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b=X2HD3rX7Stftvw/rF5B2bhz52615w6sKe4xNmr4e0mrSMG//80RBokOF2CnGLFr9M 3NKhzoN2K3BuYETUwuuZwq16hdKIMdYycLtD3T0MKBXrr7X4s61TPIXcuFju9wW+uF /rWhci3P2IvNhRPRLmY+ab++VzylLY7SRThRFLus2+mL6WXxd3YIc2y273DY4je35g BQfMu/cUQL/HuLTZtvjyakLaBnAVutOH0SEUdP5AVgnot8V27PTNLC1uBaEsn9I41D r5r+XNIbAteEgmpaF/5CEnNv2e7ePUk/E9nJM02LtO1vV0gFb7JDANDsPnAXUSCScJ Bn7DWSnNnZYrA== Received: by mail-ej1-f47.google.com with SMTP id a640c23a62f3a-b983ca059a1so96204066b.0 for ; Mon, 23 Mar 2026 17:06:07 -0700 (PDT) X-Forwarded-Encrypted: i=1; AJvYcCXnWOong8CFElv23+6HoF7vvYkcmVMin8mSvzigluQ5QTBs4fsSXXlHx89o3gUFK3hEfqCUk8LQxg==@kvack.org X-Gm-Message-State: AOJu0YwzVvvSwCSPvFmQ0Lpu+tXFYrxxN4sl3ssJMn6Mu4VKNccTNYFj ZJzxZDH/2BuaNs8AefI1L84rAJH7o/PQz/388nqT770SwX9/wavYE+lu44e+Q3W2orGDaGUpT8m uInTol65O9KVA4LZKD527XOfGQuPnOTQ= X-Received: by 2002:a17:907:e10c:b0:b97:9130:659e with SMTP id a640c23a62f3a-b982f24517dmr643307266b.3.1774310766076; Mon, 23 Mar 2026 17:06:06 -0700 (PDT) MIME-Version: 1.0 References: <20260322061038.156146-1-liwang@redhat.com> <20260322061038.156146-6-liwang@redhat.com> In-Reply-To: <20260322061038.156146-6-liwang@redhat.com> From: Yosry Ahmed Date: Mon, 23 Mar 2026 17:05:54 -0700 X-Gmail-Original-Message-ID: X-Gm-Features: AaiRm52ZVutXfSJTDOeT7WDCsAt6y8LXJOUTwVDAufe4Y2AugS55tTO1NYysUPM Message-ID: Subject: Re: [PATCH v4 5/7] selftests/cgroup: replace hardcoded page size values in test_zswap To: Li Wang Cc: akpm@linux-foundation.org, yosryahmed@google.com, nphamcs@gmail.com, hannes@cmpxchg.org, mhocko@kernel.org, mkoutny@suse.com, muchun.song@linux.dev, tj@kernel.org, roman.gushchin@linux.dev, shakeel.butt@linux.dev, longman@redhat.com, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Rspam-User: X-Stat-Signature: dr7u4s6p57iqbgjo85hjw1b9nfstxoc3 X-Rspamd-Queue-Id: 4F35720007 X-Rspamd-Server: rspam09 X-HE-Tag: 1774310768-415502 X-HE-Meta: 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 1gNbr3Qv 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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 Sat, Mar 21, 2026 at 11:11=E2=80=AFPM Li Wang wrote: > > test_zswap uses hardcoded values of 4095 and 4096 throughout as page > stride and page size, which are only correct on systems with a 4K page > size. On architectures with larger pages (e.g., 64K on arm64 or ppc64), > these constants cause memory to be touched at sub-page granularity, > leading to inefficient access patterns and incorrect page count > calculations, which can cause test failures. > > Replace all hardcoded 4095 and 4096 values with a global pagesize > variable initialized from sysconf(_SC_PAGESIZE) at startup, and remove > the redundant local sysconf() calls scattered across individual > functions. No functional change on 4K page size systems. > > Signed-off-by: Li Wang > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: Michal Koutn=C3=BD > Cc: Muchun Song > Cc: Nhat Pham > Cc: Tejun Heo > Cc: Roman Gushchin > Cc: Shakeel Butt > Cc: Yosry Ahmed Acked-by: Yosry Ahmed