That depends on the switch model you have and it's not that easy.
Smaller Catalyst switches in general use at least two forms of buffer - there's usually a interface-lavel buffer, on the smaller Catalyst (2k/3k) visible in 'show buffers' under the section named 'Interface buffer pools:':
Interface buffer pools:
Syslog ED Pool buffers, 600 bytes (total 132, permanent 132):
100 in free list (132 min, 132 max allowed)
11151 hits, 0 misses
RxQ1 buffers, 2040 bytes (total 128, permanent 128):
4 in free list (0 min, 128 max allowed)
244594209 hits, 4559839 fallbacks
RxQ2 buffers, 2040 bytes (total 128, permanent 128):
1 in free list (0 min, 128 max allowed)
202559241 hits, 1582494 fallbacks, 0 trims, 0 created
1582494 failures (0 no memory)
...and there's "public" area, where CPU is using the buffers as they're punted towards it and need servicing. The "Rx"-level buffers are part of the shared buffer to service all interfaces (on either old, legacy switches like 2950 or newest 2960S/3560X/etc) or a subset of interfaces, belonging to specific port ASIC (like 2960 or 3560/3750/3560E/3750E).
On the 4500 and 6500 in particular it gets messy, as there is a number of pools that packet can go through - input interface (ASIC) buffer, the pool at linecard level (on the 6500 at DFC), at the switch-fabric level and at the end the buffer at Supervisor level. They don't have to be physically separate memory pools, but are often mapped in different commands to different names to ease the troubleshooting process (at which step of the packet walk-through was the packet dropped for example).