On Wed, Aug 25, 2010 at 09:12:26AM +1000, Neil Brown wrote:
> Yes.... I think I developed this against 2.6.16 which has different naming
> conventions, and then forward-parted to -current without giving too much
> thought to the names. seconds_since_boot() does sound better.
>
> >
> > Oh, and
> >
> > get_seconds() - monotonic_seconds()
> >
> > isn't the most intuitive way possible to say "boot time in seconds". If
> > you want to fix either of those, fine, otherwise no big deal.)
>
> To be fair, I don't use that exactly. I use
>
> some_monotonic_based_value - monotonic_seconds() + get_seconds()
>
> to turn a monotonic_based value to a wallclock based value.
> This makes sense to me - subtract the base I don't want, and add the base
> that I do.
Sure....
> I guess you could wrap that in convert_to_wallclock and use getboottime
> directly:
>
> static inline time_t convert_to_wallclock(time_t sinceboot)
> {
> struct timespec boot;
> getboottime(&boot);
> return sinceboot + boot.tv_sec;
> }
.... But I think that makes the calculation truly, blindingly obvious.
> Following is only compile tested.
Merged into the previous patch (not pushed out yet pending some
testing). Thanks!
--b.
>
> Thanks,
> NeilBrown
>
> -------
>
> Rename monotonic_seconds to seconds_since_boot
>
> monotonic has a meaning in Linux timekeeping slight different to what we
> use in sunrpc_cache, so change the name.
>
> Also make the conversion from second_since_boot times to wallclock times less
> obscure.
>
> Signed-off-by: NeilBrown <neilb@xxxxxxx>
>
> diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c
> index 3e6aab2..97c03ca 100644
> --- a/fs/nfs/dns_resolve.c
> +++ b/fs/nfs/dns_resolve.c
> @@ -144,7 +144,7 @@ static int nfs_dns_show(struct seq_file *m, struct cache_detail *cd,
> return 0;
> }
> item = container_of(h, struct nfs_dns_ent, h);
> - ttl = item->h.expiry_time - monotonic_seconds();
> + ttl = item->h.expiry_time - seconds_since_boot();
> if (ttl < 0)
> ttl = 0;
>
> @@ -216,7 +216,7 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen)
> ttl = get_expiry(&buf);
> if (ttl == 0)
> goto out;
> - key.h.expiry_time = ttl + monotonic_seconds();
> + key.h.expiry_time = ttl + seconds_since_boot();
>
> ret = -ENOMEM;
> item = nfs_dns_lookup(cd, &key);
> @@ -278,7 +278,7 @@ static int do_cache_lookup_nowait(struct cache_detail *cd,
> goto out_err;
> ret = -ETIMEDOUT;
> if (!test_bit(CACHE_VALID, &(*item)->h.flags)
> - || (*item)->h.expiry_time < monotonic_seconds()
> + || (*item)->h.expiry_time < seconds_since_boot()
> || cd->flush_time > (*item)->h.last_refresh)
> goto out_put;
> ret = -ENOENT;
> diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
> index 6031a90..808b33a 100644
> --- a/fs/nfsd/nfs4idmap.c
> +++ b/fs/nfsd/nfs4idmap.c
> @@ -550,7 +550,7 @@ do_idmap_lookup_nowait(struct ent *(*lookup_fn)(struct ent *),
> goto out_err;
> ret = -ETIMEDOUT;
> if (!test_bit(CACHE_VALID, &(*item)->h.flags)
> - || (*item)->h.expiry_time < monotonic_seconds()
> + || (*item)->h.expiry_time < seconds_since_boot()
> || detail->flush_time > (*item)->h.last_refresh)
> goto out_put;
> ret = -ENOENT;
> diff --git a/include/linux/sunrpc/cache.h b/include/linux/sunrpc/cache.h
> index df7c19b..ece432b 100644
> --- a/include/linux/sunrpc/cache.h
> +++ b/include/linux/sunrpc/cache.h
> @@ -223,13 +223,20 @@ static inline int get_int(char **bpp, int *anint)
> * since boot. This is the best for measuring differences in
> * real time.
> */
> -static inline time_t monotonic_seconds(void)
> +static inline time_t seconds_since_boot(void)
> {
> struct timespec boot;
> getboottime(&boot);
> return get_seconds() - boot.tv_sec;
> }
>
> +static inline time_t convert_to_wallclock(time_t sinceboot)
> +{
> + struct timespec boot;
> + getboottime(&boot);
> + return boot.tv_sec + sinceboot;
> +}
> +
> static inline time_t get_expiry(char **bpp)
> {
> int rv;
> @@ -246,7 +253,7 @@ static inline time_t get_expiry(char **bpp)
> static inline void sunrpc_invalidate(struct cache_head *h,
> struct cache_detail *detail)
> {
> - h->expiry_time = monotonic_seconds() - 1;
> - detail->nextcheck = monotonic_seconds();
> + h->expiry_time = seconds_since_boot() - 1;
> + detail->nextcheck = seconds_since_boot();
> }
> #endif /* _LINUX_SUNRPC_CACHE_H_ */
> diff --git a/net/sunrpc/cache.c b/net/sunrpc/cache.c
> index 99d852e..8dc1219 100644
> --- a/net/sunrpc/cache.c
> +++ b/net/sunrpc/cache.c
> @@ -42,7 +42,7 @@ static void cache_revisit_request(struct cache_head *item);
>
> static void cache_init(struct cache_head *h)
> {
> - time_t now = monotonic_seconds();
> + time_t now = seconds_since_boot();
> h->next = NULL;
> h->flags = 0;
> kref_init(&h->ref);
> @@ -52,7 +52,7 @@ static void cache_init(struct cache_head *h)
>
> static inline int cache_is_expired(struct cache_detail *detail, struct cache_head *h)
> {
> - return (h->expiry_time < monotonic_seconds()) ||
> + return (h->expiry_time < seconds_since_boot()) ||
> (detail->flush_time > h->last_refresh);
> }
>
> @@ -127,7 +127,7 @@ static void cache_dequeue(struct cache_detail *detail, struct cache_head *ch);
> static void cache_fresh_locked(struct cache_head *head, time_t expiry)
> {
> head->expiry_time = expiry;
> - head->last_refresh = monotonic_seconds();
> + head->last_refresh = seconds_since_boot();
> set_bit(CACHE_VALID, &head->flags);
> }
>
> @@ -238,7 +238,7 @@ int cache_check(struct cache_detail *detail,
>
> /* now see if we want to start an upcall */
> refresh_age = (h->expiry_time - h->last_refresh);
> - age = monotonic_seconds() - h->last_refresh;
> + age = seconds_since_boot() - h->last_refresh;
>
> if (rqstp == NULL) {
> if (rv == -EAGAIN)
> @@ -253,7 +253,7 @@ int cache_check(struct cache_detail *detail,
> cache_revisit_request(h);
> if (rv == -EAGAIN) {
> set_bit(CACHE_NEGATIVE, &h->flags);
> - cache_fresh_locked(h, monotonic_seconds()+CACHE_NEW_EXPIRY);
> + cache_fresh_locked(h, seconds_since_boot()+CACHE_NEW_EXPIRY);
> cache_fresh_unlocked(h, detail);
> rv = -ENOENT;
> }
> @@ -388,11 +388,11 @@ static int cache_clean(void)
> return -1;
> }
> current_detail = list_entry(next, struct cache_detail, others);
> - if (current_detail->nextcheck > monotonic_seconds())
> + if (current_detail->nextcheck > seconds_since_boot())
> current_index = current_detail->hash_size;
> else {
> current_index = 0;
> - current_detail->nextcheck = monotonic_seconds()+30*60;
> + current_detail->nextcheck = seconds_since_boot()+30*60;
> }
> }
>
> @@ -477,7 +477,7 @@ EXPORT_SYMBOL_GPL(cache_flush);
> void cache_purge(struct cache_detail *detail)
> {
> detail->flush_time = LONG_MAX;
> - detail->nextcheck = monotonic_seconds();
> + detail->nextcheck = seconds_since_boot();
> cache_flush();
> detail->flush_time = 1;
> }
> @@ -902,7 +902,7 @@ static int cache_release(struct inode *inode, struct file *filp,
> filp->private_data = NULL;
> kfree(rp);
>
> - cd->last_close = monotonic_seconds();
> + cd->last_close = seconds_since_boot();
> atomic_dec(&cd->readers);
> }
> module_put(cd->owner);
> @@ -1034,7 +1034,7 @@ int sunrpc_cache_pipe_upcall(struct cache_detail *detail, struct cache_head *h,
> int len;
>
> if (atomic_read(&detail->readers) == 0 &&
> - detail->last_close < monotonic_seconds() - 30) {
> + detail->last_close < seconds_since_boot() - 30) {
> warn_no_listener(detail);
> return -EINVAL;
> }
> @@ -1219,7 +1219,7 @@ static int c_show(struct seq_file *m, void *p)
>
> ifdebug(CACHE)
> seq_printf(m, "# expiry=%ld refcnt=%d flags=%lx\n",
> - cp->expiry_time - monotonic_seconds() + get_seconds(),
> + convert_to_wallclock(cp->expiry_time),
> atomic_read(&cp->ref.refcount), cp->flags);
> cache_get(cp);
> if (cache_check(cd, cp, NULL))
> @@ -1286,8 +1286,7 @@ static ssize_t read_flush(struct file *file, char __user *buf,
> unsigned long p = *ppos;
> size_t len;
>
> - sprintf(tbuf, "%lu\n", (cd->flush_time - monotonic_seconds()
> - + get_seconds()));
> + sprintf(tbuf, "%lu\n", convert_to_wallclock(cd->flush_time));
> len = strlen(tbuf);
> if (p >= len)
> return 0;
> @@ -1318,7 +1317,7 @@ static ssize_t write_flush(struct file *file, const char __user *buf,
>
> bp = tbuf;
> cd->flush_time = get_expiry(&bp);
> - cd->nextcheck = monotonic_seconds();
> + cd->nextcheck = seconds_since_boot();
> cache_flush();
>
> *ppos += count;
--
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