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[67.174.241.145]) by smtp.gmail.com with ESMTPSA id y17-20020a170903011100b001788494b764sm10674639plc.231.2022.10.05.11.03.57 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 05 Oct 2022 11:03:58 -0700 (PDT) From: Yang Shi To: mgorman@techsingularity.net, agk@redhat.com, snitzer@kernel.org, dm-devel@redhat.com, akpm@linux-foundation.org Cc: linux-mm@kvack.org, linux-block@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/4] md: dm-crypt: use mempool page bulk allocator Date: Wed, 5 Oct 2022 11:03:41 -0700 Message-Id: <20221005180341.1738796-5-shy828301@gmail.com> X-Mailer: git-send-email 2.26.3 In-Reply-To: <20221005180341.1738796-1-shy828301@gmail.com> References: <20221005180341.1738796-1-shy828301@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org When using dm-crypt for full disk encryption, dm-crypt would allocate an out bio and allocate the same amount of pages as in bio for encryption. It currently allocates one page at a time in a loop. This is not efficient. So using mempool page bulk allocator instead of allocating one page at a time. The mempool page bulk allocator would improve the IOPS with 1M I/O by approxiamately 6%. The test is done on a VM with 80 vCPU and 64GB memory with an encrypted ram device (the impact from storage hardware could be minimized so that we could benchmark the dm-crypt layer more accurately). Before the patch: Jobs: 1 (f=1): [w(1)][100.0%][r=0KiB/s,w=402MiB/s][r=0,w=402 IOPS][eta 00m:00s] crypt: (groupid=0, jobs=1): err= 0: pid=233950: Thu Sep 15 16:23:10 2022 write: IOPS=402, BW=403MiB/s (423MB/s)(23.6GiB/60002msec) slat (usec): min=2425, max=3819, avg=2480.84, stdev=34.00 clat (usec): min=7, max=165751, avg=156398.72, stdev=4691.03 lat (msec): min=2, max=168, avg=158.88, stdev= 4.69 clat percentiles (msec): | 1.00th=[ 157], 5.00th=[ 157], 10.00th=[ 157], 20.00th=[ 157], | 30.00th=[ 157], 40.00th=[ 157], 50.00th=[ 157], 60.00th=[ 157], | 70.00th=[ 157], 80.00th=[ 157], 90.00th=[ 157], 95.00th=[ 157], | 99.00th=[ 159], 99.50th=[ 159], 99.90th=[ 165], 99.95th=[ 165], | 99.99th=[ 167] bw ( KiB/s): min=405504, max=413696, per=99.71%, avg=411845.53, stdev=1155.04, samples=120 iops : min= 396, max= 404, avg=402.17, stdev= 1.15, samples=120 lat (usec) : 10=0.01% lat (msec) : 4=0.01%, 10=0.01%, 20=0.02%, 50=0.05%, 100=0.08% lat (msec) : 250=100.09% cpu : usr=3.74%, sys=95.66%, ctx=27, majf=0, minf=4 IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=103.1% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0% issued rwts: total=0,24138,0,0 short=0,0,0,0 dropped=0,0,0,0 latency : target=0, window=0, percentile=100.00%, depth=64 Run status group 0 (all jobs): WRITE: bw=403MiB/s (423MB/s), 403MiB/s-403MiB/s (423MB/s-423MB/s), io=23.6GiB (25.4GB), run=60002-60002msec After the patch: Jobs: 1 (f=1): [w(1)][100.0%][r=0KiB/s,w=430MiB/s][r=0,w=430 IOPS][eta 00m:00s] crypt: (groupid=0, jobs=1): err= 0: pid=288730: Thu Sep 15 16:25:39 2022 write: IOPS=430, BW=431MiB/s (452MB/s)(25.3GiB/60002msec) slat (usec): min=2253, max=3213, avg=2319.49, stdev=34.29 clat (usec): min=6, max=149337, avg=146257.68, stdev=4239.52 lat (msec): min=2, max=151, avg=148.58, stdev= 4.24 clat percentiles (msec): | 1.00th=[ 146], 5.00th=[ 146], 10.00th=[ 146], 20.00th=[ 146], | 30.00th=[ 146], 40.00th=[ 146], 50.00th=[ 146], 60.00th=[ 146], | 70.00th=[ 146], 80.00th=[ 146], 90.00th=[ 148], 95.00th=[ 148], | 99.00th=[ 148], 99.50th=[ 148], 99.90th=[ 150], 99.95th=[ 150], | 99.99th=[ 150] bw ( KiB/s): min=438272, max=442368, per=99.73%, avg=440463.57, stdev=1305.60, samples=120 iops : min= 428, max= 432, avg=430.12, stdev= 1.28, samples=120 lat (usec) : 10=0.01% lat (msec) : 4=0.01%, 10=0.01%, 20=0.02%, 50=0.05%, 100=0.09% lat (msec) : 250=100.07% cpu : usr=3.78%, sys=95.37%, ctx=12778, majf=0, minf=4 IO depths : 1=0.1%, 2=0.1%, 4=0.1%, 8=0.1%, 16=0.1%, 32=0.1%, >=64=103.1% submit : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.0%, >=64=0.0% complete : 0=0.0%, 4=100.0%, 8=0.0%, 16=0.0%, 32=0.0%, 64=0.1%, >=64=0.0% issued rwts: total=0,25814,0,0 short=0,0,0,0 dropped=0,0,0,0 latency : target=0, window=0, percentile=100.00%, depth=64 Run status group 0 (all jobs): WRITE: bw=431MiB/s (452MB/s), 431MiB/s-431MiB/s (452MB/s-452MB/s), io=25.3GiB (27.1GB), run=60002-60002msec The function tracing also shows the time consumed by page allocations is reduced significantly. The test allocated 1M (256 pages) bio in the same environment. Before the patch: It took approximately 600us by excluding the bio_add_page() calls. 2720.630754 | 56) xfs_io-38859 | 2.571 us | mempool_alloc(); 2720.630757 | 56) xfs_io-38859 | 0.937 us | bio_add_page(); 2720.630758 | 56) xfs_io-38859 | 1.772 us | mempool_alloc(); 2720.630760 | 56) xfs_io-38859 | 0.852 us | bio_add_page(); …. 2720.631559 | 56) xfs_io-38859 | 2.058 us | mempool_alloc(); 2720.631561 | 56) xfs_io-38859 | 0.717 us | bio_add_page(); 2720.631562 | 56) xfs_io-38859 | 2.014 us | mempool_alloc(); 2720.631564 | 56) xfs_io-38859 | 0.620 us | bio_add_page(); After the patch: It took approxiamately 30us. 11564.266385 | 22) xfs_io-136183 | + 30.551 us | __alloc_pages_bulk(); Page allocations overhead is around 6% (600us/9853us) in dm-crypt layer shown by function trace. The data also matches the IOPS data shown by fio. And the benchmark with 4K size I/O doesn't show measurable regression. Signed-off-by: Yang Shi --- drivers/md/dm-crypt.c | 70 +++++++++++++++++++++++++------------------ 1 file changed, 41 insertions(+), 29 deletions(-) diff --git a/drivers/md/dm-crypt.c b/drivers/md/dm-crypt.c index 85ac1f9b37ae..c86bd4af4d75 100644 --- a/drivers/md/dm-crypt.c +++ b/drivers/md/dm-crypt.c @@ -1673,34 +1673,37 @@ static struct bio *crypt_alloc_buffer(struct dm_crypt_io *io, unsigned size) struct bio *clone; unsigned int nr_iovecs = (size + PAGE_SIZE - 1) >> PAGE_SHIFT; gfp_t gfp_mask = GFP_NOWAIT | __GFP_HIGHMEM; - unsigned i, len, remaining_size; + unsigned len; struct page *page; - -retry: - if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM)) - mutex_lock(&cc->bio_alloc_lock); + LIST_HEAD(page_list); clone = bio_alloc_bioset(cc->dev->bdev, nr_iovecs, io->base_bio->bi_opf, GFP_NOIO, &cc->bs); clone->bi_private = io; clone->bi_end_io = crypt_endio; - remaining_size = size; +retry: + if (unlikely(gfp_mask & __GFP_DIRECT_RECLAIM)) + mutex_lock(&cc->bio_alloc_lock); - for (i = 0; i < nr_iovecs; i++) { - page = mempool_alloc(&cc->page_pool, gfp_mask); - if (!page) { - crypt_free_buffer_pages(cc, clone); - bio_put(clone); - gfp_mask |= __GFP_DIRECT_RECLAIM; - goto retry; + if (mempool_alloc_pages_bulk_list(&cc->page_pool, gfp_mask, nr_iovecs, + &page_list)) { + while (!list_empty(&page_list)) { + page = lru_to_page(&page_list); + list_del_init(&page->lru); + len = (size > PAGE_SIZE) ? PAGE_SIZE : size; + bio_add_page(clone, page, len, 0); + size -= len; + } + } else { + while (!list_empty(&page_list)) { + page = lru_to_page(&page_list); + list_del_init(&page->lru); + mempool_free(page, &cc->page_pool); } - len = (remaining_size > PAGE_SIZE) ? PAGE_SIZE : remaining_size; - - bio_add_page(clone, page, len, 0); - - remaining_size -= len; + gfp_mask |= __GFP_DIRECT_RECLAIM; + goto retry; } /* Allocate space for integrity tags */ @@ -2654,10 +2657,13 @@ static void crypt_calculate_pages_per_client(void) dm_crypt_pages_per_client = pages; } -static void *crypt_page_alloc(gfp_t gfp_mask, void *pool_data) +static unsigned int crypt_alloc_pages_bulk(gfp_t gfp_mask, unsigned int nr, + void *pool_data, + struct list_head *page_list, + struct page **page_array) { struct crypt_config *cc = pool_data; - struct page *page; + unsigned int ret; /* * Note, percpu_counter_read_positive() may over (and under) estimate @@ -2666,13 +2672,13 @@ static void *crypt_page_alloc(gfp_t gfp_mask, void *pool_data) */ if (unlikely(percpu_counter_read_positive(&cc->n_allocated_pages) >= dm_crypt_pages_per_client) && likely(gfp_mask & __GFP_NORETRY)) - return NULL; + return 0; + + ret = alloc_pages_bulk_list(gfp_mask, nr, page_list); - page = alloc_page(gfp_mask); - if (likely(page != NULL)) - percpu_counter_add(&cc->n_allocated_pages, 1); + percpu_counter_add(&cc->n_allocated_pages, ret); - return page; + return ret; } static void crypt_page_free(void *page, void *pool_data) @@ -2704,13 +2710,17 @@ static void crypt_dtr(struct dm_target *ti) bioset_exit(&cc->bs); + /* + * With mempool bulk allocator the pages in the pool are not + * counted in n_allocated_pages. + */ + WARN_ON(percpu_counter_sum(&cc->n_allocated_pages) != 0); + percpu_counter_destroy(&cc->n_allocated_pages); + mempool_exit(&cc->page_pool); mempool_exit(&cc->req_pool); mempool_exit(&cc->tag_pool); - WARN_ON(percpu_counter_sum(&cc->n_allocated_pages) != 0); - percpu_counter_destroy(&cc->n_allocated_pages); - if (cc->iv_gen_ops && cc->iv_gen_ops->dtr) cc->iv_gen_ops->dtr(cc); @@ -3250,7 +3260,9 @@ static int crypt_ctr(struct dm_target *ti, unsigned int argc, char **argv) ALIGN(sizeof(struct dm_crypt_io) + cc->dmreq_start + additional_req_size, ARCH_KMALLOC_MINALIGN); - ret = mempool_init(&cc->page_pool, BIO_MAX_VECS, crypt_page_alloc, crypt_page_free, cc); + ret = mempool_init_pages_bulk(&cc->page_pool, BIO_MAX_VECS, + crypt_alloc_pages_bulk, crypt_page_free, + cc); if (ret) { ti->error = "Cannot allocate page mempool"; goto bad;