From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-101.freemail.mail.aliyun.com (out30-101.freemail.mail.aliyun.com [115.124.30.101]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 182652C6BB for ; Mon, 1 Jul 2024 08:33:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719822826; cv=none; b=iuVodpSJvUCKaRh7R4W0tvLjOm02QI3v9MdRApkwc+wlKuL5Ebw8siq3PYV6VpMBoAprV1ND10TcFyRYLiTBOCjR9BE4fTHtY5vDUWWtlv/I/CPk4P4e35f04DnBcwx9MI4rnGkyRm9iOnP1HtuxTI/Irn6ZgS6PK54PPSXse+U= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719822826; c=relaxed/simple; bh=58eBnkYXhzXTxsURmwzrQKbUo++8ALTqE6Ly/5vKmS0=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=QpjccPcNzb0qTKDAM6nGAGcSQD9u25VEfrupj22dJfJku6C/LtV0seSqrkavWrzDwHGYr+msqQyeWLvJ96Q4C4Oh3LuZVUPJ1MW7TTjrRjECHalM2lXkCRZqMRjOdgfNg/9BXFzBJVnDFCuZJ2qglVHS3Rs0vaI4wqILIsEFOXM= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=ZD2UhnFR; arc=none smtp.client-ip=115.124.30.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="ZD2UhnFR" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1719822815; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=BUFOSpzDuAC43YmekwvjTOLx8yMs9durOLK1l/9bwYU=; b=ZD2UhnFRrHonuzPPwyAnzUdNVqI+NNuH4gwLc8Wvhx9aaQNdTju2M39Vd1PRwoB4vfhZBIMQvfzbykKUlHnoE8XoiLGeqoNHtMjJLVYiOFFgTZLZMlm/b1Zy5vuXFb5Rj2TAFmpmAacMaQj6pn4XBu6HTd1wpEUdpokq2p0Olvk= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R551e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=maildocker-contentspam033037067112;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0W9c.k7Y_1719822814; Received: from 30.97.56.67(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W9c.k7Y_1719822814) by smtp.aliyun-inc.com; Mon, 01 Jul 2024 16:33:34 +0800 Message-ID: <4d54880e-03f4-460a-94b9-e21b8ad13119@linux.alibaba.com> Date: Mon, 1 Jul 2024 16:33:33 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH] support "THPeligible" semantics for mTHP with anonymous shmem To: Ryan Roberts , Bang Li , hughd@google.com, akpm@linux-foundation.org Cc: david@redhat.com, wangkefeng.wang@huawei.com, ziy@nvidia.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org References: <20240628104926.34209-1-libang.li@antgroup.com> <4b38db15-0716-4ffb-a38b-bd6250eb93da@arm.com> From: Baolin Wang In-Reply-To: <4b38db15-0716-4ffb-a38b-bd6250eb93da@arm.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2024/7/1 15:55, Ryan Roberts wrote: > On 28/06/2024 11:49, Bang Li wrote: >> After the commit 7fb1b252afb5 ("mm: shmem: add mTHP support for >> anonymous shmem"), we can configure different policies through >> the multi-size THP sysfs interface for anonymous shmem. But >> currently "THPeligible" indicates only whether the mapping is >> eligible for allocating THP-pages as well as the THP is PMD >> mappable or not for anonymous shmem, we need to support semantics >> for mTHP with anonymous shmem similar to those for mTHP with >> anonymous memory. >> >> Signed-off-by: Bang Li >> --- >> fs/proc/task_mmu.c | 10 +++++++--- >> include/linux/huge_mm.h | 11 +++++++++++ >> mm/shmem.c | 9 +-------- >> 3 files changed, 19 insertions(+), 11 deletions(-) >> >> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c >> index 93fb2c61b154..09b5db356886 100644 >> --- a/fs/proc/task_mmu.c >> +++ b/fs/proc/task_mmu.c >> @@ -870,6 +870,7 @@ static int show_smap(struct seq_file *m, void *v) >> { >> struct vm_area_struct *vma = v; >> struct mem_size_stats mss = {}; >> + bool thp_eligible; >> >> smap_gather_stats(vma, &mss, 0); >> >> @@ -882,9 +883,12 @@ static int show_smap(struct seq_file *m, void *v) >> >> __show_smap(m, &mss, false); >> >> - seq_printf(m, "THPeligible: %8u\n", >> - !!thp_vma_allowable_orders(vma, vma->vm_flags, >> - TVA_SMAPS | TVA_ENFORCE_SYSFS, THP_ORDERS_ALL)); >> + thp_eligible = !!thp_vma_allowable_orders(vma, vma->vm_flags, >> + TVA_SMAPS | TVA_ENFORCE_SYSFS, THP_ORDERS_ALL); >> + if (vma_is_anon_shmem(vma)) >> + thp_eligible = !!shmem_allowable_huge_orders(file_inode(vma->vm_file), >> + vma, vma->vm_pgoff, thp_eligible); > > Afraid I haven't been following the shmem mTHP support work as much as I would > have liked, but is there a reason why we need a separate function for shmem? Since shmem_allowable_huge_orders() only uses shmem specific logic to determine if huge orders are allowable, there is no need to complicate the thp_vma_allowable_orders() function by adding more shmem related logic, making it more bloated. In my view, providing a dedicated helper shmem_allowable_huge_orders(), specifically for shmem, simplifies the logic. IIUC, I agree with David's suggestion that the shmem_allowable_huge_orders() helper function could be used in thp_vma_allowable_orders() to support shmem mTHP. Something like: diff --git a/mm/huge_memory.c b/mm/huge_memory.c index c7ce28f6b7f3..9677fe6cf478 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -151,10 +151,13 @@ unsigned long __thp_vma_allowable_orders(struct vm_area_struct *vma, * Must be done before hugepage flags check since shmem has its * own flags. */ - if (!in_pf && shmem_file(vma->vm_file)) - return shmem_is_huge(file_inode(vma->vm_file), vma->vm_pgoff, - !enforce_sysfs, vma->vm_mm, vm_flags) - ? orders : 0; + if (!in_pf && shmem_file(vma->vm_file)) { + bool global_huge = shmem_is_huge(file_inode(vma->vm_file), vma->vm_pgoff, + !enforce_sysfs, vma->vm_mm, vm_flags); + + return shmem_allowable_huge_orders(file_inode(vma->vm_file), + vma, vma->vm_pgoff, global_huge); + } if (!vma_is_anonymous(vma)) { /* > Couldn't (shouldn't) thp_vma_allowable_orders() be taught to handle shmem too? > >> + seq_printf(m, "THPeligible: %8u\n", thp_eligible); >> >> if (arch_pkeys_enabled()) >> seq_printf(m, "ProtectionKey: %8u\n", vma_pkey(vma)); >> diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h >> index 212cca384d7e..f87136f38aa1 100644 >> --- a/include/linux/huge_mm.h >> +++ b/include/linux/huge_mm.h >> @@ -267,6 +267,10 @@ unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma, >> return __thp_vma_allowable_orders(vma, vm_flags, tva_flags, orders); >> } >> >> +unsigned long shmem_allowable_huge_orders(struct inode *inode, >> + struct vm_area_struct *vma, pgoff_t index, >> + bool global_huge); >> + >> struct thpsize { >> struct kobject kobj; >> struct list_head node; >> @@ -460,6 +464,13 @@ static inline unsigned long thp_vma_allowable_orders(struct vm_area_struct *vma, >> return 0; >> } >> >> +static inline unsigned long shmem_allowable_huge_orders(struct inode *inode, >> + struct vm_area_struct *vma, pgoff_t index, >> + bool global_huge) >> +{ >> + return 0; >> +} >> + >> #define transparent_hugepage_flags 0UL >> >> #define thp_get_unmapped_area NULL >> diff --git a/mm/shmem.c b/mm/shmem.c >> index d495c0701a83..aa85df9c662a 100644 >> --- a/mm/shmem.c >> +++ b/mm/shmem.c >> @@ -1622,7 +1622,7 @@ static gfp_t limit_gfp_mask(gfp_t huge_gfp, gfp_t limit_gfp) >> } >> >> #ifdef CONFIG_TRANSPARENT_HUGEPAGE >> -static unsigned long shmem_allowable_huge_orders(struct inode *inode, >> +unsigned long shmem_allowable_huge_orders(struct inode *inode, >> struct vm_area_struct *vma, pgoff_t index, >> bool global_huge) >> { >> @@ -1707,13 +1707,6 @@ static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault >> return orders; >> } >> #else >> -static unsigned long shmem_allowable_huge_orders(struct inode *inode, >> - struct vm_area_struct *vma, pgoff_t index, >> - bool global_huge) >> -{ >> - return 0; >> -} >> - >> static unsigned long shmem_suitable_orders(struct inode *inode, struct vm_fault *vmf, >> struct address_space *mapping, pgoff_t index, >> unsigned long orders)