Messages in this thread | | | Subject | Re: [External] [PATCH v4] dma-buf: Add DmaBufTotal counter in meminfo | From | Christian König <> | Date | Sat, 17 Apr 2021 17:03:30 +0200 |
| |
Am 17.04.21 um 16:21 schrieb Muchun Song: > On Sat, Apr 17, 2021 at 9:44 PM <Peter.Enderborg@sony.com> wrote: >> On 4/17/21 3:07 PM, Muchun Song wrote: >>> On Sat, Apr 17, 2021 at 6:41 PM Peter Enderborg >>> <peter.enderborg@sony.com> wrote: >>>> This adds a total used dma-buf memory. Details >>>> can be found in debugfs, however it is not for everyone >>>> and not always available. dma-buf are indirect allocated by >>>> userspace. So with this value we can monitor and detect >>>> userspace applications that have problems. >>>> >>>> Signed-off-by: Peter Enderborg <peter.enderborg@sony.com> >>>> --- >>>> drivers/dma-buf/dma-buf.c | 13 +++++++++++++ >>>> fs/proc/meminfo.c | 5 ++++- >>>> include/linux/dma-buf.h | 1 + >>>> 3 files changed, 18 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c >>>> index f264b70c383e..197e5c45dd26 100644 >>>> --- a/drivers/dma-buf/dma-buf.c >>>> +++ b/drivers/dma-buf/dma-buf.c >>>> @@ -37,6 +37,7 @@ struct dma_buf_list { >>>> }; >>>> >>>> static struct dma_buf_list db_list; >>>> +static atomic_long_t dma_buf_global_allocated; >>>> >>>> static char *dmabuffs_dname(struct dentry *dentry, char *buffer, int buflen) >>>> { >>>> @@ -79,6 +80,7 @@ static void dma_buf_release(struct dentry *dentry) >>>> if (dmabuf->resv == (struct dma_resv *)&dmabuf[1]) >>>> dma_resv_fini(dmabuf->resv); >>>> >>>> + atomic_long_sub(dmabuf->size, &dma_buf_global_allocated); >>>> module_put(dmabuf->owner); >>>> kfree(dmabuf->name); >>>> kfree(dmabuf); >>>> @@ -586,6 +588,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info) >>>> mutex_lock(&db_list.lock); >>>> list_add(&dmabuf->list_node, &db_list.head); >>>> mutex_unlock(&db_list.lock); >>>> + atomic_long_add(dmabuf->size, &dma_buf_global_allocated); >>>> >>>> return dmabuf; >>>> >>>> @@ -1346,6 +1349,16 @@ void dma_buf_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map) >>>> } >>>> EXPORT_SYMBOL_GPL(dma_buf_vunmap); >>>> >>>> +/** >>>> + * dma_buf_allocated_pages - Return the used nr of pages >>>> + * allocated for dma-buf >>>> + */ >>>> +long dma_buf_allocated_pages(void) >>>> +{ >>>> + return atomic_long_read(&dma_buf_global_allocated) >> PAGE_SHIFT; >>>> +} >>>> +EXPORT_SYMBOL_GPL(dma_buf_allocated_pages); >>> dma_buf_allocated_pages is only called from fs/proc/meminfo.c. >>> I am confused why it should be exported. If it won't be called >>> from the driver module, we should not export it. >> Ah. I thought you did not want the GPL restriction. I don't have real >> opinion about it. It's written to be following the rest of the module. >> It is not needed for the usage of dma-buf in kernel module. But I >> don't see any reason for hiding it either. > The modules do not need dma_buf_allocated_pages, hiding it > can prevent the module from calling it. So I think that > EXPORT_SYMBOL_GPL is unnecessary. If one day someone > want to call it from the module, maybe it’s not too late to export > it at that time.
Yeah, that is a rather good point. Only symbols which should be used by modules/drivers should be exported.
Christian.
> >> >>> Thanks. >>> >>>> + >>>> #ifdef CONFIG_DEBUG_FS >>>> static int dma_buf_debug_show(struct seq_file *s, void *unused) >>>> { >>>> diff --git a/fs/proc/meminfo.c b/fs/proc/meminfo.c >>>> index 6fa761c9cc78..ccc7c40c8db7 100644 >>>> --- a/fs/proc/meminfo.c >>>> +++ b/fs/proc/meminfo.c >>>> @@ -16,6 +16,7 @@ >>>> #ifdef CONFIG_CMA >>>> #include <linux/cma.h> >>>> #endif >>>> +#include <linux/dma-buf.h> >>>> #include <asm/page.h> >>>> #include "internal.h" >>>> >>>> @@ -145,7 +146,9 @@ static int meminfo_proc_show(struct seq_file *m, void *v) >>>> show_val_kb(m, "CmaFree: ", >>>> global_zone_page_state(NR_FREE_CMA_PAGES)); >>>> #endif >>>> - >>>> +#ifdef CONFIG_DMA_SHARED_BUFFER >>>> + show_val_kb(m, "DmaBufTotal: ", dma_buf_allocated_pages()); >>>> +#endif >>>> hugetlb_report_meminfo(m); >>>> >>>> arch_report_meminfo(m); >>>> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h >>>> index efdc56b9d95f..5b05816bd2cd 100644 >>>> --- a/include/linux/dma-buf.h >>>> +++ b/include/linux/dma-buf.h >>>> @@ -507,4 +507,5 @@ int dma_buf_mmap(struct dma_buf *, struct vm_area_struct *, >>>> unsigned long); >>>> int dma_buf_vmap(struct dma_buf *dmabuf, struct dma_buf_map *map); >>>> void dma_buf_vunmap(struct dma_buf *dmabuf, struct dma_buf_map *map); >>>> +long dma_buf_allocated_pages(void); >>>> #endif /* __DMA_BUF_H__ */ >>>> -- >>>> 2.17.1 >>>>
| |