[Mesa-dev] [PATCH 02/14] gallium/pipebuffer: add pb_slab utility
Marek Olšák
maraeo at gmail.com
Sun Sep 18 13:11:33 UTC 2016
Please add comments explaining all members of structures and all
non-trivial functions. For example, it's not really clear why deinit
calls reclaim.
Thanks,
Marek
On Tue, Sep 13, 2016 at 11:56 AM, Nicolai Hähnle <nhaehnle at gmail.com> wrote:
> From: Nicolai Hähnle <nicolai.haehnle at amd.com>
>
> This is a simple framework for slab allocation from buffers that fits into
> the buffer management scheme of the radeon and amdgpu winsyses where bufmgrs
> aren't used.
>
> The utility knows about different sized allocations and explicitly manages
> reclaim of allocations that have pending fences. It manages all the free lists
> but does not actually touch buffer objects directly, relying on callbacks for
> that.
> ---
> src/gallium/auxiliary/Makefile.sources | 2 +
> src/gallium/auxiliary/pipebuffer/pb_slab.c | 195 +++++++++++++++++++++++++++++
> src/gallium/auxiliary/pipebuffer/pb_slab.h | 115 +++++++++++++++++
> 3 files changed, 312 insertions(+)
> create mode 100644 src/gallium/auxiliary/pipebuffer/pb_slab.c
> create mode 100644 src/gallium/auxiliary/pipebuffer/pb_slab.h
>
> diff --git a/src/gallium/auxiliary/Makefile.sources b/src/gallium/auxiliary/Makefile.sources
> index f8954c9..ed9eaa8 100644
> --- a/src/gallium/auxiliary/Makefile.sources
> +++ b/src/gallium/auxiliary/Makefile.sources
> @@ -88,20 +88,22 @@ C_SOURCES := \
> pipebuffer/pb_bufmgr_alt.c \
> pipebuffer/pb_bufmgr_cache.c \
> pipebuffer/pb_bufmgr_debug.c \
> pipebuffer/pb_bufmgr.h \
> pipebuffer/pb_bufmgr_mm.c \
> pipebuffer/pb_bufmgr_ondemand.c \
> pipebuffer/pb_bufmgr_pool.c \
> pipebuffer/pb_bufmgr_slab.c \
> pipebuffer/pb_cache.c \
> pipebuffer/pb_cache.h \
> + pipebuffer/pb_slab.c \
> + pipebuffer/pb_slab.h \
> pipebuffer/pb_validate.c \
> pipebuffer/pb_validate.h \
> postprocess/filters.h \
> postprocess/postprocess.h \
> postprocess/pp_celshade.c \
> postprocess/pp_celshade.h \
> postprocess/pp_colors.c \
> postprocess/pp_colors.h \
> postprocess/pp_filters.h \
> postprocess/pp_init.c \
> diff --git a/src/gallium/auxiliary/pipebuffer/pb_slab.c b/src/gallium/auxiliary/pipebuffer/pb_slab.c
> new file mode 100644
> index 0000000..e419446
> --- /dev/null
> +++ b/src/gallium/auxiliary/pipebuffer/pb_slab.c
> @@ -0,0 +1,195 @@
> +/*
> + * Copyright 2016 Advanced Micro Devices, Inc.
> + * All Rights Reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining
> + * a copy of this software and associated documentation files (the
> + * "Software"), to deal in the Software without restriction, including
> + * without limitation the rights to use, copy, modify, merge, publish,
> + * distribute, sub license, and/or sell copies of the Software, and to
> + * permit persons to whom the Software is furnished to do so, subject to
> + * the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the
> + * next paragraph) shall be included in all copies or substantial portions
> + * of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
> + * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
> + * NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS, AUTHORS
> + * AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
> + * USE OR OTHER DEALINGS IN THE SOFTWARE.
> + *
> + */
> +
> +#include "pb_slab.h"
> +
> +#include "util/u_math.h"
> +#include "util/u_memory.h"
> +
> +static void
> +pb_slab_reclaim(struct pb_slabs *slabs, struct pb_slab_entry *entry)
> +{
> + struct pb_slab *slab = entry->slab;
> +
> + LIST_DEL(&entry->head); /* remove from reclaim list */
> + LIST_ADD(&entry->head, &slab->free);
> + slab->num_free++;
> +
> + /* Add slab to the group's list if it isn't already linked. */
> + if (!slab->head.next) {
> + struct pb_slab_group *group = &slabs->groups[entry->group_index];
> + LIST_ADDTAIL(&slab->head, &group->slabs);
> + }
> +
> + if (slab->num_free >= slab->num_entries) {
> + LIST_DEL(&slab->head);
> + slabs->slab_free(slabs->priv, slab);
> + }
> +}
> +
> +static void
> +pb_slabs_reclaim_locked(struct pb_slabs *slabs)
> +{
> + while (!LIST_IS_EMPTY(&slabs->reclaim)) {
> + struct pb_slab_entry *entry =
> + LIST_ENTRY(struct pb_slab_entry, slabs->reclaim.next, head);
> +
> + if (!slabs->can_reclaim(slabs->priv, entry))
> + break;
> +
> + pb_slab_reclaim(slabs, entry);
> + }
> +}
> +
> +struct pb_slab_entry *
> +pb_slab_alloc(struct pb_slabs *slabs, unsigned size, unsigned heap)
> +{
> + unsigned order = MAX2(slabs->min_order, util_logbase2_ceil(size));
> + unsigned group_index;
> + struct pb_slab_group *group;
> + struct pb_slab *slab;
> + struct pb_slab_entry *entry;
> +
> + assert(order < slabs->min_order + slabs->num_orders);
> + assert(heap < slabs->num_heaps);
> +
> + group_index = heap * slabs->num_orders + (order - slabs->min_order);
> + group = &slabs->groups[group_index];
> +
> + pipe_mutex_lock(slabs->mutex);
> +
> + /* If there is no candidate slab at all, or the first slab has no free
> + * entries, try reclaiming entries.
> + */
> + if (LIST_IS_EMPTY(&group->slabs) ||
> + LIST_IS_EMPTY(&LIST_ENTRY(struct pb_slab, group->slabs.next, head)->free))
> + pb_slabs_reclaim_locked(slabs);
> +
> + /* Remove slabs without free entries. */
> + while (!LIST_IS_EMPTY(&group->slabs)) {
> + slab = LIST_ENTRY(struct pb_slab, group->slabs.next, head);
> + if (!LIST_IS_EMPTY(&slab->free))
> + break;
> +
> + LIST_DEL(&slab->head);
> + }
> +
> + if (LIST_IS_EMPTY(&group->slabs)) {
> + /* Drop the mutex temporarily to prevent a deadlock where the allocation
> + * calls back into slab functions (most likely to happen for
> + * pb_slab_reclaim if memory is low).
> + *
> + * There's a chance that racing threads will end up allocating multiple
> + * slabs for the same group, but that doesn't hurt correctness.
> + */
> + pipe_mutex_unlock(slabs->mutex);
> + slab = slabs->slab_alloc(slabs->priv, heap, 1 << order, group_index);
> + if (!slab)
> + return NULL;
> + pipe_mutex_lock(slabs->mutex);
> +
> + LIST_ADD(&slab->head, &group->slabs);
> + }
> +
> + entry = LIST_ENTRY(struct pb_slab_entry, slab->free.next, head);
> + LIST_DEL(&entry->head);
> + slab->num_free--;
> +
> + pipe_mutex_unlock(slabs->mutex);
> +
> + return entry;
> +}
> +
> +void
> +pb_slab_free(struct pb_slabs* slabs, struct pb_slab_entry *entry)
> +{
> + pipe_mutex_lock(slabs->mutex);
> + LIST_ADDTAIL(&entry->head, &slabs->reclaim);
> + pipe_mutex_unlock(slabs->mutex);
> +}
> +
> +void
> +pb_slabs_reclaim(struct pb_slabs *slabs)
> +{
> + pipe_mutex_lock(slabs->mutex);
> + pb_slabs_reclaim_locked(slabs);
> + pipe_mutex_unlock(slabs->mutex);
> +}
> +
> +bool
> +pb_slabs_init(struct pb_slabs *slabs,
> + unsigned min_order, unsigned max_order,
> + unsigned num_heaps,
> + void *priv,
> + slab_can_reclaim_fn *can_reclaim,
> + slab_alloc_fn *slab_alloc,
> + slab_free_fn *slab_free)
> +{
> + unsigned num_groups;
> + unsigned i;
> +
> + assert(min_order <= max_order);
> + assert(max_order < sizeof(unsigned) * 8 - 1);
> +
> + slabs->min_order = min_order;
> + slabs->num_orders = max_order - min_order + 1;
> + slabs->num_heaps = num_heaps;
> +
> + slabs->priv = priv;
> + slabs->can_reclaim = can_reclaim;
> + slabs->slab_alloc = slab_alloc;
> + slabs->slab_free = slab_free;
> +
> + LIST_INITHEAD(&slabs->reclaim);
> +
> + num_groups = slabs->num_orders * slabs->num_heaps;
> + slabs->groups = CALLOC(num_groups, sizeof(*slabs->groups));
> + if (!slabs->groups)
> + return false;
> +
> + for (i = 0; i < num_groups; ++i) {
> + struct pb_slab_group *group = &slabs->groups[i];
> + LIST_INITHEAD(&group->slabs);
> + }
> +
> + pipe_mutex_init(slabs->mutex);
> +
> + return true;
> +}
> +
> +void
> +pb_slabs_deinit(struct pb_slabs *slabs)
> +{
> + while (!LIST_IS_EMPTY(&slabs->reclaim)) {
> + struct pb_slab_entry *entry =
> + LIST_ENTRY(struct pb_slab_entry, slabs->reclaim.next, head);
> + pb_slab_reclaim(slabs, entry);
> + }
> +
> + FREE(slabs->groups);
> + pipe_mutex_destroy(slabs->mutex);
> +}
> diff --git a/src/gallium/auxiliary/pipebuffer/pb_slab.h b/src/gallium/auxiliary/pipebuffer/pb_slab.h
> new file mode 100644
> index 0000000..1d5cfdc
> --- /dev/null
> +++ b/src/gallium/auxiliary/pipebuffer/pb_slab.h
> @@ -0,0 +1,115 @@
> +/*
> + * Copyright 2016 Advanced Micro Devices, Inc.
> + * All Rights Reserved.
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining
> + * a copy of this software and associated documentation files (the
> + * "Software"), to deal in the Software without restriction, including
> + * without limitation the rights to use, copy, modify, merge, publish,
> + * distribute, sub license, and/or sell copies of the Software, and to
> + * permit persons to whom the Software is furnished to do so, subject to
> + * the following conditions:
> + *
> + * The above copyright notice and this permission notice (including the
> + * next paragraph) shall be included in all copies or substantial portions
> + * of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
> + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
> + * OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
> + * NON-INFRINGEMENT. IN NO EVENT SHALL THE COPYRIGHT HOLDERS, AUTHORS
> + * AND/OR ITS SUPPLIERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
> + * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
> + * USE OR OTHER DEALINGS IN THE SOFTWARE.
> + *
> + */
> +
> +#ifndef PB_SLAB_H
> +#define PB_SLAB_H
> +
> +#include "pb_buffer.h"
> +#include "util/list.h"
> +#include "os/os_thread.h"
> +
> +struct pb_slab;
> +struct pb_slabs;
> +
> +struct pb_slab_entry
> +{
> + struct list_head head;
> + struct pb_slab *slab; /* the slab that contains this buffer */
> + unsigned group_index;
> +};
> +
> +struct pb_slab
> +{
> + struct list_head head;
> +
> + struct list_head free;
> + unsigned num_free;
> + unsigned num_entries;
> +};
> +
> +typedef struct pb_slab *(slab_alloc_fn)(void *priv,
> + unsigned heap,
> + unsigned entry_size,
> + unsigned group_index);
> +typedef void (slab_free_fn)(void *priv, struct pb_slab *);
> +typedef bool (slab_can_reclaim_fn)(void *priv, struct pb_slab_entry *);
> +
> +struct pb_slab_group
> +{
> + /* Slabs with allocation candidates. Typically, slabs in this list should
> + * have some free entries.
> + *
> + * However, when the head becomes full we purposefully keep it around
> + * until the next allocation attempt, at which time we try a reclaim.
> + * The intention is to keep serving allocations from the same slab as long
> + * as possible for better locality.
> + *
> + * Due to a race in new slab allocation, additional slabs in this list
> + * can be fully allocated as well.
> + */
> + struct list_head slabs;
> +};
> +
> +struct pb_slabs
> +{
> + pipe_mutex mutex;
> +
> + unsigned min_order;
> + unsigned num_orders;
> + unsigned num_heaps;
> +
> + struct pb_slab_group *groups;
> + struct list_head reclaim; /* list of buffers waiting to be reclaimed */
> +
> + void *priv;
> + slab_can_reclaim_fn *can_reclaim;
> + slab_alloc_fn *slab_alloc;
> + slab_free_fn *slab_free;
> +};
> +
> +struct pb_slab_entry *
> +pb_slab_alloc(struct pb_slabs *slabs, unsigned size, unsigned heap);
> +
> +void
> +pb_slab_free(struct pb_slabs* slabs, struct pb_slab_entry *entry);
> +
> +void
> +pb_slabs_reclaim(struct pb_slabs *slabs);
> +
> +bool
> +pb_slabs_init(struct pb_slabs *slabs,
> + unsigned min_order, unsigned max_order,
> + unsigned num_heaps,
> + void *priv,
> + slab_can_reclaim_fn *can_reclaim,
> + slab_alloc_fn *slab_alloc,
> + slab_free_fn *slab_free);
> +
> +void
> +pb_slabs_deinit(struct pb_slabs *slabs);
> +
> +#endif
> --
> 2.7.4
>
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