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keydata= xsDiBFk3nEQRBADAEaSw6zC/EJkiwGPXbWtPxl2xCdSoeepS07jW8UgcHNurfHvUzogEq5xk hu507c3BarVjyWCJOylMNR98Yd8VqD9UfmX0Hb8/BrA+Hl6/DB/eqGptrf4BSRwcZQM32aZK 7Pj2XbGWIUrZrd70x1eAP9QE3P79Y2oLrsCgbZJfEwCgvz9JjGmQqQkRiTVzlZVCJYcyGGsD /0tbFCzD2h20ahe8rC1gbb3K3qk+LpBtvjBu1RY9drYk0NymiGbJWZgab6t1jM7sk2vuf0Py O9Hf9XBmK0uE9IgMaiCpc32XV9oASz6UJebwkX+zF2jG5I1BfnO9g7KlotcA/v5ClMjgo6Gl MDY4HxoSRu3i1cqqSDtVlt+AOVBJBACrZcnHAUSuCXBPy0jOlBhxPqRWv6ND4c9PH1xjQ3NP nxJuMBS8rnNg22uyfAgmBKNLpLgAGVRMZGaGoJObGf72s6TeIqKJo/LtggAS9qAUiuKVnygo 3wjfkS9A3DRO+SpU7JqWdsveeIQyeyEJ/8PTowmSQLakF+3fote9ybzd880fSmFuIEJldWxp Y2ggPGpiZXVsaWNoQHN1c2UuY29tPsJgBBMRAgAgBQJZN5xEAhsDBgsJCAcDAgQVAggDBBYC AwECHgECF4AACgkQoDSui/t3IH4J+wCfQ5jHdEjCRHj23O/5ttg9r9OIruwAn3103WUITZee e7Sbg12UgcQ5lv7SzsFNBFk3nEQQCACCuTjCjFOUdi5Nm244F+78kLghRcin/awv+IrTcIWF hUpSs1Y91iQQ7KItirz5uwCPlwejSJDQJLIS+QtJHaXDXeV6NI0Uef1hP20+y8qydDiVkv6l IreXjTb7DvksRgJNvCkWtYnlS3mYvQ9NzS9PhyALWbXnH6sIJd2O9lKS1Mrfq+y0IXCP10eS FFGg+Av3IQeFatkJAyju0PPthyTqxSI4lZYuJVPknzgaeuJv/2NccrPvmeDg6Coe7ZIeQ8Yj t0ARxu2xytAkkLCel1Lz1WLmwLstV30g80nkgZf/wr+/BXJW/oIvRlonUkxv+IbBM3dX2OV8 AmRv1ySWPTP7AAMFB/9PQK/VtlNUJvg8GXj9ootzrteGfVZVVT4XBJkfwBcpC/XcPzldjv+3 HYudvpdNK3lLujXeA5fLOH+Z/G9WBc5pFVSMocI71I8bT8lIAzreg0WvkWg5V2WZsUMlnDL9 mpwIGFhlbM3gfDMs7MPMu8YQRFVdUvtSpaAs8OFfGQ0ia3LGZcjA6Ik2+xcqscEJzNH+qh8V m5jjp28yZgaqTaRbg3M/+MTbMpicpZuqF4rnB0AQD12/3BNWDR6bmh+EkYSMcEIpQmBM51qM EKYTQGybRCjpnKHGOxG0rfFY1085mBDZCH5Kx0cl0HVJuQKC+dV2ZY5AqjcKwAxpE75MLFkr wkkEGBECAAkFAlk3nEQCGwwACgkQoDSui/t3IH7nnwCfcJWUDUFKdCsBH/E5d+0ZnMQi+G0A nAuWpQkjM1ASeQwSHEeAWPgskBQL In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-purgate-ID: tlsNG-42698a/1782392695-A4F2E220-207EA23B/0/0 X-purgate-type: clean X-purgate-size: 3045 On 08.05.2026 22:27, Bernhard Kaindl wrote: > From: Alejandro Vallejo > > Add node_avail_pages[], updated under heap_lock in sync with > avail[node][zone] to cache the per-node sum of free pages. > > Use it in avail_node_heap_pages() to avoid summing all zones on each > call. Guard it with nodeid < MAX_NUMNODES and node_online(nodeid). > > Signed-off-by: Alejandro Vallejo > Signed-off-by: Bernhard Kaindl > --- > This patch was originally sent by Alejandro Vallejo: > https://lists.xenproject.org/archives/html/xen-devel/2025-03/msg01130.html > > I use node_avail_pages[] in avail_node_heap_pages() as an optimisation. > > Verification of the changes: > > 1. node_avail_pages[node] is updated whenever avail[node][zone] changes, > so the two remain in sync. > > 2. avail_node_heap_pages() previously summed all zones of a node and now > returns node_avail_pages[node], so the same free buddy pages are > counted. > > 3. avail_node_heap_pages() returns 0 for offline nodes and for nodes > >= MAX_NUMNODES as before. > > 4. avail_node_heap_pages(-1) returned the sum from all nodes, equal > to total_avail_pages, but this is not used by current callers. > avail_heap_pages(z, z, -1) is used by other callers for that instead. > To avoid dead code, a check for -1 to implement this is not added. > > Update locations: > > - free_heap_pages() increments node_avail_pages[node] alongside > avail[node][zone] when pages are freed, including during heap > initialisation. > > - alloc_heap_pages() decrements node_avail_pages[node] alongside > avail[node][zone] when pages are allocated. > > - reserve_offlined_page() decrements node_avail_pages[node] alongside > avail[node][zone] when pages are offlined. > > Colored pages do not go through the buddy allocator. > Since they do not update avail[node][zone], they are > not reflected in node_avail_pages[node] either. > > N.B. Current callers already iterate over online nodes only. > > Changes since v6: > - Preserved the 0 return for offline nodes and nodes >= MAX_NUMNODES. Hard to identify what v6 was (and who, if anyone, asked for the change) when, afaict, the patch subject changed. Reviewed-by: Jan Beulich with ... > @@ -2831,7 +2837,9 @@ unsigned long avail_domheap_pages_region( > > unsigned long avail_node_heap_pages(unsigned int nodeid) > { > - return avail_heap_pages(MEMZONE_XEN, NR_ZONES -1, nodeid); > + if ( nodeid < MAX_NUMNODES && node_online(nodeid) ) > + return node_avail_pages[nodeid]; > + return 0; > } ... a blank line inserted ahead of the "main" (not really here, just by its indentation) return. One other remark: With the function called from just a sysctl and a keyhandler, the direct array access is likely fine. Generally it would want to be array_access_nospec() though, when accessible from guests. Jan