From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-ed1-f43.google.com (mail-ed1-f43.google.com [209.85.208.43]) (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 3F5A7285CA4 for ; Mon, 15 Sep 2025 17:11:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.43 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757956292; cv=none; b=VkMhhyQFZ2ciFFqHCUMSBjjRido7pFBOVc5tDMHqq3vepMtBmWaT6GXInX1l0nmNDqJj5TrFes0woq/glWGZ4qqm7Uvjkb8aj33IOY1WvOvAhU2YjvdhFVOlrepOMl38iS5cEYxr6Lz/IIqpgRHdwYUPE3ZGLGaLp6JE4tedc1w= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757956292; c=relaxed/simple; bh=qda1dWcgxmRXR+So3Bm2FXzAIEJ6VXo2r3eN9sCdyvs=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=g6Uxehl06ol06kCOisLhqIZdOXFtgExT7/MpkXHaejPtd3nt9GfJ/QZCiovT7VbB5+09e2BILKBlV9U5jF6pJG8l0jejT8vG+BCMQpB+F4ohoECdnZzPgqSSN557l7efECbojXNxQVrC7cPjw6STuSqFXW31vcAT3uOUXKAoJlw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=Tu3/qjRC; arc=none smtp.client-ip=209.85.208.43 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="Tu3/qjRC" Received: by mail-ed1-f43.google.com with SMTP id 4fb4d7f45d1cf-62f277546abso3472928a12.3 for ; Mon, 15 Sep 2025 10:11:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1757956288; x=1758561088; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=/Tl/RXGMAL1JqyStv0MTAwh9nUwRE5C//Qnl70T6OQM=; b=Tu3/qjRCoJU31DFlIxDjfhxRXKulmnIK8dPLXi1cXZ6rGl7HGXOj1/2a8FGZwWEaqL JHB414A9wwU5z+GHwcic4TMVHeLPdaTnghqpbNF3NkjhY4xFrpnlFCRegh/9QMcy6crd 5mpaCeDqVfmOhzfANGaLdG9bRgRWTUZESAqyZy20wjXzgje2vJMy/9cmp2hrzGGnLJjs NjUsB5Ilq2EIQk4Gj2xe1O0N4ONwpCBeXjXvCe2rWqillz7WdEzIQKM5P9Csoogzt/t8 uuRBARiR4brH1nl6uybG8G39HMN434BaeVW0Y/xT9Hhkp+nlXLxFuAbauCxBUr2iFPH2 WPmg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1757956288; x=1758561088; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=/Tl/RXGMAL1JqyStv0MTAwh9nUwRE5C//Qnl70T6OQM=; b=jAyzUnzcMPX2Ic6YLesUjgUdEy8roW1So5oasARKNAL5QhTTyhw8Azt9iOaB7wLfg8 xydkdjjs1Xx9LI+7eA9Bx6cFzIU3Ywf1xCY/IwNOpdkYlh5g9zGa2uJGVDPzjgu3ZqS1 TQUH6hZfoLxZVIzNTUDMpRrcsEvAvUA10sxRPPueGHY+NBJzVjuZU4fHyOVA7DvyuUUI hieG/S4po8jrEZEjH6CFfmNcZ1Eu2MHaWPFmibz0IOEr9C1zLKgBMNyf/gz1zWE24qls k0k+vfMEwikogMCVYa+k+IxCADXcDIoPOOZKdp0RWdwOt8TNirHattJ0+jzRntSRCtYI 5oCQ== X-Forwarded-Encrypted: i=1; AJvYcCVLY+PGD73NGYW6HCp00NdcXz5G9n+/N4VESpJ39cpx0yBjOxsHUAbNxwOgIAgqTDBpOXoUsno2k/MAD5U=@vger.kernel.org X-Gm-Message-State: AOJu0Yz0Wo862SIWVpbDphr4yMnoI872wZ2dWmXeHS12KlWCek0bJgJn YeDNnlksDdOEZb0z+Ch5j8lsXgTzQVZfEnuQNZNjYar47kaNBjcOHL4lJll4vsVguLA= X-Gm-Gg: ASbGncuUVQSIBpSCqw/4pfLrq+SV9GzWBFLewnABlGNOcrJyz9zAqQQCqw+FDen5pPN SShXN+Fvw87outUHBZP6sJGCc6+Efg9jjiUXpZyEUi/HXC5kcnZPCDLgHWI/w8fzir2aMaUcUGZ ybnubVemtY0dLwhHFTSx3aUzoxRzkDm4uUy6jg3Bfy57KcRtzOsJ9RoGhHUz7ISiPaz2ns48InT b3hS9jziqjnzpEoOOIqHY/0H598WGiwLzT5lmHdmXkxp17xJftMNApEpglwnka8bch7ImFiNhSm P0KH9o8m0xNQYt3n2JYliAI1HN5ZUkYyr2o3ZqJ9WEzf1rsdH6FyLHz/oGKclnivHQMX/CGwfSf zmA5tj/GRPkcQtuQ9fL9Y1GxCA/Hl8UYu4A== X-Google-Smtp-Source: AGHT+IEU141ppPHC0f43WV7Mu6b53qnsOKX1PToxTJqKeIfoSyv68wG7aiLv2qvPkXtSZcUgUGL70A== X-Received: by 2002:a05:6402:2714:b0:62f:50ff:b675 with SMTP id 4fb4d7f45d1cf-62f50ffb8a6mr1585266a12.33.1757956288538; Mon, 15 Sep 2025 10:11:28 -0700 (PDT) Received: from localhost (109-81-31-43.rct.o2.cz. [109.81.31.43]) by smtp.gmail.com with UTF8SMTPSA id 4fb4d7f45d1cf-62f11390075sm5158227a12.40.2025.09.15.10.11.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 15 Sep 2025 10:11:28 -0700 (PDT) Date: Mon, 15 Sep 2025 19:11:27 +0200 From: Michal Hocko To: "Uladzislau Rezki (Sony)" Cc: linux-mm@kvack.org, Andrew Morton , Baoquan He , LKML Subject: Re: [PATCH v2 04/10] mm/vmalloc: Avoid cond_resched() when blocking is not permitted Message-ID: References: <20250915134041.151462-1-urezki@gmail.com> <20250915134041.151462-5-urezki@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250915134041.151462-5-urezki@gmail.com> On Mon 15-09-25 15:40:34, Uladzislau Rezki wrote: > vm_area_alloc_pages() contains the only voluntary reschedule points > along vmalloc() allocation path. They are needed to ensure forward > progress on PREEMPT_NONE kernels under contention for vmap metadata > (e.g. alloc_vmap_area()). > > However, yielding should only be done if the given GFP flags allow > blocking. This patch avoids calling cond_resched() when allocation > context is non-blocking(GFP_ATOMIC, GFP_NOWAIT). We do have cond_resched in the page allocator path, right? So unless I am missing something we can safely drope these. I thought we have discused this already. > Signed-off-by: Uladzislau Rezki (Sony) > --- > mm/vmalloc.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index 49a0f81930a8..b77e8be75f10 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -3633,7 +3633,9 @@ vm_area_alloc_pages(gfp_t gfp, int nid, > pages + nr_allocated); > > nr_allocated += nr; > - cond_resched(); > + > + if (gfpflags_allow_blocking(gfp)) > + cond_resched(); > > /* > * If zero or pages were obtained partly, > @@ -3675,7 +3677,9 @@ vm_area_alloc_pages(gfp_t gfp, int nid, > for (i = 0; i < (1U << order); i++) > pages[nr_allocated + i] = page + i; > > - cond_resched(); > + if (gfpflags_allow_blocking(gfp)) > + cond_resched(); > + > nr_allocated += 1U << order; > } > > -- > 2.47.3 -- Michal Hocko SUSE Labs