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charset="us-ascii" Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 60198100003 X-Stat-Signature: uxk3ebc6ay7pjdky5xmu1p37rqsqwjde X-HE-Tag: 1787822492-531660 X-HE-Meta: U2FsdGVkX1+2a6b8EPfF5CreueCFi3zMQNkLpkDqTLHQzQnZJgUmhtyab3YURM1wrCjWj34CPcCKqHr+zQq0e6Bn3/w5z3OIqYPqiCSyfSmGh4RqmSES+3gqyVd+lFn7TQoENNgnoaa58kvsE/9PoN6X80OLp5sNafH4bC9eFmYVhJ7vBNUNJjpGElFH3QZpGaVSGv5VQxdWAkO1uN5ioDnW/Y99Rft2Eyb+HFQCcdk7CDe8PrGRVWJHrvo1C6FVCkstC+Vgb0cSzqI/SyURlLZtXkwJImYKl5B/loWrD7JJ96HCnaEfe9xOfz8KtnDc9N+mxYw2Uh/Vciaj1fyqiKF7S7J/1n+2pwpfpwT6l+n2MD8TK4XwbSwDSySVIAl/YfmeGmgtb/rqAESJzJkiNhojcAlBwHLJKWaKveCKF+CJ44aHOOzZSd9glPVtgeMNuvWjYYdVuzdB+ADanPBhxvV0oxO9XIdIAdVvqUcMP4s54N/LhooKjdr69tdusYMTIU1RMj2ZFwHczjkWldAlWG9BEFk3Vl4upwsciU+cVOG73QA+rljIngSom3GpY8UcKdFOeipqVsiEkx+xSfX5SLA6YZhRaQkAplDyysbWidtIq2FXQ3cs3BZ/f4kKJVgin8pCl7NqHCfqqhTi8dnF7I8wSwsZayhI/Cto29JJWruN3lpiZYfrrX6fSCg9Ehn3PSejHOgXjnjOuXqD6JCZbVq0AVCgTbrREHiB67AbgrnCTvSDJZF3jgBPPt9HM8L0D0Htp6VBlQp6rsDiTHOP8yVXj46nl0T7pUCmAu7QiC4AUCNCq5Oa4yy0ad4F+/tzqg5irxoCpI/K3Rs9e2KbTgLz3dVwx+z03bFfzBOaWJ1ruVY9gcmlRezs6ViFyos63InkjpBdQPO30V+fp1AX6baw1amrNYQUZZdJzqdskhvZZc245iQMbGluu/5TMMVEOJumr0ppcaLtxrHxYus A4vbUhlI 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jul 22, 2026 at 02:35:00PM +0200, Vlastimil Babka (SUSE) wrote: > AFAICS both your v3 and the implemented Johannes' suggestion effectively > make all the compact_first logic dead code - at least for the intended THP > use case based on costly_order. It will only continue to do something for > the non-movable order>0 case. So that's a significant change which will not > show up in your results, but might affect other workloads (I'd expect mainly > by having fewer THPs). Right - the change above modifies THP allocation requests as well. So instead of applying it to every costly __GFP_NORETRY allocation, I restrict it to callers that do not ask for __GFP_THISNODE. That leaves the local-node THP attempt untouched: the same bit pair is already tested further down the function to bail out of the compact_first block (page_alloc.c:4899), and alloc_pages_mpol() sets both flags on the local-node-first attempt (mempolicy.c:2476-2478). I tested this with my PostgreSQL workload on kernel v7.2-rc7 and results look good: Baseline: 70,735 tps This version: 144,670 tps (145,280 / 144,037 / 144,694) +104.5% diff --git a/mm/page_alloc.c b/mm/page_alloc.c index ee902a468c2f..1e4b0c1e7296 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -4725,10 +4725,10 @@ static inline struct page * __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, struct alloc_context *ac) { - bool can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM; - bool can_compact = can_direct_reclaim && gfp_compaction_allowed(gfp_mask); - bool nofail = gfp_mask & __GFP_NOFAIL; const bool costly_order = order > PAGE_ALLOC_COSTLY_ORDER; + bool can_direct_reclaim; + bool can_compact; + bool nofail; struct page *page = NULL; unsigned int alloc_flags; unsigned long did_some_progress; @@ -4743,6 +4743,18 @@ __alloc_pages_slowpath(gfp_t gfp_mask, unsigned int order, bool can_retry_reserves = true; unsigned long alloc_start_time = jiffies; + /* + * Costly __GFP_NORETRY callers have a cheap fallback, so don't stall + * them in reclaim or compaction. __GFP_THISNODE callers are exempt. + */ + if (costly_order && (gfp_mask & __GFP_NORETRY) && + !(gfp_mask & __GFP_THISNODE)) + gfp_mask &= ~__GFP_DIRECT_RECLAIM; + + can_direct_reclaim = gfp_mask & __GFP_DIRECT_RECLAIM; + can_compact = can_direct_reclaim && gfp_compaction_allowed(gfp_mask); + nofail = gfp_mask & __GFP_NOFAIL; + if (unlikely(nofail)) { /* * Also we don't support __GFP_NOFAIL without __GFP_DIRECT_RECLAIM, AMAZON DEVELOPMENT CENTER ITALY SRL, viale Monte Grappa 3/5, 20124 Milano, Italia, Registro delle Imprese di Milano Monza Brianza Lodi REA n. 2504859, Capitale Sociale: 10.000 EUR i.v., Cod. 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