From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it0-f72.google.com (mail-it0-f72.google.com [209.85.214.72]) by kanga.kvack.org (Postfix) with ESMTP id 483546B0005 for ; Wed, 31 Jan 2018 03:52:22 -0500 (EST) Received: by mail-it0-f72.google.com with SMTP id g202so3373638ita.4 for ; Wed, 31 Jan 2018 00:52:22 -0800 (PST) Received: from NAM02-BL2-obe.outbound.protection.outlook.com (mail-bl2nam02on0040.outbound.protection.outlook.com. [104.47.38.40]) by mx.google.com with ESMTPS id y6si1717684itd.86.2018.01.31.00.52.20 for (version=TLS1_2 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Wed, 31 Jan 2018 00:52:21 -0800 (PST) Subject: Re: [PATCH] mm/swap: add function get_total_swap_pages to expose total_swap_pages References: <1517214582-30880-1-git-send-email-Hongbo.He@amd.com> <9ecba5f4-3d4c-0179-bf03-f89c436cff6b@amd.com> From: Chunming Zhou Message-ID: <72eb44ec-fb94-6b41-b660-f6e6f8f589fa@amd.com> Date: Wed, 31 Jan 2018 16:52:07 +0800 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset="utf-8"; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US Sender: owner-linux-mm@kvack.org List-ID: To: =?UTF-8?Q?Christian_K=c3=b6nig?= , "He, Roger" , "Zhou, David(ChunMing)" , "dri-devel@lists.freedesktop.org" Cc: "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" 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 2018a1'01ae??31ae?JPY 16:12, Christian KA?nig 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: >> A A A A 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 ; dri-devel@lists.freedesktop.org >> Cc: linux-mm@kvack.org; linux-kernel@vger.kernel.org; Koenig, >> Christian >> 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 2018a1'01ae??29ae?JPY 16:29, Roger He wrote: >>> ttm module needs it to determine its internal parameter setting. >>> >>> Signed-off-by: Roger He >>> --- >>> A A include/linux/swap.h |A 6 ++++++ >>> A A mm/swapfile.cA A A A A A A | 15 +++++++++++++++ >>> A A 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 *); >>> A A struct backing_dev_info; >>> A A extern int init_swap_address_space(unsigned int type, unsigned >>> long nr_pages); >>> A A extern void exit_swap_address_space(unsigned int type); >>> +extern long get_total_swap_pages(void); >>> A A A A #else /* CONFIG_SWAP */ >>> A A @@ -516,6 +517,11 @@ static inline void show_swap_cache_info(void) >>> A A { >>> A A } >>> A A +long get_total_swap_pages(void) >>> +{ >>> +A A A return 0; >>> +} >>> + >>> A A #define free_swap_and_cache(e) ({(is_migration_entry(e) || >>> is_device_private_entry(e));}) >>> A A #define swapcache_prepare(e) ({(is_migration_entry(e) || >>> is_device_private_entry(e));}) >>> A A 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); >>> A A A A atomic_t nr_rotate_swap = ATOMIC_INIT(0); >>> A A +/* >>> + * expose this value for others use >>> + */ >>> +long get_total_swap_pages(void) >>> +{ >>> +A A A long ret; >>> + >>> +A A A spin_lock(&swap_lock); >>> +A A A ret = total_swap_pages; >>> +A A A spin_unlock(&swap_lock); >>> + >>> +A A A return ret; >>> +} >>> +EXPORT_SYMBOL_GPL(get_total_swap_pages); >>> + >>> A A static inline unsigned char swap_count(unsigned char ent) >>> A A { >>> A A A A A A return ent & ~SWAP_HAS_CACHE;A A A /* may include SWAP_HAS_CONT >>> flag */ >> _______________________________________________ >> dri-devel mailing list >> dri-devel@lists.freedesktop.org >> https://lists.freedesktop.org/mailman/listinfo/dri-devel > -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org