From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-185.mta0.migadu.com (out-185.mta0.migadu.com [91.218.175.185]) (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 09FAC3F8898 for ; Mon, 18 May 2026 11:56:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.185 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779105368; cv=none; b=mwbqNXYiuPvzqWT4uVHVG0CxvJgaGI0mXiHtzvgSVvwpEfcqT81Kaji4EdMCJON5nmQPy7R0V8z+CTcRbPKvzZxSudm4BJg/c+iUr9KRfcKaFV3leC9sJKQZlKaSR0BISVElc6WMebLHPVMxMo4OftgbUhcyqUQVBEq1x+PhIek= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779105368; c=relaxed/simple; bh=lfpuBWpE/drB2RGskLZuxkE7ezxb0JMljtdwM6JQyMc=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=eApi02t/14pHZ0Lm+cfOdWYSwUxfc0Uwc4GGc9dtbQ3RKPWDzB9EZ9ITV6BZq5m1iRoEIjuzKvliBMYkxm8iirC3fiTYXc+YUltIASG8sTdF9II96n0kFVrtj4lP/VIwdChYTtp4aoebNwS5nT858HPHb+DJZfZGyOYprzVD7N4= 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=rdqyiaYq; arc=none smtp.client-ip=91.218.175.185 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="rdqyiaYq" X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1779105363; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=0LJeLV2647C+GmwKXUyT3/UeLI1LWOfAc30rkgrn0ms=; b=rdqyiaYqPu/3PGr8wI8hiBGi8r49XAev4HhrQSjq2yn+GuqjVSomehva6Vv/1joKeJCYm2 AxIJ3YQcKZvuKJIYrgCvb5HhkMUwLM11PF58ri2ZAi6OeIw3qVQINowz/X6q9sDGDsbjVE cg+Xr8pxJdU77R/0uRSV3F7ivZO1xE4= From: Usama Arif To: Nico Pache Cc: Usama Arif , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-trace-kernel@vger.kernel.org, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, david@kernel.org, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jack@suse.cz, jackmanb@google.com, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, liam@infradead.org, ljs@kernel.org, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, ziy@nvidia.com, zokeefe@google.com Subject: Re: [PATCH mm-unstable v17 02/14] mm/khugepaged: generalize alloc_charge_folio() Date: Mon, 18 May 2026 04:55:51 -0700 Message-ID: <20260518115553.3513034-1-usama.arif@linux.dev> In-Reply-To: <20260511185817.686831-3-npache@redhat.com> References: Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On Mon, 11 May 2026 12:58:02 -0600 Nico Pache wrote: > From: Dev Jain > > Pass order to alloc_charge_folio() and update mTHP statistics. > > Reviewed-by: Wei Yang > Reviewed-by: Lance Yang > Reviewed-by: Baolin Wang > Reviewed-by: Lorenzo Stoakes > Reviewed-by: Zi Yan > Acked-by: Usama Arif > Acked-by: David Hildenbrand (Arm) > Signed-off-by: Dev Jain > Co-developed-by: Nico Pache > Signed-off-by: Nico Pache > --- > Documentation/admin-guide/mm/transhuge.rst | 8 ++++++++ > include/linux/huge_mm.h | 2 ++ > mm/huge_memory.c | 4 ++++ > mm/khugepaged.c | 17 +++++++++++------ > 4 files changed, 25 insertions(+), 6 deletions(-) > > diff --git a/Documentation/admin-guide/mm/transhuge.rst b/Documentation/admin-guide/mm/transhuge.rst > index 5fbc3d89bb07..c51932e6275d 100644 > --- a/Documentation/admin-guide/mm/transhuge.rst > +++ b/Documentation/admin-guide/mm/transhuge.rst > @@ -639,6 +639,14 @@ anon_fault_fallback_charge > instead falls back to using huge pages with lower orders or > small pages even though the allocation was successful. > > +collapse_alloc > + is incremented every time a huge page is successfully allocated for a > + khugepaged collapse. > + > +collapse_alloc_failed > + is incremented every time a huge page allocation fails during a > + khugepaged collapse. > + > zswpout > is incremented every time a huge page is swapped out to zswap in one > piece without splitting. > diff --git a/include/linux/huge_mm.h b/include/linux/huge_mm.h > index 2949e5acff35..ba7ae6808544 100644 > --- a/include/linux/huge_mm.h > +++ b/include/linux/huge_mm.h > @@ -128,6 +128,8 @@ enum mthp_stat_item { > MTHP_STAT_ANON_FAULT_ALLOC, > MTHP_STAT_ANON_FAULT_FALLBACK, > MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE, > + MTHP_STAT_COLLAPSE_ALLOC, > + MTHP_STAT_COLLAPSE_ALLOC_FAILED, > MTHP_STAT_ZSWPOUT, > MTHP_STAT_SWPIN, > MTHP_STAT_SWPIN_FALLBACK, > diff --git a/mm/huge_memory.c b/mm/huge_memory.c > index e9d499da0ac7..05f482a72a89 100644 > --- a/mm/huge_memory.c > +++ b/mm/huge_memory.c > @@ -699,6 +699,8 @@ static struct kobj_attribute _name##_attr = __ATTR_RO(_name) > DEFINE_MTHP_STAT_ATTR(anon_fault_alloc, MTHP_STAT_ANON_FAULT_ALLOC); > DEFINE_MTHP_STAT_ATTR(anon_fault_fallback, MTHP_STAT_ANON_FAULT_FALLBACK); > DEFINE_MTHP_STAT_ATTR(anon_fault_fallback_charge, MTHP_STAT_ANON_FAULT_FALLBACK_CHARGE); > +DEFINE_MTHP_STAT_ATTR(collapse_alloc, MTHP_STAT_COLLAPSE_ALLOC); > +DEFINE_MTHP_STAT_ATTR(collapse_alloc_failed, MTHP_STAT_COLLAPSE_ALLOC_FAILED); > DEFINE_MTHP_STAT_ATTR(zswpout, MTHP_STAT_ZSWPOUT); > DEFINE_MTHP_STAT_ATTR(swpin, MTHP_STAT_SWPIN); > DEFINE_MTHP_STAT_ATTR(swpin_fallback, MTHP_STAT_SWPIN_FALLBACK); > @@ -764,6 +766,8 @@ static struct attribute *any_stats_attrs[] = { > #endif > &split_attr.attr, > &split_failed_attr.attr, > + &collapse_alloc_attr.attr, > + &collapse_alloc_failed_attr.attr, > NULL, > }; > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 979885694351..f0e29d5c7b1f 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -1068,21 +1068,26 @@ static enum scan_result __collapse_huge_page_swapin(struct mm_struct *mm, > } > > static enum scan_result alloc_charge_folio(struct folio **foliop, struct mm_struct *mm, > - struct collapse_control *cc) > + struct collapse_control *cc, unsigned int order) > { > gfp_t gfp = (cc->is_khugepaged ? alloc_hugepage_khugepaged_gfpmask() : > GFP_TRANSHUGE); > int node = collapse_find_target_node(cc); > struct folio *folio; > > - folio = __folio_alloc(gfp, HPAGE_PMD_ORDER, node, &cc->alloc_nmask); > + folio = __folio_alloc(gfp, order, node, &cc->alloc_nmask); > if (!folio) { > *foliop = NULL; > - count_vm_event(THP_COLLAPSE_ALLOC_FAILED); > + if (is_pmd_order(order)) > + count_vm_event(THP_COLLAPSE_ALLOC_FAILED); > + count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC_FAILED); > return SCAN_ALLOC_HUGE_PAGE_FAIL; > } > > - count_vm_event(THP_COLLAPSE_ALLOC); > + if (is_pmd_order(order)) > + count_vm_event(THP_COLLAPSE_ALLOC); > + count_mthp_stat(order, MTHP_STAT_COLLAPSE_ALLOC); > + The vmstat THP_COLLAPSE_ALLOC counter is pmd order only. But after this we have count_memcg_folio_events(folio, THP_COLLAPSE_ALLOC, 1); which is not being guarded with is_pmd_order(). I think we want this to be pmd order only as well so that the meaning of the vmstat and cgroup counter remains the same? > if (unlikely(mem_cgroup_charge(folio, mm, gfp))) { > folio_put(folio); > *foliop = NULL; > @@ -1118,7 +1123,7 @@ static enum scan_result collapse_huge_page(struct mm_struct *mm, unsigned long a > */ > mmap_read_unlock(mm); > > - result = alloc_charge_folio(&folio, mm, cc); > + result = alloc_charge_folio(&folio, mm, cc, HPAGE_PMD_ORDER); > if (result != SCAN_SUCCEED) > goto out_nolock; > > @@ -1899,7 +1904,7 @@ static enum scan_result collapse_file(struct mm_struct *mm, unsigned long addr, > VM_BUG_ON(!IS_ENABLED(CONFIG_READ_ONLY_THP_FOR_FS) && !is_shmem); > VM_BUG_ON(start & (HPAGE_PMD_NR - 1)); > > - result = alloc_charge_folio(&new_folio, mm, cc); > + result = alloc_charge_folio(&new_folio, mm, cc, HPAGE_PMD_ORDER); > if (result != SCAN_SUCCEED) > goto out; > > -- > 2.54.0 > >