From nobody Tue Feb 10 01:15:19 2026 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8FE0628DB71; Thu, 8 May 2025 19:41:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.17 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746733314; cv=none; b=k+z2Ueer/+/QUKTluVVQJ9kwtbYBJWBG4ZQagMUZFeG7hVlifqQzbI/fWo03hVLtwH6fFlaW3wvpR53s0pHwyCrJJ9+I4N7cubjTFlu3HDMkpOM6KHOggfRuUP4jbl+oC75cWYgKUXuldYLAfYwMaFfmQ4uVwTz8dAly7AFPnEM= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1746733314; c=relaxed/simple; bh=n8lZ8yIQmOM0rAWlBzDxJH5i5KHCUMbDeeth3crBxmU=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=ieq7NiZWsDSIpgPxEdR/HCa7zlOot9hkW0KDVaB0uqDmSaMT4O8lVkGaRHCBC9Q4itTEajUFVoBj5jlCtVeEorB8IRwG3hSmVDQJuNTivYP2sPxP5tzYR4RdQpRNdhTQtD1bJInSLhV1y5h6tziSkphCyePgGG0uc69JMOp8qQs= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com; spf=pass smtp.mailfrom=intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=HM+EFUZN; arc=none smtp.client-ip=192.198.163.17 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="HM+EFUZN" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1746733312; x=1778269312; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=n8lZ8yIQmOM0rAWlBzDxJH5i5KHCUMbDeeth3crBxmU=; b=HM+EFUZNwx1pKC9L9WYmc3LiHwXum1Yhh/v3TI1nnq8gwY/ZwCuXJNLa iYEsPepDS5ndeQp+AYa1VOBe0eFbPDGjtnoBUB+D6ydUziw15MQmkmRFC /QCO4BGLA6CmTNww3IRQIaxSD1X/H0DExbMv98SILF7MUFIlyfa1Ucfbg M4r9u8RMMCBGFetxrWB6nCjvjBtSDKDFhYxKU11lNOS+UMzFAgDuE7IoZ iHs+B1NRfta+xYwk588cgZuj4fHxraQGRQ1rXWxVYXSXMemmFEZhd0x3l IXc+MCo3xdIwPv+mZi2AFeUseSs0b25cwPa5modMJCAfQ+JZ94lre7nto g==; X-CSE-ConnectionGUID: Te1bS9JqRxOUEFWvx1Q4Yg== X-CSE-MsgGUID: ArBioeE8SZe9bx20swFffw== X-IronPort-AV: E=McAfee;i="6700,10204,11427"; a="48454802" X-IronPort-AV: E=Sophos;i="6.15,273,1739865600"; d="scan'208";a="48454802" Received: from fmviesa010.fm.intel.com ([10.60.135.150]) by fmvoesa111.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 08 May 2025 12:41:46 -0700 X-CSE-ConnectionGUID: JNac+pJqSR2ieo5YOFySZg== X-CSE-MsgGUID: /Dyhs7OhRjqMEzCE7Ai2Yg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.15,273,1739865600"; d="scan'208";a="136880890" Received: from jf5300-b11a338t.jf.intel.com ([10.242.51.115]) by fmviesa010.fm.intel.com with ESMTP; 08 May 2025 12:41:45 -0700 From: Kanchana P Sridhar To: linux-kernel@vger.kernel.org, linux-mm@kvack.org, hannes@cmpxchg.org, yosry.ahmed@linux.dev, nphamcs@gmail.com, chengming.zhou@linux.dev, usamaarif642@gmail.com, ryan.roberts@arm.com, 21cnbao@gmail.com, ying.huang@linux.alibaba.com, akpm@linux-foundation.org, senozhatsky@chromium.org, linux-crypto@vger.kernel.org, herbert@gondor.apana.org.au, davem@davemloft.net, clabbe@baylibre.com, ardb@kernel.org, ebiggers@google.com, surenb@google.com, kristen.c.accardi@intel.com, vinicius.gomes@intel.com Cc: wajdi.k.feghali@intel.com, vinodh.gopal@intel.com, kanchana.p.sridhar@intel.com Subject: [PATCH v9 17/19] mm: zswap: Allocate pool batching resources if the compressor supports batching. Date: Thu, 8 May 2025 12:41:32 -0700 Message-Id: <20250508194134.28392-18-kanchana.p.sridhar@intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20250508194134.28392-1-kanchana.p.sridhar@intel.com> References: <20250508194134.28392-1-kanchana.p.sridhar@intel.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" This patch adds support for the per-CPU acomp_ctx to track multiple compression/decompression requests and multiple compression destination buffers. zswap_cpu_comp_prepare() will get the maximum batch-size the compressor supports. If so, it will allocate the necessary batching resources (reqs/buffers), up to ZSWAP_MAX_BATCH_SIZE, which this patch defines as 8U. This patch also adds a "u8 nr_reqs" member to "struct zswap_pool". Thanks Yosry for this suggestion. Once the pool's per-CPU acomp_ctx resources have been successfully allocated, the pool->nr_reqs is set up as the minimum of ZSWAP_MAX_BATCH_SIZE and crypto_acomp_batch_size(acomp_ctx->acomp). However, zswap does not use more than one request yet. Follow-up patches will actually utilize the multiple acomp_ctx requests/buffers for batch compression/decompression of multiple pages. The newly added ZSWAP_MAX_BATCH_SIZE limits the amount of extra memory used for batching. There is a small extra memory overhead of allocating the "reqs" and "buffers" arrays for compressors that do not support batching: On x86_64, the overhead is two pointers per-CPU (i.e. 16 bytes). Suggested-by: Yosry Ahmed Signed-off-by: Kanchana P Sridhar --- mm/zswap.c | 113 ++++++++++++++++++++++++++++++++++++++--------------- 1 file changed, 81 insertions(+), 32 deletions(-) diff --git a/mm/zswap.c b/mm/zswap.c index 717835f214b2..2273dbfd460f 100644 --- a/mm/zswap.c +++ b/mm/zswap.c @@ -80,6 +80,9 @@ static bool zswap_pool_reached_full; =20 #define ZSWAP_PARAM_UNSET "" =20 +/* Limit the batch size to limit per-CPU memory usage for reqs and buffers= . */ +#define ZSWAP_MAX_BATCH_SIZE 8U + static int zswap_setup(void); =20 /* Enable/disable zswap */ @@ -145,9 +148,9 @@ bool zswap_never_enabled(void) =20 struct crypto_acomp_ctx { struct crypto_acomp *acomp; - struct acomp_req *req; + struct acomp_req **reqs; + u8 **buffers; struct crypto_wait wait; - u8 *buffer; struct mutex mutex; bool is_sleepable; }; @@ -166,6 +169,7 @@ struct zswap_pool { struct work_struct release_work; struct hlist_node node; char tfm_name[CRYPTO_MAX_ALG_NAME]; + u8 nr_reqs; }; =20 /* Global LRU lists shared by all zswap pools. */ @@ -258,16 +262,29 @@ static void __zswap_pool_empty(struct percpu_ref *ref= ); * zswap_cpu_comp_prepare(), not others. * - Cleanup acomp_ctx resources on all cores in zswap_pool_destroy(). */ -static void acomp_ctx_dealloc(struct crypto_acomp_ctx *acomp_ctx) +static void acomp_ctx_dealloc(struct crypto_acomp_ctx *acomp_ctx, u8 nr_re= qs) { + u8 i; + if (IS_ERR_OR_NULL(acomp_ctx)) return; =20 - if (!IS_ERR_OR_NULL(acomp_ctx->req)) - acomp_request_free(acomp_ctx->req); + if (acomp_ctx->reqs) { + for (i =3D 0; i < nr_reqs; ++i) { + if (!IS_ERR_OR_NULL(acomp_ctx->reqs[i])) + acomp_request_free(acomp_ctx->reqs[i]); + } + kfree(acomp_ctx->reqs); + } + if (!IS_ERR_OR_NULL(acomp_ctx->acomp)) crypto_free_acomp(acomp_ctx->acomp); - kfree(acomp_ctx->buffer); + + if (acomp_ctx->buffers) { + for (i =3D 0; i < nr_reqs; ++i) + kfree(acomp_ctx->buffers[i]); + kfree(acomp_ctx->buffers); + } } =20 static int zswap_cpu_comp_prepare(unsigned int cpu, struct hlist_node *nod= e) @@ -275,6 +292,7 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, str= uct hlist_node *node) struct zswap_pool *pool =3D hlist_entry(node, struct zswap_pool, node); struct crypto_acomp_ctx *acomp_ctx =3D per_cpu_ptr(pool->acomp_ctx, cpu); int ret =3D -ENOMEM; + u8 i, nr_reqs =3D 0; =20 /* * The per-CPU pool->acomp_ctx is zero-initialized on allocation. @@ -287,10 +305,6 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, st= ruct hlist_node *node) if (!IS_ERR_OR_NULL(acomp_ctx->acomp)) return 0; =20 - acomp_ctx->buffer =3D kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, cpu_to_node= (cpu)); - if (!acomp_ctx->buffer) - return ret; - acomp_ctx->acomp =3D crypto_alloc_acomp_node(pool->tfm_name, 0, 0, cpu_to= _node(cpu)); if (IS_ERR_OR_NULL(acomp_ctx->acomp)) { pr_err("could not alloc crypto acomp %s : %ld\n", @@ -300,33 +314,58 @@ static int zswap_cpu_comp_prepare(unsigned int cpu, s= truct hlist_node *node) } acomp_ctx->is_sleepable =3D acomp_is_async(acomp_ctx->acomp); =20 - acomp_ctx->req =3D acomp_request_alloc(acomp_ctx->acomp); - if (IS_ERR_OR_NULL(acomp_ctx->req)) { - pr_err("could not alloc crypto acomp_request %s\n", - pool->tfm_name); + nr_reqs =3D min(ZSWAP_MAX_BATCH_SIZE, + crypto_acomp_batch_size(acomp_ctx->acomp)); + + acomp_ctx->buffers =3D kcalloc_node(nr_reqs, sizeof(u8 *), + GFP_KERNEL, cpu_to_node(cpu)); + if (!acomp_ctx->buffers) goto fail; + + for (i =3D 0; i < nr_reqs; ++i) { + acomp_ctx->buffers[i] =3D kmalloc_node(PAGE_SIZE * 2, GFP_KERNEL, + cpu_to_node(cpu)); + if (!acomp_ctx->buffers[i]) + goto fail; } =20 - crypto_init_wait(&acomp_ctx->wait); + acomp_ctx->reqs =3D kcalloc_node(nr_reqs, sizeof(struct acomp_req *), + GFP_KERNEL, cpu_to_node(cpu)); + if (!acomp_ctx->reqs) + goto fail; + + for (i =3D 0; i < nr_reqs; ++i) { + acomp_ctx->reqs[i] =3D acomp_request_alloc(acomp_ctx->acomp); + if (IS_ERR_OR_NULL(acomp_ctx->reqs[i])) { + pr_err("could not alloc crypto acomp_request reqs[%d] %s\n", + i, pool->tfm_name); + goto fail; + } + } =20 /* + * All calls to crypto_acomp_[de]compress() from zswap will use + * acomp_ctx->reqs[0] with acomp_ctx->wait. * if the backend of acomp is async zip, crypto_req_done() will wakeup * crypto_wait_req(); if the backend of acomp is scomp, the callback * won't be called, crypto_wait_req() will return without blocking. */ - acomp_request_set_callback(acomp_ctx->req, CRYPTO_TFM_REQ_MAY_BACKLOG, + crypto_init_wait(&acomp_ctx->wait); + + acomp_request_set_callback(acomp_ctx->reqs[0], CRYPTO_TFM_REQ_MAY_BACKLOG, crypto_req_done, &acomp_ctx->wait); =20 mutex_init(&acomp_ctx->mutex); return 0; =20 fail: - acomp_ctx_dealloc(acomp_ctx); + acomp_ctx_dealloc(acomp_ctx, nr_reqs); return ret; } =20 static struct zswap_pool *zswap_pool_create(char *type, char *compressor) { + struct crypto_acomp_ctx *acomp_ctx; struct zswap_pool *pool; char name[38]; /* 'zswap' + 32 char (max) num + \0 */ gfp_t gfp =3D __GFP_NORETRY | __GFP_NOWARN | __GFP_KSWAPD_RECLAIM; @@ -343,6 +382,7 @@ static struct zswap_pool *zswap_pool_create(char *type,= char *compressor) return NULL; } =20 + /* Many things rely on the zero-initialization. */ pool =3D kzalloc(sizeof(*pool), GFP_KERNEL); if (!pool) return NULL; @@ -393,9 +433,18 @@ static struct zswap_pool *zswap_pool_create(char *type= , char *compressor) */ cpuhp_state_remove_instance(CPUHP_MM_ZSWP_POOL_PREPARE, &pool->node); =20 + /* + * If there was an error in adding the multi instance state, the + * zero-initialized pool->nr_reqs value will be accurate for passing to + * acomp_ctx_dealloc(). + */ if (ret) goto ref_fail; =20 + acomp_ctx =3D raw_cpu_ptr(pool->acomp_ctx); + pool->nr_reqs =3D min(ZSWAP_MAX_BATCH_SIZE, + crypto_acomp_batch_size(acomp_ctx->acomp)); + /* being the current pool takes 1 ref; this func expects the * caller to always add the new pool as the current pool */ @@ -411,7 +460,7 @@ static struct zswap_pool *zswap_pool_create(char *type,= char *compressor) =20 ref_fail: for_each_possible_cpu(cpu) - acomp_ctx_dealloc(per_cpu_ptr(pool->acomp_ctx, cpu)); + acomp_ctx_dealloc(per_cpu_ptr(pool->acomp_ctx, cpu), pool->nr_reqs); error: if (pool->acomp_ctx) free_percpu(pool->acomp_ctx); @@ -470,7 +519,7 @@ static void zswap_pool_destroy(struct zswap_pool *pool) zswap_pool_debug("destroying", pool); =20 for_each_possible_cpu(cpu) - acomp_ctx_dealloc(per_cpu_ptr(pool->acomp_ctx, cpu)); + acomp_ctx_dealloc(per_cpu_ptr(pool->acomp_ctx, cpu), pool->nr_reqs); =20 free_percpu(pool->acomp_ctx); =20 @@ -940,7 +989,7 @@ static bool zswap_compress(struct page *page, struct zs= wap_entry *entry, =20 mutex_lock(&acomp_ctx->mutex); =20 - dst =3D acomp_ctx->buffer; + dst =3D acomp_ctx->buffers[0]; sg_init_table(&input, 1); sg_set_page(&input, page, PAGE_SIZE, 0); =20 @@ -950,7 +999,7 @@ static bool zswap_compress(struct page *page, struct zs= wap_entry *entry, * giving the dst buffer with enough length to avoid buffer overflow. */ sg_init_one(&output, dst, PAGE_SIZE * 2); - acomp_request_set_params(acomp_ctx->req, &input, &output, PAGE_SIZE, dlen= ); + acomp_request_set_params(acomp_ctx->reqs[0], &input, &output, PAGE_SIZE, = dlen); =20 /* * it maybe looks a little bit silly that we send an asynchronous request, @@ -964,8 +1013,8 @@ static bool zswap_compress(struct page *page, struct z= swap_entry *entry, * but in different threads running on different cpu, we have different * acomp instance, so multiple threads can do (de)compression in parallel. */ - comp_ret =3D crypto_wait_req(crypto_acomp_compress(acomp_ctx->req), &acom= p_ctx->wait); - dlen =3D acomp_ctx->req->dlen; + comp_ret =3D crypto_wait_req(crypto_acomp_compress(acomp_ctx->reqs[0]), &= acomp_ctx->wait); + dlen =3D acomp_ctx->reqs[0]->dlen; if (comp_ret) goto unlock; =20 @@ -1001,27 +1050,27 @@ static bool zswap_decompress(struct zswap_entry *en= try, struct folio *folio) =20 acomp_ctx =3D raw_cpu_ptr(entry->pool->acomp_ctx); mutex_lock(&acomp_ctx->mutex); - obj =3D zpool_obj_read_begin(zpool, entry->handle, acomp_ctx->buffer); + obj =3D zpool_obj_read_begin(zpool, entry->handle, acomp_ctx->buffers[0]); =20 /* * zpool_obj_read_begin() might return a kmap address of highmem when - * acomp_ctx->buffer is not used. However, sg_init_one() does not - * handle highmem addresses, so copy the object to acomp_ctx->buffer. + * acomp_ctx->buffers[0] is not used. However, sg_init_one() does not + * handle highmem addresses, so copy the object to acomp_ctx->buffers[0]. */ if (virt_addr_valid(obj)) { src =3D obj; } else { - WARN_ON_ONCE(obj =3D=3D acomp_ctx->buffer); - memcpy(acomp_ctx->buffer, obj, entry->length); - src =3D acomp_ctx->buffer; + WARN_ON_ONCE(obj =3D=3D acomp_ctx->buffers[0]); + memcpy(acomp_ctx->buffers[0], obj, entry->length); + src =3D acomp_ctx->buffers[0]; } =20 sg_init_one(&input, src, entry->length); sg_init_table(&output, 1); sg_set_folio(&output, folio, PAGE_SIZE, 0); - acomp_request_set_params(acomp_ctx->req, &input, &output, entry->length, = PAGE_SIZE); - decomp_ret =3D crypto_wait_req(crypto_acomp_decompress(acomp_ctx->req), &= acomp_ctx->wait); - dlen =3D acomp_ctx->req->dlen; + acomp_request_set_params(acomp_ctx->reqs[0], &input, &output, entry->leng= th, PAGE_SIZE); + decomp_ret =3D crypto_wait_req(crypto_acomp_decompress(acomp_ctx->reqs[0]= ), &acomp_ctx->wait); + dlen =3D acomp_ctx->reqs[0]->dlen; =20 zpool_obj_read_end(zpool, entry->handle, obj); mutex_unlock(&acomp_ctx->mutex); --=20 2.27.0