diff options
| author | Punit Agrawal <punit.agrawal@bytedance.com> | 2022-09-07 16:57:46 +0100 |
|---|---|---|
| committer | Alexei Starovoitov <ast@kernel.org> | 2022-09-10 16:18:55 -0700 |
| commit | 57c92f11a215717bf90880828b7a23c736c3c0d9 (patch) | |
| tree | 68fb30e8a2deb915d17dfd8e53fd364de500e5b8 /kernel/bpf | |
| parent | cf7de6a53600ea554a8358e44fbcf47b449235f9 (diff) | |
bpf: Simplify code by using for_each_cpu_wrap()
In the percpu freelist code, it is a common pattern to iterate over
the possible CPUs mask starting with the current CPU. The pattern is
implemented using a hand rolled while loop with the loop variable
increment being open-coded.
Simplify the code by using for_each_cpu_wrap() helper to iterate over
the possible cpus starting with the current CPU. As a result, some of
the special-casing in the loop also gets simplified.
No functional change intended.
Signed-off-by: Punit Agrawal <punit.agrawal@bytedance.com>
Acked-by: Song Liu <song@kernel.org>
Link: https://lore.kernel.org/r/20220907155746.1750329-1-punit.agrawal@bytedance.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/percpu_freelist.c | 48 |
1 files changed, 16 insertions, 32 deletions
diff --git a/kernel/bpf/percpu_freelist.c b/kernel/bpf/percpu_freelist.c index 00b874c8e889..b6e7f5c5b9ab 100644 --- a/kernel/bpf/percpu_freelist.c +++ b/kernel/bpf/percpu_freelist.c @@ -58,23 +58,21 @@ static inline void ___pcpu_freelist_push_nmi(struct pcpu_freelist *s, { int cpu, orig_cpu; - orig_cpu = cpu = raw_smp_processor_id(); + orig_cpu = raw_smp_processor_id(); while (1) { - struct pcpu_freelist_head *head; + for_each_cpu_wrap(cpu, cpu_possible_mask, orig_cpu) { + struct pcpu_freelist_head *head; - head = per_cpu_ptr(s->freelist, cpu); - if (raw_spin_trylock(&head->lock)) { - pcpu_freelist_push_node(head, node); - raw_spin_unlock(&head->lock); - return; + head = per_cpu_ptr(s->freelist, cpu); + if (raw_spin_trylock(&head->lock)) { + pcpu_freelist_push_node(head, node); + raw_spin_unlock(&head->lock); + return; + } } - cpu = cpumask_next(cpu, cpu_possible_mask); - if (cpu >= nr_cpu_ids) - cpu = 0; /* cannot lock any per cpu lock, try extralist */ - if (cpu == orig_cpu && - pcpu_freelist_try_push_extra(s, node)) + if (pcpu_freelist_try_push_extra(s, node)) return; } } @@ -125,13 +123,12 @@ static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s) { struct pcpu_freelist_head *head; struct pcpu_freelist_node *node; - int orig_cpu, cpu; + int cpu; - orig_cpu = cpu = raw_smp_processor_id(); - while (1) { + for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) { head = per_cpu_ptr(s->freelist, cpu); if (!READ_ONCE(head->first)) - goto next_cpu; + continue; raw_spin_lock(&head->lock); node = head->first; if (node) { @@ -140,12 +137,6 @@ static struct pcpu_freelist_node *___pcpu_freelist_pop(struct pcpu_freelist *s) return node; } raw_spin_unlock(&head->lock); -next_cpu: - cpu = cpumask_next(cpu, cpu_possible_mask); - if (cpu >= nr_cpu_ids) - cpu = 0; - if (cpu == orig_cpu) - break; } /* per cpu lists are all empty, try extralist */ @@ -164,13 +155,12 @@ ___pcpu_freelist_pop_nmi(struct pcpu_freelist *s) { struct pcpu_freelist_head *head; struct pcpu_freelist_node *node; - int orig_cpu, cpu; + int cpu; - orig_cpu = cpu = raw_smp_processor_id(); - while (1) { + for_each_cpu_wrap(cpu, cpu_possible_mask, raw_smp_processor_id()) { head = per_cpu_ptr(s->freelist, cpu); if (!READ_ONCE(head->first)) - goto next_cpu; + continue; if (raw_spin_trylock(&head->lock)) { node = head->first; if (node) { @@ -180,12 +170,6 @@ ___pcpu_freelist_pop_nmi(struct pcpu_freelist *s) } raw_spin_unlock(&head->lock); } -next_cpu: - cpu = cpumask_next(cpu, cpu_possible_mask); - if (cpu >= nr_cpu_ids) - cpu = 0; - if (cpu == orig_cpu) - break; } /* cannot pop from per cpu lists, try extralist */ |