From 56d40a686b0504042a088943154ba7b0dde36d51 Mon Sep 17 00:00:00 2001 From: Prakash Surya Date: Thu, 12 Sep 2013 16:14:51 -0700 Subject: [PATCH] Add callbacks for displaying KSTAT_TYPE_RAW kstats The current implementation for displaying kstats of type KSTAT_TYPE_RAW is rather crude. This patch attempts to enhance this handling by allowing a kstat user to register formatting callbacks which can optionally be used. The callbacks allow the user to implement functions for interpreting their data and transposing it into a character buffer. This buffer, containing a string representation of the raw data, is then be displayed through the current /proc textual interface. Additionally the kstats are made writable because it's now possible to provide a useful handler via the existing ks_update() interface. Signed-off-by: Prakash Surya Signed-off-by: Brian Behlendorf Issue #296 --- include/sys/kstat.h | 20 ++++++- module/spl/spl-kstat.c | 119 ++++++++++++++++++++++++++++++++++++----- 2 files changed, 123 insertions(+), 16 deletions(-) diff --git a/include/sys/kstat.h b/include/sys/kstat.h index da3c5899db..75b384714c 100644 --- a/include/sys/kstat.h +++ b/include/sys/kstat.h @@ -33,6 +33,7 @@ #include #define KSTAT_STRLEN 31 +#define KSTAT_RAW_MAX (128*1024) /* For reference valid classes are: * disk, tape, net, controller, vm, kvm, hat, streams, kstat, misc @@ -79,6 +80,7 @@ #define KSTAT_WRITE 1 struct kstat_s; +typedef struct kstat_s kstat_t; typedef int kid_t; /* unique kstat id */ typedef int kstat_update_t(struct kstat_s *, int); /* dynamic update cb */ @@ -90,7 +92,13 @@ typedef struct kstat_module { struct proc_dir_entry *ksm_proc; /* proc entry */ } kstat_module_t; -typedef struct kstat_s { +typedef struct kstat_raw_ops { + int (*headers)(char *buf, size_t size); + int (*data)(char *buf, size_t size, void *data); + void *(*addr)(kstat_t *ksp, loff_t index); +} kstat_raw_ops_t; + +struct kstat_s { int ks_magic; /* magic value */ kid_t ks_kid; /* unique kstat ID */ hrtime_t ks_crtime; /* creation time */ @@ -110,7 +118,10 @@ typedef struct kstat_s { kmutex_t ks_lock; /* kstat data lock */ struct list_head ks_list; /* kstat linkage */ kstat_module_t *ks_owner; /* kstat module linkage */ -} kstat_t; + kstat_raw_ops_t ks_raw_ops; /* ops table for raw type */ + char *ks_raw_buf; /* buf used for raw ops */ + size_t ks_raw_bufsize; /* size of raw ops buffer */ +}; typedef struct kstat_named_s { char name[KSTAT_STRLEN]; /* name of counter */ @@ -188,6 +199,10 @@ typedef struct kstat_txg { int spl_kstat_init(void); void spl_kstat_fini(void); +extern void __kstat_set_raw_ops(kstat_t *ksp, + int (*headers)(char *buf, size_t size), + int (*data)(char *buf, size_t size, void *data), + void* (*addr)(kstat_t *ksp, loff_t index)); extern kstat_t *__kstat_create(const char *ks_module, int ks_instance, const char *ks_name, const char *ks_class, uchar_t ks_type, uint_t ks_ndata, @@ -195,6 +210,7 @@ extern kstat_t *__kstat_create(const char *ks_module, int ks_instance, extern void __kstat_install(kstat_t *ksp); extern void __kstat_delete(kstat_t *ksp); +#define kstat_set_raw_ops(k,h,d,a) __kstat_set_raw_ops(k,h,d,a) #define kstat_create(m,i,n,c,t,s,f) __kstat_create(m,i,n,c,t,s,f) #define kstat_install(k) __kstat_install(k) #define kstat_delete(k) __kstat_delete(k) diff --git a/module/spl/spl-kstat.c b/module/spl/spl-kstat.c index 4e900c066a..57aabe2d02 100644 --- a/module/spl/spl-kstat.c +++ b/module/spl/spl-kstat.c @@ -41,10 +41,25 @@ static kmutex_t kstat_module_lock; static struct list_head kstat_module_list; static kid_t kstat_id; -static void +static int +kstat_resize_raw(kstat_t *ksp) +{ + if (ksp->ks_raw_bufsize == KSTAT_RAW_MAX) + return ENOMEM; + + vmem_free(ksp->ks_raw_buf, ksp->ks_raw_bufsize); + ksp->ks_raw_bufsize = MIN(ksp->ks_raw_bufsize * 2, KSTAT_RAW_MAX); + ksp->ks_raw_buf = vmem_alloc(ksp->ks_raw_bufsize, KM_SLEEP); + + return 0; +} + +static int kstat_seq_show_headers(struct seq_file *f) { kstat_t *ksp = (kstat_t *)f->private; + int rc = 0; + ASSERT(ksp->ks_magic == KS_MAGIC); seq_printf(f, "%d %d 0x%02x %d %d %lld %lld\n", @@ -54,7 +69,17 @@ kstat_seq_show_headers(struct seq_file *f) switch (ksp->ks_type) { case KSTAT_TYPE_RAW: - seq_printf(f, "raw data"); +restart: + if (ksp->ks_raw_ops.headers) { + rc = ksp->ks_raw_ops.headers( + ksp->ks_raw_buf, ksp->ks_raw_bufsize); + if (rc == ENOMEM && !kstat_resize_raw(ksp)) + goto restart; + if (!rc) + seq_puts(f, ksp->ks_raw_buf); + } else { + seq_printf(f, "raw data\n"); + } break; case KSTAT_TYPE_NAMED: seq_printf(f, "%-31s %-4s %s\n", @@ -92,6 +117,8 @@ kstat_seq_show_headers(struct seq_file *f) default: PANIC("Undefined kstat type %d\n", ksp->ks_type); } + + return -rc; } static int @@ -232,9 +259,19 @@ kstat_seq_show(struct seq_file *f, void *p) switch (ksp->ks_type) { case KSTAT_TYPE_RAW: - ASSERT(ksp->ks_ndata == 1); - rc = kstat_seq_show_raw(f, ksp->ks_data, - ksp->ks_data_size); +restart: + if (ksp->ks_raw_ops.data) { + rc = ksp->ks_raw_ops.data( + ksp->ks_raw_buf, ksp->ks_raw_bufsize, p); + if (rc == ENOMEM && !kstat_resize_raw(ksp)) + goto restart; + if (!rc) + seq_puts(f, ksp->ks_raw_buf); + } else { + ASSERT(ksp->ks_ndata == 1); + rc = kstat_seq_show_raw(f, ksp->ks_data, + ksp->ks_data_size); + } break; case KSTAT_TYPE_NAMED: rc = kstat_seq_show_named(f, (kstat_named_t *)p); @@ -255,13 +292,17 @@ kstat_seq_show(struct seq_file *f, void *p) PANIC("Undefined kstat type %d\n", ksp->ks_type); } - return rc; + return -rc; } int kstat_default_update(kstat_t *ksp, int rw) { ASSERT(ksp != NULL); + + if (rw == KSTAT_WRITE) + return (EACCES); + return 0; } @@ -273,7 +314,10 @@ kstat_seq_data_addr(kstat_t *ksp, loff_t n) switch (ksp->ks_type) { case KSTAT_TYPE_RAW: - rc = ksp->ks_data; + if (ksp->ks_raw_ops.addr) + rc = ksp->ks_raw_ops.addr(ksp, n); + else + rc = ksp->ks_data; break; case KSTAT_TYPE_NAMED: rc = ksp->ks_data + n * sizeof(kstat_named_t); @@ -307,13 +351,18 @@ kstat_seq_start(struct seq_file *f, loff_t *pos) mutex_enter(&ksp->ks_lock); + if (ksp->ks_type == KSTAT_TYPE_RAW) { + ksp->ks_raw_bufsize = PAGE_SIZE; + ksp->ks_raw_buf = vmem_alloc(ksp->ks_raw_bufsize, KM_SLEEP); + } + /* Dynamically update kstat, on error existing kstats are used */ (void) ksp->ks_update(ksp, KSTAT_READ); ksp->ks_snaptime = gethrtime(); - if (!n) - kstat_seq_show_headers(f); + if (!n && kstat_seq_show_headers(f)) + SRETURN(NULL); if (n >= ksp->ks_ndata) SRETURN(NULL); @@ -341,6 +390,9 @@ kstat_seq_stop(struct seq_file *f, void *v) kstat_t *ksp = (kstat_t *)f->private; ASSERT(ksp->ks_magic == KS_MAGIC); + if (ksp->ks_type == KSTAT_TYPE_RAW) + vmem_free(ksp->ks_raw_buf, ksp->ks_raw_bufsize); + mutex_exit(&ksp->ks_lock); } @@ -408,13 +460,47 @@ proc_kstat_open(struct inode *inode, struct file *filp) return rc; } +static ssize_t +proc_kstat_write(struct file *filp, const char __user *buf, + size_t len, loff_t *ppos) +{ + struct seq_file *f = filp->private_data; + kstat_t *ksp = f->private; + int rc; + + ASSERT(ksp->ks_magic == KS_MAGIC); + + mutex_enter(ksp->ks_lock); + rc = ksp->ks_update(ksp, KSTAT_WRITE); + mutex_exit(ksp->ks_lock); + + if (rc) + return (-rc); + + *ppos += len; + return (len); +} + static struct file_operations proc_kstat_operations = { - .open = proc_kstat_open, - .read = seq_read, - .llseek = seq_lseek, - .release = seq_release, + .open = proc_kstat_open, + .write = proc_kstat_write, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, }; +void +__kstat_set_raw_ops(kstat_t *ksp, + int (*headers)(char *buf, size_t size), + int (*data)(char *buf, size_t size, void *data), + void *(*addr)(kstat_t *ksp, loff_t index)) +{ + ksp->ks_raw_ops.headers = headers; + ksp->ks_raw_ops.data = data; + ksp->ks_raw_ops.addr = addr; +} +EXPORT_SYMBOL(__kstat_set_raw_ops); + kstat_t * __kstat_create(const char *ks_module, int ks_instance, const char *ks_name, const char *ks_class, uchar_t ks_type, uint_t ks_ndata, @@ -453,6 +539,11 @@ __kstat_create(const char *ks_module, int ks_instance, const char *ks_name, ksp->ks_flags = ks_flags; ksp->ks_update = kstat_default_update; ksp->ks_private = NULL; + ksp->ks_raw_ops.headers = NULL; + ksp->ks_raw_ops.data = NULL; + ksp->ks_raw_ops.addr = NULL; + ksp->ks_raw_buf = NULL; + ksp->ks_raw_bufsize = 0; switch (ksp->ks_type) { case KSTAT_TYPE_RAW: @@ -526,7 +617,7 @@ __kstat_install(kstat_t *ksp) mutex_enter(&ksp->ks_lock); ksp->ks_owner = module; - ksp->ks_proc = proc_create_data(ksp->ks_name, 0444, + ksp->ks_proc = proc_create_data(ksp->ks_name, 0644, module->ksm_proc, &proc_kstat_operations, (void *)ksp); if (ksp->ks_proc == NULL) { list_del_init(&ksp->ks_list);