Messages in this thread | | | Subject | Re: [PATCH] mm/swap: add function get_total_swap_pages to expose total_swap_pages | From | Chunming Zhou <> | Date | Wed, 31 Jan 2018 16:52:07 +0800 |
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Discussed with Roger just now, we can try "void si_swapinfo(struct sysinfo *val)" function to get the total swap space.
Regards,
David Zhou
On 2018年01月31日 16:12, Christian König wrote: > Yeah, indeed. But what we could do is to rely on a fixed limit like > the Intel driver does and I suggested before. > > E.g. don't copy anything into a shmemfile when there is only x MB of > swap space left. > > Roger can you test that approach once more with your fix for the OOM > issues in the page fault handler? > > Thanks, > Christian. > > Am 31.01.2018 um 09:08 schrieb He, Roger: >> I think this patch isn't need at all. You can directly read >> total_swap_pages variable in TTM. >> >> Because the variable is not exported by EXPORT_SYMBOL_GPL. So direct >> using will result in: >> "WARNING: "total_swap_pages" [drivers/gpu/drm/ttm/ttm.ko] undefined!". >> >> Thanks >> Roger(Hongbo.He) >> -----Original Message----- >> From: dri-devel [mailto:dri-devel-bounces@lists.freedesktop.org] On >> Behalf Of Chunming Zhou >> Sent: Wednesday, January 31, 2018 3:15 PM >> To: He, Roger <Hongbo.He@amd.com>; dri-devel@lists.freedesktop.org >> Cc: linux-mm@kvack.org; linux-kernel@vger.kernel.org; Koenig, >> Christian <Christian.Koenig@amd.com> >> Subject: Re: [PATCH] mm/swap: add function get_total_swap_pages to >> expose total_swap_pages >> >> Hi Roger, >> >> I think this patch isn't need at all. You can directly read >> total_swap_pages variable in TTM. See the comment: >> >> /* protected with swap_lock. reading in vm_swap_full() doesn't need >> lock */ long total_swap_pages; >> >> there are many places using it directly, you just couldn't change its >> value. Reading it doesn't need lock. >> >> >> Regards, >> >> David Zhou >> >> >> On 2018年01月29日 16:29, Roger He wrote: >>> ttm module needs it to determine its internal parameter setting. >>> >>> Signed-off-by: Roger He <Hongbo.He@amd.com> >>> --- >>> include/linux/swap.h | 6 ++++++ >>> mm/swapfile.c | 15 +++++++++++++++ >>> 2 files changed, 21 insertions(+) >>> >>> diff --git a/include/linux/swap.h b/include/linux/swap.h >>> index c2b8128..708d66f 100644 >>> --- a/include/linux/swap.h >>> +++ b/include/linux/swap.h >>> @@ -484,6 +484,7 @@ extern int try_to_free_swap(struct page *); >>> struct backing_dev_info; >>> extern int init_swap_address_space(unsigned int type, unsigned >>> long nr_pages); >>> extern void exit_swap_address_space(unsigned int type); >>> +extern long get_total_swap_pages(void); >>> #else /* CONFIG_SWAP */ >>> @@ -516,6 +517,11 @@ static inline void show_swap_cache_info(void) >>> { >>> } >>> +long get_total_swap_pages(void) >>> +{ >>> + return 0; >>> +} >>> + >>> #define free_swap_and_cache(e) ({(is_migration_entry(e) || >>> is_device_private_entry(e));}) >>> #define swapcache_prepare(e) ({(is_migration_entry(e) || >>> is_device_private_entry(e));}) >>> diff --git a/mm/swapfile.c b/mm/swapfile.c >>> index 3074b02..a0062eb 100644 >>> --- a/mm/swapfile.c >>> +++ b/mm/swapfile.c >>> @@ -98,6 +98,21 @@ static atomic_t proc_poll_event = ATOMIC_INIT(0); >>> atomic_t nr_rotate_swap = ATOMIC_INIT(0); >>> +/* >>> + * expose this value for others use >>> + */ >>> +long get_total_swap_pages(void) >>> +{ >>> + long ret; >>> + >>> + spin_lock(&swap_lock); >>> + ret = total_swap_pages; >>> + spin_unlock(&swap_lock); >>> + >>> + return ret; >>> +} >>> +EXPORT_SYMBOL_GPL(get_total_swap_pages); >>> + >>> static inline unsigned char swap_count(unsigned char ent) >>> { >>> return ent & ~SWAP_HAS_CACHE; /* may include SWAP_HAS_CONT >>> flag */ >> _______________________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/dri-devel >
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