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 CD7DF3BCD11; Thu, 16 Jul 2026 13:58:23 +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=1784210304; cv=none; b=gqtv05Yh0mjDp/IX4fNttdwOVwWWTlAHUiwsQGJ5gpiP5f+XPNyMxz2ao8r0B1KrJG+gI1krukguTDzrVjEWroMsZFkSHsitL8YNu3+IY3/XW6b+SaxMtDly5gE6qfqrqEmgOAUboM2zz2yxuzP2u8YWmvkR+wd+H+j0dMy/0N8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784210304; c=relaxed/simple; bh=ZeafglfvX/hxAyhsqjQ331bwD6COfedQZ/3pdJ4UNhE=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=azr0AYr+oEPdH6sLr1sVNK8w+5/e+VIdrAvJsPXrAL5f2YIwBPoXdjnmsdNW3Qdb8EwZ4GqCcw5JUL42+vqQkV5uoGK8g8vgdN/0wAHW5x2fncXw1QCLVBKxJxxRUTyMc+yKhCju8z29xsw/tJ0uPXyHheNlhuvbfD+8JLHEnV8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=J3QpNxlK; 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="J3QpNxlK" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 37B711F00A3A; Thu, 16 Jul 2026 13:58:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784210303; bh=vZVvwb5gue2Pu5bCd5TzfBGCtT03YhDYvhjRxQgTOBY=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=J3QpNxlK+VfRxOQBqJ3Un2Zp2XZu+SBFJoDzQKLY+1pcxm5h5JkuCmJePpKOi+bV4 FcmoPvyk+dtTe+rj/Sgm5BobMog+m8r01RYWJmkuIOv+y4gep+fqYziq43dFNUuz08 lLyDEkcWlpC6SlWuyKtQIEO8wMa0Bj15QBwbmJLBSleZ56WMyiWv9K9b4vJFYfwSJc ZsEXhYV9Hl9MkVd7PMqi9AWwi1zYmgK3uH6Yc3HURviDObyLSXClZp2D/pc8IZU6Uw cTlTiafXjZZVXG2b4SciG2SOTAWlJX6xnavIdMVZezkTWpn7jQ8fiMfbMCtI7hWExJ AErWQyHw/crHA== Message-ID: Date: Thu, 16 Jul 2026 15:58:19 +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 RFC 05/12] mm/slab: abstract slabobj_ext.objcg access Content-Language: en-US To: Suren Baghdasaryan Cc: Harry Yoo , Hao Li , 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: <20260715-b4-objext_split-v1-0-9a49c4ccf4c3@kernel.org> <20260715-b4-objext_split-v1-5-9a49c4ccf4c3@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit On 7/16/26 03:27, Suren Baghdasaryan wrote: > On Wed, Jul 15, 2026 at 3:11 AM Vlastimil Babka (SUSE) > wrote: >> --- a/mm/slab.h >> +++ b/mm/slab.h >> @@ -555,7 +555,7 @@ static inline bool need_kmalloc_no_objext(void) >> */ >> struct slabobj_ext { >> #ifdef CONFIG_MEMCG >> - struct obj_cgroup *objcg; >> + struct obj_cgroup *_objcg; >> #endif >> #ifdef CONFIG_MEM_ALLOC_PROFILING >> union codetag_ref ref; >> @@ -661,6 +661,13 @@ slab_obj_ext(struct kmem_cache *s, struct slab *slab, unsigned long obj_exts, >> return kasan_reset_tag(obj_ext); >> } >> >> +#ifdef CONFIG_MEMCG >> +static inline struct obj_cgroup **slab_obj_ext_objcgp(struct slabobj_ext *obj_ext) > > I understand why you need to return obj_cgroup** but maybe instead we > can have a separate setter function and just return a pointer here? Yeah I rewrote it now and it looks better. Thanks! It ended up like this due to some previous attempt I made. > That would also help catch cases when someone wants to set > obj_ext._objcg that was optimized away (for that the setter would need > an additional parameter to identify whether we allocated optimized > objext vector). It would need passing the slab parameter to assert slab_obj_ext_has_codetag() in debug mode. I don't think it's worth it given the get/set is only called from few specialized places. > >> +{ >> + return &obj_ext->_objcg; >> +} >> +#endif >> + >> int alloc_slab_obj_exts(struct slab *slab, struct kmem_cache *s, >> gfp_t gfp, unsigned int alloc_flags); >> >> diff --git a/mm/slub.c b/mm/slub.c >> index 5e3f53bcd0d3..48e10198a3ce 100644 >> --- a/mm/slub.c >> +++ b/mm/slub.c >> @@ -2523,7 +2523,7 @@ bool memcg_slab_post_charge(void *p, gfp_t flags) >> if (obj_exts) { >> get_slab_obj_exts(obj_exts); >> obj_ext = slab_obj_ext(s, slab, obj_exts, p); >> - if (unlikely(obj_ext->objcg)) { >> + if (unlikely(*slab_obj_ext_objcgp(obj_ext))) { >> put_slab_obj_exts(obj_exts); >> return true; >> } >> >> -- >> 2.55.0 >>