From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755266AbdABFlq (ORCPT ); Mon, 2 Jan 2017 00:41:46 -0500 Received: from mailout1.samsung.com ([203.254.224.24]:42984 "EHLO mailout1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750842AbdABFlo (ORCPT ); Mon, 2 Jan 2017 00:41:44 -0500 MIME-version: 1.0 Content-type: text/plain; charset=utf-8 X-AuditID: b6c32a58-f79726d000001ac1-d0-5869e815ddb4 Content-transfer-encoding: 8BIT Subject: Re: [PATCH] mm: cma: print allocation failure reason and bitmap status To: Michal Nazarewicz , Michal Hocko Cc: gregkh@linuxfoundation.org, akpm@linux-foundation.org, labbott@redhat.com, m.szyprowski@samsung.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, jaewon31.kim@gmail.com From: Jaewon Kim Message-id: <5869E849.1040605@samsung.com> Date: Mon, 02 Jan 2017 14:42:33 +0900 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.2 In-reply-to: X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFlrGJsWRmVeSWpSXmKPExsWy7bCmhq7oi8wIgwnrtCzmrF/DZtG8eD2b RffmmYwWK/f8YLK4vGsOm8W9Nf9ZLdYeuctu8frbMmaLBcdbWB04PXbOusvusWlVJ5vHpk+T 2D1OzPjN4rF/7hp2j3V/XjF5vN93lc2jb8sqRo/Pm+QCOKNSbTJSE1NSixRS85LzUzLz0m2V vIPjneNNzQwMdQ0tLcyVFPISc1NtlVx8AnTdMnOAjlRSKEvMKQUKBSQWFyvp29kU5ZeWpCpk 5BeX2CpFGxoa6RkamOsZGRnpmZjHWhmZApUkpGY8ObSAteCIc8W0HesZGxjnmHYxcnJICJhI 7GhqYIWwxSQu3FvP1sXIxSEksJRR4sqZPiYIp51J4mXXZWaYjlcnd7BDJJYzSqzduAcswSsg KPFj8j2WLkYODmYBeYkjl7JBwswCmhIvvkxigai/zyixb+9CRpCEsECgxIaNf5hAbBEBb4kH 21aCFTELbGWU6N7ZDjaUTUBb4v2CSawQC7QkfuycDdbAIqAq8XvfUrAaUYEIiR1zP4IN5QSq 2X/uKdjZEgLX2CU2bd/BDHKRhICsxKYDUKaLxLQVtRDPCEu8Or6FHcKWlvi79BYjRGs/o8Sm hQ3MEE4Po0TH/Hao940lensuMEO8xifR+/sJE8RQXomONiGIEg+Jpzeb2SBsR4mFD1qgvj/L JDF78VXmCYzys5ACbBYiwGYhBdgCRuZVjGKpBcW56anFpgUmesWJucWleel6yfm5mxjBaVQr YgfjvxlBhxgFOBiVeHgzYjMjhFgTy4orcw8xSnAwK4nwXngKFOJNSaysSi3Kjy8qzUktPsRo Cgy+icxSosn5wBSfVxJvaGJuYW5uZm5uaWhmpCTOu6DCOkJIID2xJDU7NbUgtQimj4mDU6qB UT241mDG5NfC2fLlRtfORM4+PdFHfXvpw0bRNrETpqkn+DuFipjMVYuPltq2X3/VF2lS0eZf IVa/V3nGSX6trM17mdV+3T94XW+R0uSs1rLb26xsk9680Pf3iv+399gc5k0yBnF/DfX2n03f tJA7/ePRd+2f6pqsikKW7pZoCHh1yG3LU9ONSizFGYmGWsxFxYkAHdE30LkDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFrrIIsWRmVeSWpSXmKPExsVy+t9jAV3RF5kRBs+eM1nMWb+GzaJ58Xo2 i+7NMxktVu75wWRxedccNot7a/6zWqw9cpfd4vW3ZcwWC463sDpweuycdZfdY9OqTjaPTZ8m sXucmPGbxWP/3DXsHuv+vGLyeL/vKptH35ZVjB6fN8kFcEa52WSkJqakFimk5iXnp2Tmpdsq hYa46VooKeQl5qbaKkXo+oYEKSmUJeaUAnlGBmjAwTnAPVhJ3y7BLePJoQWsBUecK6btWM/Y wDjHtIuRk0NCwETi1ckd7BC2mMSFe+vZuhi5OIQEljJK9J+cwwSS4BUQlPgx+R5LFyMHB7OA vMSRS9kQprrElCm5EOUPGSX23exiBSkXFvCXWHBrE1iriIC3xINtK1kgis4zSTy4sJ8ZxGEW 2Moose3sXrDNbALaEu8XTGKFWKYl8WPnbLBuFgFVid/7ljKD2KICERKr110DszmBavafe8o0 gVFgFpL7ZiHcNwvhvgWMzKsYJVILkguKk9JzjfJSy/WKE3OLS/PS9ZLzczcxgqPzmfQOxsO7 3A8xCnAwKvHwvmjKjBBiTSwrrsw9xCjBwawkwnvhKVCINyWxsiq1KD++qDQntfgQoynQiROZ pUST84GJI68k3tDE3MTc2MDC3NLSxEhJnLdx9rNwIYH0xJLU7NTUgtQimD4mDk6pBkbpWqEJ iQ9Dn1959svhtMtStzXffxz9u+j/hsYzWWVfH24tnDDHIilNPnSjSuaehbyBd5dOUUjeY3r9 z4n/b6M/7vlySiArRr+69hRTSLJQ/Y1nuz8kT63gjl40oT129irPD67Rk43f8JmnzDn+vVbA NfDu7nO5Mye+KZhctsuM6fFP863HyzvSlFiKMxINtZiLihMB7P/0UeQCAAA= X-MTR: 20000000000000000@CPGS X-CMS-MailID: 20170102054141epcas5p47e7f91abb5f3dc3977b3d1e13defe1fe X-Msg-Generator: CA X-Sender-IP: 203.254.230.27 X-Local-Sender: =?UTF-8?B?6rmA7J6s7JuQG1N5c3RlbSBTL1fqsJzrsJwy6re466O5KA==?= =?UTF-8?B?66y07ISgKRvsgrzshLHsoITsnpAbUzUo7LGF7J6EKS/ssYXsnoQ=?= X-Global-Sender: =?UTF-8?B?SmFld29uIEtpbRtTeXN0ZW0gUy9XIFImRCBHcm91cCAyG1Nh?= =?UTF-8?B?bXN1bmcgRWxlY3Ryb25pY3MbUzUvU2VuaW9yIEVuZ2luZWVy?= X-Sender-Code: =?UTF-8?B?QzEwG1RFTEUbQzEwRDkxMjI=?= CMS-TYPE: 105P DLP-Filter: Pass X-CFilter-Loop: Reflected X-HopCount: 7 X-CMS-RootMailID: 20161229022722epcas5p4be0e1924f3c8d906cbfb461cab8f0374 X-RootMTR: 20161229022722epcas5p4be0e1924f3c8d906cbfb461cab8f0374 References: <1482978482-14007-1-git-send-email-jaewon31.kim@samsung.com> <20161229091449.GG29208@dhcp22.suse.cz> <58660BBE.1040807@samsung.com> <20161230094411.GD13301@dhcp22.suse.cz> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2017년 01월 02일 06:59, Michal Nazarewicz wrote: > On Fri, Dec 30 2016, Michal Hocko wrote: >> On Fri 30-12-16 16:24:46, Jaewon Kim wrote: >> [...] >>> >From 7577cc94da3af27907aa6eec590d2ef51e4b9d80 Mon Sep 17 00:00:00 2001 >>> From: Jaewon Kim >>> Date: Thu, 29 Dec 2016 11:00:16 +0900 >>> Subject: [PATCH] mm: cma: print allocation failure reason and bitmap status >>> >>> There are many reasons of CMA allocation failure such as EBUSY, ENOMEM, EINTR. >>> But we did not know error reason so far. This patch prints the error value. >>> >>> Additionally if CONFIG_CMA_DEBUG is enabled, this patch shows bitmap status to >>> know available pages. Actually CMA internally try all available regions because >>> some regions can be failed because of EBUSY. Bitmap status is useful to know in >>> detail on both ENONEM and EBUSY; >>> ENOMEM: not tried at all because of no available region >>> it could be too small total region or could be fragmentation issue >>> EBUSY: tried some region but all failed >>> >>> This is an ENOMEM example with this patch. >>> [ 13.250961] [1: Binder:715_1: 846] cma: cma_alloc: alloc failed, req-size: 256 pages, ret: -12 >>> Avabile pages also will be shown if CONFIG_CMA_DEBUG is enabled >>> [ 13.251052] [1: Binder:715_1: 846] cma: number of available pages: 4@572+7@585+7@601+8@632+38@730+166@1114+127@1921=>357 pages, total: 2048 pages >> please mention how to interpret this information. Thank you Michal Hocko. I added like this If CONFIG_CMA_DEBUG is enabled, avabile pages also will be shown as concatenated size@position format. So 4@572 means that there are 4 available pages at 572 position starting from 0 position. >> >> some more style suggestions below >>> Signed-off-by: Jaewon Kim > Acked-by: Michal Nazarewicz Thank you I added your Ack Acked-by: Michal Nazarewicz >>> --- >>> mm/cma.c | 29 ++++++++++++++++++++++++++++- >>> 1 file changed, 28 insertions(+), 1 deletion(-) >>> >>> diff --git a/mm/cma.c b/mm/cma.c >>> index c960459..1bcd9db 100644 >>> --- a/mm/cma.c >>> +++ b/mm/cma.c >>> @@ -369,7 +369,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align) >>> unsigned long start = 0; >>> unsigned long bitmap_maxno, bitmap_no, bitmap_count; >>> struct page *page = NULL; >>> - int ret; >>> + int ret = -ENOMEM; >>> >>> if (!cma || !cma->count) >>> return NULL; >>> @@ -427,6 +427,33 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align) >>> trace_cma_alloc(pfn, page, count, align); >>> >>> pr_debug("%s(): returned %p\n", __func__, page); > This line should be moved after the ‘if (ret != 0)’ block, i.e. just > before return. Thank you Michal Nazarewicz I moved the pr_debug right before return pr_debug("%s(): returned %p\n", __func__, page); return page; >>> + >>> + if (ret != 0) >> you can simply do >> if (!ret) { Thank you I changed like this, it should be if(ret) rather than if(!ret) + if (ret) { + pr_info("%s: alloc failed, req-size: %zu pages, ret: %d\n", + __func__, count, ret); + debug_show_cma_areas(cma); + } >> >> pr_info("%s: alloc failed, req-size: %zu pages, ret: %d\n", >> __func__, count, ret); >> debug_show_cma_areas(); >> } >> >> return page; >> >> static void debug_show_cma_areas(void) >> { >> #ifdef CONFIG_CMA_DEBUG >> unsigned int nr, nr_total = 0; >> unsigned long next_set_bit; >> >> mutex_lock(&cma->lock); >> pr_info("number of available pages: "); >> start = 0; >> for (;;) { >> bitmap_no = find_next_zero_bit(cma->bitmap, cma->count, start); >> if (bitmap_no >= cma->count) >> break; >> next_set_bit = find_next_bit(cma->bitmap, cma->count, bitmap_no); >> nr = next_set_bit - bitmap_no; >> pr_cont("%s%u@%lu", nr_total ? "+" : "", nr, bitmap_no); >> nr_total += nr; >> start = bitmap_no + nr; >> } >> pr_cont("=>%u pages, total: %lu pages\n", nr_total, cma->count); > Perhaps: > pr_cont("=> %u free of %lu total pages\n", nr_total, cma->count); Thank you I will take this way. + pr_cont("=> %u free of %lu total pages\n", nr_total, cma->count); > or shorter (but more cryptic): > pr_cont("=> %u/%lu pages\n", nr_total, cma->count); > >> mutex_unlock(&cma->lock); >> #endif >> } > Actually, Linux style is more like: > > #ifdef CONFIG_CMA_DEBUG > static void cma_debug_show_areas() > { > … > } > #else > static inline void cma_debug_show_areas() { } > #endif Thank you I will take this way. FYI struct cma address should be passed as a argument. +#ifdef CONFIG_CMA_DEBUG +static void debug_show_cma_areas(struct cma *cma) +{ ... +#else +static inline void debug_show_cma_areas(struct cma *cma) { } +#endif >> -- >> Michal Hocko >> SUSE Labs Thank you all of you. Let me reattach my full patch to be clear. Let me know if I resend this as a new mail thread. >>From 03bf46bac222587f66fe9935a7879da30ff42cff Mon Sep 17 00:00:00 2001 From: Jaewon Kim Date: Thu, 29 Dec 2016 11:00:16 +0900 Subject: [PATCH] mm: cma: print allocation failure reason and bitmap status There are many reasons of CMA allocation failure such as EBUSY, ENOMEM, EINTR. But we did not know error reason so far. This patch prints the error value. Additionally if CONFIG_CMA_DEBUG is enabled, this patch shows bitmap status to know available pages. Actually CMA internally tries on all available regions because some regions can be failed because of EBUSY. Bitmap status is useful to know in detail on both ENONEM and EBUSY; ENOMEM: not tried at all because of no available region it could be too small total region or could be fragmentation issue EBUSY: tried some region but all failed This is an ENOMEM example with this patch. [ 12.415458] [2: Binder:714_1: 744] cma: cma_alloc: alloc failed, req-size: 256 pages, ret: -12 If CONFIG_CMA_DEBUG is enabled, avabile pages also will be shown as concatenated size@position format. So 4@572 means that there are 4 available pages at 572 position starting from 0 position. [ 12.415503] [2: Binder:714_1: 744] cma: number of available pages: 4@572+7@585+7@601+8@632+38@730+166@1114+127@1921=> 357 free of 2048 total pages Signed-off-by: Jaewon Kim Acked-by: Michal Nazarewicz --- mm/cma.c | 34 +++++++++++++++++++++++++++++++++- 1 file changed, 33 insertions(+), 1 deletion(-) diff --git a/mm/cma.c b/mm/cma.c index c960459..9e037541 100644 --- a/mm/cma.c +++ b/mm/cma.c @@ -353,6 +353,32 @@ int __init cma_declare_contiguous(phys_addr_t base, return ret; } +#ifdef CONFIG_CMA_DEBUG +static void debug_show_cma_areas(struct cma *cma) +{ + unsigned long next_zero_bit, next_set_bit; + unsigned long start = 0; + unsigned int nr_zero, nr_total = 0; + + mutex_lock(&cma->lock); + pr_info("number of available pages: "); + for (;;) { + next_zero_bit = find_next_zero_bit(cma->bitmap, cma->count, start); + if (next_zero_bit >= cma->count) + break; + next_set_bit = find_next_bit(cma->bitmap, cma->count, next_zero_bit); + nr_zero = next_set_bit - next_zero_bit; + pr_cont("%s%u@%lu", nr_total ? "+" : "", nr_zero, next_zero_bit); + nr_total += nr_zero; + start = next_zero_bit + nr_zero; + } + pr_cont("=> %u free of %lu total pages\n", nr_total, cma->count); + mutex_unlock(&cma->lock); +} +#else +static inline void debug_show_cma_areas(struct cma *cma) { } +#endif + /** * cma_alloc() - allocate pages from contiguous area * @cma: Contiguous memory region for which the allocation is performed. @@ -369,7 +395,7 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align) unsigned long start = 0; unsigned long bitmap_maxno, bitmap_no, bitmap_count; struct page *page = NULL; - int ret; + int ret = -ENOMEM; if (!cma || !cma->count) return NULL; @@ -426,6 +452,12 @@ struct page *cma_alloc(struct cma *cma, size_t count, unsigned int align) trace_cma_alloc(pfn, page, count, align); + if (ret) { + pr_info("%s: alloc failed, req-size: %zu pages, ret: %d\n", + __func__, count, ret); + debug_show_cma_areas(cma); + } + pr_debug("%s(): returned %p\n", __func__, page); return page; } --