From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D4AEC54E49 for ; Mon, 26 Feb 2024 09:59:46 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 989B56B01A1; Mon, 26 Feb 2024 04:59:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 939006B01A2; Mon, 26 Feb 2024 04:59:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7FFFF6B01A3; Mon, 26 Feb 2024 04:59:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0015.hostedemail.com [216.40.44.15]) by kanga.kvack.org (Postfix) with ESMTP id 6A3906B01A1 for ; Mon, 26 Feb 2024 04:59:45 -0500 (EST) Received: from smtpin16.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay02.hostedemail.com (Postfix) with ESMTP id 3C792120746 for ; Mon, 26 Feb 2024 09:59:45 +0000 (UTC) X-FDA: 81833508330.16.5C7EAE1 Received: from out30-112.freemail.mail.aliyun.com (out30-112.freemail.mail.aliyun.com [115.124.30.112]) by imf07.hostedemail.com (Postfix) with ESMTP id EAE3C40014 for ; Mon, 26 Feb 2024 09:59:41 +0000 (UTC) Authentication-Results: imf07.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=FwzPtilE; dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf07.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.112 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1708941583; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=U3Y9+BuA9RX74PXr7GyTAAvmUXsvUnfoxwYUqPDTdvc=; b=oIFHXuFmCn729Ih6C4JuKM1UH+Zrsc6647HkQnE9BQvO3AIzs9nHi12ls2fFp82N+ZZVWF K42i4K60YurI6qG5Gbtg4cvqMuc5E0j+Ps6OQi2R2p2P6hDnCUGs5IW6eIsPEqMj6SHpXj yMQLXD7L7q0DSnFJZkR7lz3tQp9B6RE= ARC-Authentication-Results: i=1; imf07.hostedemail.com; dkim=pass header.d=linux.alibaba.com header.s=default header.b=FwzPtilE; dmarc=pass (policy=none) header.from=linux.alibaba.com; spf=pass (imf07.hostedemail.com: domain of baolin.wang@linux.alibaba.com designates 115.124.30.112 as permitted sender) smtp.mailfrom=baolin.wang@linux.alibaba.com ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1708941583; a=rsa-sha256; cv=none; b=Lmn5AsYksK14YnDtK7GH9gO3JRrgQi9smM/gLOe4NT7unuUga9WVWh78Qap6XOf1a3oouP jCrpUDTCyx34D17j1TLwmtC06dIgp/inHmd9epL2CZjw+FS659cGYeur+m4tdckDjR00uM 6JAPBl3clSSZZmJEAhpe96GqwVftxQA= DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1708941579; h=Message-ID:Date:MIME-Version:Subject:To:From:Content-Type; bh=U3Y9+BuA9RX74PXr7GyTAAvmUXsvUnfoxwYUqPDTdvc=; b=FwzPtilE6UbMmAD1qpWUfNCoWULBRosQZIpkVrBcDd7YI3kepd9L4ziLsrqMiJPMQik0jieTaHE6trMJFn7x4kdnkVPMGZk36aEwpFPaAjmSZuFtLjFi1vwwaAZR0WtvZ96LofFuhACndqgX5nhVSoGWXIDjWm96srWeCPfX864= X-Alimail-AntiSpam:AC=PASS;BC=-1|-1;BR=01201311R161e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045168;MF=baolin.wang@linux.alibaba.com;NM=1;PH=DS;RN=9;SR=0;TI=SMTPD_---0W1GlKCY_1708941577; Received: from 30.97.56.44(mailfrom:baolin.wang@linux.alibaba.com fp:SMTPD_---0W1GlKCY_1708941577) by smtp.aliyun-inc.com; Mon, 26 Feb 2024 17:59:38 +0800 Message-ID: Date: Mon, 26 Feb 2024 17:59:37 +0800 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [RFC PATCH 2/3] mm: hugetlb: make the hugetlb migration strategy consistent To: Oscar Salvador Cc: akpm@linux-foundation.org, muchun.song@linux.dev, david@redhat.com, linmiaohe@huawei.com, naoya.horiguchi@nec.com, mhocko@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <0514e5139b17ecf3cd9e09d86c93e586c56688dc.1708507022.git.baolin.wang@linux.alibaba.com> <0a06dc7f-3a49-42ba-8221-0b4a3777ac0b@linux.alibaba.com> <9b49d2c8-4ace-4095-8610-8becf96eb023@linux.alibaba.com> From: Baolin Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: EAE3C40014 X-Stat-Signature: m3k13jqsdh4bboeffm1x1fejbt57kpqf X-Rspam-User: X-HE-Tag: 1708941581-531805 X-HE-Meta: U2FsdGVkX19ml5exybp4ElPmz+WpDQys3I+62vAtdfoQIafijjBYZhSbX1u9lFYG+k+TJKCus8+e+LAgBtz8tkRr5TGTfHJhyFZ0V38UENHX8heQl6lcOM15TyxipQeBr6V2H+M86aqzAwDVOB4ZEoNjzDbA7HEtfr5C98zgnj+rrMWri2+lO+78nzuWwUWUILqImfNqSSVGbVuoCSU/XP4ynnBtIKXlU/MUqLbz1znK+Io2qpi0xAFU00VMWebvbtVIm4+fANNq87YUGe2QVItTrTwHWKZLmU91RJqe5falBTOBh6TzjKXDppiu9Ps+XuBv5uHqCqfm2ERK5gzrWw/IlJExLmK4gYgRS44rA2vzMRfzlr1ulidXoKbuVwFb5jObpdmX7D71MLN7gAzZxs5nRFgJMKRu3jHzFqVb0mV0x9wFqaiYrIQq4XwvD6baHX5mvYo/gpfJIgQOAyN/i/H8fDCxFrVM85zLt7pJ9rdpMQs3IxTC+hMcCrp6VEc27HXv5gN3w5zbXeKMR9d14oKaLQQGtKVGgHS+ljzSLPeJSjW6cXDifKwgGb4oXPcqrOwdeQofvS7YJWwBMe7ejAecB7akdxPvlBMJVJIFmSRkJ65mkHCFFXoXoeum7YaXYX9H6gXNTeP9ruvD8mUjaD4Jxzn3mFSVRIp2ZFdtv1Vb75uNhYhSvbaqIH1xMmRj3V0G2P87CaiV+I0XWcUGKw4tMQyyBeIUs3Szc1DdcqWbe3//qXCGfX9BOOWD/3M6ppbP/0CUpTuV+U3V9yQG5ZRfWmBcg88wyKX/hwEs8C1K2UsUWYuascENmU17dIC+M1+nemBC9sZPkljA27gjnPtCmgd6QjnCT6YKFEOoT8g8UB1S0GLF0wX+CNrYDk9o+zu4qHrq3EyCdbw64TyGdYYZ1Yu+MTGI X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 2024/2/26 17:17, Oscar Salvador wrote: > On Mon, Feb 26, 2024 at 11:34:51AM +0800, Baolin Wang wrote: >> IMO, I'm not sure whether it's appropriate to decouple >> dequeue_hugetlb_folio_nodemask() from alloc_hugetlb_folio_nodemask() into >> two separate functions for the users to call, because these details should >> be hidden within the hugetlb core implementation. >> >> Instead, I can move the gfp_mask fiddling into a new helper, and move the >> helper into alloc_migrate_hugetlb_folio(). Temporary hugetlb allocation has >> its own gfp strategy seems reasonable to me. > > An alternative would be to do the following, which does not futher carry > the "reason" argument into hugetlb code. > (Not even compile tested, just a PoC) > > diff --git a/include/linux/hugetlb.h b/include/linux/hugetlb.h > index c1ee640d87b1..8a89a1007dcb 100644 > --- a/include/linux/hugetlb.h > +++ b/include/linux/hugetlb.h > @@ -970,6 +970,24 @@ static inline gfp_t htlb_modify_alloc_mask(struct hstate *h, gfp_t gfp_mask) > return modified_mask; > } > > +static inline bool htlb_allow_fallback(int reason) > +{ > + bool allowed_fallback = false; > + > + switch (reason) { > + case MR_MEMORY_HOTPLUG: > + case MR_MEMORY_FAILURE: > + case MR_SYSCALL: > + case MR_MEMPOLICY_MBIND: > + allowed_fallback = true; > + break; > + default: > + break; > + } > + > + return allowed_fallback; > +} > + Thanks for providing an alternative implementation. However, I still prefer to hide these details into hugetlb core, since users do not need to pay excessive attention to these hugetlb details. So something like: diff --git a/mm/hugetlb.c b/mm/hugetlb.c index 418d66953224..e8eb08bbc688 100644 --- a/mm/hugetlb.c +++ b/mm/hugetlb.c @@ -2567,13 +2567,38 @@ static struct folio *alloc_surplus_hugetlb_folio(struct hstate *h, } static struct folio *alloc_migrate_hugetlb_folio(struct hstate *h, gfp_t gfp_mask, - int nid, nodemask_t *nmask) + int nid, nodemask_t *nmask, int reason) { struct folio *folio; + bool allowed_fallback = false; if (hstate_is_gigantic(h)) return NULL; + if (gfp_mask & __GFP_THISNODE) + goto alloc_new; + + /* + * Note: the memory offline, memory failure and migration syscalls will + * be allowed to fallback to other nodes due to lack of a better chioce, + * that might break the per-node hugetlb pool. While other cases will + * set the __GFP_THISNODE to avoid breaking the per-node hugetlb pool. + */ + switch (reason) { + case MR_MEMORY_HOTPLUG: + case MR_MEMORY_FAILURE: + case MR_MEMORY_FAILURE: + case MR_SYSCALL: + case MR_MEMPOLICY_MBIND: + allowed_fallback = true; + break; + default: + break; + } + + if (!allowed_fallback) + gfp_mask |= __GFP_THISNODE; + +alloc_new: folio = alloc_fresh_hugetlb_folio(h, gfp_mask, nid, nmask, NULL); if (!folio) return NULL; @@ -2621,7 +2646,7 @@ struct folio *alloc_buddy_hugetlb_folio_with_mpol(struct hstate *h, /* folio migration callback function */ struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, - nodemask_t *nmask, gfp_t gfp_mask) return NULL; @@ -2621,7 +2646,7 @@ struct folio *alloc_buddy_hugetlb_folio_with_mpol(struct hstate *h, /* folio migration callback function */ struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, - nodemask_t *nmask, gfp_t gfp_mask) + nodemask_t *nmask, gfp_t gfp_mask, int reason) { spin_lock_irq(&hugetlb_lock); if (available_huge_pages(h)) { @@ -2636,7 +2661,7 @@ struct folio *alloc_hugetlb_folio_nodemask(struct hstate *h, int preferred_nid, } spin_unlock_irq(&hugetlb_lock); - return alloc_migrate_hugetlb_folio(h, gfp_mask, preferred_nid, nmask); + return alloc_migrate_hugetlb_folio(h, gfp_mask, preferred_nid, nmask, reason); } /* @@ -6653,7 +6678,13 @@ static struct folio *alloc_hugetlb_folio_vma(struct hstate *h, gfp_mask = htlb_alloc_mask(h); node = huge_node(vma, address, gfp_mask, &mpol, &nodemask); - folio = alloc_hugetlb_folio_nodemask(h, node, nodemask, gfp_mask); + /* + * This is used to allocate a temporary hugetlb to hold the copied + * content, which will then be copied again to the final hugetlb + * consuming a reservation. Set the migrate reason to -1 to indicate + * that breaking the per-node hugetlb pool is not allowed in this case. + */ + folio = alloc_hugetlb_folio_nodemask(h, node, nodemask, gfp_mask, -1); mpol_cond_put(mpol); return folio; What do you think? Thanks.