| Message ID | 20201026091316.25680-12-jgross@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | xen: support per-cpupool scheduling granularity | expand |
On Mon, 2020-10-26 at 10:13 +0100, Juergen Gross wrote: > Add a "sched-gran" entry to the per-cpupool hypfs directories. > > For now make this entry read-only and let it contain one of the > strings "cpu", "core" or "socket". > > Signed-off-by: Juergen Gross <jgross@suse.com> > Acked-by: Dario Faggioli <dfaggioli@suse.com> Regards
On 26.10.2020 10:13, Juergen Gross wrote: > @@ -1057,6 +1063,43 @@ static struct hypfs_entry *cpupool_dir_findentry(struct hypfs_entry_dir *dir, > return hypfs_gen_dyndir_entry_id(&cpupool_pooldir, id); > } > > +static int cpupool_gran_read(const struct hypfs_entry *entry, > + XEN_GUEST_HANDLE_PARAM(void) uaddr) > +{ > + const struct hypfs_dyndir_id *data; > + struct cpupool *cpupool; const? > + const char *name = ""; > + > + data = hypfs_get_dyndata(); > + if ( !data ) > + return -ENOENT; > + > + spin_lock(&cpupool_lock); > + > + cpupool = __cpupool_find_by_id(data->id, true); > + if ( cpupool ) > + name = sched_gran_get_name(cpupool->gran); > + > + spin_unlock(&cpupool_lock); > + > + if ( !cpupool ) May I suggest to check !*name here, to avoid giving the impression of ... > + return -ENOENT; > + > + return copy_to_guest(uaddr, name, strlen(name) + 1) ? -EFAULT : 0; ... success (but an empty name) in this admittedly unlikely event? Jan
On 17.11.20 17:49, Jan Beulich wrote: > On 26.10.2020 10:13, Juergen Gross wrote: >> @@ -1057,6 +1063,43 @@ static struct hypfs_entry *cpupool_dir_findentry(struct hypfs_entry_dir *dir, >> return hypfs_gen_dyndir_entry_id(&cpupool_pooldir, id); >> } >> >> +static int cpupool_gran_read(const struct hypfs_entry *entry, >> + XEN_GUEST_HANDLE_PARAM(void) uaddr) >> +{ >> + const struct hypfs_dyndir_id *data; >> + struct cpupool *cpupool; > > const? Yes. > >> + const char *name = ""; >> + >> + data = hypfs_get_dyndata(); >> + if ( !data ) >> + return -ENOENT; >> + >> + spin_lock(&cpupool_lock); >> + >> + cpupool = __cpupool_find_by_id(data->id, true); >> + if ( cpupool ) >> + name = sched_gran_get_name(cpupool->gran); >> + >> + spin_unlock(&cpupool_lock); >> + >> + if ( !cpupool ) > > May I suggest to check !*name here, to avoid giving the impression > of ... > >> + return -ENOENT; >> + >> + return copy_to_guest(uaddr, name, strlen(name) + 1) ? -EFAULT : 0; > > ... success (but an empty name) in this admittedly unlikely event? Fine with me. Juergen
diff --git a/docs/misc/hypfs-paths.pandoc b/docs/misc/hypfs-paths.pandoc index aaca1cdf92..f1ce24d7fe 100644 --- a/docs/misc/hypfs-paths.pandoc +++ b/docs/misc/hypfs-paths.pandoc @@ -184,6 +184,10 @@ A directory of all current cpupools. The individual cpupools. Each entry is a directory with the name being the cpupool-id (e.g. /cpupool/0/). +#### /cpupool/*/sched-gran = ("cpu" | "core" | "socket") + +The scheduling granularity of a cpupool. + #### /params/ A directory of runtime parameters. diff --git a/xen/common/sched/cpupool.c b/xen/common/sched/cpupool.c index 8612ee5cf6..8674ac0fdd 100644 --- a/xen/common/sched/cpupool.c +++ b/xen/common/sched/cpupool.c @@ -42,9 +42,10 @@ static DEFINE_SPINLOCK(cpupool_lock); static enum sched_gran __read_mostly opt_sched_granularity = SCHED_GRAN_cpu; static unsigned int __read_mostly sched_granularity = 1; +#define SCHED_GRAN_NAME_LEN 8 struct sched_gran_name { enum sched_gran mode; - char name[8]; + char name[SCHED_GRAN_NAME_LEN]; }; static const struct sched_gran_name sg_name[] = { @@ -53,7 +54,7 @@ static const struct sched_gran_name sg_name[] = { {SCHED_GRAN_socket, "socket"}, }; -static void sched_gran_print(enum sched_gran mode, unsigned int gran) +static const char *sched_gran_get_name(enum sched_gran mode) { const char *name = ""; unsigned int i; @@ -67,8 +68,13 @@ static void sched_gran_print(enum sched_gran mode, unsigned int gran) } } + return name; +} + +static void sched_gran_print(enum sched_gran mode, unsigned int gran) +{ printk("Scheduling granularity: %s, %u CPU%s per sched-resource\n", - name, gran, gran == 1 ? "" : "s"); + sched_gran_get_name(mode), gran, gran == 1 ? "" : "s"); } #ifdef CONFIG_HAS_SCHED_GRANULARITY @@ -1057,6 +1063,43 @@ static struct hypfs_entry *cpupool_dir_findentry(struct hypfs_entry_dir *dir, return hypfs_gen_dyndir_entry_id(&cpupool_pooldir, id); } +static int cpupool_gran_read(const struct hypfs_entry *entry, + XEN_GUEST_HANDLE_PARAM(void) uaddr) +{ + const struct hypfs_dyndir_id *data; + struct cpupool *cpupool; + const char *name = ""; + + data = hypfs_get_dyndata(); + if ( !data ) + return -ENOENT; + + spin_lock(&cpupool_lock); + + cpupool = __cpupool_find_by_id(data->id, true); + if ( cpupool ) + name = sched_gran_get_name(cpupool->gran); + + spin_unlock(&cpupool_lock); + + if ( !cpupool ) + return -ENOENT; + + return copy_to_guest(uaddr, name, strlen(name) + 1) ? -EFAULT : 0; +} + +static struct hypfs_funcs cpupool_gran_funcs = { + .read = cpupool_gran_read, + .getsize = hypfs_getsize, +}; + +static HYPFS_VARSIZE_INIT(cpupool_gran, XEN_HYPFS_TYPE_STRING, "sched-gran", + 0, &cpupool_gran_funcs); +static char granstr[SCHED_GRAN_NAME_LEN] = { + [0 ... SCHED_GRAN_NAME_LEN - 2] = '?', + [SCHED_GRAN_NAME_LEN - 1] = 0 +}; + static struct hypfs_funcs cpupool_dir_funcs = { .read = cpupool_dir_read, .getsize = cpupool_dir_getsize, @@ -1075,6 +1118,8 @@ static int __init cpupool_init(void) #ifdef CONFIG_HYPFS hypfs_add_dir(&hypfs_root, &cpupool_dir, true); + hypfs_string_set_reference(&cpupool_gran, granstr); + hypfs_add_leaf(&cpupool_pooldir, &cpupool_gran, true); #endif cpupool0 = cpupool_create(0, 0, &err);
Add a "sched-gran" entry to the per-cpupool hypfs directories. For now make this entry read-only and let it contain one of the strings "cpu", "core" or "socket". Signed-off-by: Juergen Gross <jgross@suse.com> --- docs/misc/hypfs-paths.pandoc | 4 +++ xen/common/sched/cpupool.c | 51 +++++++++++++++++++++++++++++++++--- 2 files changed, 52 insertions(+), 3 deletions(-)