On Wed, Mar 20, 2024 at 7:55 AM Kuan-Wei Chiu <visitorckw@xxxxxxxxx> wrote: > > Drop the heap-related macros from bcachefs and replacing them with the > generic min_heap implementation from include/linux. By doing so, code > readability is improved by using functions instead of macros. Moreover, > the min_heap implementation in include/linux adopts a bottom-up > variation compared to the textbook version currently used in bcachefs. > This bottom-up variation allows for approximately 50% reduction in the > number of comparison operations during heap siftdown, without changing > the number of swaps, thus making it more efficient. > > Link: https://lkml.kernel.org/ioyfizrzq7w7mjrqcadtzsfgpuntowtjdw5pgn4qhvsdp4mqqg@nrlek5vmisbu > Signed-off-by: Kuan-Wei Chiu <visitorckw@xxxxxxxxx> Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx> Thanks, Ian > --- > Changes in v2: > - Add attribute __always_unused to the compare and swap functions that > do not use the args parameter. > - Rename min_heapify() to min_heap_sift_down(). > - Refine the commit message. > > fs/bcachefs/clock.c | 53 +++++++++++----- > fs/bcachefs/clock_types.h | 2 +- > fs/bcachefs/ec.c | 100 +++++++++++++++++++----------- > fs/bcachefs/ec_types.h | 2 +- > fs/bcachefs/util.h | 127 +++----------------------------------- > 5 files changed, 110 insertions(+), 174 deletions(-) > > diff --git a/fs/bcachefs/clock.c b/fs/bcachefs/clock.c > index 363644451106..e898f4693bd0 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 __always_unused *args) > { > - 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 __always_unused *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 082075244e16..68c5e9e928a7 100644 > --- a/fs/bcachefs/ec.c > +++ b/fs/bcachefs/ec.c > @@ -860,14 +860,15 @@ 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 +959,21 @@ 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 __always_unused *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 +981,21 @@ 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 +1003,43 @@ 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 +1051,20 @@ 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_heap_sift_down(h, i, &callbacks, &c->ec_stripes_heap); > > heap_verify_backpointer(c, idx); > > @@ -1828,12 +1856,12 @@ 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 +2187,14 @@ 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 175aee3074c7..e0c86ad04bf3 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 >
