From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta0.migadu.com (out-119.mta0.migadu.com [91.218.175.119]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A515A38F954 for ; Tue, 22 Sep 2026 02:37:31 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.119 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790044654; cv=none; b=jOkFSzUdNmwH822YtM9ZJwldqUOIo0yDELHq39l15gdLwR4LUfuNCkcpKhQHGzjfkZmQch+Tk8hRRre6zsC1gV+u6Ap10K0wPFeKf9bFpyKGHihDlfP5QJpjHCIoxP4jMNPq3L/tIL6jQcZLEMzGLjTOrewzArdk5Z0/5SMvpu0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790044654; c=relaxed/simple; bh=oXcuiUEvPpxdNGvwMoDxu13JoB6hGuqYMXZ4T/ilDvE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=sy/hHm86wFkMxzHpp/ZkK1jC4q7TrpEnWWHqV11MDG/CTsXrPfH5PdCnpxfQEvXyL/K5tD9vfS/Frap5LDDcZuW2ZG1jqk7qlY/4DBcmI8j5S6ESMeFWLSt/BIuc6pneqln9TyLggRwiGY1QQYuw6/Nt4RPn9juLWA2yyG3UEiQ= 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=EQth+ETl; arc=none smtp.client-ip=91.218.175.119 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="EQth+ETl" X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=oXcuiUEvPpxdNGvwMoDxu13JoB6hGuqYMXZ4T/ilDvE=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1790044649; v=1; x=1790649449; b=EQth+ETl80xFW214zMaf/kRRc8DXbeJAfqSwMA9pD3NSajRyxv/i20xZWyISUB8cPcxJ65li T8IKhyN5KGjoagnVOlDbVYmLLmmpUQ97RsetwOct0ar6idMKZh46qE7eka96Tmi37JJHeoHFokH m0ukylhRt/d4yYBWEoU5UTcw= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id 15abc27bba9dfcd4; Tue, 22 Sep 2026 02:37:29 +0000 X-Mizu-Trace-ID: 15abc27bba9dfcd4 X-Migadu-Flow: FLOW_OUT Message-ID: <6dfa3c07-932a-4f58-9933-f7bd050d5f51@linux.dev> Date: Tue, 22 Sep 2026 10:37:18 +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 RFC 3/4] mm/vmscan: move struct scan_control to the local trace header To: Baoquan He Cc: Steven Rostedt , Masami Hiramatsu , Johannes Weiner , Michal Hocko , Roman Gushchin , Shakeel Butt , Andrew Morton , Dave Chinner , Mathieu Desnoyers , Muchun Song , Qi Zheng , Kairui Song , Barry Song , Axel Rasmussen , Yuanchu Xie , Wei Xu , Baolin Wang , David Hildenbrand , Lorenzo Stoakes , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" , "open list:CONTROL GROUP - MEMORY RESOURCE CONTROLLER (MEMCG)" , Ridong Chen References: <20260921114606.3871820-1-ridong.chen@linux.dev> <20260921114606.3871820-4-ridong.chen@linux.dev> From: Ridong Chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 9/22/2026 10:24 AM, Baoquan He wrote: > On 09/21/26 at 07:46pm, Ridong Chen wrote: >> From: Ridong Chen >> >> Now that the vmscan tracepoints live in mm/trace_vmscan.h, move >> struct scan_control there as well so the trace events can reference >> reclaim-internal state directly. The definition is wrapped in its own >> include guard because the trace header is re-read under >> TRACE_HEADER_MULTI_READ, while a C struct may only be defined once. >> >> No functional change. >> >> Assisted-by: Claude:claude-opus-4-8 >> Signed-off-by: Ridong Chen >> --- >> mm/trace_vmscan.h | 115 ++++++++++++++++++++++++++++++++++++++++++++++ >> mm/vmscan.c | 108 ------------------------------------------- >> 2 files changed, 115 insertions(+), 108 deletions(-) >> >> diff --git a/mm/trace_vmscan.h b/mm/trace_vmscan.h >> index c5d824fef554..c8ac5d4e4043 100644 >> --- a/mm/trace_vmscan.h >> +++ b/mm/trace_vmscan.h > > This looks not good, I would rather see it's added in mm/internal.h, or > a new mm/vmscan.h. Putting scan_control in mm/trace_vmscan.h is too weird. > Thanks. I'm not sure whether the maintainers would be happy to make scan_control external. I'd prefer to move scan_control to a new mm/vmscan.h, since mm/internal.h is getting larger and larger. So I'd like to hear other opinions. >> @@ -9,8 +9,123 @@ >> #include >> #include >> #include >> +#include >> #include >> >> +/* Guard the struct against define_trace.h's repeated inclusion. */ >> +#ifndef _MM_VMSCAN_INTERNAL_H >> +#define _MM_VMSCAN_INTERNAL_H >> + >> +struct scan_control { >> + /* How many pages shrink_list() should reclaim */ >> + unsigned long nr_to_reclaim; >> + >> + /* >> + * Nodemask of nodes allowed by the caller. If NULL, all nodes >> + * are scanned. >> + */ >> + const nodemask_t *nodemask; >> + >> + /* >> + * The memory cgroup that hit its limit and as a result is the >> + * primary target of this reclaim invocation. >> + */ >> + struct mem_cgroup *target_mem_cgroup; >> + >> + /* >> + * Scan pressure balancing between anon and file LRUs >> + */ >> + unsigned long anon_cost; >> + unsigned long file_cost; >> + >> + /* Swappiness value for proactive reclaim. Always use sc_swappiness()! */ >> + int *proactive_swappiness; >> + >> + /* Can active folios be deactivated as part of reclaim? */ >> +#define DEACTIVATE_ANON 1 >> +#define DEACTIVATE_FILE 2 >> + unsigned int may_deactivate:2; >> + unsigned int force_deactivate:1; >> + unsigned int skipped_deactivate:1; >> + >> + /* zone_reclaim_mode, boost reclaim */ >> + unsigned int may_writepage:1; >> + >> + /* zone_reclaim_mode */ >> + unsigned int may_unmap:1; >> + >> + /* zone_reclaim_mode, boost reclaim, cgroup restrictions */ >> + unsigned int may_swap:1; >> + >> + /* Not allow cache_trim_mode to be turned on as part of reclaim? */ >> + unsigned int no_cache_trim_mode:1; >> + >> + /* Has cache_trim_mode failed at least once? */ >> + unsigned int cache_trim_mode_failed:1; >> + >> + /* Proactive reclaim invoked by userspace */ >> + unsigned int proactive:1; >> + >> + /* >> + * Cgroup memory below memory.low is protected as long as we >> + * don't threaten to OOM. If any cgroup is reclaimed at >> + * reduced force or passed over entirely due to its memory.low >> + * setting (memcg_low_skipped), and nothing is reclaimed as a >> + * result, then go back for one more cycle that reclaims the protected >> + * memory (memcg_low_reclaim) to avert OOM. >> + */ >> + unsigned int memcg_low_reclaim:1; >> + unsigned int memcg_low_skipped:1; >> + >> + /* Shared cgroup tree walk failed, rescan the whole tree */ >> + unsigned int memcg_full_walk:1; >> + >> + unsigned int hibernation_mode:1; >> + >> + /* One of the zones is ready for compaction */ >> + unsigned int compaction_ready:1; >> + >> + /* There is easily reclaimable cold cache in the current node */ >> + unsigned int cache_trim_mode:1; >> + >> + /* The file folios on the current node are dangerously low */ >> + unsigned int file_is_tiny:1; >> + >> + /* Always discard instead of demoting to lower tier memory */ >> + unsigned int no_demotion:1; >> + >> + /* Allocation order */ >> + s8 order; >> + >> + /* Scan (total_size >> priority) pages at once */ >> + s8 priority; >> + >> + /* The highest zone to isolate folios for reclaim from */ >> + s8 reclaim_idx; >> + >> + /* This context's GFP mask */ >> + gfp_t gfp_mask; >> + >> + /* Incremented by the number of inactive pages that were scanned */ >> + unsigned long nr_scanned; >> + >> + /* Number of pages freed so far during a call to shrink_zones() */ >> + unsigned long nr_reclaimed; >> + >> + struct { >> + unsigned int dirty; >> + unsigned int congested; >> + unsigned int writeback; >> + unsigned int immediate; >> + unsigned int taken; >> + } nr; >> + >> + /* for recording the reclaimed slab by now */ >> + struct reclaim_state reclaim_state; >> +}; >> + >> +#endif /* _MM_VMSCAN_INTERNAL_H */ >> + >> #define RECLAIM_WB_ANON 0x0001u >> #define RECLAIM_WB_FILE 0x0002u >> #define RECLAIM_WB_MIXED 0x0010u >> diff --git a/mm/vmscan.c b/mm/vmscan.c >> index 0eb7fa8e1d43..2fd9b42f89d8 100644 >> --- a/mm/vmscan.c >> +++ b/mm/vmscan.c >> @@ -73,114 +73,6 @@ >> #define CREATE_TRACE_POINTS >> #include "trace_vmscan.h" >> >> -struct scan_control { >> - /* How many pages shrink_list() should reclaim */ >> - unsigned long nr_to_reclaim; >> - >> - /* >> - * Nodemask of nodes allowed by the caller. If NULL, all nodes >> - * are scanned. >> - */ >> - const nodemask_t *nodemask; >> - >> - /* >> - * The memory cgroup that hit its limit and as a result is the >> - * primary target of this reclaim invocation. >> - */ >> - struct mem_cgroup *target_mem_cgroup; >> - >> - /* >> - * Scan pressure balancing between anon and file LRUs >> - */ >> - unsigned long anon_cost; >> - unsigned long file_cost; >> - >> - /* Swappiness value for proactive reclaim. Always use sc_swappiness()! */ >> - int *proactive_swappiness; >> - >> - /* Can active folios be deactivated as part of reclaim? */ >> -#define DEACTIVATE_ANON 1 >> -#define DEACTIVATE_FILE 2 >> - unsigned int may_deactivate:2; >> - unsigned int force_deactivate:1; >> - unsigned int skipped_deactivate:1; >> - >> - /* zone_reclaim_mode, boost reclaim */ >> - unsigned int may_writepage:1; >> - >> - /* zone_reclaim_mode */ >> - unsigned int may_unmap:1; >> - >> - /* zone_reclaim_mode, boost reclaim, cgroup restrictions */ >> - unsigned int may_swap:1; >> - >> - /* Not allow cache_trim_mode to be turned on as part of reclaim? */ >> - unsigned int no_cache_trim_mode:1; >> - >> - /* Has cache_trim_mode failed at least once? */ >> - unsigned int cache_trim_mode_failed:1; >> - >> - /* Proactive reclaim invoked by userspace */ >> - unsigned int proactive:1; >> - >> - /* >> - * Cgroup memory below memory.low is protected as long as we >> - * don't threaten to OOM. If any cgroup is reclaimed at >> - * reduced force or passed over entirely due to its memory.low >> - * setting (memcg_low_skipped), and nothing is reclaimed as a >> - * result, then go back for one more cycle that reclaims the protected >> - * memory (memcg_low_reclaim) to avert OOM. >> - */ >> - unsigned int memcg_low_reclaim:1; >> - unsigned int memcg_low_skipped:1; >> - >> - /* Shared cgroup tree walk failed, rescan the whole tree */ >> - unsigned int memcg_full_walk:1; >> - >> - unsigned int hibernation_mode:1; >> - >> - /* One of the zones is ready for compaction */ >> - unsigned int compaction_ready:1; >> - >> - /* There is easily reclaimable cold cache in the current node */ >> - unsigned int cache_trim_mode:1; >> - >> - /* The file folios on the current node are dangerously low */ >> - unsigned int file_is_tiny:1; >> - >> - /* Always discard instead of demoting to lower tier memory */ >> - unsigned int no_demotion:1; >> - >> - /* Allocation order */ >> - s8 order; >> - >> - /* Scan (total_size >> priority) pages at once */ >> - s8 priority; >> - >> - /* The highest zone to isolate folios for reclaim from */ >> - s8 reclaim_idx; >> - >> - /* This context's GFP mask */ >> - gfp_t gfp_mask; >> - >> - /* Incremented by the number of inactive pages that were scanned */ >> - unsigned long nr_scanned; >> - >> - /* Number of pages freed so far during a call to shrink_zones() */ >> - unsigned long nr_reclaimed; >> - >> - struct { >> - unsigned int dirty; >> - unsigned int congested; >> - unsigned int writeback; >> - unsigned int immediate; >> - unsigned int taken; >> - } nr; >> - >> - /* for recording the reclaimed slab by now */ >> - struct reclaim_state reclaim_state; >> -}; >> - >> #ifdef ARCH_HAS_PREFETCHW >> static inline void prefetchw_prev_lru_folio(struct folio *folio, >> struct list_head *base) >> -- >> 2.34.1 >> -- Best regards Ridong