From: Jihan LIN Currently, zcomp uses a per-CPU stream model. This design is restrictive for hardware-accelerated or batched zcomp backends. These backends often need to manage their own resources rather than relying on a generic mutex-protected per-CPU stream for batched operations. This patch introduces a hybrid model, allowing backends to optionally manage their own streams while generic per-CPU streams still remain allocated as a complementary mechanism. Introduce zstrm_mgmt flag to struct zcomp_params. Backends set this flag during zcomp_ops->setup_params() to advertise their capability to manage streams. Add zcomp_ops->{get, put}_stream() to allow zcomp backends to implement their own stream strategies. Modify zcomp_stream_get() to accept a new parameter indicating zcomp-managed streams are preferred, and update zcomp_stream_put() to route a zcomp-managed stream to the backend. If the backends advertise their capability and the caller prefers managed streams, try to get the stream from the backends; otherwise, fall back to the generic per-CPU stream. All existing call sites request the default per-CPU stream to preserve the original behavior. Signed-off-by: Jihan LIN --- drivers/block/zram/zcomp.c | 27 +++++++++++++++++++++++++-- drivers/block/zram/zcomp.h | 23 +++++++++++++++++++++-- drivers/block/zram/zram_drv.c | 6 +++--- 3 files changed, 49 insertions(+), 7 deletions(-) diff --git a/drivers/block/zram/zcomp.c b/drivers/block/zram/zcomp.c index 1614340e81dd2bebb29373411c9d180446f78f4c..86ff6ecb0293d7b95ef4fa822122568cedf78f6e 100644 --- a/drivers/block/zram/zcomp.c +++ b/drivers/block/zram/zcomp.c @@ -69,6 +69,7 @@ static int zcomp_strm_init_percpu(struct zcomp *comp, struct zcomp_strm *zstrm) zcomp_strm_free_percpu(comp, zstrm); return -ENOMEM; } + zstrm->zcomp_managed = false; return 0; } @@ -107,8 +108,18 @@ ssize_t zcomp_available_show(const char *comp, char *buf, ssize_t at) return at; } -struct zcomp_strm *zcomp_stream_get(struct zcomp *comp) +struct zcomp_strm *zcomp_stream_get(struct zcomp *comp, enum zstrm_pref pref) { + if (comp->params->zstrm_mgmt && pref == ZSTRM_PREFER_MGMT) { + struct zcomp_strm *zcomp_strm = + comp->ops->get_stream(comp->params); + + if (zcomp_strm) { + zcomp_strm->comp = comp; + return zcomp_strm; + } + } + for (;;) { struct zcomp_strm *zstrm = raw_cpu_ptr(comp->stream); @@ -131,7 +142,11 @@ struct zcomp_strm *zcomp_stream_get(struct zcomp *comp) void zcomp_stream_put(struct zcomp_strm *zstrm) { - mutex_unlock(&zstrm->lock); + if (zstrm->zcomp_managed) { + zstrm->comp->ops->put_stream(zstrm->comp->params, zstrm); + } else { + mutex_unlock(&zstrm->lock); + } } int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm, @@ -197,11 +212,19 @@ static int zcomp_init(struct zcomp *comp, struct zcomp_params *params) if (!comp->stream) return -ENOMEM; + params->zstrm_mgmt = false; comp->params = params; ret = comp->ops->setup_params(comp->params); if (ret) goto cleanup; + if (params->zstrm_mgmt && + !(comp->ops->get_stream && comp->ops->put_stream)) { + params->zstrm_mgmt = false; + pr_warn("Missing managed stream ops in %s, managed stream disabled\n", + comp->ops->name); + } + for_each_possible_cpu(cpu) mutex_init(&per_cpu_ptr(comp->stream, cpu)->lock); diff --git a/drivers/block/zram/zcomp.h b/drivers/block/zram/zcomp.h index eacfd3f7d61d9395694292713fb5da4f0023d6d7..cbe8842ea5352eed4e73e3d45fe6c12221ab9f64 100644 --- a/drivers/block/zram/zcomp.h +++ b/drivers/block/zram/zcomp.h @@ -24,6 +24,7 @@ struct zcomp_params { union { struct deflate_params deflate; }; + bool zstrm_mgmt; void *drv_data; }; @@ -31,14 +32,18 @@ struct zcomp_params { /* * Run-time driver context - scratch buffers, etc. It is modified during * request execution (compression/decompression), cannot be shared, so - * it's in per-CPU area. + * it's in per-CPU area or management by backend. */ struct zcomp_ctx { void *context; }; struct zcomp_strm { + bool zcomp_managed; + /* lock used only for per-cpu streams */ struct mutex lock; + /* pointer to zcomp valid only for zcomp-managed streams */ + struct zcomp *comp; /* compression buffer */ void *buffer; /* local copy of handle memory */ @@ -54,6 +59,11 @@ struct zcomp_req { size_t dst_len; }; +enum zstrm_pref { + ZSTRM_DEFAULT, /* always use the generic per-CPU stream */ + ZSTRM_PREFER_MGMT, /* try managed stream; fallback to per-CPU */ +}; + struct zcomp_ops { int (*compress)(struct zcomp_params *params, struct zcomp_ctx *ctx, struct zcomp_req *req); @@ -66,6 +76,15 @@ struct zcomp_ops { int (*setup_params)(struct zcomp_params *params); void (*release_params)(struct zcomp_params *params); + /* + * get_stream() needs to prepare zstrm->ctx, and backend must ensure + * returned stream sets zcomp_managed and match the per-cpu stream + * sizing: local_copy >= PAGE_SIZE, buffer >= 2 * PAGE_SIZE. + */ + struct zcomp_strm *(*get_stream)(struct zcomp_params *params); + void (*put_stream)(struct zcomp_params *params, + struct zcomp_strm *zstrm); + const char *name; }; @@ -85,7 +104,7 @@ bool zcomp_available_algorithm(const char *comp); struct zcomp *zcomp_create(const char *alg, struct zcomp_params *params); void zcomp_destroy(struct zcomp *comp); -struct zcomp_strm *zcomp_stream_get(struct zcomp *comp); +struct zcomp_strm *zcomp_stream_get(struct zcomp *comp, enum zstrm_pref pref); void zcomp_stream_put(struct zcomp_strm *zstrm); int zcomp_compress(struct zcomp *comp, struct zcomp_strm *zstrm, diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c index 5759823d631488904189168326fd133549c76141..2e5a1415e9034674e14e619f486052cd21098f50 100644 --- a/drivers/block/zram/zram_drv.c +++ b/drivers/block/zram/zram_drv.c @@ -1966,7 +1966,7 @@ static int read_compressed_page(struct zram *zram, struct page *page, u32 index) size = zram_get_obj_size(zram, index); prio = zram_get_priority(zram, index); - zstrm = zcomp_stream_get(zram->comps[prio]); + zstrm = zcomp_stream_get(zram->comps[prio], ZSTRM_DEFAULT); src = zs_obj_read_begin(zram->mem_pool, handle, zstrm->local_copy); dst = kmap_local_page(page); ret = zcomp_decompress(zram->comps[prio], zstrm, src, size, dst); @@ -2121,7 +2121,7 @@ static int zram_write_page(struct zram *zram, struct page *page, u32 index) if (same_filled) return write_same_filled_page(zram, element, index); - zstrm = zcomp_stream_get(zram->comps[ZRAM_PRIMARY_COMP]); + zstrm = zcomp_stream_get(zram->comps[ZRAM_PRIMARY_COMP], ZSTRM_DEFAULT); mem = kmap_local_page(page); ret = zcomp_compress(zram->comps[ZRAM_PRIMARY_COMP], zstrm, mem, &comp_len); @@ -2303,7 +2303,7 @@ static int recompress_slot(struct zram *zram, u32 index, struct page *page, if (!zram->comps[prio]) continue; - zstrm = zcomp_stream_get(zram->comps[prio]); + zstrm = zcomp_stream_get(zram->comps[prio], ZSTRM_DEFAULT); src = kmap_local_page(page); ret = zcomp_compress(zram->comps[prio], zstrm, src, &comp_len_new); -- 2.51.0