr, proc_dointvec)
Signed-off-by: Eric Dumazet <dada1@cosmosbay.com> diff -Nru linux-2.6.13-rc7/fs/file_table.c linux-2.6.13-rc7-ed/fs/file_table.c --- linux-2.6.13-rc7/fs/file_table.c 2005-08-24 05:39:14.000000000 +0200 +++ linux-2.6.13-rc7-ed/fs/file_table.c 2005-08-25 10:41:00.000000000 +0200 @@ -28,29 +28,21 @@ /* public. Not pretty! */ __cacheline_aligned_in_smp DEFINE_SPINLOCK(files_lock); -static DEFINE_SPINLOCK(filp_count_lock); /* slab constructors and destructors are called from arbitrary - * context and must be fully threaded - use a local spinlock - * to protect files_stat.nr_files + * context and must be fully threaded */ void filp_ctor(void * objp, struct kmem_cache_s *cachep, unsigned long cflags) { if ((cflags & (SLAB_CTOR_VERIFY|SLAB_CTOR_CONSTRUCTOR)) == SLAB_CTOR_CONSTRUCTOR) { - unsigned long flags; - spin_lock_irqsave(&filp_count_lock, flags); - files_stat.nr_files++; - spin_unlock_irqrestore(&filp_count_lock, flags); + atomic_inc(&files_stat.nr_files); } } void filp_dtor(void * objp, struct kmem_cache_s *cachep, unsigned long dflags) { - unsigned long flags; - spin_lock_irqsave(&filp_count_lock, flags); - files_stat.nr_files--; - spin_unlock_irqrestore(&filp_count_lock, flags); + atomic_dec(&files_stat.nr_files); } static inline void file_free(struct file *f) @@ -70,7 +62,7 @@ /* * Privileged users can go above max_files */ - if (files_stat.nr_files >= files_stat.max_files && + if (atomic_read(&files_stat.nr_files) >= files_stat.max_files && !capable(CAP_SYS_ADMIN)) goto over; @@ -94,10 +86,10 @@ over: /* Ran out of filps - report that */ - if (files_stat.nr_files > old_max) { + if (atomic_read(&files_stat.nr_files) > old_max) { printk(KERN_INFO "VFS: file-max limit %d reached\n", files_stat.max_files); - old_max = files_stat.nr_files; + old_max = atomic_read(&files_stat.nr_files); } goto fail; diff -Nru linux-2.6.13-rc7/fs/xfs/linux-2.6/xfs_linux.h linux-2.6.13-rc7-ed/fs/xfs/linux-2.6/xfs_linux.h --- linux-2.6.13-rc7/fs/xfs/linux-2.6/xfs_linux.h 2005-08-24 05:39:14.000000000 +0200 +++ linux-2.6.13-rc7-ed/fs/xfs/linux-2.6/xfs_linux.h 2005-08-25 10:41:00.000000000 +0200 @@ -242,7 +242,7 @@ /* IRIX uses the current size of the name cache to guess a good value */ /* - this isn't the same but is a good enough starting point for now. */ -#define DQUOT_HASH_HEURISTIC files_stat.nr_files +#define DQUOT_HASH_HEURISTIC atomic_read(&files_stat.nr_files) /* IRIX inodes maintain the project ID also, zero this field on Linux */ #define DEFAULT_PROJID 0 diff -Nru linux-2.6.13-rc7/include/linux/fs.h linux-2.6.13-rc7-ed/include/linux/fs.h --- linux-2.6.13-rc7/include/linux/fs.h 2005-08-24 05:39:14.000000000 +0200 +++ linux-2.6.13-rc7-ed/include/linux/fs.h 2005-08-25 10:41:00.000000000 +0200 @@ -30,7 +30,7 @@ /* And dynamically-tunable limits and defaults: */ struct files_stat_struct { - int nr_files; /* read only */ + atomic_t nr_files; /* read only */ int nr_free_files; /* read only */ int max_files; /* tunable */ }; | |