Re: [PATCH 13/13] bcachefs: Remove heap-related macros and switch to generic min_heap

Kuan-Wei Chiu
2024-03-20T02:55:10Z

On Tue, Mar 19, 2024 at 01:03:17PM -0700, Ian Rogers wrote:
> On Tue, Mar 19, 2024 at 11:01 AM Kuan-Wei Chiu <visitorckw@gmail.com> wrote:
> >
> > Drop the heap-related macros from bcachefs and replaces them with the
> > generic min_heap implementation from include/linux. This change
> > improves code readability by using functions instead of macros.
> >
> > Link: https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu
> > Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
> > ---
> > fs/bcachefs/clock.c | 53 +++++++++++-----
> > fs/bcachefs/clock_types.h | 2 +-
> > fs/bcachefs/ec.c | 99 ++++++++++++++++++-----------
> > fs/bcachefs/ec_types.h | 2 +-
> > fs/bcachefs/util.h | 127 +++-----------------------------------
> > 5 files changed, 109 insertions(+), 174 deletions(-)
> >
> > diff --git a/fs/bcachefs/clock.c b/fs/bcachefs/clock.c
> > index 363644451106..7a7d13f7a629 100644
> > --- a/fs/bcachefs/clock.c
> > +++ b/fs/bcachefs/clock.c
> > @@ -6,16 +6,29 @@
> > #include <linux/kthread.h>
> > #include <linux/preempt.h>
> >
> > -static inline long io_timer_cmp(io_timer_heap *h,
> > - struct io_timer *l,
> > - struct io_timer *r)
> > +static inline bool io_timer_cmp(const void *l, const void *r, void *args)
>
> Should args here and below be marked with the attribute __always_unused?
>

Thank you for bringing this to my attention.
Yes, I will add the __always_unused to the args in v2.

Regards,
Kuan-Wei

>
> > {
> > - return l->expire - r->expire;
> > + struct io_timer *_l = (struct io_timer *)l;
> > + struct io_timer *_r = (struct io_timer *)r;
> > +
> > + return _l->expire >= _r->expire;
> > +}
> > +
> > +static inline void io_timer_swp(void *l, void *r, void *args)
> > +{
> > + struct io_timer *_l = (struct io_timer *)l;
> > + struct io_timer *_r = (struct io_timer *)r;
> > +
> > + swap(*_l, *_r);
> > }
> >
> > void bch2_io_timer_add(struct io_clock *clock, struct io_timer *timer)
> > {
> > size_t i;
> > + const struct min_heap_callbacks callbacks = {
> > + .less = io_timer_cmp,
> > + .swp = io_timer_swp,
> > + };
> >
> > spin_lock(&clock->timer_lock);
> >
> > @@ -26,11 +39,11 @@ void bch2_io_timer_add(struct io_clock *clock, struct io_timer *timer)
> > return;
> > }
> >
> > - for (i = 0; i < clock->timers.used; i++)
> > - if (clock->timers.data[i] == timer)
> > + for (i = 0; i < clock->timers.heap.nr; i++)
> > + if (min_heap_peek(&clock->timers)[i] == timer)
> > goto out;
> >
> > - BUG_ON(!heap_add(&clock->timers, timer, io_timer_cmp, NULL));
> > + BUG_ON(!min_heap_push(&clock->timers, &timer, &callbacks, NULL));
> > out:
> > spin_unlock(&clock->timer_lock);
> > }
> > @@ -38,12 +51,16 @@ void bch2_io_timer_add(struct io_clock *clock, struct io_timer *timer)
> > void bch2_io_timer_del(struct io_clock *clock, struct io_timer *timer)
> > {
> > size_t i;
> > + const struct min_heap_callbacks callbacks = {
> > + .less = io_timer_cmp,
> > + .swp = io_timer_swp,
> > + };
> >
> > spin_lock(&clock->timer_lock);
> >
> > - for (i = 0; i < clock->timers.used; i++)
> > - if (clock->timers.data[i] == timer) {
> > - heap_del(&clock->timers, i, io_timer_cmp, NULL);
> > + for (i = 0; i < clock->timers.heap.nr; i++)
> > + if (min_heap_peek(&clock->timers)[i] == timer) {
> > + min_heap_pop(&clock->timers, &callbacks, NULL);
> > break;
> > }
> >
> > @@ -131,12 +148,16 @@ static struct io_timer *get_expired_timer(struct io_clock *clock,
> > unsigned long now)
> > {
> > struct io_timer *ret = NULL;
> > + const struct min_heap_callbacks callbacks = {
> > + .less = io_timer_cmp,
> > + .swp = io_timer_swp,
> > + };
> >
> > spin_lock(&clock->timer_lock);
> >
> > - if (clock->timers.used &&
> > - time_after_eq(now, clock->timers.data[0]->expire))
> > - heap_pop(&clock->timers, ret, io_timer_cmp, NULL);
> > + if (clock->timers.heap.nr &&
> > + time_after_eq(now, min_heap_peek(&clock->timers)[0]->expire))
> > + min_heap_pop(&clock->timers, &callbacks, NULL);
> >
> > spin_unlock(&clock->timer_lock);
> >
> > @@ -161,10 +182,10 @@ void bch2_io_timers_to_text(struct printbuf *out, struct io_clock *clock)
> > spin_lock(&clock->timer_lock);
> > now = atomic64_read(&clock->now);
> >
> > - for (i = 0; i < clock->timers.used; i++)
> > + for (i = 0; i < clock->timers.heap.nr; i++)
> > prt_printf(out, "%ps:\t%li\n",
> > - clock->timers.data[i]->fn,
> > - clock->timers.data[i]->expire - now);
> > + min_heap_peek(&clock->timers)[i]->fn,
> > + min_heap_peek(&clock->timers)[i]->expire - now);
> > spin_unlock(&clock->timer_lock);
> > --out->atomic;
> > }
> > diff --git a/fs/bcachefs/clock_types.h b/fs/bcachefs/clock_types.h
> > index 5fae0012d808..b02b24b9d74f 100644
> > --- a/fs/bcachefs/clock_types.h
> > +++ b/fs/bcachefs/clock_types.h
> > @@ -23,7 +23,7 @@ struct io_timer {
> > /* Amount to buffer up on a percpu counter */
> > #define IO_CLOCK_PCPU_SECTORS 128
> >
> > -typedef HEAP(struct io_timer *) io_timer_heap;
> > +typedef MIN_HEAP(struct io_timer *, io_timer_heap) io_timer_heap;
> >
> > struct io_clock {
> > atomic64_t now;
> > diff --git a/fs/bcachefs/ec.c b/fs/bcachefs/ec.c
> > index b98e2c2b8bf0..7b6a31237503 100644
> > --- a/fs/bcachefs/ec.c
> > +++ b/fs/bcachefs/ec.c
> > @@ -860,14 +860,14 @@ static int __ec_stripe_mem_alloc(struct bch_fs *c, size_t idx, gfp_t gfp)
> > {
> > ec_stripes_heap n, *h = &c->ec_stripes_heap;
> >
> > - if (idx >= h->size) {
> > + if (idx >= h->heap.size) {
> > if (!init_heap(&n, max(1024UL, roundup_pow_of_two(idx + 1)), gfp))
> > return -BCH_ERR_ENOMEM_ec_stripe_mem_alloc;
> >
> > mutex_lock(&c->ec_stripes_heap_lock);
> > - if (n.size > h->size) {
> > - memcpy(n.data, h->data, h->used * sizeof(h->data[0]));
> > - n.used = h->used;
> > + if (n.heap.size > h->heap.size) {
> > + memcpy(min_heap_peek(&n), min_heap_peek(h), h->heap.nr * sizeof(*min_heap_peek(h)));
> > + n.heap.nr = h->heap.nr;
> > swap(*h, n);
> > }
> > mutex_unlock(&c->ec_stripes_heap_lock);
> > @@ -958,20 +958,21 @@ static u64 stripe_idx_to_delete(struct bch_fs *c)
> >
> > lockdep_assert_held(&c->ec_stripes_heap_lock);
> >
> > - if (h->used &&
> > - h->data[0].blocks_nonempty == 0 &&
> > - !bch2_stripe_is_open(c, h->data[0].idx))
> > - return h->data[0].idx;
> > + if (h->heap.nr &&
> > + min_heap_peek(h)->blocks_nonempty == 0 &&
> > + !bch2_stripe_is_open(c, min_heap_peek(h)->idx))
> > + return min_heap_peek(h)->idx;
> >
> > return 0;
> > }
> >
> > -static inline int ec_stripes_heap_cmp(ec_stripes_heap *h,
> > - struct ec_stripe_heap_entry l,
> > - struct ec_stripe_heap_entry r)
> > +static inline bool ec_stripes_heap_cmp(const void *l, const void *r, void *args)
> > {
> > - return ((l.blocks_nonempty > r.blocks_nonempty) -
> > - (l.blocks_nonempty < r.blocks_nonempty));
> > + struct ec_stripe_heap_entry *_l = (struct ec_stripe_heap_entry *)l;
> > + struct ec_stripe_heap_entry *_r = (struct ec_stripe_heap_entry *)r;
> > +
> > + return ((_l->blocks_nonempty > _r->blocks_nonempty) >=
> > + (_l->blocks_nonempty < _r->blocks_nonempty));
> > }
> >
> > static inline void ec_stripes_heap_set_backpointer(ec_stripes_heap *h,
> > @@ -979,7 +980,21 @@ static inline void ec_stripes_heap_set_backpointer(ec_stripes_heap *h,
> > {
> > struct bch_fs *c = container_of(h, struct bch_fs, ec_stripes_heap);
> >
> > - genradix_ptr(&c->stripes, h->data[i].idx)->heap_idx = i;
> > + genradix_ptr(&c->stripes, min_heap_peek(h)[i].idx)->heap_idx = i;
> > +}
> > +
> > +static inline void ec_stripes_heap_swap(void *l, void *r, void *h)
> > +{
> > + struct ec_stripe_heap_entry *_l = (struct ec_stripe_heap_entry *)l;
> > + struct ec_stripe_heap_entry *_r = (struct ec_stripe_heap_entry *)r;
> > + ec_stripes_heap *_h = (ec_stripes_heap *)h;
> > + size_t i = _l - min_heap_peek(_h);
> > + size_t j = _r - min_heap_peek(_h);
> > +
> > + ec_stripes_heap_set_backpointer(_h, i);
> > + ec_stripes_heap_set_backpointer(_h, j);
> > +
> > + swap(*_l, *_r);
> > }
> >
> > static void heap_verify_backpointer(struct bch_fs *c, size_t idx)
> > @@ -987,34 +1002,43 @@ static void heap_verify_backpointer(struct bch_fs *c, size_t idx)
> > ec_stripes_heap *h = &c->ec_stripes_heap;
> > struct stripe *m = genradix_ptr(&c->stripes, idx);
> >
> > - BUG_ON(m->heap_idx >= h->used);
> > - BUG_ON(h->data[m->heap_idx].idx != idx);
> > + BUG_ON(m->heap_idx >= h->heap.nr);
> > + BUG_ON(min_heap_peek(h)[m->heap_idx].idx != idx);
> > }
> >
> > void bch2_stripes_heap_del(struct bch_fs *c,
> > struct stripe *m, size_t idx)
> > {
> > + const struct min_heap_callbacks callbacks = {
> > + .less = ec_stripes_heap_cmp,
> > + .swp = ec_stripes_heap_swap,
> > + };
> > +
> > mutex_lock(&c->ec_stripes_heap_lock);
> > heap_verify_backpointer(c, idx);
> >
> > - heap_del(&c->ec_stripes_heap, m->heap_idx,
> > - ec_stripes_heap_cmp,
> > - ec_stripes_heap_set_backpointer);
> > + min_heap_del(&c->ec_stripes_heap, m->heap_idx, &callbacks, &c->ec_stripes_heap);
> > mutex_unlock(&c->ec_stripes_heap_lock);
> > }
> >
> > void bch2_stripes_heap_insert(struct bch_fs *c,
> > struct stripe *m, size_t idx)
> > {
> > + const struct min_heap_callbacks callbacks = {
> > + .less = ec_stripes_heap_cmp,
> > + .swp = ec_stripes_heap_swap,
> > + };
> > +
> > mutex_lock(&c->ec_stripes_heap_lock);
> > - BUG_ON(heap_full(&c->ec_stripes_heap));
> > + BUG_ON(min_heap_full(&c->ec_stripes_heap));
> >
> > - heap_add(&c->ec_stripes_heap, ((struct ec_stripe_heap_entry) {
> > + genradix_ptr(&c->stripes, idx)->heap_idx = c->ec_stripes_heap.heap.nr;
> > + min_heap_push(&c->ec_stripes_heap, &((struct ec_stripe_heap_entry) {
> > .idx = idx,
> > .blocks_nonempty = m->blocks_nonempty,
> > }),
> > - ec_stripes_heap_cmp,
> > - ec_stripes_heap_set_backpointer);
> > + &callbacks,
> > + &c->ec_stripes_heap);
> >
> > heap_verify_backpointer(c, idx);
> > mutex_unlock(&c->ec_stripes_heap_lock);
> > @@ -1026,17 +1050,20 @@ void bch2_stripes_heap_update(struct bch_fs *c,
> > ec_stripes_heap *h = &c->ec_stripes_heap;
> > bool do_deletes;
> > size_t i;
> > + const struct min_heap_callbacks callbacks = {
> > + .less = ec_stripes_heap_cmp,
> > + .swp = ec_stripes_heap_swap,
> > + };
> >
> > mutex_lock(&c->ec_stripes_heap_lock);
> > heap_verify_backpointer(c, idx);
> >
> > - h->data[m->heap_idx].blocks_nonempty = m->blocks_nonempty;
> > + min_heap_peek(h)[m->heap_idx].blocks_nonempty = m->blocks_nonempty;
> >
> > i = m->heap_idx;
> > - heap_sift_up(h, i, ec_stripes_heap_cmp,
> > - ec_stripes_heap_set_backpointer);
> > - heap_sift_down(h, i, ec_stripes_heap_cmp,
> > - ec_stripes_heap_set_backpointer);
> > +
> > + min_heap_sift_up(h, i, &callbacks, &c->ec_stripes_heap);
> > + min_heapify(h, i, &callbacks, &c->ec_stripes_heap);
> >
> > heap_verify_backpointer(c, idx);
> >
> > @@ -1828,12 +1855,12 @@ static s64 get_existing_stripe(struct bch_fs *c,
> > return -1;
> >
> > mutex_lock(&c->ec_stripes_heap_lock);
> > - for (heap_idx = 0; heap_idx < h->used; heap_idx++) {
> > + for (heap_idx = 0; heap_idx < h->heap.nr; heap_idx++) {
> > /* No blocks worth reusing, stripe will just be deleted: */
> > - if (!h->data[heap_idx].blocks_nonempty)
> > + if (!min_heap_peek(h)[heap_idx].blocks_nonempty)
> > continue;
> >
> > - stripe_idx = h->data[heap_idx].idx;
> > + stripe_idx = min_heap_peek(h)[heap_idx].idx;
> >
> > m = genradix_ptr(&c->stripes, stripe_idx);
> >
> > @@ -2159,14 +2186,14 @@ void bch2_stripes_heap_to_text(struct printbuf *out, struct bch_fs *c)
> > size_t i;
> >
> > mutex_lock(&c->ec_stripes_heap_lock);
> > - for (i = 0; i < min_t(size_t, h->used, 50); i++) {
> > - m = genradix_ptr(&c->stripes, h->data[i].idx);
> > + for (i = 0; i < min_t(size_t, h->heap.nr, 50); i++) {
> > + m = genradix_ptr(&c->stripes, min_heap_peek(h)[i].idx);
> >
> > - prt_printf(out, "%zu %u/%u+%u", h->data[i].idx,
> > - h->data[i].blocks_nonempty,
> > + prt_printf(out, "%zu %u/%u+%u", min_heap_peek(h)[i].idx,
> > + min_heap_peek(h)[i].blocks_nonempty,
> > m->nr_blocks - m->nr_redundant,
> > m->nr_redundant);
> > - if (bch2_stripe_is_open(c, h->data[i].idx))
> > + if (bch2_stripe_is_open(c, min_heap_peek(h)[i].idx))
> > prt_str(out, " open");
> > prt_newline(out);
> > }
> > diff --git a/fs/bcachefs/ec_types.h b/fs/bcachefs/ec_types.h
> > index 976426da3a12..2ed67431a81c 100644
> > --- a/fs/bcachefs/ec_types.h
> > +++ b/fs/bcachefs/ec_types.h
> > @@ -36,6 +36,6 @@ struct ec_stripe_heap_entry {
> > unsigned blocks_nonempty;
> > };
> >
> > -typedef HEAP(struct ec_stripe_heap_entry) ec_stripes_heap;
> > +typedef MIN_HEAP(struct ec_stripe_heap_entry, ec_stripes_heap) ec_stripes_heap;
> >
> > #endif /* _BCACHEFS_EC_TYPES_H */
> > diff --git a/fs/bcachefs/util.h b/fs/bcachefs/util.h
> > index 7ffbddb80400..c599dc5276ac 100644
> > --- a/fs/bcachefs/util.h
> > +++ b/fs/bcachefs/util.h
> > @@ -8,6 +8,7 @@
> > #include <linux/errno.h>
> > #include <linux/freezer.h>
> > #include <linux/kernel.h>
> > +#include <linux/min_heap.h>
> > #include <linux/sched/clock.h>
> > #include <linux/llist.h>
> > #include <linux/log2.h>
> > @@ -54,134 +55,20 @@ static inline size_t buf_pages(void *p, size_t len)
> > PAGE_SIZE);
> > }
> >
> > -#define HEAP(type) \
> > -struct { \
> > - size_t size, used; \
> > - type *data; \
> > -}
> > -
> > -#define DECLARE_HEAP(type, name) HEAP(type) name
> > -
> > #define init_heap(heap, _size, gfp) \
> > ({ \
> > - (heap)->used = 0; \
> > - (heap)->size = (_size); \
> > - (heap)->data = kvmalloc((heap)->size * sizeof((heap)->data[0]),\
> > - (gfp)); \
> > -})
> > -
> > -#define free_heap(heap) \
> > -do { \
> > - kvfree((heap)->data); \
> > - (heap)->data = NULL; \
> > -} while (0)
> > -
> > -#define heap_set_backpointer(h, i, _fn) \
> > -do { \
> > - void (*fn)(typeof(h), size_t) = _fn; \
> > - if (fn) \
> > - fn(h, i); \
> > -} while (0)
> > -
> > -#define heap_swap(h, i, j, set_backpointer) \
> > -do { \
> > - swap((h)->data[i], (h)->data[j]); \
> > - heap_set_backpointer(h, i, set_backpointer); \
> > - heap_set_backpointer(h, j, set_backpointer); \
> > -} while (0)
> > -
> > -#define heap_peek(h) \
> > -({ \
> > - EBUG_ON(!(h)->used); \
> > - (h)->data[0]; \
> > -})
> > -
> > -#define heap_full(h) ((h)->used == (h)->size)
> > -
> > -#define heap_sift_down(h, i, cmp, set_backpointer) \
> > -do { \
> > - size_t _c, _j = i; \
> > - \
> > - for (; _j * 2 + 1 < (h)->used; _j = _c) { \
> > - _c = _j * 2 + 1; \
> > - if (_c + 1 < (h)->used && \
> > - cmp(h, (h)->data[_c], (h)->data[_c + 1]) >= 0) \
> > - _c++; \
> > - \
> > - if (cmp(h, (h)->data[_c], (h)->data[_j]) >= 0) \
> > - break; \
> > - heap_swap(h, _c, _j, set_backpointer); \
> > - } \
> > -} while (0)
> > -
> > -#define heap_sift_up(h, i, cmp, set_backpointer) \
> > -do { \
> > - while (i) { \
> > - size_t p = (i - 1) / 2; \
> > - if (cmp(h, (h)->data[i], (h)->data[p]) >= 0) \
> > - break; \
> > - heap_swap(h, i, p, set_backpointer); \
> > - i = p; \
> > - } \
> > -} while (0)
> > -
> > -#define __heap_add(h, d, cmp, set_backpointer) \
> > -({ \
> > - size_t _i = (h)->used++; \
> > - (h)->data[_i] = d; \
> > - heap_set_backpointer(h, _i, set_backpointer); \
> > - \
> > - heap_sift_up(h, _i, cmp, set_backpointer); \
> > - _i; \
> > -})
> > -
> > -#define heap_add(h, d, cmp, set_backpointer) \
> > -({ \
> > - bool _r = !heap_full(h); \
> > - if (_r) \
> > - __heap_add(h, d, cmp, set_backpointer); \
> > - _r; \
> > + void *data = kvmalloc(_size * sizeof(*min_heap_peek(heap)), (gfp));\
> > + min_heap_init(heap, data, _size); \
> > + min_heap_peek(heap); \
> > })
> >
> > -#define heap_add_or_replace(h, new, cmp, set_backpointer) \
> > -do { \
> > - if (!heap_add(h, new, cmp, set_backpointer) && \
> > - cmp(h, new, heap_peek(h)) >= 0) { \
> > - (h)->data[0] = new; \
> > - heap_set_backpointer(h, 0, set_backpointer); \
> > - heap_sift_down(h, 0, cmp, set_backpointer); \
> > - } \
> > -} while (0)
> >
> > -#define heap_del(h, i, cmp, set_backpointer) \
> > +#define free_heap(_heap) \
> > do { \
> > - size_t _i = (i); \
> > - \
> > - BUG_ON(_i >= (h)->used); \
> > - (h)->used--; \
> > - if ((_i) < (h)->used) { \
> > - heap_swap(h, _i, (h)->used, set_backpointer); \
> > - heap_sift_up(h, _i, cmp, set_backpointer); \
> > - heap_sift_down(h, _i, cmp, set_backpointer); \
> > - } \
> > + kvfree((_heap)->heap.data); \
> > + (_heap)->heap.data = NULL; \
> > } while (0)
> >
> > -#define heap_pop(h, d, cmp, set_backpointer) \
> > -({ \
> > - bool _r = (h)->used; \
> > - if (_r) { \
> > - (d) = (h)->data[0]; \
> > - heap_del(h, 0, cmp, set_backpointer); \
> > - } \
> > - _r; \
> > -})
> > -
> > -#define heap_resort(heap, cmp, set_backpointer) \
> > -do { \
> > - ssize_t _i; \
> > - for (_i = (ssize_t) (heap)->used / 2 - 1; _i >= 0; --_i) \
> > - heap_sift_down(heap, _i, cmp, set_backpointer); \
> > -} while (0)
> >
> > #define ANYSINT_MAX(t) \
> > ((((t) 1 << (sizeof(t) * 8 - 2)) - (t) 1) * (t) 2 + (t) 1)
> > --
> > 2.34.1
> >