Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S965702AbcKKW3Z (ORCPT ); Fri, 11 Nov 2016 17:29:25 -0500 Received: from mail-pg0-f42.google.com ([74.125.83.42]:35059 "EHLO mail-pg0-f42.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S965656AbcKKW3W (ORCPT ); Fri, 11 Nov 2016 17:29:22 -0500 From: Kees Cook To: Joel Fernandes Cc: Kees Cook , Anton Vorontsov , Colin Cross , Tony Luck , linux-kernel@vger.kernel.org Subject: [PATCH v3 5/8] ramoops: Split ftrace buffer space into per-CPU zones Date: Fri, 11 Nov 2016 14:21:50 -0800 Message-Id: <1478902913-143778-6-git-send-email-keescook@chromium.org> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1478902913-143778-1-git-send-email-keescook@chromium.org> References: <1478902913-143778-1-git-send-email-keescook@chromium.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7399 Lines: 222 From: Joel Fernandes If the RAMOOPS_FLAG_FTRACE_PER_CPU flag is passed to ramoops pdata, split the ftrace space into multiple zones depending on the number of CPUs. This speeds up the performance of function tracing by about 280% in my tests as we avoid the locking. The trade off being lesser space available per CPU. Let the ramoops user decide which option they want based on pdata flag. Signed-off-by: Joel Fernandes [kees: added max_ftrace_cnt to track size, added DT logic and docs] Signed-off-by: Kees Cook --- .../bindings/reserved-memory/ramoops.txt | 3 + fs/pstore/ram.c | 72 +++++++++++++++++----- include/linux/pstore_ram.h | 3 + 3 files changed, 61 insertions(+), 17 deletions(-) diff --git a/Documentation/devicetree/bindings/reserved-memory/ramoops.txt b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt index e81f821a2135..0eba562fe5c6 100644 --- a/Documentation/devicetree/bindings/reserved-memory/ramoops.txt +++ b/Documentation/devicetree/bindings/reserved-memory/ramoops.txt @@ -46,3 +46,6 @@ Optional properties: (defaults to buffered mappings) - no-dump-oops: if present, only dump panics (defaults to panics and oops) + +- flags: if present, pass ramoops behavioral flags (defaults to 0, + see include/linux/pstore_ram.h RAMOOPS_FLAG_* for flag values). diff --git a/fs/pstore/ram.c b/fs/pstore/ram.c index 34294c32af0b..0ed3fec04c9b 100644 --- a/fs/pstore/ram.c +++ b/fs/pstore/ram.c @@ -87,7 +87,7 @@ MODULE_PARM_DESC(ramoops_ecc, struct ramoops_context { struct persistent_ram_zone **przs; struct persistent_ram_zone *cprz; - struct persistent_ram_zone *fprz; + struct persistent_ram_zone **fprzs; struct persistent_ram_zone *mprz; phys_addr_t phys_addr; unsigned long size; @@ -97,12 +97,14 @@ struct ramoops_context { size_t ftrace_size; size_t pmsg_size; int dump_oops; + u32 flags; struct persistent_ram_ecc_info ecc_info; unsigned int max_dump_cnt; unsigned int dump_write_cnt; /* _read_cnt need clear on ramoops_pstore_open */ unsigned int dump_read_cnt; unsigned int console_read_cnt; + unsigned int max_ftrace_cnt; unsigned int ftrace_read_cnt; unsigned int pmsg_read_cnt; struct pstore_info pstore; @@ -219,9 +221,17 @@ static ssize_t ramoops_pstore_read(u64 *id, enum pstore_type_id *type, if (!prz_ok(prz)) prz = ramoops_get_next_prz(&cxt->cprz, &cxt->console_read_cnt, 1, id, type, PSTORE_TYPE_CONSOLE, 0); - if (!prz_ok(prz)) - prz = ramoops_get_next_prz(&cxt->fprz, &cxt->ftrace_read_cnt, - 1, id, type, PSTORE_TYPE_FTRACE, 0); + if (!prz_ok(prz)) { + while (cxt->ftrace_read_cnt < cxt->max_ftrace_cnt && !prz) { + prz = ramoops_get_next_prz(cxt->fprzs, + &cxt->ftrace_read_cnt, + cxt->max_ftrace_cnt, id, type, + PSTORE_TYPE_FTRACE, 0); + if (!prz_ok(prz)) + continue; + } + } + if (!prz_ok(prz)) prz = ramoops_get_next_prz(&cxt->mprz, &cxt->pmsg_read_cnt, 1, id, type, PSTORE_TYPE_PMSG, 0); @@ -283,9 +293,19 @@ static int notrace ramoops_pstore_write_buf(enum pstore_type_id type, persistent_ram_write(cxt->cprz, buf, size); return 0; } else if (type == PSTORE_TYPE_FTRACE) { - if (!cxt->fprz) + int zonenum; + + if (!cxt->fprzs) return -ENOMEM; - persistent_ram_write(cxt->fprz, buf, size); + /* + * Choose zone by if we're using per-cpu buffers. + */ + if (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) + zonenum = smp_processor_id(); + else + zonenum = 0; + + persistent_ram_write(cxt->fprzs[zonenum], buf, size); return 0; } else if (type == PSTORE_TYPE_PMSG) { pr_warn_ratelimited("PMSG shouldn't call %s\n", __func__); @@ -363,7 +383,9 @@ static int ramoops_pstore_erase(enum pstore_type_id type, u64 id, int count, prz = cxt->cprz; break; case PSTORE_TYPE_FTRACE: - prz = cxt->fprz; + if (id >= cxt->max_ftrace_cnt) + return -EINVAL; + prz = cxt->fprzs[id]; break; case PSTORE_TYPE_PMSG: prz = cxt->mprz; @@ -394,14 +416,22 @@ static void ramoops_free_przs(struct ramoops_context *cxt) { int i; - if (!cxt->przs) - return; + /* Free dump PRZs */ + if (cxt->przs) { + for (i = 0; i < cxt->max_dump_cnt; i++) + persistent_ram_free(cxt->przs[i]); - for (i = 0; i < cxt->max_dump_cnt; i++) - persistent_ram_free(cxt->przs[i]); + kfree(cxt->przs); + cxt->max_dump_cnt = 0; + } - kfree(cxt->przs); - cxt->max_dump_cnt = 0; + /* Free ftrace PRZs */ + if (cxt->fprzs) { + for (i = 0; i < cxt->max_ftrace_cnt; i++) + persistent_ram_free(cxt->fprzs[i]); + kfree(cxt->fprzs); + cxt->max_ftrace_cnt = 0; + } } static int ramoops_init_przs(struct device *dev, struct ramoops_context *cxt, @@ -567,6 +597,7 @@ static int ramoops_parse_dt(struct platform_device *pdev, parse_size("ftrace-size", pdata->ftrace_size); parse_size("pmsg-size", pdata->pmsg_size); parse_size("ecc-size", pdata->ecc_info.ecc_size); + parse_size("flags", pdata->flags); #undef parse_size @@ -624,6 +655,7 @@ static int ramoops_probe(struct platform_device *pdev) cxt->ftrace_size = pdata->ftrace_size; cxt->pmsg_size = pdata->pmsg_size; cxt->dump_oops = pdata->dump_oops; + cxt->flags = pdata->flags; cxt->ecc_info = pdata->ecc_info; paddr = cxt->phys_addr; @@ -640,8 +672,14 @@ static int ramoops_probe(struct platform_device *pdev) if (err) goto fail_init_cprz; - err = ramoops_init_prz(dev, cxt, &cxt->fprz, &paddr, cxt->ftrace_size, - LINUX_VERSION_CODE); + cxt->max_ftrace_cnt = (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) + ? nr_cpu_ids + : 1; + err = ramoops_init_przs(dev, cxt, &cxt->fprzs, &paddr, cxt->ftrace_size, + -1, &cxt->max_ftrace_cnt, + LINUX_VERSION_CODE, + (cxt->flags & RAMOOPS_FLAG_FTRACE_PER_CPU) + ? PRZ_FLAG_NO_LOCK : 0); if (err) goto fail_init_fprz; @@ -705,7 +743,6 @@ static int ramoops_probe(struct platform_device *pdev) cxt->pstore.bufsize = 0; persistent_ram_free(cxt->mprz); fail_init_mprz: - persistent_ram_free(cxt->fprz); fail_init_fprz: persistent_ram_free(cxt->cprz); fail_init_cprz: @@ -724,7 +761,6 @@ static int ramoops_remove(struct platform_device *pdev) cxt->pstore.bufsize = 0; persistent_ram_free(cxt->mprz); - persistent_ram_free(cxt->fprz); persistent_ram_free(cxt->cprz); ramoops_free_przs(cxt); @@ -766,6 +802,8 @@ static void ramoops_register_dummy(void) dummy_data->ftrace_size = ramoops_ftrace_size; dummy_data->pmsg_size = ramoops_pmsg_size; dummy_data->dump_oops = dump_oops; + dummy_data->flags = RAMOOPS_FLAG_FTRACE_PER_CPU; + /* * For backwards compatibility ramoops.ecc=1 means 16 bytes ECC * (using 1 byte for ECC isn't much of use anyway). diff --git a/include/linux/pstore_ram.h b/include/linux/pstore_ram.h index 4058bf991868..9395f06e8372 100644 --- a/include/linux/pstore_ram.h +++ b/include/linux/pstore_ram.h @@ -86,6 +86,8 @@ ssize_t persistent_ram_ecc_string(struct persistent_ram_zone *prz, * @mem_address physical memory address to contain ramoops */ +#define RAMOOPS_FLAG_FTRACE_PER_CPU BIT(0) + struct ramoops_platform_data { unsigned long mem_size; phys_addr_t mem_address; @@ -95,6 +97,7 @@ struct ramoops_platform_data { unsigned long ftrace_size; unsigned long pmsg_size; int dump_oops; + u32 flags; struct persistent_ram_ecc_info ecc_info; }; -- 2.7.4