From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f54.google.com (mail-ed1-f54.google.com [209.85.208.54]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 8749010E1 for ; Fri, 3 Jun 2022 14:56:52 +0000 (UTC) Received: by mail-ed1-f54.google.com with SMTP id z7so10476816edm.13 for ; Fri, 03 Jun 2022 07:56:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=plkRHxZRk9CMIn7YOznv+vuUGRy66YRIHBjRF967Ovg=; b=OFHroXywrVa28TjmeuM2CMND/lkHNeB16Lt8Jq4E+glKJ+M7g6kanfCClZ/vFLbsov r8u80hXBHLksypvSYoPqwzFpAvd//6QXleUWoJK13uqoAIkBMosyf14qgs97WAoRRFMS 2KC6Aydv3OfnpRsyHYsxy5s2+idac3Jr5ftWPg1lOOMhX2cY9q1vxiYomkU9wyA37TPs y092tj0B+WAidkzySllTdAu4D4oFoTQV5zFbZgVofWXuBfipvdQrWKcYFYeiqnrtaMUH 4A/YjJ4MwVGW9fEPcYOu8uvC7WZOVe5qBOe1jEhd3lz2/ZtjlZn/oDr2bvMun5l0roiS 2EfA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=plkRHxZRk9CMIn7YOznv+vuUGRy66YRIHBjRF967Ovg=; b=b8V1YsXmGWG7tW2d7Rs2Qh54Iawm82M55Utgqd7xvrJb5nJmj2eqTpHPH5q/5RavQj oVfe+eoII+kRVlRP7nNarBHcgT8FKf0s2n4CKYgJHee77enT6/6LF1Oy0N6emLNgB9Dx Znef+dMvXckPT2AeZEtRE0ZHjYzHTfdFiQfjZtA9bnivS6TE31npAhK51nvtQNwy/J5t SJLzUQCfY9N4eck6leNjgJx6oasAViblady6bT5J3vhsbDvP1OYNHjRFaiLgP+pmlpUK 7gOHaKR/nUz/OkQrtS3TOl3x4nRqMYZ+EcYab7DBDxq1F37OfWUeOi9fCVlEWAOFCr7c iCMw== X-Gm-Message-State: AOAM530IBuwX3xXkQ01kayazEsj46XvVikwmRgFl+jp0zvsQZH2OuyVN cX7Aat0zypI41HnZmKuM6fA= X-Google-Smtp-Source: ABdhPJx1tqTWq+bg3K48QBR4njKSxXrtNNk36G7Ebems4gSc3jniGgD8tYlpAFClGJES+20LMJVByg== X-Received: by 2002:a05:6402:b45:b0:42d:bf43:8db1 with SMTP id bx5-20020a0564020b4500b0042dbf438db1mr11221191edb.100.1654268210815; Fri, 03 Jun 2022 07:56:50 -0700 (PDT) Received: from orion.localdomain ([93.99.228.15]) by smtp.gmail.com with ESMTPSA id e2-20020a1709062d4200b006fec2097d53sm2917509eji.118.2022.06.03.07.56.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 03 Jun 2022 07:56:46 -0700 (PDT) Received: by orion.localdomain (Postfix, from userid 1003) id AEEECA0366; Fri, 3 Jun 2022 16:57:20 +0200 (CEST) From: =?UTF-8?q?Jakub=20Mat=C4=9Bna?= To: akpm@linux-foundation.org Cc: linux-mm@kvack.org, patches@lists.linux.dev, linux-kernel@vger.kernel.org, vbabka@suse.cz, mhocko@kernel.org, mgorman@techsingularity.net, willy@infradead.org, liam.howlett@oracle.com, hughd@google.com, kirill@shutemov.name, riel@surriel.com, rostedt@goodmis.org, peterz@infradead.org, =?UTF-8?q?Jakub=20Mat=C4=9Bna?= Subject: [PATCH v4 2/2] [PATCH 2/2] mm: add merging after mremap resize Date: Fri, 3 Jun 2022 16:57:19 +0200 Message-Id: <20220603145719.1012094-3-matenajakub@gmail.com> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220603145719.1012094-1-matenajakub@gmail.com> References: <20220603145719.1012094-1-matenajakub@gmail.com> Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When mremap call results in expansion, it might be possible to merge the VMA with the next VMA which might become adjacent. This patch adds vma_merge call after the expansion is done to try and merge. Signed-off-by: Jakub Matěna --- mm/mremap.c | 19 +++++++++- tools/testing/selftests/vm/mremap_test.c | 47 +++++++++++++++++++++++- 2 files changed, 63 insertions(+), 3 deletions(-) diff --git a/mm/mremap.c b/mm/mremap.c index 0b93fac76851..66970dcd636a 100644 --- a/mm/mremap.c +++ b/mm/mremap.c @@ -9,6 +9,7 @@ */ #include +#include #include #include #include @@ -23,6 +24,7 @@ #include #include #include +#include #include #include @@ -1014,6 +1016,9 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, /* can we just expand the current mapping? */ if (vma_expandable(vma, new_len - old_len)) { long pages = (new_len - old_len) >> PAGE_SHIFT; + unsigned long extension_start = addr + old_len; + unsigned long extension_end = addr + new_len; + pgoff_t extension_pgoff = vma->vm_pgoff + (old_len >> PAGE_SHIFT); if (vma->vm_flags & VM_ACCOUNT) { if (security_vm_enough_memory_mm(mm, pages)) { @@ -1022,8 +1027,18 @@ SYSCALL_DEFINE5(mremap, unsigned long, addr, unsigned long, old_len, } } - if (vma_adjust(vma, vma->vm_start, addr + new_len, - vma->vm_pgoff, NULL)) { + /* + * Function vma_merge() is called on the extension we are adding to + * the already existing vma, vma_merge() will merge this extension with + * the already existing vma (expand operation itself) and possibly also + * with the next vma if it becomes adjacent to the expanded vma and + * otherwise compatible. + */ + vma = vma_merge(mm, vma, extension_start, extension_end, + vma->vm_flags, vma->anon_vma, vma->vm_file, + extension_pgoff, vma_policy(vma), + vma->vm_userfaultfd_ctx, anon_vma_name(vma)); + if (!vma) { vm_unacct_memory(pages); ret = -ENOMEM; goto out; diff --git a/tools/testing/selftests/vm/mremap_test.c b/tools/testing/selftests/vm/mremap_test.c index db0270127aeb..0865a6cb5bdb 100644 --- a/tools/testing/selftests/vm/mremap_test.c +++ b/tools/testing/selftests/vm/mremap_test.c @@ -118,6 +118,48 @@ static unsigned long long get_mmap_min_addr(void) return addr; } +/* + * This test validates that merge is called when expanding a mapping. + * Mapping containing three pages is created, middle page is unmapped + * and then the mapping containing the first page is expanded so that + * it fills the created hole. The two parts should merge creating + * single mapping with three pages. + */ +static void mremap_expand_merge(unsigned long page_size) +{ + char *test_name = "mremap expand merge"; + FILE *fp; + char *line = NULL; + size_t len = 0; + bool success = false; + + char *start = mmap(NULL, 3 * page_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); + munmap(start + page_size, page_size); + mremap(start, page_size, 2 * page_size, 0); + + fp = fopen("/proc/self/maps", "r"); + if (fp == NULL) { + ksft_test_result_fail("%s\n", test_name); + return; + } + + while(getline(&line, &len, fp) != -1) { + char *first = strtok(line,"- "); + void *first_val = (void *) strtol(first, NULL, 16); + char *second = strtok(NULL,"- "); + void *second_val = (void *) strtol(second, NULL, 16); + if (first_val == start && second_val == start + 3 * page_size) { + success = true; + break; + } + } + if (success) + ksft_test_result_pass("%s\n", test_name); + else + ksft_test_result_fail("%s\n", test_name); + fclose(fp); +} + /* * Returns the start address of the mapping on success, else returns * NULL on failure. @@ -336,6 +378,7 @@ int main(int argc, char **argv) int i, run_perf_tests; unsigned int threshold_mb = VALIDATION_DEFAULT_THRESHOLD; unsigned int pattern_seed; + int num_expand_tests = 1; struct test test_cases[MAX_TEST]; struct test perf_test_cases[MAX_PERF_TEST]; int page_size; @@ -407,12 +450,14 @@ int main(int argc, char **argv) (threshold_mb * _1MB >= _1GB); ksft_set_plan(ARRAY_SIZE(test_cases) + (run_perf_tests ? - ARRAY_SIZE(perf_test_cases) : 0)); + ARRAY_SIZE(perf_test_cases) : 0) + num_expand_tests); for (i = 0; i < ARRAY_SIZE(test_cases); i++) run_mremap_test_case(test_cases[i], &failures, threshold_mb, pattern_seed); + mremap_expand_merge(page_size); + if (run_perf_tests) { ksft_print_msg("\n%s\n", "mremap HAVE_MOVE_PMD/PUD optimization time comparison for 1GB region:"); -- 2.35.1