From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-181.mta1.migadu.com (out-181.mta1.migadu.com [95.215.58.181]) (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 4D10830F534 for ; Fri, 24 Jul 2026 10:01:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.181 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784887280; cv=none; b=am3ZaTK/3eR7gwNWMiYbqtEt1FTO7mGjx4FsnlyLvASiSU6C3X58vPVchdXeKAfGIMdD+hmV7+5vi1ucsxhk2BPW7rS9I/jHNwGVcbZxKHl1Ty9dsvAYHatcfqNqLLWEgQRI/ja7/NiWFsjcjy+M9seuVThU2p6VFNoxgtOwW0w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784887280; c=relaxed/simple; bh=crGkQLk2V+MRmkSahnOVGou2BfpYCoVPGYCVYBvoZus=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HN589kq/Bub5LpquC0VOyZ+ns65fQ5HHkl0Cdst4fQYno3CJWCTGv7IEELDnVMGMub+ZS+kYxKpmBKZOlHDSmnBc+L9SZJXawojiFmDmk6tsZWGV8oanGspRqlWJrhX/WNqKwlyqc5c8O9Af9HVxEgOEXz6dDyLgTuyBzAIIbj8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=wKO0ndI5; arc=none smtp.client-ip=95.215.58.181 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="wKO0ndI5" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1784887276; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=voqrEg3r3e9QhelQXK6ZueYqOeWiNE60rZ7RF6AjkmM=; b=wKO0ndI5P+SxBerYGRpL88BFHfWrfZiklFQfdL4AfajNHGU+zPOEIB1dJgIRvZjfDlfDY4 zOGJEJshTj2ua5hAIzz0vfPVhZGaO25Y7k0ary/pB4hJVFn3WUKpH1bSbMdkrnH94oSjkm HCSSUODpDEChX8PDpTJpkxizIfNQ8qE= Date: Fri, 24 Jul 2026 11:00:48 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH v5 01/11] mm: add PMD swap entry detection support To: Dev Jain , Andrew Morton , david@kernel.org, chrisl@kernel.org, kasong@tencent.com, ljs@kernel.org, ziy@nvidia.com, linux-mm@kvack.org Cc: ying.huang@linux.alibaba.com, Baoquan He , willy@infradead.org, youngjun.park@lge.com, hannes@cmpxchg.org, riel@surriel.com, shakeel.butt@linux.dev, alex@ghiti.fr, kas@kernel.org, baohua@kernel.org, baolin.wang@linux.alibaba.com, Nico Pache , "Liam R. Howlett" , ryan.roberts@arm.com, Vlastimil Babka , lance.yang@linux.dev, linux-kernel@vger.kernel.org, nphamcs@gmail.com, shikemeng@huaweicloud.com, yosry@kernel.org, kernel-team@meta.com References: <20260722152043.2273289-1-usama.arif@linux.dev> <20260722152043.2273289-2-usama.arif@linux.dev> Content-Language: en-US X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Usama Arif In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Migadu-Flow: FLOW_OUT On 24/07/2026 07:10, Dev Jain wrote: > [------] > >> diff --git a/include/linux/leafops.h b/include/linux/leafops.h >> index 4c1476ae3234..8397193ba399 100644 >> --- a/include/linux/leafops.h >> +++ b/include/linux/leafops.h >> @@ -102,6 +102,8 @@ static inline softleaf_t softleaf_from_pmd(pmd_t pmd) >> pmd = pmd_swp_clear_soft_dirty(pmd); >> if (pmd_swp_uffd(pmd)) >> pmd = pmd_swp_clear_uffd(pmd); >> + if (pmd_swp_exclusive(pmd)) >> + pmd = pmd_swp_clear_exclusive(pmd); >> arch_entry = __pmd_to_swp_entry(pmd); >> >> /* Temporary until swp_entry_t eliminated. */ >> @@ -634,18 +636,30 @@ static inline bool pmd_is_migration_entry(pmd_t pmd) >> */ >> static inline bool softleaf_is_valid_pmd_entry(softleaf_t entry) >> { >> - /* Only device private, migration entries valid for PMD. */ >> + /* Device private, migration, and swap entries valid for PMD. */ >> return softleaf_is_device_private(entry) || >> - softleaf_is_migration(entry); >> + softleaf_is_migration(entry) || >> + softleaf_is_swap(entry); >> +} >> + >> +/** >> + * pmd_is_swap_entry() - Does this PMD entry encode an actual swap entry? >> + * @pmd: PMD entry. >> + * >> + * Returns: true if the PMD encodes a swap entry, otherwise false. >> + */ >> +static inline bool pmd_is_swap_entry(pmd_t pmd) >> +{ >> + return softleaf_is_swap(softleaf_from_pmd(pmd)); >> } >> >> /** >> * pmd_is_valid_softleaf() - Is this PMD entry a valid softleaf entry? >> * @pmd: PMD entry. >> * >> - * PMD leaf entries are valid only if they are device private or migration >> - * entries. This function asserts that a PMD leaf entry is valid in this >> - * respect. >> + * PMD leaf entries are valid only if they are device private, migration, >> + * or swap entries. This function asserts that a PMD leaf entry is valid >> + * in this respect. >> * >> * Returns: true if the PMD entry is a valid leaf entry, otherwise false. >> */ >> @@ -673,6 +687,8 @@ static inline struct folio *pmd_to_softleaf_folio(pmd_t pmd) > > Nit: This function really should have been named "softleaf_pmd_to_folio", or > "pmd_softleaf_to_folio", perhaps throw in a patch to rename? > Sounds good, will add a patch to rename. Lorenzo any preferences here for the name?> >> VM_WARN_ON_ONCE(true); >> return NULL; >> } >> + if (!softleaf_has_pfn(entry)) >> + return NULL; > > I am guessing that after the later patches add swp support, we should > never reach pmd_to_softleaf_folio() with a swap entry, in which case, > we could add a WARN_ON_ONCE() here. (didn't check if you have done that > later, just writing this here) > Will add a warn. This was one of things sashiko pointed out to add. >> return softleaf_to_folio(entry); >> } >> >> diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h >> index 8c093c119e5a..e10a7e91e426 100644 >> --- a/include/linux/pgtable.h >> +++ b/include/linux/pgtable.h >> @@ -1917,6 +1917,23 @@ static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd) >> } >> #endif >> >> +#ifndef CONFIG_ARCH_HAS_PMD_SOFTLEAVES >> +static inline pmd_t pmd_swp_mkexclusive(pmd_t pmd) >> +{ >> + return pmd; >> +} >> + >> +static inline bool pmd_swp_exclusive(pmd_t pmd) >> +{ >> + return false; >> +} >> + >> +static inline pmd_t pmd_swp_clear_exclusive(pmd_t pmd) >> +{ >> + return pmd; >> +} >> +#endif >> + >> #ifndef __HAVE_PFNMAP_TRACKING >> /* >> * Interfaces that can be used by architecture code to keep track of >