From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 AF62D15B561 for ; Mon, 1 Jul 2024 12:45:32 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719837932; cv=none; b=l7da+Zil6Enp5MQoiYNoC8PyCz7cj4wYCrUinp1gkXWJn2y37eeYg1+N+v7hpgVApmb9JXJNoU8G5wchYnFovJafEbbXWwKJKZicbwfEhpf8GpQR1+WUopPOcTanpMyQEVw/iHFqt9YjkHwZWne4QnjaE7a1KkCf9KG+xumDDfQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1719837932; c=relaxed/simple; bh=dzq15meA5udoEKFC//Z+5O/cpaVaVRkBBJqKW3rh4jY=; h=Subject:To:Cc:From:Date:Message-ID:MIME-Version:Content-Type; b=SlNIBqvpTiUP4qz027W+dbBcyMuitr9QJEb+QcrtE5ceXOQvt/IrFm5Q9fdpUzwygJ/Rr2o77BVdA7TisjZVreT/b49bw0x/4SmSONE1agt/J4IR8UOIkVMUMEcbqRf8Za2px9ERXAfwsmdRwedlxv90acV7HcMpswm/qT4FpbU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=od6PBHsk; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="od6PBHsk" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 1EB1EC116B1; Mon, 1 Jul 2024 12:45:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1719837932; bh=dzq15meA5udoEKFC//Z+5O/cpaVaVRkBBJqKW3rh4jY=; h=Subject:To:Cc:From:Date:From; b=od6PBHskm0oOPr6MVvYewIRvu1BNem5vv0hZeCldcOajx536aZDVuHr75BIPFRh96 hlxcWpDYIIrXYfDzalKvpb3DZ2FgW8VZBfEdE+1p4II91wA8uAmAZWNOn6DFmDDthZ /+OsRYE0Rmsw9Ooj/bOlcQJ6HFsyh1V0PsNle88Q= Subject: FAILED: patch "[PATCH] mm/page_alloc: Separate THP PCP into movable and non-movable" failed to apply to 6.1-stable tree To: yangge1116@126.com,21cnbao@gmail.com,akpm@linux-foundation.org,baolin.wang@linux.alibaba.com,mgorman@techsingularity.net,stable@vger.kernel.org Cc: From: Date: Mon, 01 Jul 2024 14:29:29 +0200 Message-ID: <2024070129-movable-commend-1b2a@gregkh> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to . To reproduce the conflict and resubmit, you may use the following commands: git fetch https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/ linux-6.1.y git checkout FETCH_HEAD git cherry-pick -x bf14ed81f571f8dba31cd72ab2e50fbcc877cc31 # git commit -s git send-email --to '' --in-reply-to '2024070129-movable-commend-1b2a@gregkh' --subject-prefix 'PATCH 6.1.y' HEAD^.. Possible dependencies: bf14ed81f571 ("mm/page_alloc: Separate THP PCP into movable and non-movable categories") 6303d1c553c8 ("mm: page_alloc: use the correct THP order for THP PCP") c1dc69e6ce65 ("mm/page_alloc: remove unneeded variable base") thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From bf14ed81f571f8dba31cd72ab2e50fbcc877cc31 Mon Sep 17 00:00:00 2001 From: yangge Date: Thu, 20 Jun 2024 08:59:50 +0800 Subject: [PATCH] mm/page_alloc: Separate THP PCP into movable and non-movable categories Since commit 5d0a661d808f ("mm/page_alloc: use only one PCP list for THP-sized allocations") no longer differentiates the migration type of pages in THP-sized PCP list, it's possible that non-movable allocation requests may get a CMA page from the list, in some cases, it's not acceptable. If a large number of CMA memory are configured in system (for example, the CMA memory accounts for 50% of the system memory), starting a virtual machine with device passthrough will get stuck. During starting the virtual machine, it will call pin_user_pages_remote(..., FOLL_LONGTERM, ...) to pin memory. Normally if a page is present and in CMA area, pin_user_pages_remote() will migrate the page from CMA area to non-CMA area because of FOLL_LONGTERM flag. But if non-movable allocation requests return CMA memory, migrate_longterm_unpinnable_pages() will migrate a CMA page to another CMA page, which will fail to pass the check in check_and_migrate_movable_pages() and cause migration endless. Call trace: pin_user_pages_remote --__gup_longterm_locked // endless loops in this function ----_get_user_pages_locked ----check_and_migrate_movable_pages ------migrate_longterm_unpinnable_pages --------alloc_migration_target This problem will also have a negative impact on CMA itself. For example, when CMA is borrowed by THP, and we need to reclaim it through cma_alloc() or dma_alloc_coherent(), we must move those pages out to ensure CMA's users can retrieve that contigous memory. Currently, CMA's memory is occupied by non-movable pages, meaning we can't relocate them. As a result, cma_alloc() is more likely to fail. To fix the problem above, we add one PCP list for THP, which will not introduce a new cacheline for struct per_cpu_pages. THP will have 2 PCP lists, one PCP list is used by MOVABLE allocation, and the other PCP list is used by UNMOVABLE allocation. MOVABLE allocation contains GPF_MOVABLE, and UNMOVABLE allocation contains GFP_UNMOVABLE and GFP_RECLAIMABLE. Link: https://lkml.kernel.org/r/1718845190-4456-1-git-send-email-yangge1116@126.com Fixes: 5d0a661d808f ("mm/page_alloc: use only one PCP list for THP-sized allocations") Signed-off-by: yangge Cc: Baolin Wang Cc: Barry Song <21cnbao@gmail.com> Cc: Mel Gorman Cc: Signed-off-by: Andrew Morton diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h index 8f9c9590a42c..586a8f0104d7 100644 --- a/include/linux/mmzone.h +++ b/include/linux/mmzone.h @@ -654,13 +654,12 @@ enum zone_watermarks { }; /* - * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. One additional list - * for THP which will usually be GFP_MOVABLE. Even if it is another type, - * it should not contribute to serious fragmentation causing THP allocation - * failures. + * One per migratetype for each PAGE_ALLOC_COSTLY_ORDER. Two additional lists + * are added for THP. One PCP list is used by GPF_MOVABLE, and the other PCP list + * is used by GFP_UNMOVABLE and GFP_RECLAIMABLE. */ #ifdef CONFIG_TRANSPARENT_HUGEPAGE -#define NR_PCP_THP 1 +#define NR_PCP_THP 2 #else #define NR_PCP_THP 0 #endif diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 7300aa9f14b0..9ecf99190ea2 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -504,10 +504,15 @@ static void bad_page(struct page *page, const char *reason) static inline unsigned int order_to_pindex(int migratetype, int order) { + bool __maybe_unused movable; + #ifdef CONFIG_TRANSPARENT_HUGEPAGE if (order > PAGE_ALLOC_COSTLY_ORDER) { VM_BUG_ON(order != HPAGE_PMD_ORDER); - return NR_LOWORDER_PCP_LISTS; + + movable = migratetype == MIGRATE_MOVABLE; + + return NR_LOWORDER_PCP_LISTS + movable; } #else VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER); @@ -521,7 +526,7 @@ static inline int pindex_to_order(unsigned int pindex) int order = pindex / MIGRATE_PCPTYPES; #ifdef CONFIG_TRANSPARENT_HUGEPAGE - if (pindex == NR_LOWORDER_PCP_LISTS) + if (pindex >= NR_LOWORDER_PCP_LISTS) order = HPAGE_PMD_ORDER; #else VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);