From: Baoquan He <bhe@redhat.com> To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hch@lst.de, cl@linux.com, John.p.donnelly@oracle.com, kexec@lists.infradead.org, bhe@redhat.com, 42.hyeyoo@gmail.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, vbabka@suse.cz, David.Laight@ACULAB.COM, david@redhat.com, x86@kernel.org, bp@alien8.de Subject: [PATCH v4 1/3] mm_zone: add function to check if managed dma zone exists Date: Thu, 23 Dec 2021 17:44:33 +0800 [thread overview] Message-ID: <20211223094435.248523-2-bhe@redhat.com> (raw) In-Reply-To: <20211223094435.248523-1-bhe@redhat.com> In some places of the current kernel, it assumes that dma zone must have managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. E.g in kdump kernel of x86_64, only low 1M is presented and locked down at very early stage of boot, so that there's no managed pages at all in DMA zone. This exception will always cause page allocation failure if page is requested from DMA zone. Here add function has_managed_dma() and the relevant helper functions to check if there's DMA zone with managed pages. It will be used in later patches. Fixes: 6f599d84231f ("x86/kdump: Always reserve the low 1M when the crashkernel option is specified") Cc: stable@vger.kernel.org Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> --- include/linux/mmzone.h | 9 +++++++++ mm/page_alloc.c | 15 +++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 58e744b78c2c..6e1b726e9adf 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1046,6 +1046,15 @@ static inline int is_highmem_idx(enum zone_type idx) #endif } +#ifdef CONFIG_ZONE_DMA +bool has_managed_dma(void); +#else +static inline bool has_managed_dma(void) +{ + return false; +} +#endif + /** * is_highmem - helper function to quickly check if a struct zone is a * highmem zone or not. This is an attempt to keep references diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c5952749ad40..7c7a0b5de2ff 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -9460,3 +9460,18 @@ bool take_page_off_buddy(struct page *page) return ret; } #endif + +#ifdef CONFIG_ZONE_DMA +bool has_managed_dma(void) +{ + struct pglist_data *pgdat; + + for_each_online_pgdat(pgdat) { + struct zone *zone = &pgdat->node_zones[ZONE_DMA]; + + if (managed_zone(zone)) + return true; + } + return false; +} +#endif /* CONFIG_ZONE_DMA */ -- 2.26.3
WARNING: multiple messages have this Message-ID (diff)
From: Baoquan He <bhe@redhat.com> To: linux-kernel@vger.kernel.org Cc: linux-mm@kvack.org, akpm@linux-foundation.org, hch@lst.de, cl@linux.com, John.p.donnelly@oracle.com, kexec@lists.infradead.org, bhe@redhat.com, 42.hyeyoo@gmail.com, penberg@kernel.org, rientjes@google.com, iamjoonsoo.kim@lge.com, vbabka@suse.cz, David.Laight@ACULAB.COM, david@redhat.com, x86@kernel.org, bp@alien8.de Subject: [PATCH v4 1/3] mm_zone: add function to check if managed dma zone exists Date: Thu, 23 Dec 2021 17:44:33 +0800 [thread overview] Message-ID: <20211223094435.248523-2-bhe@redhat.com> (raw) In-Reply-To: <20211223094435.248523-1-bhe@redhat.com> In some places of the current kernel, it assumes that dma zone must have managed pages if CONFIG_ZONE_DMA is enabled. While this is not always true. E.g in kdump kernel of x86_64, only low 1M is presented and locked down at very early stage of boot, so that there's no managed pages at all in DMA zone. This exception will always cause page allocation failure if page is requested from DMA zone. Here add function has_managed_dma() and the relevant helper functions to check if there's DMA zone with managed pages. It will be used in later patches. Fixes: 6f599d84231f ("x86/kdump: Always reserve the low 1M when the crashkernel option is specified") Cc: stable@vger.kernel.org Signed-off-by: Baoquan He <bhe@redhat.com> Reviewed-by: David Hildenbrand <david@redhat.com> --- include/linux/mmzone.h | 9 +++++++++ mm/page_alloc.c | 15 +++++++++++++++ 2 files changed, 24 insertions(+) diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 58e744b78c2c..6e1b726e9adf 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -1046,6 +1046,15 @@ static inline int is_highmem_idx(enum zone_type idx) #endif } +#ifdef CONFIG_ZONE_DMA +bool has_managed_dma(void); +#else +static inline bool has_managed_dma(void) +{ + return false; +} +#endif + /** * is_highmem - helper function to quickly check if a struct zone is a * highmem zone or not. This is an attempt to keep references diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c5952749ad40..7c7a0b5de2ff 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -9460,3 +9460,18 @@ bool take_page_off_buddy(struct page *page) return ret; } #endif + +#ifdef CONFIG_ZONE_DMA +bool has_managed_dma(void) +{ + struct pglist_data *pgdat; + + for_each_online_pgdat(pgdat) { + struct zone *zone = &pgdat->node_zones[ZONE_DMA]; + + if (managed_zone(zone)) + return true; + } + return false; +} +#endif /* CONFIG_ZONE_DMA */ -- 2.26.3 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec
next prev parent reply other threads:[~2021-12-23 9:45 UTC|newest] Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top 2021-12-23 9:44 [PATCH v4 0/3] Handle warning of allocation failure on DMA zone w/o managed pages Baoquan He 2021-12-23 9:44 ` Baoquan He 2021-12-23 9:44 ` Baoquan He [this message] 2021-12-23 9:44 ` [PATCH v4 1/3] mm_zone: add function to check if managed dma zone exists Baoquan He 2021-12-23 15:00 ` john.p.donnelly 2021-12-23 15:00 ` john.p.donnelly 2021-12-23 9:44 ` [PATCH v4 2/3] dma/pool: create dma atomic pool only if dma zone has managed pages Baoquan He 2021-12-23 9:44 ` Baoquan He 2021-12-23 10:21 ` Christoph Hellwig 2021-12-23 10:21 ` Christoph Hellwig 2021-12-23 15:01 ` john.p.donnelly 2021-12-23 15:01 ` john.p.donnelly 2022-01-03 9:34 ` David Hildenbrand 2022-01-03 9:34 ` David Hildenbrand 2021-12-23 9:44 ` [PATCH v4 3/3] mm/page_alloc.c: do not warn allocation failure on zone DMA if no " Baoquan He 2021-12-23 9:44 ` Baoquan He 2021-12-23 15:01 ` john.p.donnelly 2021-12-23 15:01 ` john.p.donnelly 2021-12-25 5:53 ` Hyeonggon Yoo 2021-12-25 5:53 ` Hyeonggon Yoo 2021-12-27 8:32 ` Baoquan He 2021-12-27 8:32 ` Baoquan He 2021-12-28 5:06 ` Hyeonggon Yoo 2021-12-28 5:06 ` Hyeonggon Yoo 2022-01-12 16:25 ` [PATCH v4 0/3] Handle warning of allocation failure on DMA zone w/o " john.p.donnelly 2022-01-12 16:25 ` john.p.donnelly
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