From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 CB79D349B19; Fri, 24 Jul 2026 16:38:11 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784911092; cv=none; b=HPC6lpUY5PaO5jLR7fGrPhHpp26JuP1nXErTYIstKttJpDbm5+ZYeSOM5gw3kcbsggMNC6FQckvmbYOjcmO5Xx4Zi+FXKP0vpgj2U/fckI/1VJdh74NWJWIG3M0yozK5JxRCma+Lp2YWdi0EsDMTFkaFFFWSYlap9cauQ8JLWUE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784911092; c=relaxed/simple; bh=6hKxzkBJRuU09ad5t2u9WIMh+QRP2pLVgQ1mN+XI7VU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=ornpDavJODRQb2xCOK4YZo6dhNaVTS/Y0+x5JqMchbdkCkFi1Ghy++jvJ1El4TGM0Lhh4J6p4CFrEOYJuRsb62r68H3hBP+xjQQ+K9lwcb4wiBcA4gU55N2A+RDfy9QLVEq4AFzFuAuKW2SkchgdqLp3Ij058pFpW7mRfC36wdY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BK5WT+u/; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BK5WT+u/" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C181D1F000E9; Fri, 24 Jul 2026 16:38:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784911091; bh=wd1DKhAbb8cJYdRWggg6oDhJJGI9y5gRdzf50Fk9NXk=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=BK5WT+u/jG/YwWgmMNVYKSRGAqq1RQ0cFEKg0ostULv8PBqUHRlYFc2FeAQsFwh9i hnkuxnvV0dz+TT4rsRVgjbLTIhUWTCCA3c7V1A6X7/onRZCq7fcKxeR/d5r0Wn9nii gI1eNkhyw95hn9TxvWoioE49yYasWGAeNidwt0mJAbeus3XAgKSzAGYtOv12lppLIB xFsHN3oxvvZrPcxsMTSxf/UB0Xq1zWm7r7aelvtfaZW5mhGc/bYezLgbQligXeG2cv kXp2Qx6r6i4GDVRvEcVwAoH+8uKiQ99iNCdNfKjj+6XCDi3nGuwe4pTtue0gordN1O 68ug5cgnJCOiQ== Message-ID: Date: Fri, 24 Jul 2026 18:38:07 +0200 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 12/13] mm/slab: add cache_ and slab_needs_objcg() helpers Content-Language: en-US To: Hao Li Cc: Harry Yoo , Suren Baghdasaryan , Shakeel Butt , Alexander Potapenko , Marco Elver , Andrew Morton , Christoph Lameter , David Rientjes , Roman Gushchin , linux-mm@kvack.org, linux-kernel@vger.kernel.org, cgroups@vger.kernel.org References: <20260720-b4-objext_split-v2-0-2fa7c6f60dbe@kernel.org> <20260720-b4-objext_split-v2-12-2fa7c6f60dbe@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 7/24/26 11:41, Hao Li wrote: > On Mon, Jul 20, 2026 at 04:16:26PM +0200, Vlastimil Babka (SUSE) wrote: >> @@ -984,11 +991,19 @@ new_kmalloc_cache(int idx, enum kmalloc_cache_type type) >> #endif >> >> /* >> - * If CONFIG_MEMCG is enabled, disable cache merging for >> - * KMALLOC_NORMAL caches. >> + * If memcg_kmem is enabled and this is a KMALLOC_NORMAL cache and not >> + * aliased with any other type, make sure it's never merged with any other >> + * cache. >> + * >> + * In other cases the kmalloc cache may end up being used for a >> + * __GFP_ACCOUNT allocation so mark it as such >> */ >> - if (IS_ENABLED(CONFIG_MEMCG) && (type == KMALLOC_NORMAL)) >> - flags |= SLAB_NO_MERGE; >> + if (!mem_cgroup_kmem_disabled()) { >> + if (type == KMALLOC_NORMAL && KMALLOC_RECLAIM != KMALLOC_NORMAL) > > With only those checks, the dedicated KMALLOC_NO_OBJ_EXT cache will also have > the SLAB_MAY_ACCOUNT flag, which might be a bit misleading. is it worth > explicitly excluding SLAB_MAY_ACCOUNT for dedicated KMALLOC_NO_OBJ_EXT cache? Yeah good point, will do! Thanks! >> + flags |= SLAB_NO_MERGE; >> + else >> + flags |= SLAB_MAY_ACCOUNT; >> + } >> >> if (minalign > ARCH_KMALLOC_MINALIGN) { >> aligned_size = ALIGN(aligned_size, minalign); >> diff --git a/mm/slub.c b/mm/slub.c >> index d78d3e50c877..30435e2509ea 100644 >> --- a/mm/slub.c >> +++ b/mm/slub.c >> @@ -2557,7 +2557,7 @@ bool memcg_slab_post_charge(void *p, gfp_t flags) >> * of slab_obj_exts being allocated from the same slab and thus the slab >> * becoming effectively unfreeable. >> */ >> - if (is_kmalloc_normal(s)) >> + if (!cache_needs_objcg(s)) >> return true; >> >> /* Ignore already charged objects. */ >> @@ -3435,6 +3435,10 @@ static struct slab *allocate_slab(struct kmem_cache *s, gfp_t flags, >> >> slab->objects = oo_objects(oo); >> >> +#ifdef CONFIG_64BIT >> + if (cache_needs_objcg(s)) >> + slab->obj_exts_needs_objcg = 1; >> +#endif >> slab->slab_cache = s; >> >> kasan_poison_slab(slab); >> >> -- >> 2.55.0 >> >