diff options
| -rw-r--r-- | runtime/ChangeLog | 13 | ||||
| -rw-r--r-- | runtime/task_finder.c | 2 | ||||
| -rw-r--r-- | runtime/task_finder_vma.c | 69 |
3 files changed, 80 insertions, 4 deletions
diff --git a/runtime/ChangeLog b/runtime/ChangeLog index a05abb5c..f12b5d9a 100644 --- a/runtime/ChangeLog +++ b/runtime/ChangeLog @@ -1,3 +1,16 @@ +2008-07-21 David Smith <dsmith@redhat.com> + + * task_finder_vma.c (__stp_tf_vma_initialize): New function to + initialize the free list. + (__stp_tf_vma_put_free_entry): Puts a vma entry back on the free + list. + (__stp_tf_add_vma): Instead of allocating a vma entry, grab one + from the free list by calling __stp_tf_vma_put_free_entry(). + (__stp_tf_remove_vma_entry): Instead of freeing a vma entry, call + __stp_tf_vma_put_free_entry() to put it on the free list instead. + * task_finder.c (stap_start_task_finder): Calls + __stp_tf_vma_initialize(). + 2008-07-18 Frank Ch. Eigler <fche@elastic.org> BZ 442528, From Masami Hiramatsu <mhiramat@redhat.com> diff --git a/runtime/task_finder.c b/runtime/task_finder.c index fc573eb6..b22a60a8 100644 --- a/runtime/task_finder.c +++ b/runtime/task_finder.c @@ -921,6 +921,8 @@ stap_start_task_finder(void) return ENOMEM; } + __stp_tf_vma_initialize(); + atomic_set(&__stp_task_finder_state, __STP_TF_RUNNING); rcu_read_lock(); diff --git a/runtime/task_finder_vma.c b/runtime/task_finder_vma.c index 76b5c059..c0a018ab 100644 --- a/runtime/task_finder_vma.c +++ b/runtime/task_finder_vma.c @@ -2,12 +2,20 @@ #include <linux/jhash.h> #include <linux/mutex.h> +// When handling memcpy() syscall tracing to notice memory map +// changes, we need to cache memcpy() entry parameter values for +// processing at memcpy() exit. + // __stp_tf_vma_mutex protects the hash table. static DEFINE_MUTEX(__stp_tf_vma_mutex); #define __STP_TF_HASH_BITS 4 #define __STP_TF_TABLE_SIZE (1 << __STP_TF_HASH_BITS) +#ifndef TASK_FINDER_VMA_ENTRY_ITEMS +#define TASK_FINDER_VMA_ENTRY_ITEMS 100 +#endif + struct __stp_tf_vma_entry { struct hlist_node hlist; @@ -19,8 +27,62 @@ struct __stp_tf_vma_entry { // Is that enough? Should we store a dcookie for vm_file? }; +static struct __stp_tf_vma_entry +__stp_tf_vma_free_list_items[TASK_FINDER_VMA_ENTRY_ITEMS]; + +static struct hlist_head __stp_tf_vma_free_list[1]; + static struct hlist_head __stp_tf_vma_table[__STP_TF_TABLE_SIZE]; +// __stp_tf_vma_initialize(): Initialize the free list. Grabs the +// mutex. +static void +__stp_tf_vma_initialize(void) +{ + int i; + struct hlist_head *head = &__stp_tf_vma_free_list[0]; + + mutex_lock(&__stp_tf_vma_mutex); + for (i = 0; i < TASK_FINDER_VMA_ENTRY_ITEMS; i++) { + hlist_add_head(&__stp_tf_vma_free_list_items[i].hlist, head); + } + mutex_unlock(&__stp_tf_vma_mutex); +} + + +// __stp_tf_vma_get_free_entry(): Returns an entry from the free list +// or NULL. The __stp_tf_vma_mutex must be locked before calling this +// function. +static struct __stp_tf_vma_entry * +__stp_tf_vma_get_free_entry(void) +{ + struct hlist_head *head = &__stp_tf_vma_free_list[0]; + struct hlist_node *node; + struct __stp_tf_vma_entry *entry; + + if (hlist_empty(head)) + return NULL; + hlist_for_each_entry(entry, node, head, hlist) { + break; + } + if (entry != NULL) + hlist_del(&entry->hlist); + return entry; +} + + +// __stp_tf_vma_put_free_entry(): Puts an entry back on the free +// list. The __stp_tf_vma_mutex must be locked before calling this +// function. +static void +__stp_tf_vma_put_free_entry(struct __stp_tf_vma_entry *entry) +{ + struct hlist_head *head = &__stp_tf_vma_free_list[0]; + hlist_add_head(&entry->hlist, head); +} + + +// __stp_tf_vma_hash(): Compute the vma hash. static inline u32 __stp_tf_vma_hash(struct task_struct *tsk, unsigned long addr) { @@ -77,9 +139,8 @@ __stp_tf_add_vma(struct task_struct *tsk, unsigned long addr, } } - // Using kmalloc here to allocate an element. Could cause some - // memory fragmentation if overused. - entry = kmalloc(sizeof(struct __stp_tf_vma_entry), GFP_KERNEL); + // Get an element from the free list. + entry = __stp_tf_vma_get_free_entry(); if (!entry) { mutex_unlock(&__stp_tf_vma_mutex); return -ENOMEM; @@ -105,7 +166,7 @@ __stp_tf_remove_vma_entry(struct __stp_tf_vma_entry *entry) if (entry != NULL) { mutex_lock(&__stp_tf_vma_mutex); hlist_del(&entry->hlist); - kfree(entry); + __stp_tf_vma_put_free_entry(entry); mutex_unlock(&__stp_tf_vma_mutex); } return 0; |