From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal =?iso-8859-1?Q?Koutn=FD?= Subject: Re: [PATCH 2/3] mm: Charge active memcg when no mm is set Date: Fri, 25 Jun 2021 16:47:37 +0200 Message-ID: References: <20210610173944.1203706-1-schatzberg.dan@gmail.com> <20210610173944.1203706-3-schatzberg.dan@gmail.com> Mime-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="U5WOJVgZJrEeE8ml" Return-path: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1624632459; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=3p/On6fxHbGfSoHEo45QdpoOPSq8wVMdaUq/e8JoVzM=; b=V6ru4Mh7I4N9RUtnfdD/F1oqSMcxR0NwfguTHDRgm7jLX1iGu9ywsAgYmLHMaX0ue7CM2h HsotDztIV9C6/zeL6JPC5htFaQThnNqOThsBU4wSJg3zshzFPFLkBEHa7OD92x+a+LVuqs 7uvRx1Tho+a9wZ/F9qQQKbqhSaCDv6c= DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1624632459; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=3p/On6fxHbGfSoHEo45QdpoOPSq8wVMdaUq/e8JoVzM=; b=V6ru4Mh7I4N9RUtnfdD/F1oqSMcxR0NwfguTHDRgm7jLX1iGu9ywsAgYmLHMaX0ue7CM2h HsotDztIV9C6/zeL6JPC5htFaQThnNqOThsBU4wSJg3zshzFPFLkBEHa7OD92x+a+LVuqs 7uvRx1Tho+a9wZ/F9qQQKbqhSaCDv6c= Content-Disposition: inline In-Reply-To: <20210610173944.1203706-3-schatzberg.dan@gmail.com> List-ID: To: Dan Schatzberg Cc: Andrew Morton , "open list:BLOCK LAYER" , open list , "open list:CONTROL GROUP (CGROUP)" , "open list:MEMORY MANAGEMENT" , Johannes Weiner , Tejun Heo , Chris Down , Jens Axboe , Shakeel Butt --U5WOJVgZJrEeE8ml Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Thu, Jun 10, 2021 at 10:39:43AM -0700, Dan Schatzberg wrote: > @@ -926,8 +937,17 @@ struct mem_cgroup *get_mem_cgroup_from_mm(struct mm_= struct *mm) > * counting is disabled on the root level in the > * cgroup core. See CSS_NO_REF. > */ > - if (unlikely(!mm)) > - return root_mem_cgroup; > + if (unlikely(!mm)) { > + memcg =3D active_memcg(); > + if (unlikely(memcg)) { > + /* remote memcg must hold a ref */ > + css_get(&memcg->css); > + return memcg; > + } > + mm =3D current->mm; > + if (unlikely(!mm)) > + return root_mem_cgroup; > + } With the change in __add_to_page_cache_locked() all page cache charges will supply null mm, so the first !mm unlikely hint may not be warranted anymore. Just an interesting point, generally, I'm adding Reviewed-by: Michal Koutn=FD --U5WOJVgZJrEeE8ml Content-Type: application/pgp-signature; name="signature.asc" Content-Description: Digital signature -----BEGIN PGP SIGNATURE----- iQIzBAEBCAAdFiEEEoQaUCWq8F2Id1tNia1+riC5qSgFAmDV7IUACgkQia1+riC5 qSirkA/7BTqxM98NGuM6kg3YoDN9bafGVLtaEZ2J3nRIXBJpWkyGxDpmaRsEAq8B SDejdzmPaIsNlgn3+POS5ozNnhqVXh0/oZ/09Cs68TCGNQk/pZaZeyBitqhP+1MW MoNiFqifltGHeyfr6EupwmYp1qsvQHCeiIwrEZ1TJjxG9WZd0xPcVv3dtdFZ2euW 3p303SgVvQ3TytBvDQ5ORpTmFKQO/td1khxtFv7XcTXyMoaTu9EbBVFCxIb16oCk xaGLmQuCMyv6m2uZONDq/WhMKHUQOVEooBz4pZg/sR2T3swSYVj6q+x/NbbNk/MP nXZ8TN8IgedfvKKyBPwn4JxOU2zxgoaa07fHvhYdHBHY+PhB0rLuQ/XLoJm8RozE 3DpSSSi0x5I+2jXajeJ9vfjjKj+B1sq66tST5N9ZJ1NfCr7JAtTgwv3F7sR90cIJ W9d+ZqvtVuAsbU0aQA0Tqexvu+IlERRij4dXzrk5ewOz8CDxcdoyPXnANVLniSAc rXir95NJNIksHOpXyCyF9qOY5nqdIJeYpG9bZYqWojnVhkDJfj0K7O4HZ79EtxLY U/I5+MvvhY6unE8O9Jc6F+/ctC0IY26boMzT14nSepJOcqtBLmX0v5VTRNgwK4PT ZiDOTsKgnEn6o/A0O203BEcvuzl2t2WMFam+1lkHLS5ZtZMNOuY= =EYsZ -----END PGP SIGNATURE----- --U5WOJVgZJrEeE8ml--