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Mercier" Cc: Suren Baghdasaryan , Kent Overstreet , Janghyuck Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] alloc_tag: Handle incomplete bulk allocations in vm_module_tags_populate Message-Id: <20250409140848.da67768ac1f5e79d7296de4d@linux-foundation.org> In-Reply-To: <20250409195448.3697351-1-tjmercier@google.com> References: <20250409195448.3697351-1-tjmercier@google.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 52348100002 X-Stat-Signature: bgr7is34m6qca514koudq7sqw8xxup1n X-Rspam-User: X-HE-Tag: 1744232930-23352 X-HE-Meta: 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 VQyKuCDo GoLqpfLDBhPbu2fuKG3EbLzY1jsRYe9V661f87OxL0Ov8tyQcPa/HQeEAe+24h2gTRAsI6AhQtL+TS6HCPVjyYA7XZveJNiLBa540v7sIKLk77GAw6EAFzD4FyjJP0dSwnVhm2GsCcUn5K/4EHp6E3CKgA2InUg5eaSrD5d0lI1922wXFu0NbRjStkFY5I2ilVoVrPNib1FA5hzTcQMtvR8jNiuetlF9eElzq1sFNxh/fO8ikO3CgLEfDuEeeNl38NfViTd3nOhFCqzLYDdDvYAo6BEviT2t7SFMDK7cz0pRxfkShxSYj9GUYfMSLDapfCACQnoIqu67fsGl6DKWoSBWYZyLKMrga74Kx2yLs6haGYzv7EAUR3utiRA== X-Bogosity: Ham, tests=bogofilter, spamicity=0.000305, 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 Wed, 9 Apr 2025 19:54:47 +0000 "T.J. Mercier" wrote: > alloc_pages_bulk_node may partially succeed and allocate fewer than the > requested nr_pages. There are several conditions under which this can > occur, but we have encountered the case where CONFIG_PAGE_OWNER is > enabled causing all bulk allocations to always fallback to single page > allocations due to commit 187ad460b841 ("mm/page_alloc: avoid page > allocator recursion with pagesets.lock held"). > > Currently vm_module_tags_populate immediately fails when > alloc_pages_bulk_node returns fewer than the requested number of pages. > This patch causes vm_module_tags_populate to retry bulk allocations for > the remaining memory instead. Please describe the userspace-visible runtime effects of this change. In a way which permits a user who is experiencing some problem can recognize that this patch will address that problem.